EmbeddedArtists AB
Graphical demo for the LPC4088 Experiment Base Board with one of the Display Expansion Kits. This program decodes decodes and shows two png images.
Diff: lodepng.cpp
- Revision:
- 0:b567d56a59d7
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/lodepng.cpp Fri Oct 03 13:30:09 2014 +0000
@@ -0,0 +1,6260 @@
+/*
+LodePNG version 20131222
+
+Copyright (c) 2005-2013 Lode Vandevenne
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+ 1. The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+
+ 2. Altered source versions must be plainly marked as such, and must not be
+ misrepresented as being the original software.
+
+ 3. This notice may not be removed or altered from any source
+ distribution.
+*/
+
+/*
+The manual and changelog are in the header file "lodepng.h"
+Rename this file to lodepng.cpp to use it for C++, or to lodepng.c to use it for C.
+*/
+
+#include "lodepng.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#ifdef LODEPNG_COMPILE_CPP
+#include <fstream>
+#endif /*LODEPNG_COMPILE_CPP*/
+
+#define VERSION_STRING "20131222"
+
+/*
+This source file is built up in the following large parts. The code sections
+with the "LODEPNG_COMPILE_" #defines divide this up further in an intermixed way.
+-Tools for C and common code for PNG and Zlib
+-C Code for Zlib (huffman, deflate, ...)
+-C Code for PNG (file format chunks, adam7, PNG filters, color conversions, ...)
+-The C++ wrapper around all of the above
+*/
+
+/*The malloc, realloc and free functions defined here with "lodepng_" in front
+of the name, so that you can easily change them to others related to your
+platform if needed. Everything else in the code calls these. Pass
+-DLODEPNG_NO_COMPILE_ALLOCATORS to the compiler, or comment out
+#define LODEPNG_COMPILE_ALLOCATORS in the header, to disable the ones here and
+define them in your own project's source files without needing to change
+lodepng source code. Don't forget to remove "static" if you copypaste them
+from here.*/
+
+#ifdef LODEPNG_COMPILE_ALLOCATORS
+static void* lodepng_malloc(size_t size)
+{
+ return malloc(size);
+}
+
+static void* lodepng_realloc(void* ptr, size_t new_size)
+{
+ return realloc(ptr, new_size);
+}
+
+static void lodepng_free(void* ptr)
+{
+ free(ptr);
+}
+#else /*LODEPNG_COMPILE_ALLOCATORS*/
+void* lodepng_malloc(size_t size);
+void* lodepng_realloc(void* ptr, size_t new_size);
+void lodepng_free(void* ptr);
+#endif /*LODEPNG_COMPILE_ALLOCATORS*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // Tools for C, and common code for PNG and Zlib. // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*
+Often in case of an error a value is assigned to a variable and then it breaks
+out of a loop (to go to the cleanup phase of a function). This macro does that.
+It makes the error handling code shorter and more readable.
+
+Example: if(!uivector_resizev(&frequencies_ll, 286, 0)) ERROR_BREAK(83);
+*/
+#define CERROR_BREAK(errorvar, code)\
+{\
+ errorvar = code;\
+ break;\
+}
+
+/*version of CERROR_BREAK that assumes the common case where the error variable is named "error"*/
+#define ERROR_BREAK(code) CERROR_BREAK(error, code)
+
+/*Set error var to the error code, and return it.*/
+#define CERROR_RETURN_ERROR(errorvar, code)\
+{\
+ errorvar = code;\
+ return code;\
+}
+
+/*Try the code, if it returns error, also return the error.*/
+#define CERROR_TRY_RETURN(call)\
+{\
+ unsigned error = call;\
+ if(error) return error;\
+}
+
+/*
+About uivector, ucvector and string:
+-All of them wrap dynamic arrays or text strings in a similar way.
+-LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version.
+-The string tools are made to avoid problems with compilers that declare things like strncat as deprecated.
+-They're not used in the interface, only internally in this file as static functions.
+-As with many other structs in this file, the init and cleanup functions serve as ctor and dtor.
+*/
+
+#ifdef LODEPNG_COMPILE_ZLIB
+/*dynamic vector of unsigned ints*/
+typedef struct uivector
+{
+ unsigned* data;
+ size_t size; /*size in number of unsigned longs*/
+ size_t allocsize; /*allocated size in bytes*/
+} uivector;
+
+static void uivector_cleanup(void* p)
+{
+ ((uivector*)p)->size = ((uivector*)p)->allocsize = 0;
+ lodepng_free(((uivector*)p)->data);
+ ((uivector*)p)->data = NULL;
+}
+
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned uivector_resize(uivector* p, size_t size)
+{
+ if(size * sizeof(unsigned) > p->allocsize)
+ {
+ size_t newsize = size * sizeof(unsigned) * 2;
+ void* data = lodepng_realloc(p->data, newsize);
+ if(data)
+ {
+ p->allocsize = newsize;
+ p->data = (unsigned*)data;
+ p->size = size;
+ }
+ else return 0;
+ }
+ else p->size = size;
+ return 1;
+}
+
+/*resize and give all new elements the value*/
+static unsigned uivector_resizev(uivector* p, size_t size, unsigned value)
+{
+ size_t oldsize = p->size, i;
+ if(!uivector_resize(p, size)) return 0;
+ for(i = oldsize; i < size; i++) p->data[i] = value;
+ return 1;
+}
+
+static void uivector_init(uivector* p)
+{
+ p->data = NULL;
+ p->size = p->allocsize = 0;
+}
+
+#ifdef LODEPNG_COMPILE_ENCODER
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned uivector_push_back(uivector* p, unsigned c)
+{
+ if(!uivector_resize(p, p->size + 1)) return 0;
+ p->data[p->size - 1] = c;
+ return 1;
+}
+
+/*copy q to p, returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned uivector_copy(uivector* p, const uivector* q)
+{
+ size_t i;
+ if(!uivector_resize(p, q->size)) return 0;
+ for(i = 0; i < q->size; i++) p->data[i] = q->data[i];
+ return 1;
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#endif /*LODEPNG_COMPILE_ZLIB*/
+
+/* /////////////////////////////////////////////////////////////////////////// */
+
+/*dynamic vector of unsigned chars*/
+typedef struct ucvector
+{
+ unsigned char* data;
+ size_t size; /*used size*/
+ size_t allocsize; /*allocated size*/
+} ucvector;
+
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned ucvector_resize(ucvector* p, size_t size)
+{
+ if(size * sizeof(unsigned char) > p->allocsize)
+ {
+ size_t newsize = size * sizeof(unsigned char) * 2;
+ void* data = lodepng_realloc(p->data, newsize);
+ if(data)
+ {
+ p->allocsize = newsize;
+ p->data = (unsigned char*)data;
+ p->size = size;
+ }
+ else return 0; /*error: not enough memory*/
+ }
+ else p->size = size;
+ return 1;
+}
+
+#ifdef LODEPNG_COMPILE_PNG
+
+static void ucvector_cleanup(void* p)
+{
+ ((ucvector*)p)->size = ((ucvector*)p)->allocsize = 0;
+ lodepng_free(((ucvector*)p)->data);
+ ((ucvector*)p)->data = NULL;
+}
+
+static void ucvector_init(ucvector* p)
+{
+ p->data = NULL;
+ p->size = p->allocsize = 0;
+}
+
+#ifdef LODEPNG_COMPILE_DECODER
+/*resize and give all new elements the value*/
+static unsigned ucvector_resizev(ucvector* p, size_t size, unsigned char value)
+{
+ size_t oldsize = p->size, i;
+ if(!ucvector_resize(p, size)) return 0;
+ for(i = oldsize; i < size; i++) p->data[i] = value;
+ return 1;
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#endif /*LODEPNG_COMPILE_PNG*/
+
+#ifdef LODEPNG_COMPILE_ZLIB
+/*you can both convert from vector to buffer&size and vica versa. If you use
+init_buffer to take over a buffer and size, it is not needed to use cleanup*/
+static void ucvector_init_buffer(ucvector* p, unsigned char* buffer, size_t size)
+{
+ p->data = buffer;
+ p->allocsize = p->size = size;
+}
+#endif /*LODEPNG_COMPILE_ZLIB*/
+
+#if (defined(LODEPNG_COMPILE_PNG) && defined(LODEPNG_COMPILE_ANCILLARY_CHUNKS)) || defined(LODEPNG_COMPILE_ENCODER)
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned ucvector_push_back(ucvector* p, unsigned char c)
+{
+ if(!ucvector_resize(p, p->size + 1)) return 0;
+ p->data[p->size - 1] = c;
+ return 1;
+}
+#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/
+
+
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_PNG
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*returns 1 if success, 0 if failure ==> nothing done*/
+static unsigned string_resize(char** out, size_t size)
+{
+ char* data = (char*)lodepng_realloc(*out, size + 1);
+ if(data)
+ {
+ data[size] = 0; /*null termination char*/
+ *out = data;
+ }
+ return data != 0;
+}
+
+/*init a {char*, size_t} pair for use as string*/
+static void string_init(char** out)
+{
+ *out = NULL;
+ string_resize(out, 0);
+}
+
+/*free the above pair again*/
+static void string_cleanup(char** out)
+{
+ lodepng_free(*out);
+ *out = NULL;
+}
+
+static void string_set(char** out, const char* in)
+{
+ size_t insize = strlen(in), i = 0;
+ if(string_resize(out, insize))
+ {
+ for(i = 0; i < insize; i++)
+ {
+ (*out)[i] = in[i];
+ }
+ }
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+#endif /*LODEPNG_COMPILE_PNG*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+
+unsigned lodepng_read32bitInt(const unsigned char* buffer)
+{
+ return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
+}
+
+#if defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)
+/*buffer must have at least 4 allocated bytes available*/
+static void lodepng_set32bitInt(unsigned char* buffer, unsigned value)
+{
+ buffer[0] = (unsigned char)((value >> 24) & 0xff);
+ buffer[1] = (unsigned char)((value >> 16) & 0xff);
+ buffer[2] = (unsigned char)((value >> 8) & 0xff);
+ buffer[3] = (unsigned char)((value ) & 0xff);
+}
+#endif /*defined(LODEPNG_COMPILE_PNG) || defined(LODEPNG_COMPILE_ENCODER)*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+static void lodepng_add32bitInt(ucvector* buffer, unsigned value)
+{
+ ucvector_resize(buffer, buffer->size + 4); /*todo: give error if resize failed*/
+ lodepng_set32bitInt(&buffer->data[buffer->size - 4], value);
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / File IO / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_DISK
+
+unsigned lodepng_load_file(unsigned char** out, size_t* outsize, const char* filename)
+{
+ FILE* file;
+ long size;
+
+ /*provide some proper output values if error will happen*/
+ *out = 0;
+ *outsize = 0;
+
+ file = fopen(filename, "rb");
+ if(!file) return 78;
+
+ /*get filesize:*/
+ fseek(file , 0 , SEEK_END);
+ size = ftell(file);
+ rewind(file);
+
+ /*read contents of the file into the vector*/
+ *outsize = 0;
+ *out = (unsigned char*)lodepng_malloc((size_t)size);
+ if(size && (*out)) (*outsize) = fread(*out, 1, (size_t)size, file);
+
+ fclose(file);
+ if(!(*out) && size) return 83; /*the above malloc failed*/
+ return 0;
+}
+
+/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
+unsigned lodepng_save_file(const unsigned char* buffer, size_t buffersize, const char* filename)
+{
+ FILE* file;
+ file = fopen(filename, "wb" );
+ if(!file) return 79;
+ fwrite((char*)buffer , 1 , buffersize, file);
+ fclose(file);
+ return 0;
+}
+
+#endif /*LODEPNG_COMPILE_DISK*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // End of common code and tools. Begin of Zlib related code. // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_ZLIB
+#ifdef LODEPNG_COMPILE_ENCODER
+/*TODO: this ignores potential out of memory errors*/
+#define addBitToStream(/*size_t**/ bitpointer, /*ucvector**/ bitstream, /*unsigned char*/ bit)\
+{\
+ /*add a new byte at the end*/\
+ if(((*bitpointer) & 7) == 0) ucvector_push_back(bitstream, (unsigned char)0);\
+ /*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/\
+ (bitstream->data[bitstream->size - 1]) |= (bit << ((*bitpointer) & 0x7));\
+ (*bitpointer)++;\
+}
+
+static void addBitsToStream(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits)
+{
+ size_t i;
+ for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> i) & 1));
+}
+
+static void addBitsToStreamReversed(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits)
+{
+ size_t i;
+ for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> (nbits - 1 - i)) & 1));
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+#define READBIT(bitpointer, bitstream) ((bitstream[bitpointer >> 3] >> (bitpointer & 0x7)) & (unsigned char)1)
+
+static unsigned char readBitFromStream(size_t* bitpointer, const unsigned char* bitstream)
+{
+ unsigned char result = (unsigned char)(READBIT(*bitpointer, bitstream));
+ (*bitpointer)++;
+ return result;
+}
+
+static unsigned readBitsFromStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits)
+{
+ unsigned result = 0, i;
+ for(i = 0; i < nbits; i++)
+ {
+ result += ((unsigned)READBIT(*bitpointer, bitstream)) << i;
+ (*bitpointer)++;
+ }
+ return result;
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Deflate - Huffman / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#define FIRST_LENGTH_CODE_INDEX 257
+#define LAST_LENGTH_CODE_INDEX 285
+/*256 literals, the end code, some length codes, and 2 unused codes*/
+#define NUM_DEFLATE_CODE_SYMBOLS 288
+/*the distance codes have their own symbols, 30 used, 2 unused*/
+#define NUM_DISTANCE_SYMBOLS 32
+/*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/
+#define NUM_CODE_LENGTH_CODES 19
+
+/*the base lengths represented by codes 257-285*/
+static const unsigned LENGTHBASE[29]
+ = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59,
+ 67, 83, 99, 115, 131, 163, 195, 227, 258};
+
+/*the extra bits used by codes 257-285 (added to base length)*/
+static const unsigned LENGTHEXTRA[29]
+ = {0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3,
+ 4, 4, 4, 4, 5, 5, 5, 5, 0};
+
+/*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/
+static const unsigned DISTANCEBASE[30]
+ = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513,
+ 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
+
+/*the extra bits of backwards distances (added to base)*/
+static const unsigned DISTANCEEXTRA[30]
+ = {0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8,
+ 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13};
+
+/*the order in which "code length alphabet code lengths" are stored, out of this
+the huffman tree of the dynamic huffman tree lengths is generated*/
+static const unsigned CLCL_ORDER[NUM_CODE_LENGTH_CODES]
+ = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};
+
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*
+Huffman tree struct, containing multiple representations of the tree
+*/
+typedef struct HuffmanTree
+{
+ unsigned* tree2d;
+ unsigned* tree1d;
+ unsigned* lengths; /*the lengths of the codes of the 1d-tree*/
+ unsigned maxbitlen; /*maximum number of bits a single code can get*/
+ unsigned numcodes; /*number of symbols in the alphabet = number of codes*/
+} HuffmanTree;
+
+/*function used for debug purposes to draw the tree in ascii art with C++*/
+/*
+static void HuffmanTree_draw(HuffmanTree* tree)
+{
+ std::cout << "tree. length: " << tree->numcodes << " maxbitlen: " << tree->maxbitlen << std::endl;
+ for(size_t i = 0; i < tree->tree1d.size; i++)
+ {
+ if(tree->lengths.data[i])
+ std::cout << i << " " << tree->tree1d.data[i] << " " << tree->lengths.data[i] << std::endl;
+ }
+ std::cout << std::endl;
+}*/
+
+static void HuffmanTree_init(HuffmanTree* tree)
+{
+ tree->tree2d = 0;
+ tree->tree1d = 0;
+ tree->lengths = 0;
+}
+
+static void HuffmanTree_cleanup(HuffmanTree* tree)
+{
+ lodepng_free(tree->tree2d);
+ lodepng_free(tree->tree1d);
+ lodepng_free(tree->lengths);
+}
+
+/*the tree representation used by the decoder. return value is error*/
+static unsigned HuffmanTree_make2DTree(HuffmanTree* tree)
+{
+ unsigned nodefilled = 0; /*up to which node it is filled*/
+ unsigned treepos = 0; /*position in the tree (1 of the numcodes columns)*/
+ unsigned n, i;
+
+ tree->tree2d = (unsigned*)lodepng_malloc(tree->numcodes * 2 * sizeof(unsigned));
+ if(!tree->tree2d) return 83; /*alloc fail*/
+
+ /*
+ convert tree1d[] to tree2d[][]. In the 2D array, a value of 32767 means
+ uninited, a value >= numcodes is an address to another bit, a value < numcodes
+ is a code. The 2 rows are the 2 possible bit values (0 or 1), there are as
+ many columns as codes - 1.
+ A good huffmann tree has N * 2 - 1 nodes, of which N - 1 are internal nodes.
+ Here, the internal nodes are stored (what their 0 and 1 option point to).
+ There is only memory for such good tree currently, if there are more nodes
+ (due to too long length codes), error 55 will happen
+ */
+ for(n = 0; n < tree->numcodes * 2; n++)
+ {
+ tree->tree2d[n] = 32767; /*32767 here means the tree2d isn't filled there yet*/
+ }
+
+ for(n = 0; n < tree->numcodes; n++) /*the codes*/
+ {
+ for(i = 0; i < tree->lengths[n]; i++) /*the bits for this code*/
+ {
+ unsigned char bit = (unsigned char)((tree->tree1d[n] >> (tree->lengths[n] - i - 1)) & 1);
+ if(treepos > tree->numcodes - 2) return 55; /*oversubscribed, see comment in lodepng_error_text*/
+ if(tree->tree2d[2 * treepos + bit] == 32767) /*not yet filled in*/
+ {
+ if(i + 1 == tree->lengths[n]) /*last bit*/
+ {
+ tree->tree2d[2 * treepos + bit] = n; /*put the current code in it*/
+ treepos = 0;
+ }
+ else
+ {
+ /*put address of the next step in here, first that address has to be found of course
+ (it's just nodefilled + 1)...*/
+ nodefilled++;
+ /*addresses encoded with numcodes added to it*/
+ tree->tree2d[2 * treepos + bit] = nodefilled + tree->numcodes;
+ treepos = nodefilled;
+ }
+ }
+ else treepos = tree->tree2d[2 * treepos + bit] - tree->numcodes;
+ }
+ }
+
+ for(n = 0; n < tree->numcodes * 2; n++)
+ {
+ if(tree->tree2d[n] == 32767) tree->tree2d[n] = 0; /*remove possible remaining 32767's*/
+ }
+
+ return 0;
+}
+
+/*
+Second step for the ...makeFromLengths and ...makeFromFrequencies functions.
+numcodes, lengths and maxbitlen must already be filled in correctly. return
+value is error.
+*/
+static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree)
+{
+ uivector blcount;
+ uivector nextcode;
+ unsigned bits, n, error = 0;
+
+ uivector_init(&blcount);
+ uivector_init(&nextcode);
+
+ tree->tree1d = (unsigned*)lodepng_malloc(tree->numcodes * sizeof(unsigned));
+ if(!tree->tree1d) error = 83; /*alloc fail*/
+
+ if(!uivector_resizev(&blcount, tree->maxbitlen + 1, 0)
+ || !uivector_resizev(&nextcode, tree->maxbitlen + 1, 0))
+ error = 83; /*alloc fail*/
+
+ if(!error)
+ {
+ /*step 1: count number of instances of each code length*/
+ for(bits = 0; bits < tree->numcodes; bits++) blcount.data[tree->lengths[bits]]++;
+ /*step 2: generate the nextcode values*/
+ for(bits = 1; bits <= tree->maxbitlen; bits++)
+ {
+ nextcode.data[bits] = (nextcode.data[bits - 1] + blcount.data[bits - 1]) << 1;
+ }
+ /*step 3: generate all the codes*/
+ for(n = 0; n < tree->numcodes; n++)
+ {
+ if(tree->lengths[n] != 0) tree->tree1d[n] = nextcode.data[tree->lengths[n]]++;
+ }
+ }
+
+ uivector_cleanup(&blcount);
+ uivector_cleanup(&nextcode);
+
+ if(!error) return HuffmanTree_make2DTree(tree);
+ else return error;
+}
+
+/*
+given the code lengths (as stored in the PNG file), generate the tree as defined
+by Deflate. maxbitlen is the maximum bits that a code in the tree can have.
+return value is error.
+*/
+static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen,
+ size_t numcodes, unsigned maxbitlen)
+{
+ unsigned i;
+ tree->lengths = (unsigned*)lodepng_malloc(numcodes * sizeof(unsigned));
+ if(!tree->lengths) return 83; /*alloc fail*/
+ for(i = 0; i < numcodes; i++) tree->lengths[i] = bitlen[i];
+ tree->numcodes = (unsigned)numcodes; /*number of symbols*/
+ tree->maxbitlen = maxbitlen;
+ return HuffmanTree_makeFromLengths2(tree);
+}
+
+#ifdef LODEPNG_COMPILE_ENCODER
+
+/*
+A coin, this is the terminology used for the package-merge algorithm and the
+coin collector's problem. This is used to generate the huffman tree.
+A coin can be multiple coins (when they're merged)
+*/
+typedef struct Coin
+{
+ uivector symbols;
+ float weight; /*the sum of all weights in this coin*/
+} Coin;
+
+static void coin_init(Coin* c)
+{
+ uivector_init(&c->symbols);
+}
+
+/*argument c is void* so that this dtor can be given as function pointer to the vector resize function*/
+static void coin_cleanup(void* c)
+{
+ uivector_cleanup(&((Coin*)c)->symbols);
+}
+
+static void coin_copy(Coin* c1, const Coin* c2)
+{
+ c1->weight = c2->weight;
+ uivector_copy(&c1->symbols, &c2->symbols);
+}
+
+static void add_coins(Coin* c1, const Coin* c2)
+{
+ size_t i;
+ for(i = 0; i < c2->symbols.size; i++) uivector_push_back(&c1->symbols, c2->symbols.data[i]);
+ c1->weight += c2->weight;
+}
+
+static void init_coins(Coin* coins, size_t num)
+{
+ size_t i;
+ for(i = 0; i < num; i++) coin_init(&coins[i]);
+}
+
+static void cleanup_coins(Coin* coins, size_t num)
+{
+ size_t i;
+ for(i = 0; i < num; i++) coin_cleanup(&coins[i]);
+}
+
+static int coin_compare(const void* a, const void* b) {
+ float wa = ((const Coin*)a)->weight;
+ float wb = ((const Coin*)b)->weight;
+ return wa > wb ? 1 : wa < wb ? -1 : 0;
+}
+
+static unsigned append_symbol_coins(Coin* coins, const unsigned* frequencies, unsigned numcodes, size_t sum)
+{
+ unsigned i;
+ unsigned j = 0; /*index of present symbols*/
+ for(i = 0; i < numcodes; i++)
+ {
+ if(frequencies[i] != 0) /*only include symbols that are present*/
+ {
+ coins[j].weight = frequencies[i] / (float)sum;
+ uivector_push_back(&coins[j].symbols, i);
+ j++;
+ }
+ }
+ return 0;
+}
+
+unsigned lodepng_huffman_code_lengths(unsigned* lengths, const unsigned* frequencies,
+ size_t numcodes, unsigned maxbitlen)
+{
+ unsigned i, j;
+ size_t sum = 0, numpresent = 0;
+ unsigned error = 0;
+ Coin* coins; /*the coins of the currently calculated row*/
+ Coin* prev_row; /*the previous row of coins*/
+ unsigned numcoins;
+ unsigned coinmem;
+
+ if(numcodes == 0) return 80; /*error: a tree of 0 symbols is not supposed to be made*/
+
+ for(i = 0; i < numcodes; i++)
+ {
+ if(frequencies[i] > 0)
+ {
+ numpresent++;
+ sum += frequencies[i];
+ }
+ }
+
+ for(i = 0; i < numcodes; i++) lengths[i] = 0;
+
+ /*ensure at least two present symbols. There should be at least one symbol
+ according to RFC 1951 section 3.2.7. To decoders incorrectly require two. To
+ make these work as well ensure there are at least two symbols. The
+ Package-Merge code below also doesn't work correctly if there's only one
+ symbol, it'd give it the theoritical 0 bits but in practice zlib wants 1 bit*/
+ if(numpresent == 0)
+ {
+ lengths[0] = lengths[1] = 1; /*note that for RFC 1951 section 3.2.7, only lengths[0] = 1 is needed*/
+ }
+ else if(numpresent == 1)
+ {
+ for(i = 0; i < numcodes; i++)
+ {
+ if(frequencies[i])
+ {
+ lengths[i] = 1;
+ lengths[i == 0 ? 1 : 0] = 1;
+ break;
+ }
+ }
+ }
+ else
+ {
+ /*Package-Merge algorithm represented by coin collector's problem
+ For every symbol, maxbitlen coins will be created*/
+
+ coinmem = numpresent * 2; /*max amount of coins needed with the current algo*/
+ coins = (Coin*)lodepng_malloc(sizeof(Coin) * coinmem);
+ prev_row = (Coin*)lodepng_malloc(sizeof(Coin) * coinmem);
+ if(!coins || !prev_row)
+ {
+ lodepng_free(coins);
+ lodepng_free(prev_row);
+ return 83; /*alloc fail*/
+ }
+ init_coins(coins, coinmem);
+ init_coins(prev_row, coinmem);
+
+ /*first row, lowest denominator*/
+ error = append_symbol_coins(coins, frequencies, numcodes, sum);
+ numcoins = numpresent;
+ qsort(coins, numcoins, sizeof(Coin), coin_compare);
+ if(!error)
+ {
+ unsigned numprev = 0;
+ for(j = 1; j <= maxbitlen && !error; j++) /*each of the remaining rows*/
+ {
+ unsigned tempnum;
+ Coin* tempcoins;
+ /*swap prev_row and coins, and their amounts*/
+ tempcoins = prev_row; prev_row = coins; coins = tempcoins;
+ tempnum = numprev; numprev = numcoins; numcoins = tempnum;
+
+ cleanup_coins(coins, numcoins);
+ init_coins(coins, numcoins);
+
+ numcoins = 0;
+
+ /*fill in the merged coins of the previous row*/
+ for(i = 0; i + 1 < numprev; i += 2)
+ {
+ /*merge prev_row[i] and prev_row[i + 1] into new coin*/
+ Coin* coin = &coins[numcoins++];
+ coin_copy(coin, &prev_row[i]);
+ add_coins(coin, &prev_row[i + 1]);
+ }
+ /*fill in all the original symbols again*/
+ if(j < maxbitlen)
+ {
+ error = append_symbol_coins(coins + numcoins, frequencies, numcodes, sum);
+ numcoins += numpresent;
+ }
+ qsort(coins, numcoins, sizeof(Coin), coin_compare);
+ }
+ }
+
+ if(!error)
+ {
+ /*calculate the lenghts of each symbol, as the amount of times a coin of each symbol is used*/
+ for(i = 0; i < numpresent - 1; i++)
+ {
+ Coin* coin = &coins[i];
+ for(j = 0; j < coin->symbols.size; j++) lengths[coin->symbols.data[j]]++;
+ }
+ }
+
+ cleanup_coins(coins, coinmem);
+ lodepng_free(coins);
+ cleanup_coins(prev_row, coinmem);
+ lodepng_free(prev_row);
+ }
+
+ return error;
+}
+
+/*Create the Huffman tree given the symbol frequencies*/
+static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies,
+ size_t mincodes, size_t numcodes, unsigned maxbitlen)
+{
+ unsigned error = 0;
+ while(!frequencies[numcodes - 1] && numcodes > mincodes) numcodes--; /*trim zeroes*/
+ tree->maxbitlen = maxbitlen;
+ tree->numcodes = (unsigned)numcodes; /*number of symbols*/
+ tree->lengths = (unsigned*)lodepng_realloc(tree->lengths, numcodes * sizeof(unsigned));
+ if(!tree->lengths) return 83; /*alloc fail*/
+ /*initialize all lengths to 0*/
+ memset(tree->lengths, 0, numcodes * sizeof(unsigned));
+
+ error = lodepng_huffman_code_lengths(tree->lengths, frequencies, numcodes, maxbitlen);
+ if(!error) error = HuffmanTree_makeFromLengths2(tree);
+ return error;
+}
+
+static unsigned HuffmanTree_getCode(const HuffmanTree* tree, unsigned index)
+{
+ return tree->tree1d[index];
+}
+
+static unsigned HuffmanTree_getLength(const HuffmanTree* tree, unsigned index)
+{
+ return tree->lengths[index];
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+/*get the literal and length code tree of a deflated block with fixed tree, as per the deflate specification*/
+static unsigned generateFixedLitLenTree(HuffmanTree* tree)
+{
+ unsigned i, error = 0;
+ unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
+ if(!bitlen) return 83; /*alloc fail*/
+
+ /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/
+ for(i = 0; i <= 143; i++) bitlen[i] = 8;
+ for(i = 144; i <= 255; i++) bitlen[i] = 9;
+ for(i = 256; i <= 279; i++) bitlen[i] = 7;
+ for(i = 280; i <= 287; i++) bitlen[i] = 8;
+
+ error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DEFLATE_CODE_SYMBOLS, 15);
+
+ lodepng_free(bitlen);
+ return error;
+}
+
+/*get the distance code tree of a deflated block with fixed tree, as specified in the deflate specification*/
+static unsigned generateFixedDistanceTree(HuffmanTree* tree)
+{
+ unsigned i, error = 0;
+ unsigned* bitlen = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
+ if(!bitlen) return 83; /*alloc fail*/
+
+ /*there are 32 distance codes, but 30-31 are unused*/
+ for(i = 0; i < NUM_DISTANCE_SYMBOLS; i++) bitlen[i] = 5;
+ error = HuffmanTree_makeFromLengths(tree, bitlen, NUM_DISTANCE_SYMBOLS, 15);
+
+ lodepng_free(bitlen);
+ return error;
+}
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+/*
+returns the code, or (unsigned)(-1) if error happened
+inbitlength is the length of the complete buffer, in bits (so its byte length times 8)
+*/
+static unsigned huffmanDecodeSymbol(const unsigned char* in, size_t* bp,
+ const HuffmanTree* codetree, size_t inbitlength)
+{
+ unsigned treepos = 0, ct;
+ for(;;)
+ {
+ if(*bp >= inbitlength) return (unsigned)(-1); /*error: end of input memory reached without endcode*/
+ /*
+ decode the symbol from the tree. The "readBitFromStream" code is inlined in
+ the expression below because this is the biggest bottleneck while decoding
+ */
+ ct = codetree->tree2d[(treepos << 1) + READBIT(*bp, in)];
+ (*bp)++;
+ if(ct < codetree->numcodes) return ct; /*the symbol is decoded, return it*/
+ else treepos = ct - codetree->numcodes; /*symbol not yet decoded, instead move tree position*/
+
+ if(treepos >= codetree->numcodes) return (unsigned)(-1); /*error: it appeared outside the codetree*/
+ }
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Inflator (Decompressor) / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*get the tree of a deflated block with fixed tree, as specified in the deflate specification*/
+static void getTreeInflateFixed(HuffmanTree* tree_ll, HuffmanTree* tree_d)
+{
+ /*TODO: check for out of memory errors*/
+ generateFixedLitLenTree(tree_ll);
+ generateFixedDistanceTree(tree_d);
+}
+
+/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/
+static unsigned getTreeInflateDynamic(HuffmanTree* tree_ll, HuffmanTree* tree_d,
+ const unsigned char* in, size_t* bp, size_t inlength)
+{
+ /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/
+ unsigned error = 0;
+ unsigned n, HLIT, HDIST, HCLEN, i;
+ size_t inbitlength = inlength * 8;
+
+ /*see comments in deflateDynamic for explanation of the context and these variables, it is analogous*/
+ unsigned* bitlen_ll = 0; /*lit,len code lengths*/
+ unsigned* bitlen_d = 0; /*dist code lengths*/
+ /*code length code lengths ("clcl"), the bit lengths of the huffman tree used to compress bitlen_ll and bitlen_d*/
+ unsigned* bitlen_cl = 0;
+ HuffmanTree tree_cl; /*the code tree for code length codes (the huffman tree for compressed huffman trees)*/
+
+ if((*bp) >> 3 >= inlength - 2) return 49; /*error: the bit pointer is or will go past the memory*/
+
+ /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/
+ HLIT = readBitsFromStream(bp, in, 5) + 257;
+ /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/
+ HDIST = readBitsFromStream(bp, in, 5) + 1;
+ /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/
+ HCLEN = readBitsFromStream(bp, in, 4) + 4;
+
+ HuffmanTree_init(&tree_cl);
+
+ while(!error)
+ {
+ /*read the code length codes out of 3 * (amount of code length codes) bits*/
+
+ bitlen_cl = (unsigned*)lodepng_malloc(NUM_CODE_LENGTH_CODES * sizeof(unsigned));
+ if(!bitlen_cl) ERROR_BREAK(83 /*alloc fail*/);
+
+ for(i = 0; i < NUM_CODE_LENGTH_CODES; i++)
+ {
+ if(i < HCLEN) bitlen_cl[CLCL_ORDER[i]] = readBitsFromStream(bp, in, 3);
+ else bitlen_cl[CLCL_ORDER[i]] = 0; /*if not, it must stay 0*/
+ }
+
+ error = HuffmanTree_makeFromLengths(&tree_cl, bitlen_cl, NUM_CODE_LENGTH_CODES, 7);
+ if(error) break;
+
+ /*now we can use this tree to read the lengths for the tree that this function will return*/
+ bitlen_ll = (unsigned*)lodepng_malloc(NUM_DEFLATE_CODE_SYMBOLS * sizeof(unsigned));
+ bitlen_d = (unsigned*)lodepng_malloc(NUM_DISTANCE_SYMBOLS * sizeof(unsigned));
+ if(!bitlen_ll || !bitlen_d) ERROR_BREAK(83 /*alloc fail*/);
+ for(i = 0; i < NUM_DEFLATE_CODE_SYMBOLS; i++) bitlen_ll[i] = 0;
+ for(i = 0; i < NUM_DISTANCE_SYMBOLS; i++) bitlen_d[i] = 0;
+
+ /*i is the current symbol we're reading in the part that contains the code lengths of lit/len and dist codes*/
+ i = 0;
+ while(i < HLIT + HDIST)
+ {
+ unsigned code = huffmanDecodeSymbol(in, bp, &tree_cl, inbitlength);
+ if(code <= 15) /*a length code*/
+ {
+ if(i < HLIT) bitlen_ll[i] = code;
+ else bitlen_d[i - HLIT] = code;
+ i++;
+ }
+ else if(code == 16) /*repeat previous*/
+ {
+ unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/
+ unsigned value; /*set value to the previous code*/
+
+ if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/
+ if (i == 0) ERROR_BREAK(54); /*can't repeat previous if i is 0*/
+
+ replength += readBitsFromStream(bp, in, 2);
+
+ if(i < HLIT + 1) value = bitlen_ll[i - 1];
+ else value = bitlen_d[i - HLIT - 1];
+ /*repeat this value in the next lengths*/
+ for(n = 0; n < replength; n++)
+ {
+ if(i >= HLIT + HDIST) ERROR_BREAK(13); /*error: i is larger than the amount of codes*/
+ if(i < HLIT) bitlen_ll[i] = value;
+ else bitlen_d[i - HLIT] = value;
+ i++;
+ }
+ }
+ else if(code == 17) /*repeat "0" 3-10 times*/
+ {
+ unsigned replength = 3; /*read in the bits that indicate repeat length*/
+ if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/
+
+ replength += readBitsFromStream(bp, in, 3);
+
+ /*repeat this value in the next lengths*/
+ for(n = 0; n < replength; n++)
+ {
+ if(i >= HLIT + HDIST) ERROR_BREAK(14); /*error: i is larger than the amount of codes*/
+
+ if(i < HLIT) bitlen_ll[i] = 0;
+ else bitlen_d[i - HLIT] = 0;
+ i++;
+ }
+ }
+ else if(code == 18) /*repeat "0" 11-138 times*/
+ {
+ unsigned replength = 11; /*read in the bits that indicate repeat length*/
+ if(*bp >= inbitlength) ERROR_BREAK(50); /*error, bit pointer jumps past memory*/
+
+ replength += readBitsFromStream(bp, in, 7);
+
+ /*repeat this value in the next lengths*/
+ for(n = 0; n < replength; n++)
+ {
+ if(i >= HLIT + HDIST) ERROR_BREAK(15); /*error: i is larger than the amount of codes*/
+
+ if(i < HLIT) bitlen_ll[i] = 0;
+ else bitlen_d[i - HLIT] = 0;
+ i++;
+ }
+ }
+ else /*if(code == (unsigned)(-1))*/ /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/
+ {
+ if(code == (unsigned)(-1))
+ {
+ /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
+ (10=no endcode, 11=wrong jump outside of tree)*/
+ error = (*bp) > inbitlength ? 10 : 11;
+ }
+ else error = 16; /*unexisting code, this can never happen*/
+ break;
+ }
+ }
+ if(error) break;
+
+ if(bitlen_ll[256] == 0) ERROR_BREAK(64); /*the length of the end code 256 must be larger than 0*/
+
+ /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/
+ error = HuffmanTree_makeFromLengths(tree_ll, bitlen_ll, NUM_DEFLATE_CODE_SYMBOLS, 15);
+ if(error) break;
+ error = HuffmanTree_makeFromLengths(tree_d, bitlen_d, NUM_DISTANCE_SYMBOLS, 15);
+
+ break; /*end of error-while*/
+ }
+
+ lodepng_free(bitlen_cl);
+ lodepng_free(bitlen_ll);
+ lodepng_free(bitlen_d);
+ HuffmanTree_cleanup(&tree_cl);
+
+ return error;
+}
+
+/*inflate a block with dynamic of fixed Huffman tree*/
+static unsigned inflateHuffmanBlock(ucvector* out, const unsigned char* in, size_t* bp,
+ size_t* pos, size_t inlength, unsigned btype)
+{
+ unsigned error = 0;
+ HuffmanTree tree_ll; /*the huffman tree for literal and length codes*/
+ HuffmanTree tree_d; /*the huffman tree for distance codes*/
+ size_t inbitlength = inlength * 8;
+
+ HuffmanTree_init(&tree_ll);
+ HuffmanTree_init(&tree_d);
+
+ if(btype == 1) getTreeInflateFixed(&tree_ll, &tree_d);
+ else if(btype == 2) error = getTreeInflateDynamic(&tree_ll, &tree_d, in, bp, inlength);
+
+ while(!error) /*decode all symbols until end reached, breaks at end code*/
+ {
+ /*code_ll is literal, length or end code*/
+ unsigned code_ll = huffmanDecodeSymbol(in, bp, &tree_ll, inbitlength);
+ if(code_ll <= 255) /*literal symbol*/
+ {
+ if((*pos) >= out->size)
+ {
+ /*reserve more room at once*/
+ if(!ucvector_resize(out, ((*pos) + 1) * 2)) ERROR_BREAK(83 /*alloc fail*/);
+ }
+ out->data[(*pos)] = (unsigned char)(code_ll);
+ (*pos)++;
+ }
+ else if(code_ll >= FIRST_LENGTH_CODE_INDEX && code_ll <= LAST_LENGTH_CODE_INDEX) /*length code*/
+ {
+ unsigned code_d, distance;
+ unsigned numextrabits_l, numextrabits_d; /*extra bits for length and distance*/
+ size_t start, forward, backward, length;
+
+ /*part 1: get length base*/
+ length = LENGTHBASE[code_ll - FIRST_LENGTH_CODE_INDEX];
+
+ /*part 2: get extra bits and add the value of that to length*/
+ numextrabits_l = LENGTHEXTRA[code_ll - FIRST_LENGTH_CODE_INDEX];
+ if(*bp >= inbitlength) ERROR_BREAK(51); /*error, bit pointer will jump past memory*/
+ length += readBitsFromStream(bp, in, numextrabits_l);
+
+ /*part 3: get distance code*/
+ code_d = huffmanDecodeSymbol(in, bp, &tree_d, inbitlength);
+ if(code_d > 29)
+ {
+ if(code_ll == (unsigned)(-1)) /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/
+ {
+ /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
+ (10=no endcode, 11=wrong jump outside of tree)*/
+ error = (*bp) > inlength * 8 ? 10 : 11;
+ }
+ else error = 18; /*error: invalid distance code (30-31 are never used)*/
+ break;
+ }
+ distance = DISTANCEBASE[code_d];
+
+ /*part 4: get extra bits from distance*/
+ numextrabits_d = DISTANCEEXTRA[code_d];
+ if(*bp >= inbitlength) ERROR_BREAK(51); /*error, bit pointer will jump past memory*/
+
+ distance += readBitsFromStream(bp, in, numextrabits_d);
+
+ /*part 5: fill in all the out[n] values based on the length and dist*/
+ start = (*pos);
+ if(distance > start) ERROR_BREAK(52); /*too long backward distance*/
+ backward = start - distance;
+ if((*pos) + length >= out->size)
+ {
+ /*reserve more room at once*/
+ if(!ucvector_resize(out, ((*pos) + length) * 2)) ERROR_BREAK(83 /*alloc fail*/);
+ }
+
+ for(forward = 0; forward < length; forward++)
+ {
+ out->data[(*pos)] = out->data[backward];
+ (*pos)++;
+ backward++;
+ if(backward >= start) backward = start - distance;
+ }
+ }
+ else if(code_ll == 256)
+ {
+ break; /*end code, break the loop*/
+ }
+ else /*if(code == (unsigned)(-1))*/ /*huffmanDecodeSymbol returns (unsigned)(-1) in case of error*/
+ {
+ /*return error code 10 or 11 depending on the situation that happened in huffmanDecodeSymbol
+ (10=no endcode, 11=wrong jump outside of tree)*/
+ error = (*bp) > inlength * 8 ? 10 : 11;
+ break;
+ }
+ }
+
+ HuffmanTree_cleanup(&tree_ll);
+ HuffmanTree_cleanup(&tree_d);
+
+ return error;
+}
+
+static unsigned inflateNoCompression(ucvector* out, const unsigned char* in, size_t* bp, size_t* pos, size_t inlength)
+{
+ /*go to first boundary of byte*/
+ size_t p;
+ unsigned LEN, NLEN, n, error = 0;
+ while(((*bp) & 0x7) != 0) (*bp)++;
+ p = (*bp) / 8; /*byte position*/
+
+ /*read LEN (2 bytes) and NLEN (2 bytes)*/
+ if(p >= inlength - 4) return 52; /*error, bit pointer will jump past memory*/
+ LEN = in[p] + 256 * in[p + 1]; p += 2;
+ NLEN = in[p] + 256 * in[p + 1]; p += 2;
+
+ /*check if 16-bit NLEN is really the one's complement of LEN*/
+ if(LEN + NLEN != 65535) return 21; /*error: NLEN is not one's complement of LEN*/
+
+ if((*pos) + LEN >= out->size)
+ {
+ if(!ucvector_resize(out, (*pos) + LEN)) return 83; /*alloc fail*/
+ }
+
+ /*read the literal data: LEN bytes are now stored in the out buffer*/
+ if(p + LEN > inlength) return 23; /*error: reading outside of in buffer*/
+ for(n = 0; n < LEN; n++) out->data[(*pos)++] = in[p++];
+
+ (*bp) = p * 8;
+
+ return error;
+}
+
+static unsigned lodepng_inflatev(ucvector* out,
+ const unsigned char* in, size_t insize,
+ const LodePNGDecompressSettings* settings)
+{
+ /*bit pointer in the "in" data, current byte is bp >> 3, current bit is bp & 0x7 (from lsb to msb of the byte)*/
+ size_t bp = 0;
+ unsigned BFINAL = 0;
+ size_t pos = 0; /*byte position in the out buffer*/
+
+ unsigned error = 0;
+
+ (void)settings;
+
+ while(!BFINAL)
+ {
+ unsigned BTYPE;
+ if(bp + 2 >= insize * 8) return 52; /*error, bit pointer will jump past memory*/
+ BFINAL = readBitFromStream(&bp, in);
+ BTYPE = 1 * readBitFromStream(&bp, in);
+ BTYPE += 2 * readBitFromStream(&bp, in);
+
+ if(BTYPE == 3) return 20; /*error: invalid BTYPE*/
+ else if(BTYPE == 0) error = inflateNoCompression(out, in, &bp, &pos, insize); /*no compression*/
+ else error = inflateHuffmanBlock(out, in, &bp, &pos, insize, BTYPE); /*compression, BTYPE 01 or 10*/
+
+ if(error) return error;
+ }
+
+ /*Only now we know the true size of out, resize it to that*/
+ if(!ucvector_resize(out, pos)) error = 83; /*alloc fail*/
+
+ return error;
+}
+
+unsigned lodepng_inflate(unsigned char** out, size_t* outsize,
+ const unsigned char* in, size_t insize,
+ const LodePNGDecompressSettings* settings)
+{
+ unsigned error;
+ ucvector v;
+ ucvector_init_buffer(&v, *out, *outsize);
+ error = lodepng_inflatev(&v, in, insize, settings);
+ *out = v.data;
+ *outsize = v.size;
+ return error;
+}
+
+static unsigned inflate(unsigned char** out, size_t* outsize,
+ const unsigned char* in, size_t insize,
+ const LodePNGDecompressSettings* settings)
+{
+ if(settings->custom_inflate)
+ {
+ return settings->custom_inflate(out, outsize, in, insize, settings);
+ }
+ else
+ {
+ return lodepng_inflate(out, outsize, in, insize, settings);
+ }
+}
+
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Deflator (Compressor) / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258;
+
+/*bitlen is the size in bits of the code*/
+static void addHuffmanSymbol(size_t* bp, ucvector* compressed, unsigned code, unsigned bitlen)
+{
+ addBitsToStreamReversed(bp, compressed, code, bitlen);
+}
+
+/*search the index in the array, that has the largest value smaller than or equal to the given value,
+given array must be sorted (if no value is smaller, it returns the size of the given array)*/
+static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value)
+{
+ /*linear search implementation*/
+ /*for(size_t i = 1; i < array_size; i++) if(array[i] > value) return i - 1;
+ return array_size - 1;*/
+
+ /*binary search implementation (not that much faster) (precondition: array_size > 0)*/
+ size_t left = 1;
+ size_t right = array_size - 1;
+ while(left <= right)
+ {
+ size_t mid = (left + right) / 2;
+ if(array[mid] <= value) left = mid + 1; /*the value to find is more to the right*/
+ else if(array[mid - 1] > value) right = mid - 1; /*the value to find is more to the left*/
+ else return mid - 1;
+ }
+ return array_size - 1;
+}
+
+static void addLengthDistance(uivector* values, size_t length, size_t distance)
+{
+ /*values in encoded vector are those used by deflate:
+ 0-255: literal bytes
+ 256: end
+ 257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits)
+ 286-287: invalid*/
+
+ unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length);
+ unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]);
+ unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance);
+ unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]);
+
+ uivector_push_back(values, length_code + FIRST_LENGTH_CODE_INDEX);
+ uivector_push_back(values, extra_length);
+ uivector_push_back(values, dist_code);
+ uivector_push_back(values, extra_distance);
+}
+
+static const unsigned HASH_BIT_MASK = 65535;
+static const unsigned HASH_NUM_VALUES = 65536;
+static const unsigned HASH_NUM_CHARACTERS = 3;
+static const unsigned HASH_SHIFT = 2;
+/*
+The HASH_NUM_CHARACTERS value is used to make encoding faster by using longer
+sequences to generate a hash value from the stream bytes. Setting it to 3
+gives exactly the same compression as the brute force method, since deflate's
+run length encoding starts with lengths of 3. Setting it to higher values,
+like 6, can make the encoding faster (not always though!), but will cause the
+encoding to miss any length between 3 and this value, so that the compression
+may be worse (but this can vary too depending on the image, sometimes it is
+even a bit better instead).
+The HASH_NUM_VALUES is the amount of unique possible hash values that
+combinations of bytes can give, the higher it is the more memory is needed, but
+if it's too low the advantage of hashing is gone.
+*/
+
+typedef struct Hash
+{
+ int* head; /*hash value to head circular pos*/
+ int* val; /*circular pos to hash value*/
+ /*circular pos to prev circular pos*/
+ unsigned short* chain;
+ unsigned short* zeros;
+} Hash;
+
+static unsigned hash_init(Hash* hash, unsigned windowsize)
+{
+ unsigned i;
+ hash->head = (int*)lodepng_malloc(sizeof(int) * HASH_NUM_VALUES);
+ hash->val = (int*)lodepng_malloc(sizeof(int) * windowsize);
+ hash->chain = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
+ hash->zeros = (unsigned short*)lodepng_malloc(sizeof(unsigned short) * windowsize);
+
+ if(!hash->head || !hash->val || !hash->chain || !hash->zeros) return 83; /*alloc fail*/
+
+ /*initialize hash table*/
+ for(i = 0; i < HASH_NUM_VALUES; i++) hash->head[i] = -1;
+ for(i = 0; i < windowsize; i++) hash->val[i] = -1;
+ for(i = 0; i < windowsize; i++) hash->chain[i] = i; /*same value as index indicates uninitialized*/
+
+ return 0;
+}
+
+static void hash_cleanup(Hash* hash)
+{
+ lodepng_free(hash->head);
+ lodepng_free(hash->val);
+ lodepng_free(hash->chain);
+ lodepng_free(hash->zeros);
+}
+
+static unsigned getHash(const unsigned char* data, size_t size, size_t pos)
+{
+ unsigned result = 0;
+ if (HASH_NUM_CHARACTERS == 3 && pos + 2 < size) {
+ result ^= (data[pos + 0] << (0 * HASH_SHIFT));
+ result ^= (data[pos + 1] << (1 * HASH_SHIFT));
+ result ^= (data[pos + 2] << (2 * HASH_SHIFT));
+ } else {
+ size_t amount, i;
+ if(pos >= size) return 0;
+ amount = HASH_NUM_CHARACTERS;
+ if(pos + amount >= size) amount = size - pos;
+ for(i = 0; i < amount; i++) result ^= (data[pos + i] << (i * HASH_SHIFT));
+ }
+ return result & HASH_BIT_MASK;
+}
+
+static unsigned countZeros(const unsigned char* data, size_t size, size_t pos)
+{
+ const unsigned char* start = data + pos;
+ const unsigned char* end = start + MAX_SUPPORTED_DEFLATE_LENGTH;
+ if(end > data + size) end = data + size;
+ data = start;
+ while (data != end && *data == 0) data++;
+ /*subtracting two addresses returned as 32-bit number (max value is MAX_SUPPORTED_DEFLATE_LENGTH)*/
+ return (unsigned)(data - start);
+}
+
+/*wpos = pos & (windowsize - 1)*/
+static void updateHashChain(Hash* hash, size_t wpos, int hashval)
+{
+ hash->val[wpos] = hashval;
+ if(hash->head[hashval] != -1) hash->chain[wpos] = hash->head[hashval];
+ hash->head[hashval] = wpos;
+}
+
+/*
+LZ77-encode the data. Return value is error code. The input are raw bytes, the output
+is in the form of unsigned integers with codes representing for example literal bytes, or
+length/distance pairs.
+It uses a hash table technique to let it encode faster. When doing LZ77 encoding, a
+sliding window (of windowsize) is used, and all past bytes in that window can be used as
+the "dictionary". A brute force search through all possible distances would be slow, and
+this hash technique is one out of several ways to speed this up.
+*/
+static unsigned encodeLZ77(uivector* out, Hash* hash,
+ const unsigned char* in, size_t inpos, size_t insize, unsigned windowsize,
+ unsigned minmatch, unsigned nicematch, unsigned lazymatching)
+{
+ unsigned pos, i, error = 0;
+ /*for large window lengths, assume the user wants no compression loss. Otherwise, max hash chain length speedup.*/
+ unsigned maxchainlength = windowsize >= 8192 ? windowsize : windowsize / 8;
+ unsigned maxlazymatch = windowsize >= 8192 ? MAX_SUPPORTED_DEFLATE_LENGTH : 64;
+
+ unsigned usezeros = 1; /*not sure if setting it to false for windowsize < 8192 is better or worse*/
+ unsigned numzeros = 0;
+
+ unsigned offset; /*the offset represents the distance in LZ77 terminology*/
+ unsigned length;
+ unsigned lazy = 0;
+ unsigned lazylength = 0, lazyoffset = 0;
+ unsigned hashval;
+ unsigned current_offset, current_length;
+ const unsigned char *lastptr, *foreptr, *backptr;
+ unsigned hashpos, prevpos;
+
+ if(windowsize <= 0 || windowsize > 32768) return 60; /*error: windowsize smaller/larger than allowed*/
+ if((windowsize & (windowsize - 1)) != 0) return 90; /*error: must be power of two*/
+
+ if(nicematch > MAX_SUPPORTED_DEFLATE_LENGTH) nicematch = MAX_SUPPORTED_DEFLATE_LENGTH;
+
+ for(pos = inpos; pos < insize; pos++)
+ {
+ size_t wpos = pos & (windowsize - 1); /*position for in 'circular' hash buffers*/
+ unsigned chainlength = 0;
+
+ hashval = getHash(in, insize, pos);
+ updateHashChain(hash, wpos, hashval);
+
+ if(usezeros && hashval == 0)
+ {
+ if (numzeros == 0) numzeros = countZeros(in, insize, pos);
+ else if (pos + numzeros >= insize || in[pos + numzeros - 1] != 0) numzeros--;
+ hash->zeros[wpos] = numzeros;
+ }
+ else
+ {
+ numzeros = 0;
+ }
+
+ /*the length and offset found for the current position*/
+ length = 0;
+ offset = 0;
+
+ prevpos = hash->head[hashval];
+ hashpos = hash->chain[prevpos];
+
+ lastptr = &in[insize < pos + MAX_SUPPORTED_DEFLATE_LENGTH ? insize : pos + MAX_SUPPORTED_DEFLATE_LENGTH];
+
+ /*search for the longest string*/
+ for(;;)
+ {
+ /*stop when went completely around the circular buffer*/
+ if(prevpos < wpos && hashpos > prevpos && hashpos <= wpos) break;
+ if(prevpos > wpos && (hashpos <= wpos || hashpos > prevpos)) break;
+ if(chainlength++ >= maxchainlength) break;
+
+ current_offset = hashpos <= wpos ? wpos - hashpos : wpos - hashpos + windowsize;
+ if(current_offset > 0)
+ {
+ /*test the next characters*/
+ foreptr = &in[pos];
+ backptr = &in[pos - current_offset];
+
+ /*common case in PNGs is lots of zeros. Quickly skip over them as a speedup*/
+ if(usezeros && hashval == 0 && hash->val[hashpos] == 0 /*hashval[hashpos] may be out of date*/)
+ {
+ unsigned skip = hash->zeros[hashpos];
+ if(skip > numzeros) skip = numzeros;
+ backptr += skip;
+ foreptr += skip;
+ }
+
+ while(foreptr != lastptr && *backptr == *foreptr) /*maximum supported length by deflate is max length*/
+ {
+ ++backptr;
+ ++foreptr;
+ }
+ current_length = (unsigned)(foreptr - &in[pos]);
+
+ if(current_length > length)
+ {
+ length = current_length; /*the longest length*/
+ offset = current_offset; /*the offset that is related to this longest length*/
+ /*jump out once a length of max length is found (speed gain). This also jumps
+ out if length is MAX_SUPPORTED_DEFLATE_LENGTH*/
+ if(current_length >= nicematch) break;
+ }
+ }
+
+ if(hashpos == hash->chain[hashpos]) break;
+
+ prevpos = hashpos;
+ hashpos = hash->chain[hashpos];
+ }
+
+ if(lazymatching)
+ {
+ if(!lazy && length >= 3 && length <= maxlazymatch && length < MAX_SUPPORTED_DEFLATE_LENGTH)
+ {
+ lazy = 1;
+ lazylength = length;
+ lazyoffset = offset;
+ continue; /*try the next byte*/
+ }
+ if(lazy)
+ {
+ lazy = 0;
+ if(pos == 0) ERROR_BREAK(81);
+ if(length > lazylength + 1)
+ {
+ /*push the previous character as literal*/
+ if(!uivector_push_back(out, in[pos - 1])) ERROR_BREAK(83 /*alloc fail*/);
+ }
+ else
+ {
+ length = lazylength;
+ offset = lazyoffset;
+ hash->head[hashval] = -1; /*the same hashchain update will be done, this ensures no wrong alteration*/
+ pos--;
+ }
+ }
+ }
+ if(length >= 3 && offset > windowsize) ERROR_BREAK(86 /*too big (or overflown negative) offset*/);
+
+ /*encode it as length/distance pair or literal value*/
+ if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/
+ {
+ if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/);
+ }
+ else if(length < minmatch || (length == 3 && offset > 4096))
+ {
+ /*compensate for the fact that longer offsets have more extra bits, a
+ length of only 3 may be not worth it then*/
+ if(!uivector_push_back(out, in[pos])) ERROR_BREAK(83 /*alloc fail*/);
+ }
+ else
+ {
+ addLengthDistance(out, length, offset);
+ for(i = 1; i < length; i++)
+ {
+ pos++;
+ wpos = pos & (windowsize - 1);
+ hashval = getHash(in, insize, pos);
+ updateHashChain(hash, wpos, hashval);
+ if(usezeros && hashval == 0)
+ {
+ if (numzeros == 0) numzeros = countZeros(in, insize, pos);
+ else if (pos + numzeros >= insize || in[pos + numzeros - 1] != 0) numzeros--;
+ hash->zeros[wpos] = numzeros;
+ }
+ else
+ {
+ numzeros = 0;
+ }
+ }
+ }
+ } /*end of the loop through each character of input*/
+
+ return error;
+}
+
+/* /////////////////////////////////////////////////////////////////////////// */
+
+static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize)
+{
+ /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte,
+ 2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/
+
+ size_t i, j, numdeflateblocks = (datasize + 65534) / 65535;
+ unsigned datapos = 0;
+ for(i = 0; i < numdeflateblocks; i++)
+ {
+ unsigned BFINAL, BTYPE, LEN, NLEN;
+ unsigned char firstbyte;
+
+ BFINAL = (i == numdeflateblocks - 1);
+ BTYPE = 0;
+
+ firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1) << 1) + ((BTYPE & 2) << 1));
+ ucvector_push_back(out, firstbyte);
+
+ LEN = 65535;
+ if(datasize - datapos < 65535) LEN = (unsigned)datasize - datapos;
+ NLEN = 65535 - LEN;
+
+ ucvector_push_back(out, (unsigned char)(LEN % 256));
+ ucvector_push_back(out, (unsigned char)(LEN / 256));
+ ucvector_push_back(out, (unsigned char)(NLEN % 256));
+ ucvector_push_back(out, (unsigned char)(NLEN / 256));
+
+ /*Decompressed data*/
+ for(j = 0; j < 65535 && datapos < datasize; j++)
+ {
+ ucvector_push_back(out, data[datapos++]);
+ }
+ }
+
+ return 0;
+}
+
+/*
+write the lz77-encoded data, which has lit, len and dist codes, to compressed stream using huffman trees.
+tree_ll: the tree for lit and len codes.
+tree_d: the tree for distance codes.
+*/
+static void writeLZ77data(size_t* bp, ucvector* out, const uivector* lz77_encoded,
+ const HuffmanTree* tree_ll, const HuffmanTree* tree_d)
+{
+ size_t i = 0;
+ for(i = 0; i < lz77_encoded->size; i++)
+ {
+ unsigned val = lz77_encoded->data[i];
+ addHuffmanSymbol(bp, out, HuffmanTree_getCode(tree_ll, val), HuffmanTree_getLength(tree_ll, val));
+ if(val > 256) /*for a length code, 3 more things have to be added*/
+ {
+ unsigned length_index = val - FIRST_LENGTH_CODE_INDEX;
+ unsigned n_length_extra_bits = LENGTHEXTRA[length_index];
+ unsigned length_extra_bits = lz77_encoded->data[++i];
+
+ unsigned distance_code = lz77_encoded->data[++i];
+
+ unsigned distance_index = distance_code;
+ unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index];
+ unsigned distance_extra_bits = lz77_encoded->data[++i];
+
+ addBitsToStream(bp, out, length_extra_bits, n_length_extra_bits);
+ addHuffmanSymbol(bp, out, HuffmanTree_getCode(tree_d, distance_code),
+ HuffmanTree_getLength(tree_d, distance_code));
+ addBitsToStream(bp, out, distance_extra_bits, n_distance_extra_bits);
+ }
+ }
+}
+
+/*Deflate for a block of type "dynamic", that is, with freely, optimally, created huffman trees*/
+static unsigned deflateDynamic(ucvector* out, size_t* bp, Hash* hash,
+ const unsigned char* data, size_t datapos, size_t dataend,
+ const LodePNGCompressSettings* settings, int final)
+{
+ unsigned error = 0;
+
+ /*
+ A block is compressed as follows: The PNG data is lz77 encoded, resulting in
+ literal bytes and length/distance pairs. This is then huffman compressed with
+ two huffman trees. One huffman tree is used for the lit and len values ("ll"),
+ another huffman tree is used for the dist values ("d"). These two trees are
+ stored using their code lengths, and to compress even more these code lengths
+ are also run-length encoded and huffman compressed. This gives a huffman tree
+ of code lengths "cl". The code lenghts used to describe this third tree are
+ the code length code lengths ("clcl").
+ */
+
+ /*The lz77 encoded data, represented with integers since there will also be length and distance codes in it*/
+ uivector lz77_encoded;
+ HuffmanTree tree_ll; /*tree for lit,len values*/
+ HuffmanTree tree_d; /*tree for distance codes*/
+ HuffmanTree tree_cl; /*tree for encoding the code lengths representing tree_ll and tree_d*/
+ uivector frequencies_ll; /*frequency of lit,len codes*/
+ uivector frequencies_d; /*frequency of dist codes*/
+ uivector frequencies_cl; /*frequency of code length codes*/
+ uivector bitlen_lld; /*lit,len,dist code lenghts (int bits), literally (without repeat codes).*/
+ uivector bitlen_lld_e; /*bitlen_lld encoded with repeat codes (this is a rudemtary run length compression)*/
+ /*bitlen_cl is the code length code lengths ("clcl"). The bit lengths of codes to represent tree_cl
+ (these are written as is in the file, it would be crazy to compress these using yet another huffman
+ tree that needs to be represented by yet another set of code lengths)*/
+ uivector bitlen_cl;
+ size_t datasize = dataend - datapos;
+
+ /*
+ Due to the huffman compression of huffman tree representations ("two levels"), there are some anologies:
+ bitlen_lld is to tree_cl what data is to tree_ll and tree_d.
+ bitlen_lld_e is to bitlen_lld what lz77_encoded is to data.
+ bitlen_cl is to bitlen_lld_e what bitlen_lld is to lz77_encoded.
+ */
+
+ unsigned BFINAL = final;
+ size_t numcodes_ll, numcodes_d, i;
+ unsigned HLIT, HDIST, HCLEN;
+
+ uivector_init(&lz77_encoded);
+ HuffmanTree_init(&tree_ll);
+ HuffmanTree_init(&tree_d);
+ HuffmanTree_init(&tree_cl);
+ uivector_init(&frequencies_ll);
+ uivector_init(&frequencies_d);
+ uivector_init(&frequencies_cl);
+ uivector_init(&bitlen_lld);
+ uivector_init(&bitlen_lld_e);
+ uivector_init(&bitlen_cl);
+
+ /*This while loop never loops due to a break at the end, it is here to
+ allow breaking out of it to the cleanup phase on error conditions.*/
+ while(!error)
+ {
+ if(settings->use_lz77)
+ {
+ error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize,
+ settings->minmatch, settings->nicematch, settings->lazymatching);
+ if(error) break;
+ }
+ else
+ {
+ if(!uivector_resize(&lz77_encoded, datasize)) ERROR_BREAK(83 /*alloc fail*/);
+ for(i = datapos; i < dataend; i++) lz77_encoded.data[i] = data[i]; /*no LZ77, but still will be Huffman compressed*/
+ }
+
+ if(!uivector_resizev(&frequencies_ll, 286, 0)) ERROR_BREAK(83 /*alloc fail*/);
+ if(!uivector_resizev(&frequencies_d, 30, 0)) ERROR_BREAK(83 /*alloc fail*/);
+
+ /*Count the frequencies of lit, len and dist codes*/
+ for(i = 0; i < lz77_encoded.size; i++)
+ {
+ unsigned symbol = lz77_encoded.data[i];
+ frequencies_ll.data[symbol]++;
+ if(symbol > 256)
+ {
+ unsigned dist = lz77_encoded.data[i + 2];
+ frequencies_d.data[dist]++;
+ i += 3;
+ }
+ }
+ frequencies_ll.data[256] = 1; /*there will be exactly 1 end code, at the end of the block*/
+
+ /*Make both huffman trees, one for the lit and len codes, one for the dist codes*/
+ error = HuffmanTree_makeFromFrequencies(&tree_ll, frequencies_ll.data, 257, frequencies_ll.size, 15);
+ if(error) break;
+ /*2, not 1, is chosen for mincodes: some buggy PNG decoders require at least 2 symbols in the dist tree*/
+ error = HuffmanTree_makeFromFrequencies(&tree_d, frequencies_d.data, 2, frequencies_d.size, 15);
+ if(error) break;
+
+ numcodes_ll = tree_ll.numcodes; if(numcodes_ll > 286) numcodes_ll = 286;
+ numcodes_d = tree_d.numcodes; if(numcodes_d > 30) numcodes_d = 30;
+ /*store the code lengths of both generated trees in bitlen_lld*/
+ for(i = 0; i < numcodes_ll; i++) uivector_push_back(&bitlen_lld, HuffmanTree_getLength(&tree_ll, (unsigned)i));
+ for(i = 0; i < numcodes_d; i++) uivector_push_back(&bitlen_lld, HuffmanTree_getLength(&tree_d, (unsigned)i));
+
+ /*run-length compress bitlen_ldd into bitlen_lld_e by using repeat codes 16 (copy length 3-6 times),
+ 17 (3-10 zeroes), 18 (11-138 zeroes)*/
+ for(i = 0; i < (unsigned)bitlen_lld.size; i++)
+ {
+ unsigned j = 0; /*amount of repititions*/
+ while(i + j + 1 < (unsigned)bitlen_lld.size && bitlen_lld.data[i + j + 1] == bitlen_lld.data[i]) j++;
+
+ if(bitlen_lld.data[i] == 0 && j >= 2) /*repeat code for zeroes*/
+ {
+ j++; /*include the first zero*/
+ if(j <= 10) /*repeat code 17 supports max 10 zeroes*/
+ {
+ uivector_push_back(&bitlen_lld_e, 17);
+ uivector_push_back(&bitlen_lld_e, j - 3);
+ }
+ else /*repeat code 18 supports max 138 zeroes*/
+ {
+ if(j > 138) j = 138;
+ uivector_push_back(&bitlen_lld_e, 18);
+ uivector_push_back(&bitlen_lld_e, j - 11);
+ }
+ i += (j - 1);
+ }
+ else if(j >= 3) /*repeat code for value other than zero*/
+ {
+ size_t k;
+ unsigned num = j / 6, rest = j % 6;
+ uivector_push_back(&bitlen_lld_e, bitlen_lld.data[i]);
+ for(k = 0; k < num; k++)
+ {
+ uivector_push_back(&bitlen_lld_e, 16);
+ uivector_push_back(&bitlen_lld_e, 6 - 3);
+ }
+ if(rest >= 3)
+ {
+ uivector_push_back(&bitlen_lld_e, 16);
+ uivector_push_back(&bitlen_lld_e, rest - 3);
+ }
+ else j -= rest;
+ i += j;
+ }
+ else /*too short to benefit from repeat code*/
+ {
+ uivector_push_back(&bitlen_lld_e, bitlen_lld.data[i]);
+ }
+ }
+
+ /*generate tree_cl, the huffmantree of huffmantrees*/
+
+ if(!uivector_resizev(&frequencies_cl, NUM_CODE_LENGTH_CODES, 0)) ERROR_BREAK(83 /*alloc fail*/);
+ for(i = 0; i < bitlen_lld_e.size; i++)
+ {
+ frequencies_cl.data[bitlen_lld_e.data[i]]++;
+ /*after a repeat code come the bits that specify the number of repetitions,
+ those don't need to be in the frequencies_cl calculation*/
+ if(bitlen_lld_e.data[i] >= 16) i++;
+ }
+
+ error = HuffmanTree_makeFromFrequencies(&tree_cl, frequencies_cl.data,
+ frequencies_cl.size, frequencies_cl.size, 7);
+ if(error) break;
+
+ if(!uivector_resize(&bitlen_cl, tree_cl.numcodes)) ERROR_BREAK(83 /*alloc fail*/);
+ for(i = 0; i < tree_cl.numcodes; i++)
+ {
+ /*lenghts of code length tree is in the order as specified by deflate*/
+ bitlen_cl.data[i] = HuffmanTree_getLength(&tree_cl, CLCL_ORDER[i]);
+ }
+ while(bitlen_cl.data[bitlen_cl.size - 1] == 0 && bitlen_cl.size > 4)
+ {
+ /*remove zeros at the end, but minimum size must be 4*/
+ if(!uivector_resize(&bitlen_cl, bitlen_cl.size - 1)) ERROR_BREAK(83 /*alloc fail*/);
+ }
+ if(error) break;
+
+ /*
+ Write everything into the output
+
+ After the BFINAL and BTYPE, the dynamic block consists out of the following:
+ - 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN
+ - (HCLEN+4)*3 bits code lengths of code length alphabet
+ - HLIT + 257 code lenghts of lit/length alphabet (encoded using the code length
+ alphabet, + possible repetition codes 16, 17, 18)
+ - HDIST + 1 code lengths of distance alphabet (encoded using the code length
+ alphabet, + possible repetition codes 16, 17, 18)
+ - compressed data
+ - 256 (end code)
+ */
+
+ /*Write block type*/
+ addBitToStream(bp, out, BFINAL);
+ addBitToStream(bp, out, 0); /*first bit of BTYPE "dynamic"*/
+ addBitToStream(bp, out, 1); /*second bit of BTYPE "dynamic"*/
+
+ /*write the HLIT, HDIST and HCLEN values*/
+ HLIT = (unsigned)(numcodes_ll - 257);
+ HDIST = (unsigned)(numcodes_d - 1);
+ HCLEN = (unsigned)bitlen_cl.size - 4;
+ /*trim zeroes for HCLEN. HLIT and HDIST were already trimmed at tree creation*/
+ while(!bitlen_cl.data[HCLEN + 4 - 1] && HCLEN > 0) HCLEN--;
+ addBitsToStream(bp, out, HLIT, 5);
+ addBitsToStream(bp, out, HDIST, 5);
+ addBitsToStream(bp, out, HCLEN, 4);
+
+ /*write the code lenghts of the code length alphabet*/
+ for(i = 0; i < HCLEN + 4; i++) addBitsToStream(bp, out, bitlen_cl.data[i], 3);
+
+ /*write the lenghts of the lit/len AND the dist alphabet*/
+ for(i = 0; i < bitlen_lld_e.size; i++)
+ {
+ addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_cl, bitlen_lld_e.data[i]),
+ HuffmanTree_getLength(&tree_cl, bitlen_lld_e.data[i]));
+ /*extra bits of repeat codes*/
+ if(bitlen_lld_e.data[i] == 16) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 2);
+ else if(bitlen_lld_e.data[i] == 17) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 3);
+ else if(bitlen_lld_e.data[i] == 18) addBitsToStream(bp, out, bitlen_lld_e.data[++i], 7);
+ }
+
+ /*write the compressed data symbols*/
+ writeLZ77data(bp, out, &lz77_encoded, &tree_ll, &tree_d);
+ /*error: the length of the end code 256 must be larger than 0*/
+ if(HuffmanTree_getLength(&tree_ll, 256) == 0) ERROR_BREAK(64);
+
+ /*write the end code*/
+ addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, 256), HuffmanTree_getLength(&tree_ll, 256));
+
+ break; /*end of error-while*/
+ }
+
+ /*cleanup*/
+ uivector_cleanup(&lz77_encoded);
+ HuffmanTree_cleanup(&tree_ll);
+ HuffmanTree_cleanup(&tree_d);
+ HuffmanTree_cleanup(&tree_cl);
+ uivector_cleanup(&frequencies_ll);
+ uivector_cleanup(&frequencies_d);
+ uivector_cleanup(&frequencies_cl);
+ uivector_cleanup(&bitlen_lld_e);
+ uivector_cleanup(&bitlen_lld);
+ uivector_cleanup(&bitlen_cl);
+
+ return error;
+}
+
+static unsigned deflateFixed(ucvector* out, size_t* bp, Hash* hash,
+ const unsigned char* data,
+ size_t datapos, size_t dataend,
+ const LodePNGCompressSettings* settings, int final)
+{
+ HuffmanTree tree_ll; /*tree for literal values and length codes*/
+ HuffmanTree tree_d; /*tree for distance codes*/
+
+ unsigned BFINAL = final;
+ unsigned error = 0;
+ size_t i;
+
+ HuffmanTree_init(&tree_ll);
+ HuffmanTree_init(&tree_d);
+
+ generateFixedLitLenTree(&tree_ll);
+ generateFixedDistanceTree(&tree_d);
+
+ addBitToStream(bp, out, BFINAL);
+ addBitToStream(bp, out, 1); /*first bit of BTYPE*/
+ addBitToStream(bp, out, 0); /*second bit of BTYPE*/
+
+ if(settings->use_lz77) /*LZ77 encoded*/
+ {
+ uivector lz77_encoded;
+ uivector_init(&lz77_encoded);
+ error = encodeLZ77(&lz77_encoded, hash, data, datapos, dataend, settings->windowsize,
+ settings->minmatch, settings->nicematch, settings->lazymatching);
+ if(!error) writeLZ77data(bp, out, &lz77_encoded, &tree_ll, &tree_d);
+ uivector_cleanup(&lz77_encoded);
+ }
+ else /*no LZ77, but still will be Huffman compressed*/
+ {
+ for(i = datapos; i < dataend; i++)
+ {
+ addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, data[i]), HuffmanTree_getLength(&tree_ll, data[i]));
+ }
+ }
+ /*add END code*/
+ if(!error) addHuffmanSymbol(bp, out, HuffmanTree_getCode(&tree_ll, 256), HuffmanTree_getLength(&tree_ll, 256));
+
+ /*cleanup*/
+ HuffmanTree_cleanup(&tree_ll);
+ HuffmanTree_cleanup(&tree_d);
+
+ return error;
+}
+
+static unsigned lodepng_deflatev(ucvector* out, const unsigned char* in, size_t insize,
+ const LodePNGCompressSettings* settings)
+{
+ unsigned error = 0;
+ size_t i, blocksize, numdeflateblocks;
+ size_t bp = 0; /*the bit pointer*/
+ Hash hash;
+
+ if(settings->btype > 2) return 61;
+ else if(settings->btype == 0) return deflateNoCompression(out, in, insize);
+ else if(settings->btype == 1) blocksize = insize;
+ else /*if(settings->btype == 2)*/
+ {
+ blocksize = insize / 8 + 8;
+ if(blocksize < 65535) blocksize = 65535;
+ }
+
+ numdeflateblocks = (insize + blocksize - 1) / blocksize;
+ if(numdeflateblocks == 0) numdeflateblocks = 1;
+
+ error = hash_init(&hash, settings->windowsize);
+ if(error) return error;
+
+ for(i = 0; i < numdeflateblocks && !error; i++)
+ {
+ int final = i == numdeflateblocks - 1;
+ size_t start = i * blocksize;
+ size_t end = start + blocksize;
+ if(end > insize) end = insize;
+
+ if(settings->btype == 1) error = deflateFixed(out, &bp, &hash, in, start, end, settings, final);
+ else if(settings->btype == 2) error = deflateDynamic(out, &bp, &hash, in, start, end, settings, final);
+ }
+
+ hash_cleanup(&hash);
+
+ return error;
+}
+
+unsigned lodepng_deflate(unsigned char** out, size_t* outsize,
+ const unsigned char* in, size_t insize,
+ const LodePNGCompressSettings* settings)
+{
+ unsigned error;
+ ucvector v;
+ ucvector_init_buffer(&v, *out, *outsize);
+ error = lodepng_deflatev(&v, in, insize, settings);
+ *out = v.data;
+ *outsize = v.size;
+ return error;
+}
+
+static unsigned deflate(unsigned char** out, size_t* outsize,
+ const unsigned char* in, size_t insize,
+ const LodePNGCompressSettings* settings)
+{
+ if(settings->custom_deflate)
+ {
+ return settings->custom_deflate(out, outsize, in, insize, settings);
+ }
+ else
+ {
+ return lodepng_deflate(out, outsize, in, insize, settings);
+ }
+}
+
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Adler32 */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len)
+{
+ unsigned s1 = adler & 0xffff;
+ unsigned s2 = (adler >> 16) & 0xffff;
+
+ while(len > 0)
+ {
+ /*at least 5550 sums can be done before the sums overflow, saving a lot of module divisions*/
+ unsigned amount = len > 5550 ? 5550 : len;
+ len -= amount;
+ while(amount > 0)
+ {
+ s1 += (*data++);
+ s2 += s1;
+ amount--;
+ }
+ s1 %= 65521;
+ s2 %= 65521;
+ }
+
+ return (s2 << 16) | s1;
+}
+
+/*Return the adler32 of the bytes data[0..len-1]*/
+static unsigned adler32(const unsigned char* data, unsigned len)
+{
+ return update_adler32(1L, data, len);
+}
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Zlib / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+unsigned lodepng_zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in,
+ size_t insize, const LodePNGDecompressSettings* settings)
+{
+ unsigned error = 0;
+ unsigned CM, CINFO, FDICT;
+
+ if(insize < 2) return 53; /*error, size of zlib data too small*/
+ /*read information from zlib header*/
+ if((in[0] * 256 + in[1]) % 31 != 0)
+ {
+ /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/
+ return 24;
+ }
+
+ CM = in[0] & 15;
+ CINFO = (in[0] >> 4) & 15;
+ /*FCHECK = in[1] & 31;*/ /*FCHECK is already tested above*/
+ FDICT = (in[1] >> 5) & 1;
+ /*FLEVEL = (in[1] >> 6) & 3;*/ /*FLEVEL is not used here*/
+
+ if(CM != 8 || CINFO > 7)
+ {
+ /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/
+ return 25;
+ }
+ if(FDICT != 0)
+ {
+ /*error: the specification of PNG says about the zlib stream:
+ "The additional flags shall not specify a preset dictionary."*/
+ return 26;
+ }
+
+ error = inflate(out, outsize, in + 2, insize - 2, settings);
+ if(error) return error;
+
+ if(!settings->ignore_adler32)
+ {
+ unsigned ADLER32 = lodepng_read32bitInt(&in[insize - 4]);
+ unsigned checksum = adler32(*out, (unsigned)(*outsize));
+ if(checksum != ADLER32) return 58; /*error, adler checksum not correct, data must be corrupted*/
+ }
+
+ return 0; /*no error*/
+}
+
+static unsigned zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in,
+ size_t insize, const LodePNGDecompressSettings* settings)
+{
+ if(settings->custom_zlib)
+ {
+ return settings->custom_zlib(out, outsize, in, insize, settings);
+ }
+ else
+ {
+ return lodepng_zlib_decompress(out, outsize, in, insize, settings);
+ }
+}
+
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#ifdef LODEPNG_COMPILE_ENCODER
+
+unsigned lodepng_zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
+ size_t insize, const LodePNGCompressSettings* settings)
+{
+ /*initially, *out must be NULL and outsize 0, if you just give some random *out
+ that's pointing to a non allocated buffer, this'll crash*/
+ ucvector outv;
+ size_t i;
+ unsigned error;
+ unsigned char* deflatedata = 0;
+ size_t deflatesize = 0;
+
+ unsigned ADLER32;
+ /*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/
+ unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/
+ unsigned FLEVEL = 0;
+ unsigned FDICT = 0;
+ unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64;
+ unsigned FCHECK = 31 - CMFFLG % 31;
+ CMFFLG += FCHECK;
+
+ /*ucvector-controlled version of the output buffer, for dynamic array*/
+ ucvector_init_buffer(&outv, *out, *outsize);
+
+ ucvector_push_back(&outv, (unsigned char)(CMFFLG / 256));
+ ucvector_push_back(&outv, (unsigned char)(CMFFLG % 256));
+
+ error = deflate(&deflatedata, &deflatesize, in, insize, settings);
+
+ if(!error)
+ {
+ ADLER32 = adler32(in, (unsigned)insize);
+ for(i = 0; i < deflatesize; i++) ucvector_push_back(&outv, deflatedata[i]);
+ lodepng_free(deflatedata);
+ lodepng_add32bitInt(&outv, ADLER32);
+ }
+
+ *out = outv.data;
+ *outsize = outv.size;
+
+ return error;
+}
+
+/* compress using the default or custom zlib function */
+static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
+ size_t insize, const LodePNGCompressSettings* settings)
+{
+ if(settings->custom_zlib)
+ {
+ return settings->custom_zlib(out, outsize, in, insize, settings);
+ }
+ else
+ {
+ return lodepng_zlib_compress(out, outsize, in, insize, settings);
+ }
+}
+
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+#else /*no LODEPNG_COMPILE_ZLIB*/
+
+#ifdef LODEPNG_COMPILE_DECODER
+static unsigned zlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in,
+ size_t insize, const LodePNGDecompressSettings* settings)
+{
+ if (!settings->custom_zlib) return 87; /*no custom zlib function provided */
+ return settings->custom_zlib(out, outsize, in, insize, settings);
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+static unsigned zlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in,
+ size_t insize, const LodePNGCompressSettings* settings)
+{
+ if (!settings->custom_zlib) return 87; /*no custom zlib function provided */
+ return settings->custom_zlib(out, outsize, in, insize, settings);
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+#endif /*LODEPNG_COMPILE_ZLIB*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_ENCODER
+
+/*this is a good tradeoff between speed and compression ratio*/
+#define DEFAULT_WINDOWSIZE 2048
+
+void lodepng_compress_settings_init(LodePNGCompressSettings* settings)
+{
+ /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/
+ settings->btype = 2;
+ settings->use_lz77 = 1;
+ settings->windowsize = DEFAULT_WINDOWSIZE;
+ settings->minmatch = 3;
+ settings->nicematch = 128;
+ settings->lazymatching = 1;
+
+ settings->custom_zlib = 0;
+ settings->custom_deflate = 0;
+ settings->custom_context = 0;
+}
+
+const LodePNGCompressSettings lodepng_default_compress_settings = {2, 1, DEFAULT_WINDOWSIZE, 3, 128, 1, 0, 0, 0};
+
+
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+void lodepng_decompress_settings_init(LodePNGDecompressSettings* settings)
+{
+ settings->ignore_adler32 = 0;
+
+ settings->custom_zlib = 0;
+ settings->custom_inflate = 0;
+ settings->custom_context = 0;
+}
+
+const LodePNGDecompressSettings lodepng_default_decompress_settings = {0, 0, 0, 0};
+
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // End of Zlib related code. Begin of PNG related code. // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_PNG
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / CRC32 / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/* CRC polynomial: 0xedb88320 */
+static unsigned lodepng_crc32_table[256] = {
+ 0u, 1996959894u, 3993919788u, 2567524794u, 124634137u, 1886057615u, 3915621685u, 2657392035u,
+ 249268274u, 2044508324u, 3772115230u, 2547177864u, 162941995u, 2125561021u, 3887607047u, 2428444049u,
+ 498536548u, 1789927666u, 4089016648u, 2227061214u, 450548861u, 1843258603u, 4107580753u, 2211677639u,
+ 325883990u, 1684777152u, 4251122042u, 2321926636u, 335633487u, 1661365465u, 4195302755u, 2366115317u,
+ 997073096u, 1281953886u, 3579855332u, 2724688242u, 1006888145u, 1258607687u, 3524101629u, 2768942443u,
+ 901097722u, 1119000684u, 3686517206u, 2898065728u, 853044451u, 1172266101u, 3705015759u, 2882616665u,
+ 651767980u, 1373503546u, 3369554304u, 3218104598u, 565507253u, 1454621731u, 3485111705u, 3099436303u,
+ 671266974u, 1594198024u, 3322730930u, 2970347812u, 795835527u, 1483230225u, 3244367275u, 3060149565u,
+ 1994146192u, 31158534u, 2563907772u, 4023717930u, 1907459465u, 112637215u, 2680153253u, 3904427059u,
+ 2013776290u, 251722036u, 2517215374u, 3775830040u, 2137656763u, 141376813u, 2439277719u, 3865271297u,
+ 1802195444u, 476864866u, 2238001368u, 4066508878u, 1812370925u, 453092731u, 2181625025u, 4111451223u,
+ 1706088902u, 314042704u, 2344532202u, 4240017532u, 1658658271u, 366619977u, 2362670323u, 4224994405u,
+ 1303535960u, 984961486u, 2747007092u, 3569037538u, 1256170817u, 1037604311u, 2765210733u, 3554079995u,
+ 1131014506u, 879679996u, 2909243462u, 3663771856u, 1141124467u, 855842277u, 2852801631u, 3708648649u,
+ 1342533948u, 654459306u, 3188396048u, 3373015174u, 1466479909u, 544179635u, 3110523913u, 3462522015u,
+ 1591671054u, 702138776u, 2966460450u, 3352799412u, 1504918807u, 783551873u, 3082640443u, 3233442989u,
+ 3988292384u, 2596254646u, 62317068u, 1957810842u, 3939845945u, 2647816111u, 81470997u, 1943803523u,
+ 3814918930u, 2489596804u, 225274430u, 2053790376u, 3826175755u, 2466906013u, 167816743u, 2097651377u,
+ 4027552580u, 2265490386u, 503444072u, 1762050814u, 4150417245u, 2154129355u, 426522225u, 1852507879u,
+ 4275313526u, 2312317920u, 282753626u, 1742555852u, 4189708143u, 2394877945u, 397917763u, 1622183637u,
+ 3604390888u, 2714866558u, 953729732u, 1340076626u, 3518719985u, 2797360999u, 1068828381u, 1219638859u,
+ 3624741850u, 2936675148u, 906185462u, 1090812512u, 3747672003u, 2825379669u, 829329135u, 1181335161u,
+ 3412177804u, 3160834842u, 628085408u, 1382605366u, 3423369109u, 3138078467u, 570562233u, 1426400815u,
+ 3317316542u, 2998733608u, 733239954u, 1555261956u, 3268935591u, 3050360625u, 752459403u, 1541320221u,
+ 2607071920u, 3965973030u, 1969922972u, 40735498u, 2617837225u, 3943577151u, 1913087877u, 83908371u,
+ 2512341634u, 3803740692u, 2075208622u, 213261112u, 2463272603u, 3855990285u, 2094854071u, 198958881u,
+ 2262029012u, 4057260610u, 1759359992u, 534414190u, 2176718541u, 4139329115u, 1873836001u, 414664567u,
+ 2282248934u, 4279200368u, 1711684554u, 285281116u, 2405801727u, 4167216745u, 1634467795u, 376229701u,
+ 2685067896u, 3608007406u, 1308918612u, 956543938u, 2808555105u, 3495958263u, 1231636301u, 1047427035u,
+ 2932959818u, 3654703836u, 1088359270u, 936918000u, 2847714899u, 3736837829u, 1202900863u, 817233897u,
+ 3183342108u, 3401237130u, 1404277552u, 615818150u, 3134207493u, 3453421203u, 1423857449u, 601450431u,
+ 3009837614u, 3294710456u, 1567103746u, 711928724u, 3020668471u, 3272380065u, 1510334235u, 755167117u
+};
+
+/*Return the CRC of the bytes buf[0..len-1].*/
+unsigned lodepng_crc32(const unsigned char* buf, size_t len)
+{
+ unsigned c = 0xffffffffL;
+ size_t n;
+
+ for(n = 0; n < len; n++)
+ {
+ c = lodepng_crc32_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
+ }
+ return c ^ 0xffffffffL;
+}
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Reading and writing single bits and bytes from/to stream for LodePNG / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream)
+{
+ unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1);
+ (*bitpointer)++;
+ return result;
+}
+
+static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits)
+{
+ unsigned result = 0;
+ size_t i;
+ for(i = nbits - 1; i < nbits; i--)
+ {
+ result += (unsigned)readBitFromReversedStream(bitpointer, bitstream) << i;
+ }
+ return result;
+}
+
+#ifdef LODEPNG_COMPILE_DECODER
+static void setBitOfReversedStream0(size_t* bitpointer, unsigned char* bitstream, unsigned char bit)
+{
+ /*the current bit in bitstream must be 0 for this to work*/
+ if(bit)
+ {
+ /*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/
+ bitstream[(*bitpointer) >> 3] |= (bit << (7 - ((*bitpointer) & 0x7)));
+ }
+ (*bitpointer)++;
+}
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit)
+{
+ /*the current bit in bitstream may be 0 or 1 for this to work*/
+ if(bit == 0) bitstream[(*bitpointer) >> 3] &= (unsigned char)(~(1 << (7 - ((*bitpointer) & 0x7))));
+ else bitstream[(*bitpointer) >> 3] |= (1 << (7 - ((*bitpointer) & 0x7)));
+ (*bitpointer)++;
+}
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / PNG chunks / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+unsigned lodepng_chunk_length(const unsigned char* chunk)
+{
+ return lodepng_read32bitInt(&chunk[0]);
+}
+
+void lodepng_chunk_type(char type[5], const unsigned char* chunk)
+{
+ unsigned i;
+ for(i = 0; i < 4; i++) type[i] = chunk[4 + i];
+ type[4] = 0; /*null termination char*/
+}
+
+unsigned char lodepng_chunk_type_equals(const unsigned char* chunk, const char* type)
+{
+ if(strlen(type) != 4) return 0;
+ return (chunk[4] == type[0] && chunk[5] == type[1] && chunk[6] == type[2] && chunk[7] == type[3]);
+}
+
+unsigned char lodepng_chunk_ancillary(const unsigned char* chunk)
+{
+ return((chunk[4] & 32) != 0);
+}
+
+unsigned char lodepng_chunk_private(const unsigned char* chunk)
+{
+ return((chunk[6] & 32) != 0);
+}
+
+unsigned char lodepng_chunk_safetocopy(const unsigned char* chunk)
+{
+ return((chunk[7] & 32) != 0);
+}
+
+unsigned char* lodepng_chunk_data(unsigned char* chunk)
+{
+ return &chunk[8];
+}
+
+const unsigned char* lodepng_chunk_data_const(const unsigned char* chunk)
+{
+ return &chunk[8];
+}
+
+unsigned lodepng_chunk_check_crc(const unsigned char* chunk)
+{
+ unsigned length = lodepng_chunk_length(chunk);
+ unsigned CRC = lodepng_read32bitInt(&chunk[length + 8]);
+ /*the CRC is taken of the data and the 4 chunk type letters, not the length*/
+ unsigned checksum = lodepng_crc32(&chunk[4], length + 4);
+ if(CRC != checksum) return 1;
+ else return 0;
+}
+
+void lodepng_chunk_generate_crc(unsigned char* chunk)
+{
+ unsigned length = lodepng_chunk_length(chunk);
+ unsigned CRC = lodepng_crc32(&chunk[4], length + 4);
+ lodepng_set32bitInt(chunk + 8 + length, CRC);
+}
+
+unsigned char* lodepng_chunk_next(unsigned char* chunk)
+{
+ unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12;
+ return &chunk[total_chunk_length];
+}
+
+const unsigned char* lodepng_chunk_next_const(const unsigned char* chunk)
+{
+ unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12;
+ return &chunk[total_chunk_length];
+}
+
+unsigned lodepng_chunk_append(unsigned char** out, size_t* outlength, const unsigned char* chunk)
+{
+ unsigned i;
+ unsigned total_chunk_length = lodepng_chunk_length(chunk) + 12;
+ unsigned char *chunk_start, *new_buffer;
+ size_t new_length = (*outlength) + total_chunk_length;
+ if(new_length < total_chunk_length || new_length < (*outlength)) return 77; /*integer overflow happened*/
+
+ new_buffer = (unsigned char*)lodepng_realloc(*out, new_length);
+ if(!new_buffer) return 83; /*alloc fail*/
+ (*out) = new_buffer;
+ (*outlength) = new_length;
+ chunk_start = &(*out)[new_length - total_chunk_length];
+
+ for(i = 0; i < total_chunk_length; i++) chunk_start[i] = chunk[i];
+
+ return 0;
+}
+
+unsigned lodepng_chunk_create(unsigned char** out, size_t* outlength, unsigned length,
+ const char* type, const unsigned char* data)
+{
+ unsigned i;
+ unsigned char *chunk, *new_buffer;
+ size_t new_length = (*outlength) + length + 12;
+ if(new_length < length + 12 || new_length < (*outlength)) return 77; /*integer overflow happened*/
+ new_buffer = (unsigned char*)lodepng_realloc(*out, new_length);
+ if(!new_buffer) return 83; /*alloc fail*/
+ (*out) = new_buffer;
+ (*outlength) = new_length;
+ chunk = &(*out)[(*outlength) - length - 12];
+
+ /*1: length*/
+ lodepng_set32bitInt(chunk, (unsigned)length);
+
+ /*2: chunk name (4 letters)*/
+ chunk[4] = type[0];
+ chunk[5] = type[1];
+ chunk[6] = type[2];
+ chunk[7] = type[3];
+
+ /*3: the data*/
+ for(i = 0; i < length; i++) chunk[8 + i] = data[i];
+
+ /*4: CRC (of the chunkname characters and the data)*/
+ lodepng_chunk_generate_crc(chunk);
+
+ return 0;
+}
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / Color types and such / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*return type is a LodePNG error code*/
+static unsigned checkColorValidity(LodePNGColorType colortype, unsigned bd) /*bd = bitdepth*/
+{
+ switch(colortype)
+ {
+ case 0: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break; /*grey*/
+ case 2: if(!( bd == 8 || bd == 16)) return 37; break; /*RGB*/
+ case 3: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 )) return 37; break; /*palette*/
+ case 4: if(!( bd == 8 || bd == 16)) return 37; break; /*grey + alpha*/
+ case 6: if(!( bd == 8 || bd == 16)) return 37; break; /*RGBA*/
+ default: return 31;
+ }
+ return 0; /*allowed color type / bits combination*/
+}
+
+static unsigned getNumColorChannels(LodePNGColorType colortype)
+{
+ switch(colortype)
+ {
+ case 0: return 1; /*grey*/
+ case 2: return 3; /*RGB*/
+ case 3: return 1; /*palette*/
+ case 4: return 2; /*grey + alpha*/
+ case 6: return 4; /*RGBA*/
+ }
+ return 0; /*unexisting color type*/
+}
+
+static unsigned lodepng_get_bpp_lct(LodePNGColorType colortype, unsigned bitdepth)
+{
+ /*bits per pixel is amount of channels * bits per channel*/
+ return getNumColorChannels(colortype) * bitdepth;
+}
+
+/* ////////////////////////////////////////////////////////////////////////// */
+
+void lodepng_color_mode_init(LodePNGColorMode* info)
+{
+ info->key_defined = 0;
+ info->key_r = info->key_g = info->key_b = 0;
+ info->colortype = LCT_RGBA;
+ info->bitdepth = 8;
+ info->palette = 0;
+ info->palettesize = 0;
+}
+
+void lodepng_color_mode_cleanup(LodePNGColorMode* info)
+{
+ lodepng_palette_clear(info);
+}
+
+unsigned lodepng_color_mode_copy(LodePNGColorMode* dest, const LodePNGColorMode* source)
+{
+ size_t i;
+ lodepng_color_mode_cleanup(dest);
+ *dest = *source;
+ if(source->palette)
+ {
+ dest->palette = (unsigned char*)lodepng_malloc(1024);
+ if(!dest->palette && source->palettesize) return 83; /*alloc fail*/
+ for(i = 0; i < source->palettesize * 4; i++) dest->palette[i] = source->palette[i];
+ }
+ return 0;
+}
+
+static int lodepng_color_mode_equal(const LodePNGColorMode* a, const LodePNGColorMode* b)
+{
+ size_t i;
+ if(a->colortype != b->colortype) return 0;
+ if(a->bitdepth != b->bitdepth) return 0;
+ if(a->key_defined != b->key_defined) return 0;
+ if(a->key_defined)
+ {
+ if(a->key_r != b->key_r) return 0;
+ if(a->key_g != b->key_g) return 0;
+ if(a->key_b != b->key_b) return 0;
+ }
+ if(a->palettesize != b->palettesize) return 0;
+ for(i = 0; i < a->palettesize * 4; i++)
+ {
+ if(a->palette[i] != b->palette[i]) return 0;
+ }
+ return 1;
+}
+
+void lodepng_palette_clear(LodePNGColorMode* info)
+{
+ if(info->palette) lodepng_free(info->palette);
+ info->palette = 0;
+ info->palettesize = 0;
+}
+
+unsigned lodepng_palette_add(LodePNGColorMode* info,
+ unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+ unsigned char* data;
+ /*the same resize technique as C++ std::vectors is used, and here it's made so that for a palette with
+ the max of 256 colors, it'll have the exact alloc size*/
+ if(!info->palette) /*allocate palette if empty*/
+ {
+ /*room for 256 colors with 4 bytes each*/
+ data = (unsigned char*)lodepng_realloc(info->palette, 1024);
+ if(!data) return 83; /*alloc fail*/
+ else info->palette = data;
+ }
+ info->palette[4 * info->palettesize + 0] = r;
+ info->palette[4 * info->palettesize + 1] = g;
+ info->palette[4 * info->palettesize + 2] = b;
+ info->palette[4 * info->palettesize + 3] = a;
+ info->palettesize++;
+ return 0;
+}
+
+unsigned lodepng_get_bpp(const LodePNGColorMode* info)
+{
+ /*calculate bits per pixel out of colortype and bitdepth*/
+ return lodepng_get_bpp_lct(info->colortype, info->bitdepth);
+}
+
+unsigned lodepng_get_channels(const LodePNGColorMode* info)
+{
+ return getNumColorChannels(info->colortype);
+}
+
+unsigned lodepng_is_greyscale_type(const LodePNGColorMode* info)
+{
+ return info->colortype == LCT_GREY || info->colortype == LCT_GREY_ALPHA;
+}
+
+unsigned lodepng_is_alpha_type(const LodePNGColorMode* info)
+{
+ return (info->colortype & 4) != 0; /*4 or 6*/
+}
+
+unsigned lodepng_is_palette_type(const LodePNGColorMode* info)
+{
+ return info->colortype == LCT_PALETTE;
+}
+
+unsigned lodepng_has_palette_alpha(const LodePNGColorMode* info)
+{
+ size_t i;
+ for(i = 0; i < info->palettesize; i++)
+ {
+ if(info->palette[i * 4 + 3] < 255) return 1;
+ }
+ return 0;
+}
+
+unsigned lodepng_can_have_alpha(const LodePNGColorMode* info)
+{
+ return info->key_defined
+ || lodepng_is_alpha_type(info)
+ || lodepng_has_palette_alpha(info);
+}
+
+size_t lodepng_get_raw_size(unsigned w, unsigned h, const LodePNGColorMode* color)
+{
+ return (w * h * lodepng_get_bpp(color) + 7) / 8;
+}
+
+size_t lodepng_get_raw_size_lct(unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth)
+{
+ return (w * h * lodepng_get_bpp_lct(colortype, bitdepth) + 7) / 8;
+}
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+
+static void LodePNGUnknownChunks_init(LodePNGInfo* info)
+{
+ unsigned i;
+ for(i = 0; i < 3; i++) info->unknown_chunks_data[i] = 0;
+ for(i = 0; i < 3; i++) info->unknown_chunks_size[i] = 0;
+}
+
+static void LodePNGUnknownChunks_cleanup(LodePNGInfo* info)
+{
+ unsigned i;
+ for(i = 0; i < 3; i++) lodepng_free(info->unknown_chunks_data[i]);
+}
+
+static unsigned LodePNGUnknownChunks_copy(LodePNGInfo* dest, const LodePNGInfo* src)
+{
+ unsigned i;
+
+ LodePNGUnknownChunks_cleanup(dest);
+
+ for(i = 0; i < 3; i++)
+ {
+ size_t j;
+ dest->unknown_chunks_size[i] = src->unknown_chunks_size[i];
+ dest->unknown_chunks_data[i] = (unsigned char*)lodepng_malloc(src->unknown_chunks_size[i]);
+ if(!dest->unknown_chunks_data[i] && dest->unknown_chunks_size[i]) return 83; /*alloc fail*/
+ for(j = 0; j < src->unknown_chunks_size[i]; j++)
+ {
+ dest->unknown_chunks_data[i][j] = src->unknown_chunks_data[i][j];
+ }
+ }
+
+ return 0;
+}
+
+/******************************************************************************/
+
+static void LodePNGText_init(LodePNGInfo* info)
+{
+ info->text_num = 0;
+ info->text_keys = NULL;
+ info->text_strings = NULL;
+}
+
+static void LodePNGText_cleanup(LodePNGInfo* info)
+{
+ size_t i;
+ for(i = 0; i < info->text_num; i++)
+ {
+ string_cleanup(&info->text_keys[i]);
+ string_cleanup(&info->text_strings[i]);
+ }
+ lodepng_free(info->text_keys);
+ lodepng_free(info->text_strings);
+}
+
+static unsigned LodePNGText_copy(LodePNGInfo* dest, const LodePNGInfo* source)
+{
+ size_t i = 0;
+ dest->text_keys = 0;
+ dest->text_strings = 0;
+ dest->text_num = 0;
+ for(i = 0; i < source->text_num; i++)
+ {
+ CERROR_TRY_RETURN(lodepng_add_text(dest, source->text_keys[i], source->text_strings[i]));
+ }
+ return 0;
+}
+
+void lodepng_clear_text(LodePNGInfo* info)
+{
+ LodePNGText_cleanup(info);
+}
+
+unsigned lodepng_add_text(LodePNGInfo* info, const char* key, const char* str)
+{
+ char** new_keys = (char**)(lodepng_realloc(info->text_keys, sizeof(char*) * (info->text_num + 1)));
+ char** new_strings = (char**)(lodepng_realloc(info->text_strings, sizeof(char*) * (info->text_num + 1)));
+ if(!new_keys || !new_strings)
+ {
+ lodepng_free(new_keys);
+ lodepng_free(new_strings);
+ return 83; /*alloc fail*/
+ }
+
+ info->text_num++;
+ info->text_keys = new_keys;
+ info->text_strings = new_strings;
+
+ string_init(&info->text_keys[info->text_num - 1]);
+ string_set(&info->text_keys[info->text_num - 1], key);
+
+ string_init(&info->text_strings[info->text_num - 1]);
+ string_set(&info->text_strings[info->text_num - 1], str);
+
+ return 0;
+}
+
+/******************************************************************************/
+
+static void LodePNGIText_init(LodePNGInfo* info)
+{
+ info->itext_num = 0;
+ info->itext_keys = NULL;
+ info->itext_langtags = NULL;
+ info->itext_transkeys = NULL;
+ info->itext_strings = NULL;
+}
+
+static void LodePNGIText_cleanup(LodePNGInfo* info)
+{
+ size_t i;
+ for(i = 0; i < info->itext_num; i++)
+ {
+ string_cleanup(&info->itext_keys[i]);
+ string_cleanup(&info->itext_langtags[i]);
+ string_cleanup(&info->itext_transkeys[i]);
+ string_cleanup(&info->itext_strings[i]);
+ }
+ lodepng_free(info->itext_keys);
+ lodepng_free(info->itext_langtags);
+ lodepng_free(info->itext_transkeys);
+ lodepng_free(info->itext_strings);
+}
+
+static unsigned LodePNGIText_copy(LodePNGInfo* dest, const LodePNGInfo* source)
+{
+ size_t i = 0;
+ dest->itext_keys = 0;
+ dest->itext_langtags = 0;
+ dest->itext_transkeys = 0;
+ dest->itext_strings = 0;
+ dest->itext_num = 0;
+ for(i = 0; i < source->itext_num; i++)
+ {
+ CERROR_TRY_RETURN(lodepng_add_itext(dest, source->itext_keys[i], source->itext_langtags[i],
+ source->itext_transkeys[i], source->itext_strings[i]));
+ }
+ return 0;
+}
+
+void lodepng_clear_itext(LodePNGInfo* info)
+{
+ LodePNGIText_cleanup(info);
+}
+
+unsigned lodepng_add_itext(LodePNGInfo* info, const char* key, const char* langtag,
+ const char* transkey, const char* str)
+{
+ char** new_keys = (char**)(lodepng_realloc(info->itext_keys, sizeof(char*) * (info->itext_num + 1)));
+ char** new_langtags = (char**)(lodepng_realloc(info->itext_langtags, sizeof(char*) * (info->itext_num + 1)));
+ char** new_transkeys = (char**)(lodepng_realloc(info->itext_transkeys, sizeof(char*) * (info->itext_num + 1)));
+ char** new_strings = (char**)(lodepng_realloc(info->itext_strings, sizeof(char*) * (info->itext_num + 1)));
+ if(!new_keys || !new_langtags || !new_transkeys || !new_strings)
+ {
+ lodepng_free(new_keys);
+ lodepng_free(new_langtags);
+ lodepng_free(new_transkeys);
+ lodepng_free(new_strings);
+ return 83; /*alloc fail*/
+ }
+
+ info->itext_num++;
+ info->itext_keys = new_keys;
+ info->itext_langtags = new_langtags;
+ info->itext_transkeys = new_transkeys;
+ info->itext_strings = new_strings;
+
+ string_init(&info->itext_keys[info->itext_num - 1]);
+ string_set(&info->itext_keys[info->itext_num - 1], key);
+
+ string_init(&info->itext_langtags[info->itext_num - 1]);
+ string_set(&info->itext_langtags[info->itext_num - 1], langtag);
+
+ string_init(&info->itext_transkeys[info->itext_num - 1]);
+ string_set(&info->itext_transkeys[info->itext_num - 1], transkey);
+
+ string_init(&info->itext_strings[info->itext_num - 1]);
+ string_set(&info->itext_strings[info->itext_num - 1], str);
+
+ return 0;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+void lodepng_info_init(LodePNGInfo* info)
+{
+ lodepng_color_mode_init(&info->color);
+ info->interlace_method = 0;
+ info->compression_method = 0;
+ info->filter_method = 0;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ info->background_defined = 0;
+ info->background_r = info->background_g = info->background_b = 0;
+
+ LodePNGText_init(info);
+ LodePNGIText_init(info);
+
+ info->time_defined = 0;
+ info->phys_defined = 0;
+
+ LodePNGUnknownChunks_init(info);
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+
+void lodepng_info_cleanup(LodePNGInfo* info)
+{
+ lodepng_color_mode_cleanup(&info->color);
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ LodePNGText_cleanup(info);
+ LodePNGIText_cleanup(info);
+
+ LodePNGUnknownChunks_cleanup(info);
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+
+unsigned lodepng_info_copy(LodePNGInfo* dest, const LodePNGInfo* source)
+{
+ lodepng_info_cleanup(dest);
+ *dest = *source;
+ lodepng_color_mode_init(&dest->color);
+ CERROR_TRY_RETURN(lodepng_color_mode_copy(&dest->color, &source->color));
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ CERROR_TRY_RETURN(LodePNGText_copy(dest, source));
+ CERROR_TRY_RETURN(LodePNGIText_copy(dest, source));
+
+ LodePNGUnknownChunks_init(dest);
+ CERROR_TRY_RETURN(LodePNGUnknownChunks_copy(dest, source));
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ return 0;
+}
+
+void lodepng_info_swap(LodePNGInfo* a, LodePNGInfo* b)
+{
+ LodePNGInfo temp = *a;
+ *a = *b;
+ *b = temp;
+}
+
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*index: bitgroup index, bits: bitgroup size(1, 2 or 4), in: bitgroup value, out: octet array to add bits to*/
+static void addColorBits(unsigned char* out, size_t index, unsigned bits, unsigned in)
+{
+ unsigned m = bits == 1 ? 7 : bits == 2 ? 3 : 1; /*8 / bits - 1*/
+ /*p = the partial index in the byte, e.g. with 4 palettebits it is 0 for first half or 1 for second half*/
+ unsigned p = index & m;
+ in &= (1 << bits) - 1; /*filter out any other bits of the input value*/
+ in = in << (bits * (m - p));
+ if(p == 0) out[index * bits / 8] = in;
+ else out[index * bits / 8] |= in;
+}
+
+typedef struct ColorTree ColorTree;
+
+/*
+One node of a color tree
+This is the data structure used to count the number of unique colors and to get a palette
+index for a color. It's like an octree, but because the alpha channel is used too, each
+node has 16 instead of 8 children.
+*/
+struct ColorTree
+{
+ ColorTree* children[16]; /*up to 16 pointers to ColorTree of next level*/
+ int index; /*the payload. Only has a meaningful value if this is in the last level*/
+};
+
+static void color_tree_init(ColorTree* tree)
+{
+ int i;
+ for(i = 0; i < 16; i++) tree->children[i] = 0;
+ tree->index = -1;
+}
+
+static void color_tree_cleanup(ColorTree* tree)
+{
+ int i;
+ for(i = 0; i < 16; i++)
+ {
+ if(tree->children[i])
+ {
+ color_tree_cleanup(tree->children[i]);
+ lodepng_free(tree->children[i]);
+ }
+ }
+}
+
+/*returns -1 if color not present, its index otherwise*/
+static int color_tree_get(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+ int bit = 0;
+ for(bit = 0; bit < 8; bit++)
+ {
+ int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
+ if(!tree->children[i]) return -1;
+ else tree = tree->children[i];
+ }
+ return tree ? tree->index : -1;
+}
+
+#ifdef LODEPNG_COMPILE_ENCODER
+static int color_tree_has(ColorTree* tree, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+ return color_tree_get(tree, r, g, b, a) >= 0;
+}
+#endif /*LODEPNG_COMPILE_ENCODER*/
+
+/*color is not allowed to already exist.
+Index should be >= 0 (it's signed to be compatible with using -1 for "doesn't exist")*/
+static void color_tree_add(ColorTree* tree,
+ unsigned char r, unsigned char g, unsigned char b, unsigned char a, int index)
+{
+ int bit;
+ for(bit = 0; bit < 8; bit++)
+ {
+ int i = 8 * ((r >> bit) & 1) + 4 * ((g >> bit) & 1) + 2 * ((b >> bit) & 1) + 1 * ((a >> bit) & 1);
+ if(!tree->children[i])
+ {
+ tree->children[i] = (ColorTree*)lodepng_malloc(sizeof(ColorTree));
+ color_tree_init(tree->children[i]);
+ }
+ tree = tree->children[i];
+ }
+ tree->index = index;
+}
+
+/*put a pixel, given its RGBA color, into image of any color type*/
+static unsigned rgba8ToPixel(unsigned char* out, size_t i,
+ const LodePNGColorMode* mode, ColorTree* tree /*for palette*/,
+ unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+{
+ if(mode->colortype == LCT_GREY)
+ {
+ unsigned char grey = r; /*((unsigned short)r + g + b) / 3*/;
+ if(mode->bitdepth == 8) out[i] = grey;
+ else if(mode->bitdepth == 16) out[i * 2 + 0] = out[i * 2 + 1] = grey;
+ else
+ {
+ /*take the most significant bits of grey*/
+ grey = (grey >> (8 - mode->bitdepth)) & ((1 << mode->bitdepth) - 1);
+ addColorBits(out, i, mode->bitdepth, grey);
+ }
+ }
+ else if(mode->colortype == LCT_RGB)
+ {
+ if(mode->bitdepth == 8)
+ {
+ out[i * 3 + 0] = r;
+ out[i * 3 + 1] = g;
+ out[i * 3 + 2] = b;
+ }
+ else
+ {
+ out[i * 6 + 0] = out[i * 6 + 1] = r;
+ out[i * 6 + 2] = out[i * 6 + 3] = g;
+ out[i * 6 + 4] = out[i * 6 + 5] = b;
+ }
+ }
+ else if(mode->colortype == LCT_PALETTE)
+ {
+ int index = color_tree_get(tree, r, g, b, a);
+ if(index < 0) return 82; /*color not in palette*/
+ if(mode->bitdepth == 8) out[i] = index;
+ else addColorBits(out, i, mode->bitdepth, index);
+ }
+ else if(mode->colortype == LCT_GREY_ALPHA)
+ {
+ unsigned char grey = r; /*((unsigned short)r + g + b) / 3*/;
+ if(mode->bitdepth == 8)
+ {
+ out[i * 2 + 0] = grey;
+ out[i * 2 + 1] = a;
+ }
+ else if(mode->bitdepth == 16)
+ {
+ out[i * 4 + 0] = out[i * 4 + 1] = grey;
+ out[i * 4 + 2] = out[i * 4 + 3] = a;
+ }
+ }
+ else if(mode->colortype == LCT_RGBA)
+ {
+ if(mode->bitdepth == 8)
+ {
+ out[i * 4 + 0] = r;
+ out[i * 4 + 1] = g;
+ out[i * 4 + 2] = b;
+ out[i * 4 + 3] = a;
+ }
+ else
+ {
+ out[i * 8 + 0] = out[i * 8 + 1] = r;
+ out[i * 8 + 2] = out[i * 8 + 3] = g;
+ out[i * 8 + 4] = out[i * 8 + 5] = b;
+ out[i * 8 + 6] = out[i * 8 + 7] = a;
+ }
+ }
+
+ return 0; /*no error*/
+}
+
+/*put a pixel, given its RGBA16 color, into image of any color 16-bitdepth type*/
+static unsigned rgba16ToPixel(unsigned char* out, size_t i,
+ const LodePNGColorMode* mode,
+ unsigned short r, unsigned short g, unsigned short b, unsigned short a)
+{
+ if(mode->bitdepth != 16) return 85; /*must be 16 for this function*/
+ if(mode->colortype == LCT_GREY)
+ {
+ unsigned short grey = r; /*((unsigned)r + g + b) / 3*/;
+ out[i * 2 + 0] = (grey >> 8) & 255;
+ out[i * 2 + 1] = grey & 255;
+ }
+ else if(mode->colortype == LCT_RGB)
+ {
+ out[i * 6 + 0] = (r >> 8) & 255;
+ out[i * 6 + 1] = r & 255;
+ out[i * 6 + 2] = (g >> 8) & 255;
+ out[i * 6 + 3] = g & 255;
+ out[i * 6 + 4] = (b >> 8) & 255;
+ out[i * 6 + 5] = b & 255;
+ }
+ else if(mode->colortype == LCT_GREY_ALPHA)
+ {
+ unsigned short grey = r; /*((unsigned)r + g + b) / 3*/;
+ out[i * 4 + 0] = (grey >> 8) & 255;
+ out[i * 4 + 1] = grey & 255;
+ out[i * 4 + 2] = (a >> 8) & 255;
+ out[i * 4 + 3] = a & 255;
+ }
+ else if(mode->colortype == LCT_RGBA)
+ {
+ out[i * 8 + 0] = (r >> 8) & 255;
+ out[i * 8 + 1] = r & 255;
+ out[i * 8 + 2] = (g >> 8) & 255;
+ out[i * 8 + 3] = g & 255;
+ out[i * 8 + 4] = (b >> 8) & 255;
+ out[i * 8 + 5] = b & 255;
+ out[i * 8 + 6] = (a >> 8) & 255;
+ out[i * 8 + 7] = a & 255;
+ }
+
+ return 0; /*no error*/
+}
+
+/*Get RGBA8 color of pixel with index i (y * width + x) from the raw image with given color type.*/
+static unsigned getPixelColorRGBA8(unsigned char* r, unsigned char* g,
+ unsigned char* b, unsigned char* a,
+ const unsigned char* in, size_t i,
+ const LodePNGColorMode* mode,
+ unsigned fix_png)
+{
+ if(mode->colortype == LCT_GREY)
+ {
+ if(mode->bitdepth == 8)
+ {
+ *r = *g = *b = in[i];
+ if(mode->key_defined && *r == mode->key_r) *a = 0;
+ else *a = 255;
+ }
+ else if(mode->bitdepth == 16)
+ {
+ *r = *g = *b = in[i * 2 + 0];
+ if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
+ else *a = 255;
+ }
+ else
+ {
+ unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
+ size_t j = i * mode->bitdepth;
+ unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
+ *r = *g = *b = (value * 255) / highest;
+ if(mode->key_defined && value == mode->key_r) *a = 0;
+ else *a = 255;
+ }
+ }
+ else if(mode->colortype == LCT_RGB)
+ {
+ if(mode->bitdepth == 8)
+ {
+ *r = in[i * 3 + 0]; *g = in[i * 3 + 1]; *b = in[i * 3 + 2];
+ if(mode->key_defined && *r == mode->key_r && *g == mode->key_g && *b == mode->key_b) *a = 0;
+ else *a = 255;
+ }
+ else
+ {
+ *r = in[i * 6 + 0];
+ *g = in[i * 6 + 2];
+ *b = in[i * 6 + 4];
+ if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
+ && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
+ && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
+ else *a = 255;
+ }
+ }
+ else if(mode->colortype == LCT_PALETTE)
+ {
+ unsigned index;
+ if(mode->bitdepth == 8) index = in[i];
+ else
+ {
+ size_t j = i * mode->bitdepth;
+ index = readBitsFromReversedStream(&j, in, mode->bitdepth);
+ }
+
+ if(index >= mode->palettesize)
+ {
+ /*This is an error according to the PNG spec, but fix_png can ignore it*/
+ if(!fix_png) return (mode->bitdepth == 8 ? 46 : 47); /*index out of palette*/
+ *r = *g = *b = 0;
+ *a = 255;
+ }
+ else
+ {
+ *r = mode->palette[index * 4 + 0];
+ *g = mode->palette[index * 4 + 1];
+ *b = mode->palette[index * 4 + 2];
+ *a = mode->palette[index * 4 + 3];
+ }
+ }
+ else if(mode->colortype == LCT_GREY_ALPHA)
+ {
+ if(mode->bitdepth == 8)
+ {
+ *r = *g = *b = in[i * 2 + 0];
+ *a = in[i * 2 + 1];
+ }
+ else
+ {
+ *r = *g = *b = in[i * 4 + 0];
+ *a = in[i * 4 + 2];
+ }
+ }
+ else if(mode->colortype == LCT_RGBA)
+ {
+ if(mode->bitdepth == 8)
+ {
+ *r = in[i * 4 + 0];
+ *g = in[i * 4 + 1];
+ *b = in[i * 4 + 2];
+ *a = in[i * 4 + 3];
+ }
+ else
+ {
+ *r = in[i * 8 + 0];
+ *g = in[i * 8 + 2];
+ *b = in[i * 8 + 4];
+ *a = in[i * 8 + 6];
+ }
+ }
+
+ return 0; /*no error*/
+}
+
+/*Similar to getPixelColorRGBA8, but with all the for loops inside of the color
+mode test cases, optimized to convert the colors much faster, when converting
+to RGBA or RGB with 8 bit per cannel. buffer must be RGBA or RGB output with
+enough memory, if has_alpha is true the output is RGBA. mode has the color mode
+of the input buffer.*/
+static unsigned getPixelColorsRGBA8(unsigned char* buffer, size_t numpixels,
+ unsigned has_alpha, const unsigned char* in,
+ const LodePNGColorMode* mode,
+ unsigned fix_png)
+{
+ unsigned num_channels = has_alpha ? 4 : 3;
+ size_t i;
+ if(mode->colortype == LCT_GREY)
+ {
+ if(mode->bitdepth == 8)
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = buffer[1] = buffer[2] = in[i];
+ if(has_alpha) buffer[3] = mode->key_defined && in[i] == mode->key_r ? 0 : 255;
+ }
+ }
+ else if(mode->bitdepth == 16)
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = buffer[1] = buffer[2] = in[i * 2];
+ if(has_alpha) buffer[3] = mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r ? 0 : 255;
+ }
+ }
+ else
+ {
+ unsigned highest = ((1U << mode->bitdepth) - 1U); /*highest possible value for this bit depth*/
+ size_t j = 0;
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ unsigned value = readBitsFromReversedStream(&j, in, mode->bitdepth);
+ buffer[0] = buffer[1] = buffer[2] = (value * 255) / highest;
+ if(has_alpha) buffer[3] = mode->key_defined && value == mode->key_r ? 0 : 255;
+ }
+ }
+ }
+ else if(mode->colortype == LCT_RGB)
+ {
+ if(mode->bitdepth == 8)
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = in[i * 3 + 0];
+ buffer[1] = in[i * 3 + 1];
+ buffer[2] = in[i * 3 + 2];
+ if(has_alpha) buffer[3] = mode->key_defined && buffer[0] == mode->key_r
+ && buffer[1]== mode->key_g && buffer[2] == mode->key_b ? 0 : 255;
+ }
+ }
+ else
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = in[i * 6 + 0];
+ buffer[1] = in[i * 6 + 2];
+ buffer[2] = in[i * 6 + 4];
+ if(has_alpha) buffer[3] = mode->key_defined
+ && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
+ && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
+ && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b ? 0 : 255;
+ }
+ }
+ }
+ else if(mode->colortype == LCT_PALETTE)
+ {
+ unsigned index;
+ size_t j = 0;
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ if(mode->bitdepth == 8) index = in[i];
+ else index = readBitsFromReversedStream(&j, in, mode->bitdepth);
+
+ if(index >= mode->palettesize)
+ {
+ /*This is an error according to the PNG spec, but fix_png can ignore it*/
+ if(!fix_png) return (mode->bitdepth == 8 ? 46 : 47); /*index out of palette*/
+ buffer[0] = buffer[1] = buffer[2] = 0;
+ if(has_alpha) buffer[3] = 255;
+ }
+ else
+ {
+ buffer[0] = mode->palette[index * 4 + 0];
+ buffer[1] = mode->palette[index * 4 + 1];
+ buffer[2] = mode->palette[index * 4 + 2];
+ if(has_alpha) buffer[3] = mode->palette[index * 4 + 3];
+ }
+ }
+ }
+ else if(mode->colortype == LCT_GREY_ALPHA)
+ {
+ if(mode->bitdepth == 8)
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = buffer[1] = buffer[2] = in[i * 2 + 0];
+ if(has_alpha) buffer[3] = in[i * 2 + 1];
+ }
+ }
+ else
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = buffer[1] = buffer[2] = in[i * 4 + 0];
+ if(has_alpha) buffer[3] = in[i * 4 + 2];
+ }
+ }
+ }
+ else if(mode->colortype == LCT_RGBA)
+ {
+ if(mode->bitdepth == 8)
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = in[i * 4 + 0];
+ buffer[1] = in[i * 4 + 1];
+ buffer[2] = in[i * 4 + 2];
+ if(has_alpha) buffer[3] = in[i * 4 + 3];
+ }
+ }
+ else
+ {
+ for(i = 0; i < numpixels; i++, buffer += num_channels)
+ {
+ buffer[0] = in[i * 8 + 0];
+ buffer[1] = in[i * 8 + 2];
+ buffer[2] = in[i * 8 + 4];
+ if(has_alpha) buffer[3] = in[i * 8 + 6];
+ }
+ }
+ }
+
+ return 0; /*no error*/
+}
+
+/*Get RGBA16 color of pixel with index i (y * width + x) from the raw image with
+given color type, but the given color type must be 16-bit itself.*/
+static unsigned getPixelColorRGBA16(unsigned short* r, unsigned short* g, unsigned short* b, unsigned short* a,
+ const unsigned char* in, size_t i, const LodePNGColorMode* mode)
+{
+ if(mode->bitdepth != 16) return 85; /*error: this function only supports 16-bit input*/
+
+ if(mode->colortype == LCT_GREY)
+ {
+ *r = *g = *b = 256 * in[i * 2 + 0] + in[i * 2 + 1];
+ if(mode->key_defined && 256U * in[i * 2 + 0] + in[i * 2 + 1] == mode->key_r) *a = 0;
+ else *a = 65535;
+ }
+ else if(mode->colortype == LCT_RGB)
+ {
+ *r = 256 * in[i * 6 + 0] + in[i * 6 + 1];
+ *g = 256 * in[i * 6 + 2] + in[i * 6 + 3];
+ *b = 256 * in[i * 6 + 4] + in[i * 6 + 5];
+ if(mode->key_defined && 256U * in[i * 6 + 0] + in[i * 6 + 1] == mode->key_r
+ && 256U * in[i * 6 + 2] + in[i * 6 + 3] == mode->key_g
+ && 256U * in[i * 6 + 4] + in[i * 6 + 5] == mode->key_b) *a = 0;
+ else *a = 65535;
+ }
+ else if(mode->colortype == LCT_GREY_ALPHA)
+ {
+ *r = *g = *b = 256 * in[i * 4 + 0] + in[i * 4 + 1];
+ *a = 256 * in[i * 4 + 2] + in[i * 4 + 3];
+ }
+ else if(mode->colortype == LCT_RGBA)
+ {
+ *r = 256 * in[i * 8 + 0] + in[i * 8 + 1];
+ *g = 256 * in[i * 8 + 2] + in[i * 8 + 3];
+ *b = 256 * in[i * 8 + 4] + in[i * 8 + 5];
+ *a = 256 * in[i * 8 + 6] + in[i * 8 + 7];
+ }
+ else return 85; /*error: this function only supports 16-bit input, not palettes*/
+
+ return 0; /*no error*/
+}
+
+/*
+converts from any color type to 24-bit or 32-bit (later maybe more supported). return value = LodePNG error code
+the out buffer must have (w * h * bpp + 7) / 8 bytes, where bpp is the bits per pixel of the output color type
+(lodepng_get_bpp) for < 8 bpp images, there may _not_ be padding bits at the end of scanlines.
+*/
+unsigned lodepng_convert(unsigned char* out, const unsigned char* in,
+ LodePNGColorMode* mode_out, const LodePNGColorMode* mode_in,
+ unsigned w, unsigned h, unsigned fix_png)
+{
+ unsigned error = 0;
+ size_t i;
+ ColorTree tree;
+ size_t numpixels = w * h;
+
+ if(lodepng_color_mode_equal(mode_out, mode_in))
+ {
+ size_t numbytes = lodepng_get_raw_size(w, h, mode_in);
+ for(i = 0; i < numbytes; i++) out[i] = in[i];
+ return error;
+ }
+
+ if(mode_out->colortype == LCT_PALETTE)
+ {
+ size_t palsize = 1 << mode_out->bitdepth;
+ if(mode_out->palettesize < palsize) palsize = mode_out->palettesize;
+ color_tree_init(&tree);
+ for(i = 0; i < palsize; i++)
+ {
+ unsigned char* p = &mode_out->palette[i * 4];
+ color_tree_add(&tree, p[0], p[1], p[2], p[3], i);
+ }
+ }
+
+ if(mode_in->bitdepth == 16 && mode_out->bitdepth == 16)
+ {
+ for(i = 0; i < numpixels; i++)
+ {
+ unsigned short r = 0, g = 0, b = 0, a = 0;
+ error = getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode_in);
+ if(error) break;
+ error = rgba16ToPixel(out, i, mode_out, r, g, b, a);
+ if(error) break;
+ }
+ }
+ else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGBA)
+ {
+ error = getPixelColorsRGBA8(out, numpixels, 1, in, mode_in, fix_png);
+ }
+ else if(mode_out->bitdepth == 8 && mode_out->colortype == LCT_RGB)
+ {
+ error = getPixelColorsRGBA8(out, numpixels, 0, in, mode_in, fix_png);
+ }
+ else
+ {
+ unsigned char r = 0, g = 0, b = 0, a = 0;
+ for(i = 0; i < numpixels; i++)
+ {
+ error = getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode_in, fix_png);
+ if(error) break;
+ error = rgba8ToPixel(out, i, mode_out, &tree, r, g, b, a);
+ if(error) break;
+ }
+ }
+
+ if(mode_out->colortype == LCT_PALETTE)
+ {
+ color_tree_cleanup(&tree);
+ }
+
+ return error;
+}
+
+#ifdef LODEPNG_COMPILE_ENCODER
+
+typedef struct ColorProfile
+{
+ unsigned char sixteenbit; /*needs more than 8 bits per channel*/
+ unsigned char sixteenbit_done;
+
+
+ unsigned char colored; /*not greyscale*/
+ unsigned char colored_done;
+
+ unsigned char key; /*a color key is required, or more*/
+ unsigned short key_r; /*these values are always in 16-bit bitdepth in the profile*/
+ unsigned short key_g;
+ unsigned short key_b;
+ unsigned char alpha; /*alpha channel, or alpha palette, required*/
+ unsigned char alpha_done;
+
+ unsigned numcolors;
+ ColorTree tree; /*for listing the counted colors, up to 256*/
+ unsigned char* palette; /*size 1024. Remember up to the first 256 RGBA colors*/
+ unsigned maxnumcolors; /*if more than that amount counted*/
+ unsigned char numcolors_done;
+
+ unsigned greybits; /*amount of bits required for greyscale (1, 2, 4, 8). Does not take 16 bit into account.*/
+ unsigned char greybits_done;
+
+} ColorProfile;
+
+static void color_profile_init(ColorProfile* profile, const LodePNGColorMode* mode)
+{
+ profile->sixteenbit = 0;
+ profile->sixteenbit_done = mode->bitdepth == 16 ? 0 : 1;
+
+ profile->colored = 0;
+ profile->colored_done = lodepng_is_greyscale_type(mode) ? 1 : 0;
+
+ profile->key = 0;
+ profile->alpha = 0;
+ profile->alpha_done = lodepng_can_have_alpha(mode) ? 0 : 1;
+
+ profile->numcolors = 0;
+ color_tree_init(&profile->tree);
+ profile->palette = (unsigned char*)lodepng_malloc(1024);
+ profile->maxnumcolors = 257;
+ if(lodepng_get_bpp(mode) <= 8)
+ {
+ int bpp = lodepng_get_bpp(mode);
+ profile->maxnumcolors = bpp == 1 ? 2 : (bpp == 2 ? 4 : (bpp == 4 ? 16 : 256));
+ }
+ profile->numcolors_done = 0;
+
+ profile->greybits = 1;
+ profile->greybits_done = lodepng_get_bpp(mode) == 1 ? 1 : 0;
+}
+
+static void color_profile_cleanup(ColorProfile* profile)
+{
+ color_tree_cleanup(&profile->tree);
+ lodepng_free(profile->palette);
+}
+
+/*function used for debug purposes with C++*/
+/*void printColorProfile(ColorProfile* p)
+{
+ std::cout << "sixteenbit: " << (int)p->sixteenbit << std::endl;
+ std::cout << "sixteenbit_done: " << (int)p->sixteenbit_done << std::endl;
+ std::cout << "colored: " << (int)p->colored << std::endl;
+ std::cout << "colored_done: " << (int)p->colored_done << std::endl;
+ std::cout << "key: " << (int)p->key << std::endl;
+ std::cout << "key_r: " << (int)p->key_r << std::endl;
+ std::cout << "key_g: " << (int)p->key_g << std::endl;
+ std::cout << "key_b: " << (int)p->key_b << std::endl;
+ std::cout << "alpha: " << (int)p->alpha << std::endl;
+ std::cout << "alpha_done: " << (int)p->alpha_done << std::endl;
+ std::cout << "numcolors: " << (int)p->numcolors << std::endl;
+ std::cout << "maxnumcolors: " << (int)p->maxnumcolors << std::endl;
+ std::cout << "numcolors_done: " << (int)p->numcolors_done << std::endl;
+ std::cout << "greybits: " << (int)p->greybits << std::endl;
+ std::cout << "greybits_done: " << (int)p->greybits_done << std::endl;
+}*/
+
+/*Returns how many bits needed to represent given value (max 8 bit)*/
+unsigned getValueRequiredBits(unsigned short value)
+{
+ if(value == 0 || value == 255) return 1;
+ /*The scaling of 2-bit and 4-bit values uses multiples of 85 and 17*/
+ if(value % 17 == 0) return value % 85 == 0 ? 2 : 4;
+ return 8;
+}
+
+/*profile must already have been inited with mode.
+It's ok to set some parameters of profile to done already.*/
+static unsigned get_color_profile(ColorProfile* profile,
+ const unsigned char* in,
+ size_t numpixels /*must be full image size, for certain filesize based choices*/,
+ const LodePNGColorMode* mode,
+ unsigned fix_png)
+{
+ unsigned error = 0;
+ size_t i;
+
+ if(mode->bitdepth == 16)
+ {
+ for(i = 0; i < numpixels; i++)
+ {
+ unsigned short r, g, b, a;
+ error = getPixelColorRGBA16(&r, &g, &b, &a, in, i, mode);
+ if(error) break;
+
+ /*a color is considered good for 8-bit if the first byte and the second byte are equal,
+ (so if it's divisible through 257), NOT necessarily if the second byte is 0*/
+ if(!profile->sixteenbit_done
+ && (((r & 255) != ((r >> 8) & 255))
+ || ((g & 255) != ((g >> 8) & 255))
+ || ((b & 255) != ((b >> 8) & 255))))
+ {
+ profile->sixteenbit = 1;
+ profile->sixteenbit_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore at 16-bit*/
+ profile->numcolors_done = 1; /*counting colors no longer useful, palette doesn't support 16-bit*/
+ }
+
+ if(!profile->colored_done && (r != g || r != b))
+ {
+ profile->colored = 1;
+ profile->colored_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore*/
+ }
+
+ if(!profile->alpha_done && a != 65535)
+ {
+ /*only use color key if numpixels large enough to justify tRNS chunk size*/
+ if(a == 0 && numpixels > 16 && !(profile->key && (r != profile->key_r || g != profile->key_g || b != profile->key_b)))
+ {
+ if(!profile->alpha && !profile->key)
+ {
+ profile->key = 1;
+ profile->key_r = r;
+ profile->key_g = g;
+ profile->key_b = b;
+ }
+ }
+ else
+ {
+ profile->alpha = 1;
+ profile->alpha_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore*/
+ }
+ }
+
+ /* Color key cannot be used if an opaque pixel also has that RGB color. */
+ if(!profile->alpha_done && a == 65535 && profile->key
+ && r == profile->key_r && g == profile->key_g && b == profile->key_b)
+ {
+ profile->alpha = 1;
+ profile->alpha_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore*/
+ }
+
+ if(!profile->greybits_done)
+ {
+ /*assuming 8-bit r, this test does not care about 16-bit*/
+ unsigned bits = getValueRequiredBits(r);
+ if(bits > profile->greybits) profile->greybits = bits;
+ if(profile->greybits >= 8) profile->greybits_done = 1;
+ }
+
+ if(!profile->numcolors_done)
+ {
+ /*assuming 8-bit rgba, this test does not care about 16-bit*/
+ if(!color_tree_has(&profile->tree, (unsigned char)r, (unsigned char)g, (unsigned char)b, (unsigned char)a))
+ {
+ color_tree_add(&profile->tree, (unsigned char)r, (unsigned char)g, (unsigned char)b, (unsigned char)a,
+ profile->numcolors);
+ if(profile->numcolors < 256)
+ {
+ unsigned char* p = profile->palette;
+ unsigned i = profile->numcolors;
+ p[i * 4 + 0] = (unsigned char)r;
+ p[i * 4 + 1] = (unsigned char)g;
+ p[i * 4 + 2] = (unsigned char)b;
+ p[i * 4 + 3] = (unsigned char)a;
+ }
+ profile->numcolors++;
+ if(profile->numcolors >= profile->maxnumcolors) profile->numcolors_done = 1;
+ }
+ }
+
+ if(profile->alpha_done && profile->numcolors_done
+ && profile->colored_done && profile->sixteenbit_done && profile->greybits_done)
+ {
+ break;
+ }
+ };
+ }
+ else /* < 16-bit */
+ {
+ for(i = 0; i < numpixels; i++)
+ {
+ unsigned char r = 0, g = 0, b = 0, a = 0;
+ error = getPixelColorRGBA8(&r, &g, &b, &a, in, i, mode, fix_png);
+ if(error) break;
+
+ if(!profile->colored_done && (r != g || r != b))
+ {
+ profile->colored = 1;
+ profile->colored_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore*/
+ }
+
+ if(!profile->alpha_done && a != 255)
+ {
+ if(a == 0 && !(profile->key && (r != profile->key_r || g != profile->key_g || b != profile->key_b)))
+ {
+ if(!profile->key)
+ {
+ profile->key = 1;
+ profile->key_r = r;
+ profile->key_g = g;
+ profile->key_b = b;
+ }
+ }
+ else
+ {
+ profile->alpha = 1;
+ profile->alpha_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore*/
+ }
+ }
+
+ /* Color key cannot be used if an opaque pixel also has that RGB color. */
+ if(!profile->alpha_done && a == 255 && profile->key
+ && r == profile->key_r && g == profile->key_g && b == profile->key_b)
+ {
+ profile->alpha = 1;
+ profile->alpha_done = 1;
+ profile->greybits_done = 1; /*greybits is not applicable anymore*/
+ }
+
+ if(!profile->greybits_done)
+ {
+ unsigned bits = getValueRequiredBits(r);
+ if(bits > profile->greybits) profile->greybits = bits;
+ if(profile->greybits >= 8) profile->greybits_done = 1;
+ }
+
+ if(!profile->numcolors_done)
+ {
+ if(!color_tree_has(&profile->tree, r, g, b, a))
+ {
+
+ color_tree_add(&profile->tree, r, g, b, a, profile->numcolors);
+ if(profile->numcolors < 256)
+ {
+ unsigned char* p = profile->palette;
+ unsigned i = profile->numcolors;
+ p[i * 4 + 0] = r;
+ p[i * 4 + 1] = g;
+ p[i * 4 + 2] = b;
+ p[i * 4 + 3] = a;
+ }
+ profile->numcolors++;
+ if(profile->numcolors >= profile->maxnumcolors) profile->numcolors_done = 1;
+ }
+ }
+
+ if(profile->alpha_done && profile->numcolors_done && profile->colored_done && profile->greybits_done)
+ {
+ break;
+ }
+ };
+ }
+
+ /*make the profile's key always 16-bit for consistency*/
+ if(mode->bitdepth < 16)
+ {
+ /*repeat each byte twice*/
+ profile->key_r *= 257;
+ profile->key_g *= 257;
+ profile->key_b *= 257;
+ }
+
+ return error;
+}
+
+static void setColorKeyFrom16bit(LodePNGColorMode* mode_out, unsigned r, unsigned g, unsigned b, unsigned bitdepth)
+{
+ unsigned mask = (1 << bitdepth) - 1;
+ mode_out->key_defined = 1;
+ mode_out->key_r = r & mask;
+ mode_out->key_g = g & mask;
+ mode_out->key_b = b & mask;
+}
+
+/*updates values of mode with a potentially smaller color model. mode_out should
+contain the user chosen color model, but will be overwritten with the new chosen one.*/
+unsigned lodepng_auto_choose_color(LodePNGColorMode* mode_out,
+ const unsigned char* image, unsigned w, unsigned h,
+ const LodePNGColorMode* mode_in,
+ LodePNGAutoConvert auto_convert)
+{
+ ColorProfile profile;
+ unsigned error = 0;
+ int no_nibbles = auto_convert == LAC_AUTO_NO_NIBBLES || auto_convert == LAC_AUTO_NO_NIBBLES_NO_PALETTE;
+ int no_palette = auto_convert == LAC_AUTO_NO_PALETTE || auto_convert == LAC_AUTO_NO_NIBBLES_NO_PALETTE;
+
+ if(auto_convert == LAC_ALPHA)
+ {
+ if(mode_out->colortype != LCT_RGBA && mode_out->colortype != LCT_GREY_ALPHA) return 0;
+ }
+
+ color_profile_init(&profile, mode_in);
+ if(auto_convert == LAC_ALPHA)
+ {
+ profile.colored_done = 1;
+ profile.greybits_done = 1;
+ profile.numcolors_done = 1;
+ profile.sixteenbit_done = 1;
+ }
+ error = get_color_profile(&profile, image, w * h, mode_in, 0 /*fix_png*/);
+ if(!error && auto_convert == LAC_ALPHA)
+ {
+ if(!profile.alpha)
+ {
+ mode_out->colortype = (mode_out->colortype == LCT_RGBA ? LCT_RGB : LCT_GREY);
+ if(profile.key) setColorKeyFrom16bit(mode_out, profile.key_r, profile.key_g, profile.key_b, mode_out->bitdepth);
+ }
+ }
+ else if(!error && auto_convert != LAC_ALPHA)
+ {
+ mode_out->key_defined = 0;
+
+ if(profile.sixteenbit)
+ {
+ mode_out->bitdepth = 16;
+ if(profile.alpha)
+ {
+ mode_out->colortype = profile.colored ? LCT_RGBA : LCT_GREY_ALPHA;
+ }
+ else
+ {
+ mode_out->colortype = profile.colored ? LCT_RGB : LCT_GREY;
+ if(profile.key) setColorKeyFrom16bit(mode_out, profile.key_r, profile.key_g, profile.key_b, mode_out->bitdepth);
+ }
+ }
+ else /*less than 16 bits per channel*/
+ {
+ /*don't add palette overhead if image hasn't got a lot of pixels*/
+ unsigned n = profile.numcolors;
+ int palette_ok = !no_palette && n <= 256 && (n * 2 < w * h);
+ unsigned palettebits = n <= 2 ? 1 : (n <= 4 ? 2 : (n <= 16 ? 4 : 8));
+ int grey_ok = !profile.colored && !profile.alpha; /*grey without alpha, with potentially low bits*/
+ if(palette_ok || grey_ok)
+ {
+ if(!palette_ok || (grey_ok && profile.greybits <= palettebits))
+ {
+ unsigned grey = profile.key_r;
+ mode_out->colortype = LCT_GREY;
+ mode_out->bitdepth = profile.greybits;
+ if(profile.key) setColorKeyFrom16bit(mode_out, grey, grey, grey, mode_out->bitdepth);
+ }
+ else
+ {
+ /*fill in the palette*/
+ unsigned i;
+ unsigned char* p = profile.palette;
+ /*remove potential earlier palette*/
+ lodepng_palette_clear(mode_out);
+ for(i = 0; i < profile.numcolors; i++)
+ {
+ error = lodepng_palette_add(mode_out, p[i * 4 + 0], p[i * 4 + 1], p[i * 4 + 2], p[i * 4 + 3]);
+ if(error) break;
+ }
+
+ mode_out->colortype = LCT_PALETTE;
+ mode_out->bitdepth = palettebits;
+ }
+ }
+ else /*8-bit per channel*/
+ {
+ mode_out->bitdepth = 8;
+ if(profile.alpha)
+ {
+ mode_out->colortype = profile.colored ? LCT_RGBA : LCT_GREY_ALPHA;
+ }
+ else
+ {
+ mode_out->colortype = profile.colored ? LCT_RGB : LCT_GREY /*LCT_GREY normally won't occur, already done earlier*/;
+ if(profile.key) setColorKeyFrom16bit(mode_out, profile.key_r, profile.key_g, profile.key_b, mode_out->bitdepth);
+ }
+ }
+ }
+ }
+
+ color_profile_cleanup(&profile);
+
+ if(mode_out->colortype == LCT_PALETTE && mode_in->palettesize == mode_out->palettesize)
+ {
+ /*In this case keep the palette order of the input, so that the user can choose an optimal one*/
+ size_t i;
+ for(i = 0; i < mode_in->palettesize * 4; i++)
+ {
+ mode_out->palette[i] = mode_in->palette[i];
+ }
+ }
+
+ if(no_nibbles && mode_out->bitdepth < 8)
+ {
+ /*palette can keep its small amount of colors, as long as no indices use it*/
+ mode_out->bitdepth = 8;
+ }
+
+ return error;
+}
+
+#endif /* #ifdef LODEPNG_COMPILE_ENCODER */
+
+/*
+Paeth predicter, used by PNG filter type 4
+The parameters are of type short, but should come from unsigned chars, the shorts
+are only needed to make the paeth calculation correct.
+*/
+static unsigned char paethPredictor(short a, short b, short c)
+{
+ short pa = abs(b - c);
+ short pb = abs(a - c);
+ short pc = abs(a + b - c - c);
+
+ if(pc < pa && pc < pb) return (unsigned char)c;
+ else if(pb < pa) return (unsigned char)b;
+ else return (unsigned char)a;
+}
+
+/*shared values used by multiple Adam7 related functions*/
+
+static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/
+static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/
+static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/
+static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/
+
+/*
+Outputs various dimensions and positions in the image related to the Adam7 reduced images.
+passw: output containing the width of the 7 passes
+passh: output containing the height of the 7 passes
+filter_passstart: output containing the index of the start and end of each
+ reduced image with filter bytes
+padded_passstart output containing the index of the start and end of each
+ reduced image when without filter bytes but with padded scanlines
+passstart: output containing the index of the start and end of each reduced
+ image without padding between scanlines, but still padding between the images
+w, h: width and height of non-interlaced image
+bpp: bits per pixel
+"padded" is only relevant if bpp is less than 8 and a scanline or image does not
+ end at a full byte
+*/
+static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8],
+ size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp)
+{
+ /*the passstart values have 8 values: the 8th one indicates the byte after the end of the 7th (= last) pass*/
+ unsigned i;
+
+ /*calculate width and height in pixels of each pass*/
+ for(i = 0; i < 7; i++)
+ {
+ passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i];
+ passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i];
+ if(passw[i] == 0) passh[i] = 0;
+ if(passh[i] == 0) passw[i] = 0;
+ }
+
+ filter_passstart[0] = padded_passstart[0] = passstart[0] = 0;
+ for(i = 0; i < 7; i++)
+ {
+ /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/
+ filter_passstart[i + 1] = filter_passstart[i]
+ + ((passw[i] && passh[i]) ? passh[i] * (1 + (passw[i] * bpp + 7) / 8) : 0);
+ /*bits padded if needed to fill full byte at end of each scanline*/
+ padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7) / 8);
+ /*only padded at end of reduced image*/
+ passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7) / 8;
+ }
+}
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / PNG Decoder / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*read the information from the header and store it in the LodePNGInfo. return value is error*/
+unsigned lodepng_inspect(unsigned* w, unsigned* h, LodePNGState* state,
+ const unsigned char* in, size_t insize)
+{
+ LodePNGInfo* info = &state->info_png;
+ if(insize == 0 || in == 0)
+ {
+ CERROR_RETURN_ERROR(state->error, 48); /*error: the given data is empty*/
+ }
+ if(insize < 29)
+ {
+ CERROR_RETURN_ERROR(state->error, 27); /*error: the data length is smaller than the length of a PNG header*/
+ }
+
+ /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/
+ lodepng_info_cleanup(info);
+ lodepng_info_init(info);
+
+ if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71
+ || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10)
+ {
+ CERROR_RETURN_ERROR(state->error, 28); /*error: the first 8 bytes are not the correct PNG signature*/
+ }
+ if(in[12] != 'I' || in[13] != 'H' || in[14] != 'D' || in[15] != 'R')
+ {
+ CERROR_RETURN_ERROR(state->error, 29); /*error: it doesn't start with a IHDR chunk!*/
+ }
+
+ /*read the values given in the header*/
+ *w = lodepng_read32bitInt(&in[16]);
+ *h = lodepng_read32bitInt(&in[20]);
+ info->color.bitdepth = in[24];
+ info->color.colortype = (LodePNGColorType)in[25];
+ info->compression_method = in[26];
+ info->filter_method = in[27];
+ info->interlace_method = in[28];
+
+ if(!state->decoder.ignore_crc)
+ {
+ unsigned CRC = lodepng_read32bitInt(&in[29]);
+ unsigned checksum = lodepng_crc32(&in[12], 17);
+ if(CRC != checksum)
+ {
+ CERROR_RETURN_ERROR(state->error, 57); /*invalid CRC*/
+ }
+ }
+
+ /*error: only compression method 0 is allowed in the specification*/
+ if(info->compression_method != 0) CERROR_RETURN_ERROR(state->error, 32);
+ /*error: only filter method 0 is allowed in the specification*/
+ if(info->filter_method != 0) CERROR_RETURN_ERROR(state->error, 33);
+ /*error: only interlace methods 0 and 1 exist in the specification*/
+ if(info->interlace_method > 1) CERROR_RETURN_ERROR(state->error, 34);
+
+ state->error = checkColorValidity(info->color.colortype, info->color.bitdepth);
+ return state->error;
+}
+
+static unsigned unfilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon,
+ size_t bytewidth, unsigned char filterType, size_t length)
+{
+ /*
+ For PNG filter method 0
+ unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte,
+ the filter works byte per byte (bytewidth = 1)
+ precon is the previous unfiltered scanline, recon the result, scanline the current one
+ the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead
+ recon and scanline MAY be the same memory address! precon must be disjoint.
+ */
+
+ size_t i;
+ switch(filterType)
+ {
+ case 0:
+ for(i = 0; i < length; i++) recon[i] = scanline[i];
+ break;
+ case 1:
+ for(i = 0; i < bytewidth; i++) recon[i] = scanline[i];
+ for(i = bytewidth; i < length; i++) recon[i] = scanline[i] + recon[i - bytewidth];
+ break;
+ case 2:
+ if(precon)
+ {
+ for(i = 0; i < length; i++) recon[i] = scanline[i] + precon[i];
+ }
+ else
+ {
+ for(i = 0; i < length; i++) recon[i] = scanline[i];
+ }
+ break;
+ case 3:
+ if(precon)
+ {
+ for(i = 0; i < bytewidth; i++) recon[i] = scanline[i] + precon[i] / 2;
+ for(i = bytewidth; i < length; i++) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) / 2);
+ }
+ else
+ {
+ for(i = 0; i < bytewidth; i++) recon[i] = scanline[i];
+ for(i = bytewidth; i < length; i++) recon[i] = scanline[i] + recon[i - bytewidth] / 2;
+ }
+ break;
+ case 4:
+ if(precon)
+ {
+ for(i = 0; i < bytewidth; i++)
+ {
+ recon[i] = (scanline[i] + precon[i]); /*paethPredictor(0, precon[i], 0) is always precon[i]*/
+ }
+ for(i = bytewidth; i < length; i++)
+ {
+ recon[i] = (scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth]));
+ }
+ }
+ else
+ {
+ for(i = 0; i < bytewidth; i++)
+ {
+ recon[i] = scanline[i];
+ }
+ for(i = bytewidth; i < length; i++)
+ {
+ /*paethPredictor(recon[i - bytewidth], 0, 0) is always recon[i - bytewidth]*/
+ recon[i] = (scanline[i] + recon[i - bytewidth]);
+ }
+ }
+ break;
+ default: return 36; /*error: unexisting filter type given*/
+ }
+ return 0;
+}
+
+static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp)
+{
+ /*
+ For PNG filter method 0
+ this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 seven times)
+ out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline
+ w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
+ in and out are allowed to be the same memory address (but aren't the same size since in has the extra filter bytes)
+ */
+
+ unsigned y;
+ unsigned char* prevline = 0;
+
+ /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
+ size_t bytewidth = (bpp + 7) / 8;
+ size_t linebytes = (w * bpp + 7) / 8;
+
+ for(y = 0; y < h; y++)
+ {
+ size_t outindex = linebytes * y;
+ size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
+ unsigned char filterType = in[inindex];
+
+ CERROR_TRY_RETURN(unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes));
+
+ prevline = &out[outindex];
+ }
+
+ return 0;
+}
+
+/*
+in: Adam7 interlaced image, with no padding bits between scanlines, but between
+ reduced images so that each reduced image starts at a byte.
+out: the same pixels, but re-ordered so that they're now a non-interlaced image with size w*h
+bpp: bits per pixel
+out has the following size in bits: w * h * bpp.
+in is possibly bigger due to padding bits between reduced images.
+out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation
+(because that's likely a little bit faster)
+NOTE: comments about padding bits are only relevant if bpp < 8
+*/
+static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp)
+{
+ unsigned passw[7], passh[7];
+ size_t filter_passstart[8], padded_passstart[8], passstart[8];
+ unsigned i;
+
+ Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+
+ if(bpp >= 8)
+ {
+ for(i = 0; i < 7; i++)
+ {
+ unsigned x, y, b;
+ size_t bytewidth = bpp / 8;
+ for(y = 0; y < passh[i]; y++)
+ for(x = 0; x < passw[i]; x++)
+ {
+ size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth;
+ size_t pixeloutstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
+ for(b = 0; b < bytewidth; b++)
+ {
+ out[pixeloutstart + b] = in[pixelinstart + b];
+ }
+ }
+ }
+ }
+ else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/
+ {
+ for(i = 0; i < 7; i++)
+ {
+ unsigned x, y, b;
+ unsigned ilinebits = bpp * passw[i];
+ unsigned olinebits = bpp * w;
+ size_t obp, ibp; /*bit pointers (for out and in buffer)*/
+ for(y = 0; y < passh[i]; y++)
+ for(x = 0; x < passw[i]; x++)
+ {
+ ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
+ obp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
+ for(b = 0; b < bpp; b++)
+ {
+ unsigned char bit = readBitFromReversedStream(&ibp, in);
+ /*note that this function assumes the out buffer is completely 0, use setBitOfReversedStream otherwise*/
+ setBitOfReversedStream0(&obp, out, bit);
+ }
+ }
+ }
+ }
+}
+
+static void removePaddingBits(unsigned char* out, const unsigned char* in,
+ size_t olinebits, size_t ilinebits, unsigned h)
+{
+ /*
+ After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need
+ to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers
+ for the Adam7 code, the color convert code and the output to the user.
+ in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must
+ have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits
+ also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7
+ only useful if (ilinebits - olinebits) is a value in the range 1..7
+ */
+ unsigned y;
+ size_t diff = ilinebits - olinebits;
+ size_t ibp = 0, obp = 0; /*input and output bit pointers*/
+ for(y = 0; y < h; y++)
+ {
+ size_t x;
+ for(x = 0; x < olinebits; x++)
+ {
+ unsigned char bit = readBitFromReversedStream(&ibp, in);
+ setBitOfReversedStream(&obp, out, bit);
+ }
+ ibp += diff;
+ }
+}
+
+/*out must be buffer big enough to contain full image, and in must contain the full decompressed data from
+the IDAT chunks (with filter index bytes and possible padding bits)
+return value is error*/
+static unsigned postProcessScanlines(unsigned char* out, unsigned char* in,
+ unsigned w, unsigned h, const LodePNGInfo* info_png)
+{
+ /*
+ This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype.
+ Steps:
+ *) if no Adam7: 1) unfilter 2) remove padding bits (= posible extra bits per scanline if bpp < 8)
+ *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace
+ NOTE: the in buffer will be overwritten with intermediate data!
+ */
+ unsigned bpp = lodepng_get_bpp(&info_png->color);
+ if(bpp == 0) return 31; /*error: invalid colortype*/
+
+ if(info_png->interlace_method == 0)
+ {
+ if(bpp < 8 && w * bpp != ((w * bpp + 7) / 8) * 8)
+ {
+ CERROR_TRY_RETURN(unfilter(in, in, w, h, bpp));
+ removePaddingBits(out, in, w * bpp, ((w * bpp + 7) / 8) * 8, h);
+ }
+ /*we can immediatly filter into the out buffer, no other steps needed*/
+ else CERROR_TRY_RETURN(unfilter(out, in, w, h, bpp));
+ }
+ else /*interlace_method is 1 (Adam7)*/
+ {
+ unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
+ unsigned i;
+
+ Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+
+ for(i = 0; i < 7; i++)
+ {
+ CERROR_TRY_RETURN(unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp));
+ /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline,
+ move bytes instead of bits or move not at all*/
+ if(bpp < 8)
+ {
+ /*remove padding bits in scanlines; after this there still may be padding
+ bits between the different reduced images: each reduced image still starts nicely at a byte*/
+ removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp,
+ ((passw[i] * bpp + 7) / 8) * 8, passh[i]);
+ }
+ }
+
+ Adam7_deinterlace(out, in, w, h, bpp);
+ }
+
+ return 0;
+}
+
+static unsigned readChunk_PLTE(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength)
+{
+ unsigned pos = 0, i;
+ if(color->palette) lodepng_free(color->palette);
+ color->palettesize = chunkLength / 3;
+ color->palette = (unsigned char*)lodepng_malloc(4 * color->palettesize);
+ if(!color->palette && color->palettesize)
+ {
+ color->palettesize = 0;
+ return 83; /*alloc fail*/
+ }
+ if(color->palettesize > 256) return 38; /*error: palette too big*/
+
+ for(i = 0; i < color->palettesize; i++)
+ {
+ color->palette[4 * i + 0] = data[pos++]; /*R*/
+ color->palette[4 * i + 1] = data[pos++]; /*G*/
+ color->palette[4 * i + 2] = data[pos++]; /*B*/
+ color->palette[4 * i + 3] = 255; /*alpha*/
+ }
+
+ return 0; /* OK */
+}
+
+static unsigned readChunk_tRNS(LodePNGColorMode* color, const unsigned char* data, size_t chunkLength)
+{
+ unsigned i;
+ if(color->colortype == LCT_PALETTE)
+ {
+ /*error: more alpha values given than there are palette entries*/
+ if(chunkLength > color->palettesize) return 38;
+
+ for(i = 0; i < chunkLength; i++) color->palette[4 * i + 3] = data[i];
+ }
+ else if(color->colortype == LCT_GREY)
+ {
+ /*error: this chunk must be 2 bytes for greyscale image*/
+ if(chunkLength != 2) return 30;
+
+ color->key_defined = 1;
+ color->key_r = color->key_g = color->key_b = 256 * data[0] + data[1];
+ }
+ else if(color->colortype == LCT_RGB)
+ {
+ /*error: this chunk must be 6 bytes for RGB image*/
+ if(chunkLength != 6) return 41;
+
+ color->key_defined = 1;
+ color->key_r = 256 * data[0] + data[1];
+ color->key_g = 256 * data[2] + data[3];
+ color->key_b = 256 * data[4] + data[5];
+ }
+ else return 42; /*error: tRNS chunk not allowed for other color models*/
+
+ return 0; /* OK */
+}
+
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+/*background color chunk (bKGD)*/
+static unsigned readChunk_bKGD(LodePNGInfo* info, const unsigned char* data, size_t chunkLength)
+{
+ if(info->color.colortype == LCT_PALETTE)
+ {
+ /*error: this chunk must be 1 byte for indexed color image*/
+ if(chunkLength != 1) return 43;
+
+ info->background_defined = 1;
+ info->background_r = info->background_g = info->background_b = data[0];
+ }
+ else if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA)
+ {
+ /*error: this chunk must be 2 bytes for greyscale image*/
+ if(chunkLength != 2) return 44;
+
+ info->background_defined = 1;
+ info->background_r = info->background_g = info->background_b
+ = 256 * data[0] + data[1];
+ }
+ else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA)
+ {
+ /*error: this chunk must be 6 bytes for greyscale image*/
+ if(chunkLength != 6) return 45;
+
+ info->background_defined = 1;
+ info->background_r = 256 * data[0] + data[1];
+ info->background_g = 256 * data[2] + data[3];
+ info->background_b = 256 * data[4] + data[5];
+ }
+
+ return 0; /* OK */
+}
+
+/*text chunk (tEXt)*/
+static unsigned readChunk_tEXt(LodePNGInfo* info, const unsigned char* data, size_t chunkLength)
+{
+ unsigned error = 0;
+ char *key = 0, *str = 0;
+ unsigned i;
+
+ while(!error) /*not really a while loop, only used to break on error*/
+ {
+ unsigned length, string2_begin;
+
+ length = 0;
+ while(length < chunkLength && data[length] != 0) length++;
+ /*even though it's not allowed by the standard, no error is thrown if
+ there's no null termination char, if the text is empty*/
+ if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
+
+ key = (char*)lodepng_malloc(length + 1);
+ if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
+
+ key[length] = 0;
+ for(i = 0; i < length; i++) key[i] = data[i];
+
+ string2_begin = length + 1; /*skip keyword null terminator*/
+
+ length = chunkLength < string2_begin ? 0 : chunkLength - string2_begin;
+ str = (char*)lodepng_malloc(length + 1);
+ if(!str) CERROR_BREAK(error, 83); /*alloc fail*/
+
+ str[length] = 0;
+ for(i = 0; i < length; i++) str[i] = data[string2_begin + i];
+
+ error = lodepng_add_text(info, key, str);
+
+ break;
+ }
+
+ lodepng_free(key);
+ lodepng_free(str);
+
+ return error;
+}
+
+/*compressed text chunk (zTXt)*/
+static unsigned readChunk_zTXt(LodePNGInfo* info, const LodePNGDecompressSettings* zlibsettings,
+ const unsigned char* data, size_t chunkLength)
+{
+ unsigned error = 0;
+ unsigned i;
+
+ unsigned length, string2_begin;
+ char *key = 0;
+ ucvector decoded;
+
+ ucvector_init(&decoded);
+
+ while(!error) /*not really a while loop, only used to break on error*/
+ {
+ for(length = 0; length < chunkLength && data[length] != 0; length++) ;
+ if(length + 2 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
+ if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
+
+ key = (char*)lodepng_malloc(length + 1);
+ if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
+
+ key[length] = 0;
+ for(i = 0; i < length; i++) key[i] = data[i];
+
+ if(data[length + 1] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/
+
+ string2_begin = length + 2;
+ if(string2_begin > chunkLength) CERROR_BREAK(error, 75); /*no null termination, corrupt?*/
+
+ length = chunkLength - string2_begin;
+ /*will fail if zlib error, e.g. if length is too small*/
+ error = zlib_decompress(&decoded.data, &decoded.size,
+ (unsigned char*)(&data[string2_begin]),
+ length, zlibsettings);
+ if(error) break;
+ ucvector_push_back(&decoded, 0);
+
+ error = lodepng_add_text(info, key, (char*)decoded.data);
+
+ break;
+ }
+
+ lodepng_free(key);
+ ucvector_cleanup(&decoded);
+
+ return error;
+}
+
+/*international text chunk (iTXt)*/
+static unsigned readChunk_iTXt(LodePNGInfo* info, const LodePNGDecompressSettings* zlibsettings,
+ const unsigned char* data, size_t chunkLength)
+{
+ unsigned error = 0;
+ unsigned i;
+
+ unsigned length, begin, compressed;
+ char *key = 0, *langtag = 0, *transkey = 0;
+ ucvector decoded;
+ ucvector_init(&decoded);
+
+ while(!error) /*not really a while loop, only used to break on error*/
+ {
+ /*Quick check if the chunk length isn't too small. Even without check
+ it'd still fail with other error checks below if it's too short. This just gives a different error code.*/
+ if(chunkLength < 5) CERROR_BREAK(error, 30); /*iTXt chunk too short*/
+
+ /*read the key*/
+ for(length = 0; length < chunkLength && data[length] != 0; length++) ;
+ if(length + 3 >= chunkLength) CERROR_BREAK(error, 75); /*no null termination char, corrupt?*/
+ if(length < 1 || length > 79) CERROR_BREAK(error, 89); /*keyword too short or long*/
+
+ key = (char*)lodepng_malloc(length + 1);
+ if(!key) CERROR_BREAK(error, 83); /*alloc fail*/
+
+ key[length] = 0;
+ for(i = 0; i < length; i++) key[i] = data[i];
+
+ /*read the compression method*/
+ compressed = data[length + 1];
+ if(data[length + 2] != 0) CERROR_BREAK(error, 72); /*the 0 byte indicating compression must be 0*/
+
+ /*even though it's not allowed by the standard, no error is thrown if
+ there's no null termination char, if the text is empty for the next 3 texts*/
+
+ /*read the langtag*/
+ begin = length + 3;
+ length = 0;
+ for(i = begin; i < chunkLength && data[i] != 0; i++) length++;
+
+ langtag = (char*)lodepng_malloc(length + 1);
+ if(!langtag) CERROR_BREAK(error, 83); /*alloc fail*/
+
+ langtag[length] = 0;
+ for(i = 0; i < length; i++) langtag[i] = data[begin + i];
+
+ /*read the transkey*/
+ begin += length + 1;
+ length = 0;
+ for(i = begin; i < chunkLength && data[i] != 0; i++) length++;
+
+ transkey = (char*)lodepng_malloc(length + 1);
+ if(!transkey) CERROR_BREAK(error, 83); /*alloc fail*/
+
+ transkey[length] = 0;
+ for(i = 0; i < length; i++) transkey[i] = data[begin + i];
+
+ /*read the actual text*/
+ begin += length + 1;
+
+ length = chunkLength < begin ? 0 : chunkLength - begin;
+
+ if(compressed)
+ {
+ /*will fail if zlib error, e.g. if length is too small*/
+ error = zlib_decompress(&decoded.data, &decoded.size,
+ (unsigned char*)(&data[begin]),
+ length, zlibsettings);
+ if(error) break;
+ if(decoded.allocsize < decoded.size) decoded.allocsize = decoded.size;
+ ucvector_push_back(&decoded, 0);
+ }
+ else
+ {
+ if(!ucvector_resize(&decoded, length + 1)) CERROR_BREAK(error, 83 /*alloc fail*/);
+
+ decoded.data[length] = 0;
+ for(i = 0; i < length; i++) decoded.data[i] = data[begin + i];
+ }
+
+ error = lodepng_add_itext(info, key, langtag, transkey, (char*)decoded.data);
+
+ break;
+ }
+
+ lodepng_free(key);
+ lodepng_free(langtag);
+ lodepng_free(transkey);
+ ucvector_cleanup(&decoded);
+
+ return error;
+}
+
+static unsigned readChunk_tIME(LodePNGInfo* info, const unsigned char* data, size_t chunkLength)
+{
+ if(chunkLength != 7) return 73; /*invalid tIME chunk size*/
+
+ info->time_defined = 1;
+ info->time.year = 256 * data[0] + data[+ 1];
+ info->time.month = data[2];
+ info->time.day = data[3];
+ info->time.hour = data[4];
+ info->time.minute = data[5];
+ info->time.second = data[6];
+
+ return 0; /* OK */
+}
+
+static unsigned readChunk_pHYs(LodePNGInfo* info, const unsigned char* data, size_t chunkLength)
+{
+ if(chunkLength != 9) return 74; /*invalid pHYs chunk size*/
+
+ info->phys_defined = 1;
+ info->phys_x = 16777216 * data[0] + 65536 * data[1] + 256 * data[2] + data[3];
+ info->phys_y = 16777216 * data[4] + 65536 * data[5] + 256 * data[6] + data[7];
+ info->phys_unit = data[8];
+
+ return 0; /* OK */
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/
+static void decodeGeneric(unsigned char** out, unsigned* w, unsigned* h,
+ LodePNGState* state,
+ const unsigned char* in, size_t insize)
+{
+ unsigned char IEND = 0;
+ const unsigned char* chunk;
+ size_t i;
+ ucvector idat; /*the data from idat chunks*/
+ ucvector scanlines;
+
+ /*for unknown chunk order*/
+ unsigned unknown = 0;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ unsigned critical_pos = 1; /*1 = after IHDR, 2 = after PLTE, 3 = after IDAT*/
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+ /*provide some proper output values if error will happen*/
+ *out = 0;
+
+ state->error = lodepng_inspect(w, h, state, in, insize); /*reads header and resets other parameters in state->info_png*/
+ if(state->error) return;
+
+ ucvector_init(&idat);
+ chunk = &in[33]; /*first byte of the first chunk after the header*/
+
+ /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk.
+ IDAT data is put at the start of the in buffer*/
+ while(!IEND && !state->error)
+ {
+ unsigned chunkLength;
+ const unsigned char* data; /*the data in the chunk*/
+
+ /*error: size of the in buffer too small to contain next chunk*/
+ if((size_t)((chunk - in) + 12) > insize || chunk < in) CERROR_BREAK(state->error, 30);
+
+ /*length of the data of the chunk, excluding the length bytes, chunk type and CRC bytes*/
+ chunkLength = lodepng_chunk_length(chunk);
+ /*error: chunk length larger than the max PNG chunk size*/
+ if(chunkLength > 2147483647) CERROR_BREAK(state->error, 63);
+
+ if((size_t)((chunk - in) + chunkLength + 12) > insize || (chunk + chunkLength + 12) < in)
+ {
+ CERROR_BREAK(state->error, 64); /*error: size of the in buffer too small to contain next chunk*/
+ }
+
+ data = lodepng_chunk_data_const(chunk);
+
+ /*IDAT chunk, containing compressed image data*/
+ if(lodepng_chunk_type_equals(chunk, "IDAT"))
+ {
+ size_t oldsize = idat.size;
+ if(!ucvector_resize(&idat, oldsize + chunkLength)) CERROR_BREAK(state->error, 83 /*alloc fail*/);
+ for(i = 0; i < chunkLength; i++) idat.data[oldsize + i] = data[i];
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ critical_pos = 3;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ }
+ /*IEND chunk*/
+ else if(lodepng_chunk_type_equals(chunk, "IEND"))
+ {
+ IEND = 1;
+ }
+ /*palette chunk (PLTE)*/
+ else if(lodepng_chunk_type_equals(chunk, "PLTE"))
+ {
+ state->error = readChunk_PLTE(&state->info_png.color, data, chunkLength);
+ if(state->error) break;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ critical_pos = 2;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ }
+ /*palette transparency chunk (tRNS)*/
+ else if(lodepng_chunk_type_equals(chunk, "tRNS"))
+ {
+ state->error = readChunk_tRNS(&state->info_png.color, data, chunkLength);
+ if(state->error) break;
+ }
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ /*background color chunk (bKGD)*/
+ else if(lodepng_chunk_type_equals(chunk, "bKGD"))
+ {
+ state->error = readChunk_bKGD(&state->info_png, data, chunkLength);
+ if(state->error) break;
+ }
+ /*text chunk (tEXt)*/
+ else if(lodepng_chunk_type_equals(chunk, "tEXt"))
+ {
+ if(state->decoder.read_text_chunks)
+ {
+ state->error = readChunk_tEXt(&state->info_png, data, chunkLength);
+ if(state->error) break;
+ }
+ }
+ /*compressed text chunk (zTXt)*/
+ else if(lodepng_chunk_type_equals(chunk, "zTXt"))
+ {
+ if(state->decoder.read_text_chunks)
+ {
+ state->error = readChunk_zTXt(&state->info_png, &state->decoder.zlibsettings, data, chunkLength);
+ if(state->error) break;
+ }
+ }
+ /*international text chunk (iTXt)*/
+ else if(lodepng_chunk_type_equals(chunk, "iTXt"))
+ {
+ if(state->decoder.read_text_chunks)
+ {
+ state->error = readChunk_iTXt(&state->info_png, &state->decoder.zlibsettings, data, chunkLength);
+ if(state->error) break;
+ }
+ }
+ else if(lodepng_chunk_type_equals(chunk, "tIME"))
+ {
+ state->error = readChunk_tIME(&state->info_png, data, chunkLength);
+ if(state->error) break;
+ }
+ else if(lodepng_chunk_type_equals(chunk, "pHYs"))
+ {
+ state->error = readChunk_pHYs(&state->info_png, data, chunkLength);
+ if(state->error) break;
+ }
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ else /*it's not an implemented chunk type, so ignore it: skip over the data*/
+ {
+ /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/
+ if(!lodepng_chunk_ancillary(chunk)) CERROR_BREAK(state->error, 69);
+
+ unknown = 1;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ if(state->decoder.remember_unknown_chunks)
+ {
+ state->error = lodepng_chunk_append(&state->info_png.unknown_chunks_data[critical_pos - 1],
+ &state->info_png.unknown_chunks_size[critical_pos - 1], chunk);
+ if(state->error) break;
+ }
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ }
+
+ if(!state->decoder.ignore_crc && !unknown) /*check CRC if wanted, only on known chunk types*/
+ {
+ if(lodepng_chunk_check_crc(chunk)) CERROR_BREAK(state->error, 57); /*invalid CRC*/
+ }
+
+ if(!IEND) chunk = lodepng_chunk_next_const(chunk);
+ }
+
+ ucvector_init(&scanlines);
+ if(!state->error)
+ {
+ /*maximum final image length is already reserved in the vector's length - this is not really necessary*/
+ if(!ucvector_resize(&scanlines, lodepng_get_raw_size(*w, *h, &state->info_png.color) + *h))
+ {
+ state->error = 83; /*alloc fail*/
+ }
+ }
+ if(!state->error)
+ {
+ /*decompress with the Zlib decompressor*/
+ state->error = zlib_decompress(&scanlines.data, &scanlines.size, idat.data,
+ idat.size, &state->decoder.zlibsettings);
+ }
+ ucvector_cleanup(&idat);
+
+ if(!state->error)
+ {
+ ucvector outv;
+ ucvector_init(&outv);
+ if(!ucvector_resizev(&outv,
+ lodepng_get_raw_size(*w, *h, &state->info_png.color), 0)) state->error = 83; /*alloc fail*/
+ if(!state->error) state->error = postProcessScanlines(outv.data, scanlines.data, *w, *h, &state->info_png);
+ *out = outv.data;
+ }
+ ucvector_cleanup(&scanlines);
+}
+
+unsigned lodepng_decode(unsigned char** out, unsigned* w, unsigned* h,
+ LodePNGState* state,
+ const unsigned char* in, size_t insize)
+{
+ *out = 0;
+ decodeGeneric(out, w, h, state, in, insize);
+ if(state->error) return state->error;
+ if(!state->decoder.color_convert || lodepng_color_mode_equal(&state->info_raw, &state->info_png.color))
+ {
+ /*same color type, no copying or converting of data needed*/
+ /*store the info_png color settings on the info_raw so that the info_raw still reflects what colortype
+ the raw image has to the end user*/
+ if(!state->decoder.color_convert)
+ {
+ state->error = lodepng_color_mode_copy(&state->info_raw, &state->info_png.color);
+ if(state->error) return state->error;
+ }
+ }
+ else
+ {
+ /*color conversion needed; sort of copy of the data*/
+ unsigned char* data = *out;
+ size_t outsize;
+
+ /*TODO: check if this works according to the statement in the documentation: "The converter can convert
+ from greyscale input color type, to 8-bit greyscale or greyscale with alpha"*/
+ if(!(state->info_raw.colortype == LCT_RGB || state->info_raw.colortype == LCT_RGBA)
+ && !(state->info_raw.bitdepth == 8))
+ {
+ return 56; /*unsupported color mode conversion*/
+ }
+
+ outsize = lodepng_get_raw_size(*w, *h, &state->info_raw);
+ *out = (unsigned char*)lodepng_malloc(outsize);
+ if(!(*out))
+ {
+ state->error = 83; /*alloc fail*/
+ }
+ else state->error = lodepng_convert(*out, data, &state->info_raw, &state->info_png.color, *w, *h, state->decoder.fix_png);
+ lodepng_free(data);
+ }
+ return state->error;
+}
+
+unsigned lodepng_decode_memory(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in,
+ size_t insize, LodePNGColorType colortype, unsigned bitdepth)
+{
+ unsigned error;
+ LodePNGState state;
+ lodepng_state_init(&state);
+ state.info_raw.colortype = colortype;
+ state.info_raw.bitdepth = bitdepth;
+ error = lodepng_decode(out, w, h, &state, in, insize);
+ lodepng_state_cleanup(&state);
+ return error;
+}
+
+unsigned lodepng_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize)
+{
+ return lodepng_decode_memory(out, w, h, in, insize, LCT_RGBA, 8);
+}
+
+unsigned lodepng_decode24(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize)
+{
+ return lodepng_decode_memory(out, w, h, in, insize, LCT_RGB, 8);
+}
+
+#ifdef LODEPNG_COMPILE_DISK
+unsigned lodepng_decode_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ unsigned char* buffer;
+ size_t buffersize;
+ unsigned error;
+ error = lodepng_load_file(&buffer, &buffersize, filename);
+ if(!error) error = lodepng_decode_memory(out, w, h, buffer, buffersize, colortype, bitdepth);
+ lodepng_free(buffer);
+ return error;
+}
+
+unsigned lodepng_decode32_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename)
+{
+ return lodepng_decode_file(out, w, h, filename, LCT_RGBA, 8);
+}
+
+unsigned lodepng_decode24_file(unsigned char** out, unsigned* w, unsigned* h, const char* filename)
+{
+ return lodepng_decode_file(out, w, h, filename, LCT_RGB, 8);
+}
+#endif /*LODEPNG_COMPILE_DISK*/
+
+void lodepng_decoder_settings_init(LodePNGDecoderSettings* settings)
+{
+ settings->color_convert = 1;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ settings->read_text_chunks = 1;
+ settings->remember_unknown_chunks = 0;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ settings->ignore_crc = 0;
+ settings->fix_png = 0;
+ lodepng_decompress_settings_init(&settings->zlibsettings);
+}
+
+#endif /*LODEPNG_COMPILE_DECODER*/
+
+#if defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER)
+
+void lodepng_state_init(LodePNGState* state)
+{
+#ifdef LODEPNG_COMPILE_DECODER
+ lodepng_decoder_settings_init(&state->decoder);
+#endif /*LODEPNG_COMPILE_DECODER*/
+#ifdef LODEPNG_COMPILE_ENCODER
+ lodepng_encoder_settings_init(&state->encoder);
+#endif /*LODEPNG_COMPILE_ENCODER*/
+ lodepng_color_mode_init(&state->info_raw);
+ lodepng_info_init(&state->info_png);
+ state->error = 1;
+}
+
+void lodepng_state_cleanup(LodePNGState* state)
+{
+ lodepng_color_mode_cleanup(&state->info_raw);
+ lodepng_info_cleanup(&state->info_png);
+}
+
+void lodepng_state_copy(LodePNGState* dest, const LodePNGState* source)
+{
+ lodepng_state_cleanup(dest);
+ *dest = *source;
+ lodepng_color_mode_init(&dest->info_raw);
+ lodepng_info_init(&dest->info_png);
+ dest->error = lodepng_color_mode_copy(&dest->info_raw, &source->info_raw); if(dest->error) return;
+ dest->error = lodepng_info_copy(&dest->info_png, &source->info_png); if(dest->error) return;
+}
+
+#endif /* defined(LODEPNG_COMPILE_DECODER) || defined(LODEPNG_COMPILE_ENCODER) */
+
+#ifdef LODEPNG_COMPILE_ENCODER
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* / PNG Encoder / */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+/*chunkName must be string of 4 characters*/
+static unsigned addChunk(ucvector* out, const char* chunkName, const unsigned char* data, size_t length)
+{
+ CERROR_TRY_RETURN(lodepng_chunk_create(&out->data, &out->size, (unsigned)length, chunkName, data));
+ out->allocsize = out->size; /*fix the allocsize again*/
+ return 0;
+}
+
+static void writeSignature(ucvector* out)
+{
+ /*8 bytes PNG signature, aka the magic bytes*/
+ ucvector_push_back(out, 137);
+ ucvector_push_back(out, 80);
+ ucvector_push_back(out, 78);
+ ucvector_push_back(out, 71);
+ ucvector_push_back(out, 13);
+ ucvector_push_back(out, 10);
+ ucvector_push_back(out, 26);
+ ucvector_push_back(out, 10);
+}
+
+static unsigned addChunk_IHDR(ucvector* out, unsigned w, unsigned h,
+ LodePNGColorType colortype, unsigned bitdepth, unsigned interlace_method)
+{
+ unsigned error = 0;
+ ucvector header;
+ ucvector_init(&header);
+
+ lodepng_add32bitInt(&header, w); /*width*/
+ lodepng_add32bitInt(&header, h); /*height*/
+ ucvector_push_back(&header, (unsigned char)bitdepth); /*bit depth*/
+ ucvector_push_back(&header, (unsigned char)colortype); /*color type*/
+ ucvector_push_back(&header, 0); /*compression method*/
+ ucvector_push_back(&header, 0); /*filter method*/
+ ucvector_push_back(&header, interlace_method); /*interlace method*/
+
+ error = addChunk(out, "IHDR", header.data, header.size);
+ ucvector_cleanup(&header);
+
+ return error;
+}
+
+static unsigned addChunk_PLTE(ucvector* out, const LodePNGColorMode* info)
+{
+ unsigned error = 0;
+ size_t i;
+ ucvector PLTE;
+ ucvector_init(&PLTE);
+ for(i = 0; i < info->palettesize * 4; i++)
+ {
+ /*add all channels except alpha channel*/
+ if(i % 4 != 3) ucvector_push_back(&PLTE, info->palette[i]);
+ }
+ error = addChunk(out, "PLTE", PLTE.data, PLTE.size);
+ ucvector_cleanup(&PLTE);
+
+ return error;
+}
+
+static unsigned addChunk_tRNS(ucvector* out, const LodePNGColorMode* info)
+{
+ unsigned error = 0;
+ size_t i;
+ ucvector tRNS;
+ ucvector_init(&tRNS);
+ if(info->colortype == LCT_PALETTE)
+ {
+ size_t amount = info->palettesize;
+ /*the tail of palette values that all have 255 as alpha, does not have to be encoded*/
+ for(i = info->palettesize; i > 0; i--)
+ {
+ if(info->palette[4 * (i - 1) + 3] == 255) amount--;
+ else break;
+ }
+ /*add only alpha channel*/
+ for(i = 0; i < amount; i++) ucvector_push_back(&tRNS, info->palette[4 * i + 3]);
+ }
+ else if(info->colortype == LCT_GREY)
+ {
+ if(info->key_defined)
+ {
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_r / 256));
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_r % 256));
+ }
+ }
+ else if(info->colortype == LCT_RGB)
+ {
+ if(info->key_defined)
+ {
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_r / 256));
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_r % 256));
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_g / 256));
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_g % 256));
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_b / 256));
+ ucvector_push_back(&tRNS, (unsigned char)(info->key_b % 256));
+ }
+ }
+
+ error = addChunk(out, "tRNS", tRNS.data, tRNS.size);
+ ucvector_cleanup(&tRNS);
+
+ return error;
+}
+
+static unsigned addChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize,
+ LodePNGCompressSettings* zlibsettings)
+{
+ ucvector zlibdata;
+ unsigned error = 0;
+
+ /*compress with the Zlib compressor*/
+ ucvector_init(&zlibdata);
+ error = zlib_compress(&zlibdata.data, &zlibdata.size, data, datasize, zlibsettings);
+ if(!error) error = addChunk(out, "IDAT", zlibdata.data, zlibdata.size);
+ ucvector_cleanup(&zlibdata);
+
+ return error;
+}
+
+static unsigned addChunk_IEND(ucvector* out)
+{
+ unsigned error = 0;
+ error = addChunk(out, "IEND", 0, 0);
+ return error;
+}
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+
+static unsigned addChunk_tEXt(ucvector* out, const char* keyword, const char* textstring)
+{
+ unsigned error = 0;
+ size_t i;
+ ucvector text;
+ ucvector_init(&text);
+ for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&text, (unsigned char)keyword[i]);
+ if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/
+ ucvector_push_back(&text, 0); /*0 termination char*/
+ for(i = 0; textstring[i] != 0; i++) ucvector_push_back(&text, (unsigned char)textstring[i]);
+ error = addChunk(out, "tEXt", text.data, text.size);
+ ucvector_cleanup(&text);
+
+ return error;
+}
+
+static unsigned addChunk_zTXt(ucvector* out, const char* keyword, const char* textstring,
+ LodePNGCompressSettings* zlibsettings)
+{
+ unsigned error = 0;
+ ucvector data, compressed;
+ size_t i, textsize = strlen(textstring);
+
+ ucvector_init(&data);
+ ucvector_init(&compressed);
+ for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&data, (unsigned char)keyword[i]);
+ if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/
+ ucvector_push_back(&data, 0); /*0 termination char*/
+ ucvector_push_back(&data, 0); /*compression method: 0*/
+
+ error = zlib_compress(&compressed.data, &compressed.size,
+ (unsigned char*)textstring, textsize, zlibsettings);
+ if(!error)
+ {
+ for(i = 0; i < compressed.size; i++) ucvector_push_back(&data, compressed.data[i]);
+ error = addChunk(out, "zTXt", data.data, data.size);
+ }
+
+ ucvector_cleanup(&compressed);
+ ucvector_cleanup(&data);
+ return error;
+}
+
+static unsigned addChunk_iTXt(ucvector* out, unsigned compressed, const char* keyword, const char* langtag,
+ const char* transkey, const char* textstring, LodePNGCompressSettings* zlibsettings)
+{
+ unsigned error = 0;
+ ucvector data;
+ size_t i, textsize = strlen(textstring);
+
+ ucvector_init(&data);
+
+ for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&data, (unsigned char)keyword[i]);
+ if(i < 1 || i > 79) return 89; /*error: invalid keyword size*/
+ ucvector_push_back(&data, 0); /*null termination char*/
+ ucvector_push_back(&data, compressed ? 1 : 0); /*compression flag*/
+ ucvector_push_back(&data, 0); /*compression method*/
+ for(i = 0; langtag[i] != 0; i++) ucvector_push_back(&data, (unsigned char)langtag[i]);
+ ucvector_push_back(&data, 0); /*null termination char*/
+ for(i = 0; transkey[i] != 0; i++) ucvector_push_back(&data, (unsigned char)transkey[i]);
+ ucvector_push_back(&data, 0); /*null termination char*/
+
+ if(compressed)
+ {
+ ucvector compressed_data;
+ ucvector_init(&compressed_data);
+ error = zlib_compress(&compressed_data.data, &compressed_data.size,
+ (unsigned char*)textstring, textsize, zlibsettings);
+ if(!error)
+ {
+ for(i = 0; i < compressed_data.size; i++) ucvector_push_back(&data, compressed_data.data[i]);
+ }
+ ucvector_cleanup(&compressed_data);
+ }
+ else /*not compressed*/
+ {
+ for(i = 0; textstring[i] != 0; i++) ucvector_push_back(&data, (unsigned char)textstring[i]);
+ }
+
+ if(!error) error = addChunk(out, "iTXt", data.data, data.size);
+ ucvector_cleanup(&data);
+ return error;
+}
+
+static unsigned addChunk_bKGD(ucvector* out, const LodePNGInfo* info)
+{
+ unsigned error = 0;
+ ucvector bKGD;
+ ucvector_init(&bKGD);
+ if(info->color.colortype == LCT_GREY || info->color.colortype == LCT_GREY_ALPHA)
+ {
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_r / 256));
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256));
+ }
+ else if(info->color.colortype == LCT_RGB || info->color.colortype == LCT_RGBA)
+ {
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_r / 256));
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256));
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_g / 256));
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_g % 256));
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_b / 256));
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_b % 256));
+ }
+ else if(info->color.colortype == LCT_PALETTE)
+ {
+ ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256)); /*palette index*/
+ }
+
+ error = addChunk(out, "bKGD", bKGD.data, bKGD.size);
+ ucvector_cleanup(&bKGD);
+
+ return error;
+}
+
+static unsigned addChunk_tIME(ucvector* out, const LodePNGTime* time)
+{
+ unsigned error = 0;
+ unsigned char* data = (unsigned char*)lodepng_malloc(7);
+ if(!data) return 83; /*alloc fail*/
+ data[0] = (unsigned char)(time->year / 256);
+ data[1] = (unsigned char)(time->year % 256);
+ data[2] = time->month;
+ data[3] = time->day;
+ data[4] = time->hour;
+ data[5] = time->minute;
+ data[6] = time->second;
+ error = addChunk(out, "tIME", data, 7);
+ lodepng_free(data);
+ return error;
+}
+
+static unsigned addChunk_pHYs(ucvector* out, const LodePNGInfo* info)
+{
+ unsigned error = 0;
+ ucvector data;
+ ucvector_init(&data);
+
+ lodepng_add32bitInt(&data, info->phys_x);
+ lodepng_add32bitInt(&data, info->phys_y);
+ ucvector_push_back(&data, info->phys_unit);
+
+ error = addChunk(out, "pHYs", data.data, data.size);
+ ucvector_cleanup(&data);
+
+ return error;
+}
+
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+static void filterScanline(unsigned char* out, const unsigned char* scanline, const unsigned char* prevline,
+ size_t length, size_t bytewidth, unsigned char filterType)
+{
+ size_t i;
+ switch(filterType)
+ {
+ case 0: /*None*/
+ for(i = 0; i < length; i++) out[i] = scanline[i];
+ break;
+ case 1: /*Sub*/
+ if(prevline)
+ {
+ for(i = 0; i < bytewidth; i++) out[i] = scanline[i];
+ for(i = bytewidth; i < length; i++) out[i] = scanline[i] - scanline[i - bytewidth];
+ }
+ else
+ {
+ for(i = 0; i < bytewidth; i++) out[i] = scanline[i];
+ for(i = bytewidth; i < length; i++) out[i] = scanline[i] - scanline[i - bytewidth];
+ }
+ break;
+ case 2: /*Up*/
+ if(prevline)
+ {
+ for(i = 0; i < length; i++) out[i] = scanline[i] - prevline[i];
+ }
+ else
+ {
+ for(i = 0; i < length; i++) out[i] = scanline[i];
+ }
+ break;
+ case 3: /*Average*/
+ if(prevline)
+ {
+ for(i = 0; i < bytewidth; i++) out[i] = scanline[i] - prevline[i] / 2;
+ for(i = bytewidth; i < length; i++) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) / 2);
+ }
+ else
+ {
+ for(i = 0; i < bytewidth; i++) out[i] = scanline[i];
+ for(i = bytewidth; i < length; i++) out[i] = scanline[i] - scanline[i - bytewidth] / 2;
+ }
+ break;
+ case 4: /*Paeth*/
+ if(prevline)
+ {
+ /*paethPredictor(0, prevline[i], 0) is always prevline[i]*/
+ for(i = 0; i < bytewidth; i++) out[i] = (scanline[i] - prevline[i]);
+ for(i = bytewidth; i < length; i++)
+ {
+ out[i] = (scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth]));
+ }
+ }
+ else
+ {
+ for(i = 0; i < bytewidth; i++) out[i] = scanline[i];
+ /*paethPredictor(scanline[i - bytewidth], 0, 0) is always scanline[i - bytewidth]*/
+ for(i = bytewidth; i < length; i++) out[i] = (scanline[i] - scanline[i - bytewidth]);
+ }
+ break;
+ default: return; /*unexisting filter type given*/
+ }
+}
+
+/* log2 approximation. A slight bit faster than std::log. */
+static float flog2(float f)
+{
+ float result = 0;
+ while(f > 32) { result += 4; f /= 16; }
+ while(f > 2) { result++; f /= 2; }
+ return result + 1.442695f * (f * f * f / 3 - 3 * f * f / 2 + 3 * f - 1.83333f);
+}
+
+static unsigned filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h,
+ const LodePNGColorMode* info, const LodePNGEncoderSettings* settings)
+{
+ /*
+ For PNG filter method 0
+ out must be a buffer with as size: h + (w * h * bpp + 7) / 8, because there are
+ the scanlines with 1 extra byte per scanline
+ */
+
+ unsigned bpp = lodepng_get_bpp(info);
+ /*the width of a scanline in bytes, not including the filter type*/
+ size_t linebytes = (w * bpp + 7) / 8;
+ /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
+ size_t bytewidth = (bpp + 7) / 8;
+ const unsigned char* prevline = 0;
+ unsigned x, y;
+ unsigned error = 0;
+ LodePNGFilterStrategy strategy = settings->filter_strategy;
+
+ /*
+ There is a heuristic called the minimum sum of absolute differences heuristic, suggested by the PNG standard:
+ * If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e.
+ use fixed filtering, with the filter None).
+ * (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is
+ not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply
+ all five filters and select the filter that produces the smallest sum of absolute values per row.
+ This heuristic is used if filter strategy is LFS_MINSUM and filter_palette_zero is true.
+
+ If filter_palette_zero is true and filter_strategy is not LFS_MINSUM, the above heuristic is followed,
+ but for "the other case", whatever strategy filter_strategy is set to instead of the minimum sum
+ heuristic is used.
+ */
+ if(settings->filter_palette_zero &&
+ (info->colortype == LCT_PALETTE || info->bitdepth < 8)) strategy = LFS_ZERO;
+
+ if(bpp == 0) return 31; /*error: invalid color type*/
+
+ if(strategy == LFS_ZERO)
+ {
+ for(y = 0; y < h; y++)
+ {
+ size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
+ size_t inindex = linebytes * y;
+ out[outindex] = 0; /*filter type byte*/
+ filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, 0);
+ prevline = &in[inindex];
+ }
+ }
+ else if(strategy == LFS_MINSUM)
+ {
+ /*adaptive filtering*/
+ size_t sum[5];
+ ucvector attempt[5]; /*five filtering attempts, one for each filter type*/
+ size_t smallest = 0;
+ unsigned type, bestType = 0;
+
+ for(type = 0; type < 5; type++)
+ {
+ ucvector_init(&attempt[type]);
+ if(!ucvector_resize(&attempt[type], linebytes)) return 83; /*alloc fail*/
+ }
+
+ if(!error)
+ {
+ for(y = 0; y < h; y++)
+ {
+ /*try the 5 filter types*/
+ for(type = 0; type < 5; type++)
+ {
+ filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type);
+
+ /*calculate the sum of the result*/
+ sum[type] = 0;
+ if(type == 0)
+ {
+ for(x = 0; x < linebytes; x++) sum[type] += (unsigned char)(attempt[type].data[x]);
+ }
+ else
+ {
+ for(x = 0; x < linebytes; x++)
+ {
+ /*For differences, each byte should be treated as signed, values above 127 are negative
+ (converted to signed char). Filtertype 0 isn't a difference though, so use unsigned there.
+ This means filtertype 0 is almost never chosen, but that is justified.*/
+ signed char s = (signed char)(attempt[type].data[x]);
+ sum[type] += s < 0 ? -s : s;
+ }
+ }
+
+ /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
+ if(type == 0 || sum[type] < smallest)
+ {
+ bestType = type;
+ smallest = sum[type];
+ }
+ }
+
+ prevline = &in[y * linebytes];
+
+ /*now fill the out values*/
+ out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
+ for(x = 0; x < linebytes; x++) out[y * (linebytes + 1) + 1 + x] = attempt[bestType].data[x];
+ }
+ }
+
+ for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]);
+ }
+ else if(strategy == LFS_ENTROPY)
+ {
+ float sum[5];
+ ucvector attempt[5]; /*five filtering attempts, one for each filter type*/
+ float smallest = 0;
+ unsigned type, bestType = 0;
+ unsigned count[256];
+
+ for(type = 0; type < 5; type++)
+ {
+ ucvector_init(&attempt[type]);
+ if(!ucvector_resize(&attempt[type], linebytes)) return 83; /*alloc fail*/
+ }
+
+ for(y = 0; y < h; y++)
+ {
+ /*try the 5 filter types*/
+ for(type = 0; type < 5; type++)
+ {
+ filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type);
+ for(x = 0; x < 256; x++) count[x] = 0;
+ for(x = 0; x < linebytes; x++) count[attempt[type].data[x]]++;
+ count[type]++; /*the filter type itself is part of the scanline*/
+ sum[type] = 0;
+ for(x = 0; x < 256; x++)
+ {
+ float p = count[x] / (float)(linebytes + 1);
+ sum[type] += count[x] == 0 ? 0 : flog2(1 / p) * p;
+ }
+ /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
+ if(type == 0 || sum[type] < smallest)
+ {
+ bestType = type;
+ smallest = sum[type];
+ }
+ }
+
+ prevline = &in[y * linebytes];
+
+ /*now fill the out values*/
+ out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
+ for(x = 0; x < linebytes; x++) out[y * (linebytes + 1) + 1 + x] = attempt[bestType].data[x];
+ }
+
+ for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]);
+ }
+ else if(strategy == LFS_PREDEFINED)
+ {
+ for(y = 0; y < h; y++)
+ {
+ size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
+ size_t inindex = linebytes * y;
+ unsigned type = settings->predefined_filters[y];
+ out[outindex] = type; /*filter type byte*/
+ filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, type);
+ prevline = &in[inindex];
+ }
+ }
+ else if(strategy == LFS_BRUTE_FORCE)
+ {
+ /*brute force filter chooser.
+ deflate the scanline after every filter attempt to see which one deflates best.
+ This is very slow and gives only slightly smaller, sometimes even larger, result*/
+ size_t size[5];
+ ucvector attempt[5]; /*five filtering attempts, one for each filter type*/
+ size_t smallest = 0;
+ unsigned type = 0, bestType = 0;
+ unsigned char* dummy;
+ LodePNGCompressSettings zlibsettings = settings->zlibsettings;
+ /*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose,
+ to simulate the true case where the tree is the same for the whole image. Sometimes it gives
+ better result with dynamic tree anyway. Using the fixed tree sometimes gives worse, but in rare
+ cases better compression. It does make this a bit less slow, so it's worth doing this.*/
+ zlibsettings.btype = 1;
+ /*a custom encoder likely doesn't read the btype setting and is optimized for complete PNG
+ images only, so disable it*/
+ zlibsettings.custom_zlib = 0;
+ zlibsettings.custom_deflate = 0;
+ for(type = 0; type < 5; type++)
+ {
+ ucvector_init(&attempt[type]);
+ ucvector_resize(&attempt[type], linebytes); /*todo: give error if resize failed*/
+ }
+ for(y = 0; y < h; y++) /*try the 5 filter types*/
+ {
+ for(type = 0; type < 5; type++)
+ {
+ unsigned testsize = attempt[type].size;
+ /*if(testsize > 8) testsize /= 8;*/ /*it already works good enough by testing a part of the row*/
+
+ filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type);
+ size[type] = 0;
+ dummy = 0;
+ zlib_compress(&dummy, &size[type], attempt[type].data, testsize, &zlibsettings);
+ lodepng_free(dummy);
+ /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/
+ if(type == 0 || size[type] < smallest)
+ {
+ bestType = type;
+ smallest = size[type];
+ }
+ }
+ prevline = &in[y * linebytes];
+ out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
+ for(x = 0; x < linebytes; x++) out[y * (linebytes + 1) + 1 + x] = attempt[bestType].data[x];
+ }
+ for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]);
+ }
+ else return 88; /* unknown filter strategy */
+
+ return error;
+}
+
+static void addPaddingBits(unsigned char* out, const unsigned char* in,
+ size_t olinebits, size_t ilinebits, unsigned h)
+{
+ /*The opposite of the removePaddingBits function
+ olinebits must be >= ilinebits*/
+ unsigned y;
+ size_t diff = olinebits - ilinebits;
+ size_t obp = 0, ibp = 0; /*bit pointers*/
+ for(y = 0; y < h; y++)
+ {
+ size_t x;
+ for(x = 0; x < ilinebits; x++)
+ {
+ unsigned char bit = readBitFromReversedStream(&ibp, in);
+ setBitOfReversedStream(&obp, out, bit);
+ }
+ /*obp += diff; --> no, fill in some value in the padding bits too, to avoid
+ "Use of uninitialised value of size ###" warning from valgrind*/
+ for(x = 0; x < diff; x++) setBitOfReversedStream(&obp, out, 0);
+ }
+}
+
+/*
+in: non-interlaced image with size w*h
+out: the same pixels, but re-ordered according to PNG's Adam7 interlacing, with
+ no padding bits between scanlines, but between reduced images so that each
+ reduced image starts at a byte.
+bpp: bits per pixel
+there are no padding bits, not between scanlines, not between reduced images
+in has the following size in bits: w * h * bpp.
+out is possibly bigger due to padding bits between reduced images
+NOTE: comments about padding bits are only relevant if bpp < 8
+*/
+static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp)
+{
+ unsigned passw[7], passh[7];
+ size_t filter_passstart[8], padded_passstart[8], passstart[8];
+ unsigned i;
+
+ Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+
+ if(bpp >= 8)
+ {
+ for(i = 0; i < 7; i++)
+ {
+ unsigned x, y, b;
+ size_t bytewidth = bpp / 8;
+ for(y = 0; y < passh[i]; y++)
+ for(x = 0; x < passw[i]; x++)
+ {
+ size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
+ size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth;
+ for(b = 0; b < bytewidth; b++)
+ {
+ out[pixeloutstart + b] = in[pixelinstart + b];
+ }
+ }
+ }
+ }
+ else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/
+ {
+ for(i = 0; i < 7; i++)
+ {
+ unsigned x, y, b;
+ unsigned ilinebits = bpp * passw[i];
+ unsigned olinebits = bpp * w;
+ size_t obp, ibp; /*bit pointers (for out and in buffer)*/
+ for(y = 0; y < passh[i]; y++)
+ for(x = 0; x < passw[i]; x++)
+ {
+ ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
+ obp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
+ for(b = 0; b < bpp; b++)
+ {
+ unsigned char bit = readBitFromReversedStream(&ibp, in);
+ setBitOfReversedStream(&obp, out, bit);
+ }
+ }
+ }
+ }
+}
+
+/*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image.
+return value is error**/
+static unsigned preProcessScanlines(unsigned char** out, size_t* outsize, const unsigned char* in,
+ unsigned w, unsigned h,
+ const LodePNGInfo* info_png, const LodePNGEncoderSettings* settings)
+{
+ /*
+ This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps:
+ *) if no Adam7: 1) add padding bits (= posible extra bits per scanline if bpp < 8) 2) filter
+ *) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter
+ */
+ unsigned bpp = lodepng_get_bpp(&info_png->color);
+ unsigned error = 0;
+
+ if(info_png->interlace_method == 0)
+ {
+ *outsize = h + (h * ((w * bpp + 7) / 8)); /*image size plus an extra byte per scanline + possible padding bits*/
+ *out = (unsigned char*)lodepng_malloc(*outsize);
+ if(!(*out) && (*outsize)) error = 83; /*alloc fail*/
+
+ if(!error)
+ {
+ /*non multiple of 8 bits per scanline, padding bits needed per scanline*/
+ if(bpp < 8 && w * bpp != ((w * bpp + 7) / 8) * 8)
+ {
+ unsigned char* padded = (unsigned char*)lodepng_malloc(h * ((w * bpp + 7) / 8));
+ if(!padded) error = 83; /*alloc fail*/
+ if(!error)
+ {
+ addPaddingBits(padded, in, ((w * bpp + 7) / 8) * 8, w * bpp, h);
+ error = filter(*out, padded, w, h, &info_png->color, settings);
+ }
+ lodepng_free(padded);
+ }
+ else
+ {
+ /*we can immediatly filter into the out buffer, no other steps needed*/
+ error = filter(*out, in, w, h, &info_png->color, settings);
+ }
+ }
+ }
+ else /*interlace_method is 1 (Adam7)*/
+ {
+ unsigned passw[7], passh[7];
+ size_t filter_passstart[8], padded_passstart[8], passstart[8];
+ unsigned char* adam7;
+
+ Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
+
+ *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/
+ *out = (unsigned char*)lodepng_malloc(*outsize);
+ if(!(*out)) error = 83; /*alloc fail*/
+
+ adam7 = (unsigned char*)lodepng_malloc(passstart[7]);
+ if(!adam7 && passstart[7]) error = 83; /*alloc fail*/
+
+ if(!error)
+ {
+ unsigned i;
+
+ Adam7_interlace(adam7, in, w, h, bpp);
+ for(i = 0; i < 7; i++)
+ {
+ if(bpp < 8)
+ {
+ unsigned char* padded = (unsigned char*)lodepng_malloc(padded_passstart[i + 1] - padded_passstart[i]);
+ if(!padded) ERROR_BREAK(83); /*alloc fail*/
+ addPaddingBits(padded, &adam7[passstart[i]],
+ ((passw[i] * bpp + 7) / 8) * 8, passw[i] * bpp, passh[i]);
+ error = filter(&(*out)[filter_passstart[i]], padded,
+ passw[i], passh[i], &info_png->color, settings);
+ lodepng_free(padded);
+ }
+ else
+ {
+ error = filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]],
+ passw[i], passh[i], &info_png->color, settings);
+ }
+
+ if(error) break;
+ }
+ }
+
+ lodepng_free(adam7);
+ }
+
+ return error;
+}
+
+/*
+palette must have 4 * palettesize bytes allocated, and given in format RGBARGBARGBARGBA...
+returns 0 if the palette is opaque,
+returns 1 if the palette has a single color with alpha 0 ==> color key
+returns 2 if the palette is semi-translucent.
+*/
+static unsigned getPaletteTranslucency(const unsigned char* palette, size_t palettesize)
+{
+ size_t i, key = 0;
+ unsigned r = 0, g = 0, b = 0; /*the value of the color with alpha 0, so long as color keying is possible*/
+ for(i = 0; i < palettesize; i++)
+ {
+ if(!key && palette[4 * i + 3] == 0)
+ {
+ r = palette[4 * i + 0]; g = palette[4 * i + 1]; b = palette[4 * i + 2];
+ key = 1;
+ i = (size_t)(-1); /*restart from beginning, to detect earlier opaque colors with key's value*/
+ }
+ else if(palette[4 * i + 3] != 255) return 2;
+ /*when key, no opaque RGB may have key's RGB*/
+ else if(key && r == palette[i * 4 + 0] && g == palette[i * 4 + 1] && b == palette[i * 4 + 2]) return 2;
+ }
+ return key;
+}
+
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+static unsigned addUnknownChunks(ucvector* out, unsigned char* data, size_t datasize)
+{
+ unsigned char* inchunk = data;
+ while((size_t)(inchunk - data) < datasize)
+ {
+ CERROR_TRY_RETURN(lodepng_chunk_append(&out->data, &out->size, inchunk));
+ out->allocsize = out->size; /*fix the allocsize again*/
+ inchunk = lodepng_chunk_next(inchunk);
+ }
+ return 0;
+}
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+
+unsigned lodepng_encode(unsigned char** out, size_t* outsize,
+ const unsigned char* image, unsigned w, unsigned h,
+ LodePNGState* state)
+{
+ LodePNGInfo info;
+ ucvector outv;
+ unsigned char* data = 0; /*uncompressed version of the IDAT chunk data*/
+ size_t datasize = 0;
+
+ /*provide some proper output values if error will happen*/
+ *out = 0;
+ *outsize = 0;
+ state->error = 0;
+
+ lodepng_info_init(&info);
+ lodepng_info_copy(&info, &state->info_png);
+
+ if((info.color.colortype == LCT_PALETTE || state->encoder.force_palette)
+ && (info.color.palettesize == 0 || info.color.palettesize > 256))
+ {
+ state->error = 68; /*invalid palette size, it is only allowed to be 1-256*/
+ return state->error;
+ }
+
+ if(state->encoder.auto_convert != LAC_NO)
+ {
+ state->error = lodepng_auto_choose_color(&info.color, image, w, h, &state->info_raw,
+ state->encoder.auto_convert);
+ }
+ if(state->error) return state->error;
+
+ if(state->encoder.zlibsettings.btype > 2)
+ {
+ CERROR_RETURN_ERROR(state->error, 61); /*error: unexisting btype*/
+ }
+ if(state->info_png.interlace_method > 1)
+ {
+ CERROR_RETURN_ERROR(state->error, 71); /*error: unexisting interlace mode*/
+ }
+
+ state->error = checkColorValidity(info.color.colortype, info.color.bitdepth);
+ if(state->error) return state->error; /*error: unexisting color type given*/
+ state->error = checkColorValidity(state->info_raw.colortype, state->info_raw.bitdepth);
+ if(state->error) return state->error; /*error: unexisting color type given*/
+
+ if(!lodepng_color_mode_equal(&state->info_raw, &info.color))
+ {
+ unsigned char* converted;
+ size_t size = (w * h * lodepng_get_bpp(&info.color) + 7) / 8;
+
+ converted = (unsigned char*)lodepng_malloc(size);
+ if(!converted && size) state->error = 83; /*alloc fail*/
+ if(!state->error)
+ {
+ state->error = lodepng_convert(converted, image, &info.color, &state->info_raw, w, h, 0 /*fix_png*/);
+ }
+ if(!state->error) preProcessScanlines(&data, &datasize, converted, w, h, &info, &state->encoder);
+ lodepng_free(converted);
+ }
+ else preProcessScanlines(&data, &datasize, image, w, h, &info, &state->encoder);
+
+ ucvector_init(&outv);
+ while(!state->error) /*while only executed once, to break on error*/
+ {
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ size_t i;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ /*write signature and chunks*/
+ writeSignature(&outv);
+ /*IHDR*/
+ addChunk_IHDR(&outv, w, h, info.color.colortype, info.color.bitdepth, info.interlace_method);
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ /*unknown chunks between IHDR and PLTE*/
+ if(info.unknown_chunks_data[0])
+ {
+ state->error = addUnknownChunks(&outv, info.unknown_chunks_data[0], info.unknown_chunks_size[0]);
+ if(state->error) break;
+ }
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ /*PLTE*/
+ if(info.color.colortype == LCT_PALETTE)
+ {
+ addChunk_PLTE(&outv, &info.color);
+ }
+ if(state->encoder.force_palette && (info.color.colortype == LCT_RGB || info.color.colortype == LCT_RGBA))
+ {
+ addChunk_PLTE(&outv, &info.color);
+ }
+ /*tRNS*/
+ if(info.color.colortype == LCT_PALETTE && getPaletteTranslucency(info.color.palette, info.color.palettesize) != 0)
+ {
+ addChunk_tRNS(&outv, &info.color);
+ }
+ if((info.color.colortype == LCT_GREY || info.color.colortype == LCT_RGB) && info.color.key_defined)
+ {
+ addChunk_tRNS(&outv, &info.color);
+ }
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ /*bKGD (must come between PLTE and the IDAt chunks*/
+ if(info.background_defined) addChunk_bKGD(&outv, &info);
+ /*pHYs (must come before the IDAT chunks)*/
+ if(info.phys_defined) addChunk_pHYs(&outv, &info);
+
+ /*unknown chunks between PLTE and IDAT*/
+ if(info.unknown_chunks_data[1])
+ {
+ state->error = addUnknownChunks(&outv, info.unknown_chunks_data[1], info.unknown_chunks_size[1]);
+ if(state->error) break;
+ }
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ /*IDAT (multiple IDAT chunks must be consecutive)*/
+ state->error = addChunk_IDAT(&outv, data, datasize, &state->encoder.zlibsettings);
+ if(state->error) break;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ /*tIME*/
+ if(info.time_defined) addChunk_tIME(&outv, &info.time);
+ /*tEXt and/or zTXt*/
+ for(i = 0; i < info.text_num; i++)
+ {
+ if(strlen(info.text_keys[i]) > 79)
+ {
+ state->error = 66; /*text chunk too large*/
+ break;
+ }
+ if(strlen(info.text_keys[i]) < 1)
+ {
+ state->error = 67; /*text chunk too small*/
+ break;
+ }
+ if(state->encoder.text_compression)
+ {
+ addChunk_zTXt(&outv, info.text_keys[i], info.text_strings[i], &state->encoder.zlibsettings);
+ }
+ else
+ {
+ addChunk_tEXt(&outv, info.text_keys[i], info.text_strings[i]);
+ }
+ }
+ /*LodePNG version id in text chunk*/
+ if(state->encoder.add_id)
+ {
+ unsigned alread_added_id_text = 0;
+ for(i = 0; i < info.text_num; i++)
+ {
+ if(!strcmp(info.text_keys[i], "LodePNG"))
+ {
+ alread_added_id_text = 1;
+ break;
+ }
+ }
+ if(alread_added_id_text == 0)
+ {
+ addChunk_tEXt(&outv, "LodePNG", VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/
+ }
+ }
+ /*iTXt*/
+ for(i = 0; i < info.itext_num; i++)
+ {
+ if(strlen(info.itext_keys[i]) > 79)
+ {
+ state->error = 66; /*text chunk too large*/
+ break;
+ }
+ if(strlen(info.itext_keys[i]) < 1)
+ {
+ state->error = 67; /*text chunk too small*/
+ break;
+ }
+ addChunk_iTXt(&outv, state->encoder.text_compression,
+ info.itext_keys[i], info.itext_langtags[i], info.itext_transkeys[i], info.itext_strings[i],
+ &state->encoder.zlibsettings);
+ }
+
+ /*unknown chunks between IDAT and IEND*/
+ if(info.unknown_chunks_data[2])
+ {
+ state->error = addUnknownChunks(&outv, info.unknown_chunks_data[2], info.unknown_chunks_size[2]);
+ if(state->error) break;
+ }
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+ addChunk_IEND(&outv);
+
+ break; /*this isn't really a while loop; no error happened so break out now!*/
+ }
+
+ lodepng_info_cleanup(&info);
+ lodepng_free(data);
+ /*instead of cleaning the vector up, give it to the output*/
+ *out = outv.data;
+ *outsize = outv.size;
+
+ return state->error;
+}
+
+unsigned lodepng_encode_memory(unsigned char** out, size_t* outsize, const unsigned char* image,
+ unsigned w, unsigned h, LodePNGColorType colortype, unsigned bitdepth)
+{
+ unsigned error;
+ LodePNGState state;
+ lodepng_state_init(&state);
+ state.info_raw.colortype = colortype;
+ state.info_raw.bitdepth = bitdepth;
+ state.info_png.color.colortype = colortype;
+ state.info_png.color.bitdepth = bitdepth;
+ lodepng_encode(out, outsize, image, w, h, &state);
+ error = state.error;
+ lodepng_state_cleanup(&state);
+ return error;
+}
+
+unsigned lodepng_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h)
+{
+ return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGBA, 8);
+}
+
+unsigned lodepng_encode24(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h)
+{
+ return lodepng_encode_memory(out, outsize, image, w, h, LCT_RGB, 8);
+}
+
+#ifdef LODEPNG_COMPILE_DISK
+unsigned lodepng_encode_file(const char* filename, const unsigned char* image, unsigned w, unsigned h,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ unsigned char* buffer;
+ size_t buffersize;
+ unsigned error = lodepng_encode_memory(&buffer, &buffersize, image, w, h, colortype, bitdepth);
+ if(!error) error = lodepng_save_file(buffer, buffersize, filename);
+ lodepng_free(buffer);
+ return error;
+}
+
+unsigned lodepng_encode32_file(const char* filename, const unsigned char* image, unsigned w, unsigned h)
+{
+ return lodepng_encode_file(filename, image, w, h, LCT_RGBA, 8);
+}
+
+unsigned lodepng_encode24_file(const char* filename, const unsigned char* image, unsigned w, unsigned h)
+{
+ return lodepng_encode_file(filename, image, w, h, LCT_RGB, 8);
+}
+#endif /*LODEPNG_COMPILE_DISK*/
+
+void lodepng_encoder_settings_init(LodePNGEncoderSettings* settings)
+{
+ lodepng_compress_settings_init(&settings->zlibsettings);
+ settings->filter_palette_zero = 1;
+ settings->filter_strategy = LFS_MINSUM;
+ settings->auto_convert = LAC_AUTO;
+ settings->force_palette = 0;
+ settings->predefined_filters = 0;
+#ifdef LODEPNG_COMPILE_ANCILLARY_CHUNKS
+ settings->add_id = 0;
+ settings->text_compression = 1;
+#endif /*LODEPNG_COMPILE_ANCILLARY_CHUNKS*/
+}
+
+#endif /*LODEPNG_COMPILE_ENCODER*/
+#endif /*LODEPNG_COMPILE_PNG*/
+
+#ifdef LODEPNG_COMPILE_ERROR_TEXT
+/*
+This returns the description of a numerical error code in English. This is also
+the documentation of all the error codes.
+*/
+const char* lodepng_error_text(unsigned code)
+{
+ switch(code)
+ {
+ case 0: return "no error, everything went ok";
+ case 1: return "nothing done yet"; /*the Encoder/Decoder has done nothing yet, error checking makes no sense yet*/
+ case 10: return "end of input memory reached without huffman end code"; /*while huffman decoding*/
+ case 11: return "error in code tree made it jump outside of huffman tree"; /*while huffman decoding*/
+ case 13: return "problem while processing dynamic deflate block";
+ case 14: return "problem while processing dynamic deflate block";
+ case 15: return "problem while processing dynamic deflate block";
+ case 16: return "unexisting code while processing dynamic deflate block";
+ case 17: return "end of out buffer memory reached while inflating";
+ case 18: return "invalid distance code while inflating";
+ case 19: return "end of out buffer memory reached while inflating";
+ case 20: return "invalid deflate block BTYPE encountered while decoding";
+ case 21: return "NLEN is not ones complement of LEN in a deflate block";
+ /*end of out buffer memory reached while inflating:
+ This can happen if the inflated deflate data is longer than the amount of bytes required to fill up
+ all the pixels of the image, given the color depth and image dimensions. Something that doesn't
+ happen in a normal, well encoded, PNG image.*/
+ case 22: return "end of out buffer memory reached while inflating";
+ case 23: return "end of in buffer memory reached while inflating";
+ case 24: return "invalid FCHECK in zlib header";
+ case 25: return "invalid compression method in zlib header";
+ case 26: return "FDICT encountered in zlib header while it's not used for PNG";
+ case 27: return "PNG file is smaller than a PNG header";
+ /*Checks the magic file header, the first 8 bytes of the PNG file*/
+ case 28: return "incorrect PNG signature, it's no PNG or corrupted";
+ case 29: return "first chunk is not the header chunk";
+ case 30: return "chunk length too large, chunk broken off at end of file";
+ case 31: return "illegal PNG color type or bpp";
+ case 32: return "illegal PNG compression method";
+ case 33: return "illegal PNG filter method";
+ case 34: return "illegal PNG interlace method";
+ case 35: return "chunk length of a chunk is too large or the chunk too small";
+ case 36: return "illegal PNG filter type encountered";
+ case 37: return "illegal bit depth for this color type given";
+ case 38: return "the palette is too big"; /*more than 256 colors*/
+ case 39: return "more palette alpha values given in tRNS chunk than there are colors in the palette";
+ case 40: return "tRNS chunk has wrong size for greyscale image";
+ case 41: return "tRNS chunk has wrong size for RGB image";
+ case 42: return "tRNS chunk appeared while it was not allowed for this color type";
+ case 43: return "bKGD chunk has wrong size for palette image";
+ case 44: return "bKGD chunk has wrong size for greyscale image";
+ case 45: return "bKGD chunk has wrong size for RGB image";
+ /*Is the palette too small?*/
+ case 46: return "a value in indexed image is larger than the palette size (bitdepth = 8)";
+ /*Is the palette too small?*/
+ case 47: return "a value in indexed image is larger than the palette size (bitdepth < 8)";
+ /*the input data is empty, maybe a PNG file doesn't exist or is in the wrong path*/
+ case 48: return "empty input or file doesn't exist";
+ case 49: return "jumped past memory while generating dynamic huffman tree";
+ case 50: return "jumped past memory while generating dynamic huffman tree";
+ case 51: return "jumped past memory while inflating huffman block";
+ case 52: return "jumped past memory while inflating";
+ case 53: return "size of zlib data too small";
+ case 54: return "repeat symbol in tree while there was no value symbol yet";
+ /*jumped past tree while generating huffman tree, this could be when the
+ tree will have more leaves than symbols after generating it out of the
+ given lenghts. They call this an oversubscribed dynamic bit lengths tree in zlib.*/
+ case 55: return "jumped past tree while generating huffman tree";
+ case 56: return "given output image colortype or bitdepth not supported for color conversion";
+ case 57: return "invalid CRC encountered (checking CRC can be disabled)";
+ case 58: return "invalid ADLER32 encountered (checking ADLER32 can be disabled)";
+ case 59: return "requested color conversion not supported";
+ case 60: return "invalid window size given in the settings of the encoder (must be 0-32768)";
+ case 61: return "invalid BTYPE given in the settings of the encoder (only 0, 1 and 2 are allowed)";
+ /*LodePNG leaves the choice of RGB to greyscale conversion formula to the user.*/
+ case 62: return "conversion from color to greyscale not supported";
+ case 63: return "length of a chunk too long, max allowed for PNG is 2147483647 bytes per chunk"; /*(2^31-1)*/
+ /*this would result in the inability of a deflated block to ever contain an end code. It must be at least 1.*/
+ case 64: return "the length of the END symbol 256 in the Huffman tree is 0";
+ case 66: return "the length of a text chunk keyword given to the encoder is longer than the maximum of 79 bytes";
+ case 67: return "the length of a text chunk keyword given to the encoder is smaller than the minimum of 1 byte";
+ case 68: return "tried to encode a PLTE chunk with a palette that has less than 1 or more than 256 colors";
+ case 69: return "unknown chunk type with 'critical' flag encountered by the decoder";
+ case 71: return "unexisting interlace mode given to encoder (must be 0 or 1)";
+ case 72: return "while decoding, unexisting compression method encountering in zTXt or iTXt chunk (it must be 0)";
+ case 73: return "invalid tIME chunk size";
+ case 74: return "invalid pHYs chunk size";
+ /*length could be wrong, or data chopped off*/
+ case 75: return "no null termination char found while decoding text chunk";
+ case 76: return "iTXt chunk too short to contain required bytes";
+ case 77: return "integer overflow in buffer size";
+ case 78: return "failed to open file for reading"; /*file doesn't exist or couldn't be opened for reading*/
+ case 79: return "failed to open file for writing";
+ case 80: return "tried creating a tree of 0 symbols";
+ case 81: return "lazy matching at pos 0 is impossible";
+ case 82: return "color conversion to palette requested while a color isn't in palette";
+ case 83: return "memory allocation failed";
+ case 84: return "given image too small to contain all pixels to be encoded";
+ case 85: return "internal color conversion bug";
+ case 86: return "impossible offset in lz77 encoding (internal bug)";
+ case 87: return "must provide custom zlib function pointer if LODEPNG_COMPILE_ZLIB is not defined";
+ case 88: return "invalid filter strategy given for LodePNGEncoderSettings.filter_strategy";
+ case 89: return "text chunk keyword too short or long: must have size 1-79";
+ /*the windowsize in the LodePNGCompressSettings. Requiring POT(==> & instead of %) makes encoding 12% faster.*/
+ case 90: return "windowsize must be a power of two";
+ }
+ return "unknown error code";
+}
+#endif /*LODEPNG_COMPILE_ERROR_TEXT*/
+
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* // C++ Wrapper // */
+/* ////////////////////////////////////////////////////////////////////////// */
+/* ////////////////////////////////////////////////////////////////////////// */
+
+#ifdef LODEPNG_COMPILE_CPP
+namespace lodepng
+{
+
+#ifdef LODEPNG_COMPILE_DISK
+void load_file(std::vector<unsigned char>& buffer, const std::string& filename)
+{
+ std::ifstream file(filename.c_str(), std::ios::in|std::ios::binary|std::ios::ate);
+
+ /*get filesize*/
+ std::streamsize size = 0;
+ if(file.seekg(0, std::ios::end).good()) size = file.tellg();
+ if(file.seekg(0, std::ios::beg).good()) size -= file.tellg();
+
+ /*read contents of the file into the vector*/
+ buffer.resize(size_t(size));
+ if(size > 0) file.read((char*)(&buffer[0]), size);
+}
+
+/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
+void save_file(const std::vector<unsigned char>& buffer, const std::string& filename)
+{
+ std::ofstream file(filename.c_str(), std::ios::out|std::ios::binary);
+ file.write(buffer.empty() ? 0 : (char*)&buffer[0], std::streamsize(buffer.size()));
+}
+#endif //LODEPNG_COMPILE_DISK
+
+#ifdef LODEPNG_COMPILE_ZLIB
+#ifdef LODEPNG_COMPILE_DECODER
+unsigned decompress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
+ const LodePNGDecompressSettings& settings)
+{
+ unsigned char* buffer = 0;
+ size_t buffersize = 0;
+ unsigned error = zlib_decompress(&buffer, &buffersize, in, insize, &settings);
+ if(buffer)
+ {
+ out.insert(out.end(), &buffer[0], &buffer[buffersize]);
+ lodepng_free(buffer);
+ }
+ return error;
+}
+
+unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
+ const LodePNGDecompressSettings& settings)
+{
+ return decompress(out, in.empty() ? 0 : &in[0], in.size(), settings);
+}
+#endif //LODEPNG_COMPILE_DECODER
+
+#ifdef LODEPNG_COMPILE_ENCODER
+unsigned compress(std::vector<unsigned char>& out, const unsigned char* in, size_t insize,
+ const LodePNGCompressSettings& settings)
+{
+ unsigned char* buffer = 0;
+ size_t buffersize = 0;
+ unsigned error = zlib_compress(&buffer, &buffersize, in, insize, &settings);
+ if(buffer)
+ {
+ out.insert(out.end(), &buffer[0], &buffer[buffersize]);
+ lodepng_free(buffer);
+ }
+ return error;
+}
+
+unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in,
+ const LodePNGCompressSettings& settings)
+{
+ return compress(out, in.empty() ? 0 : &in[0], in.size(), settings);
+}
+#endif //LODEPNG_COMPILE_ENCODER
+#endif //LODEPNG_COMPILE_ZLIB
+
+
+#ifdef LODEPNG_COMPILE_PNG
+
+State::State()
+{
+ lodepng_state_init(this);
+}
+
+State::State(const State& other)
+{
+ lodepng_state_init(this);
+ lodepng_state_copy(this, &other);
+}
+
+State::~State()
+{
+ lodepng_state_cleanup(this);
+}
+
+State& State::operator=(const State& other)
+{
+ lodepng_state_copy(this, &other);
+ return *this;
+}
+
+#ifdef LODEPNG_COMPILE_DECODER
+
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const unsigned char* in,
+ size_t insize, LodePNGColorType colortype, unsigned bitdepth)
+{
+ unsigned char* buffer;
+ unsigned error = lodepng_decode_memory(&buffer, &w, &h, in, insize, colortype, bitdepth);
+ if(buffer && !error)
+ {
+ State state;
+ state.info_raw.colortype = colortype;
+ state.info_raw.bitdepth = bitdepth;
+ size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
+ out.insert(out.end(), &buffer[0], &buffer[buffersize]);
+ lodepng_free(buffer);
+ }
+ return error;
+}
+
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+ const std::vector<unsigned char>& in, LodePNGColorType colortype, unsigned bitdepth)
+{
+ return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colortype, bitdepth);
+}
+
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+ State& state,
+ const unsigned char* in, size_t insize)
+{
+ unsigned char* buffer = NULL;
+ unsigned error = lodepng_decode(&buffer, &w, &h, &state, in, insize);
+ if(buffer && !error)
+ {
+ size_t buffersize = lodepng_get_raw_size(w, h, &state.info_raw);
+ out.insert(out.end(), &buffer[0], &buffer[buffersize]);
+ }
+ lodepng_free(buffer);
+ return error;
+}
+
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h,
+ State& state,
+ const std::vector<unsigned char>& in)
+{
+ return decode(out, w, h, state, in.empty() ? 0 : &in[0], in.size());
+}
+
+#ifdef LODEPNG_COMPILE_DISK
+unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::string& filename,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ std::vector<unsigned char> buffer;
+ load_file(buffer, filename);
+ return decode(out, w, h, buffer, colortype, bitdepth);
+}
+#endif //LODEPNG_COMPILE_DECODER
+#endif //LODEPNG_COMPILE_DISK
+
+#ifdef LODEPNG_COMPILE_ENCODER
+unsigned encode(std::vector<unsigned char>& out, const unsigned char* in, unsigned w, unsigned h,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ unsigned char* buffer;
+ size_t buffersize;
+ unsigned error = lodepng_encode_memory(&buffer, &buffersize, in, w, h, colortype, bitdepth);
+ if(buffer)
+ {
+ out.insert(out.end(), &buffer[0], &buffer[buffersize]);
+ lodepng_free(buffer);
+ }
+ return error;
+}
+
+unsigned encode(std::vector<unsigned char>& out,
+ const std::vector<unsigned char>& in, unsigned w, unsigned h,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
+ return encode(out, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
+}
+
+unsigned encode(std::vector<unsigned char>& out,
+ const unsigned char* in, unsigned w, unsigned h,
+ State& state)
+{
+ unsigned char* buffer;
+ size_t buffersize;
+ unsigned error = lodepng_encode(&buffer, &buffersize, in, w, h, &state);
+ if(buffer)
+ {
+ out.insert(out.end(), &buffer[0], &buffer[buffersize]);
+ lodepng_free(buffer);
+ }
+ return error;
+}
+
+unsigned encode(std::vector<unsigned char>& out,
+ const std::vector<unsigned char>& in, unsigned w, unsigned h,
+ State& state)
+{
+ if(lodepng_get_raw_size(w, h, &state.info_raw) > in.size()) return 84;
+ return encode(out, in.empty() ? 0 : &in[0], w, h, state);
+}
+
+#ifdef LODEPNG_COMPILE_DISK
+unsigned encode(const std::string& filename,
+ const unsigned char* in, unsigned w, unsigned h,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ std::vector<unsigned char> buffer;
+ unsigned error = encode(buffer, in, w, h, colortype, bitdepth);
+ if(!error) save_file(buffer, filename);
+ return error;
+}
+
+unsigned encode(const std::string& filename,
+ const std::vector<unsigned char>& in, unsigned w, unsigned h,
+ LodePNGColorType colortype, unsigned bitdepth)
+{
+ if(lodepng_get_raw_size_lct(w, h, colortype, bitdepth) > in.size()) return 84;
+ return encode(filename, in.empty() ? 0 : &in[0], w, h, colortype, bitdepth);
+}
+#endif //LODEPNG_COMPILE_DISK
+#endif //LODEPNG_COMPILE_ENCODER
+#endif //LODEPNG_COMPILE_PNG
+} //namespace lodepng
+#endif /*LODEPNG_COMPILE_CPP*/