Wei Chang Shen / DMemWin

Dependencies:   emwin_lib

Fork of DMemWin by Embedded Artists

png/pngrio.c@2:0e2ef1edf01b, 2016-06-02 (annotated)

Committer:
destinyXfate
Date:
Thu Jun 02 04:52:54 2016 +0000
Revision:
2:0e2ef1edf01b
;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
destinyXfate 2:0e2ef1edf01b 1
destinyXfate 2:0e2ef1edf01b 2 /* pngrio.c - functions for data input
destinyXfate 2:0e2ef1edf01b 3 *
destinyXfate 2:0e2ef1edf01b 4 * Last changed in libpng 1.2.13 November 13, 2006
destinyXfate 2:0e2ef1edf01b 5 * For conditions of distribution and use, see copyright notice in png.h
destinyXfate 2:0e2ef1edf01b 6 * Copyright (c) 1998-2006 Glenn Randers-Pehrson
destinyXfate 2:0e2ef1edf01b 7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
destinyXfate 2:0e2ef1edf01b 8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
destinyXfate 2:0e2ef1edf01b 9 *
destinyXfate 2:0e2ef1edf01b 10 * This file provides a location for all input. Users who need
destinyXfate 2:0e2ef1edf01b 11 * special handling are expected to write a function that has the same
destinyXfate 2:0e2ef1edf01b 12 * arguments as this and performs a similar function, but that possibly
destinyXfate 2:0e2ef1edf01b 13 * has a different input method. Note that you shouldn't change this
destinyXfate 2:0e2ef1edf01b 14 * function, but rather write a replacement function and then make
destinyXfate 2:0e2ef1edf01b 15 * libpng use it at run time with png_set_read_fn(...).
destinyXfate 2:0e2ef1edf01b 16 */
destinyXfate 2:0e2ef1edf01b 17
destinyXfate 2:0e2ef1edf01b 18 #define PNG_INTERNAL
destinyXfate 2:0e2ef1edf01b 19 #include "png.h"
destinyXfate 2:0e2ef1edf01b 20
destinyXfate 2:0e2ef1edf01b 21 #if defined(PNG_READ_SUPPORTED)
destinyXfate 2:0e2ef1edf01b 22
destinyXfate 2:0e2ef1edf01b 23 /* Read the data from whatever input you are using. The default routine
destinyXfate 2:0e2ef1edf01b 24 reads from a file pointer. Note that this routine sometimes gets called
destinyXfate 2:0e2ef1edf01b 25 with very small lengths, so you should implement some kind of simple
destinyXfate 2:0e2ef1edf01b 26 buffering if you are using unbuffered reads. This should never be asked
destinyXfate 2:0e2ef1edf01b 27 to read more then 64K on a 16 bit machine. */
destinyXfate 2:0e2ef1edf01b 28 void /* PRIVATE */
destinyXfate 2:0e2ef1edf01b 29 png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
destinyXfate 2:0e2ef1edf01b 30 {
destinyXfate 2:0e2ef1edf01b 31 png_debug1(4,"reading %d bytes\n", (int)length);
destinyXfate 2:0e2ef1edf01b 32 if (png_ptr->read_data_fn != NULL)
destinyXfate 2:0e2ef1edf01b 33 (*(png_ptr->read_data_fn))(png_ptr, data, length);
destinyXfate 2:0e2ef1edf01b 34 else
destinyXfate 2:0e2ef1edf01b 35 png_error(png_ptr, "Call to NULL read function");
destinyXfate 2:0e2ef1edf01b 36 }
destinyXfate 2:0e2ef1edf01b 37
destinyXfate 2:0e2ef1edf01b 38 #if !defined(PNG_NO_STDIO)
destinyXfate 2:0e2ef1edf01b 39 /* This is the function that does the actual reading of data. If you are
destinyXfate 2:0e2ef1edf01b 40 not reading from a standard C stream, you should create a replacement
destinyXfate 2:0e2ef1edf01b 41 read_data function and use it at run time with png_set_read_fn(), rather
destinyXfate 2:0e2ef1edf01b 42 than changing the library. */
destinyXfate 2:0e2ef1edf01b 43 #ifndef USE_FAR_KEYWORD
destinyXfate 2:0e2ef1edf01b 44 void PNGAPI
destinyXfate 2:0e2ef1edf01b 45 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
destinyXfate 2:0e2ef1edf01b 46 {
destinyXfate 2:0e2ef1edf01b 47 png_size_t check;
destinyXfate 2:0e2ef1edf01b 48
destinyXfate 2:0e2ef1edf01b 49 if(png_ptr == NULL) return;
destinyXfate 2:0e2ef1edf01b 50 /* fread() returns 0 on error, so it is OK to store this in a png_size_t
destinyXfate 2:0e2ef1edf01b 51 * instead of an int, which is what fread() actually returns.
destinyXfate 2:0e2ef1edf01b 52 */
destinyXfate 2:0e2ef1edf01b 53 #if defined(_WIN32_WCE)
destinyXfate 2:0e2ef1edf01b 54 if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
destinyXfate 2:0e2ef1edf01b 55 check = 0;
destinyXfate 2:0e2ef1edf01b 56 #else
destinyXfate 2:0e2ef1edf01b 57 check = (png_size_t)fread(data, (png_size_t)1, length,
destinyXfate 2:0e2ef1edf01b 58 (png_FILE_p)png_ptr->io_ptr);
destinyXfate 2:0e2ef1edf01b 59 #endif
destinyXfate 2:0e2ef1edf01b 60
destinyXfate 2:0e2ef1edf01b 61 if (check != length)
destinyXfate 2:0e2ef1edf01b 62 png_error(png_ptr, "Read Error");
destinyXfate 2:0e2ef1edf01b 63 }
destinyXfate 2:0e2ef1edf01b 64 #else
destinyXfate 2:0e2ef1edf01b 65 /* this is the model-independent version. Since the standard I/O library
destinyXfate 2:0e2ef1edf01b 66 can't handle far buffers in the medium and small models, we have to copy
destinyXfate 2:0e2ef1edf01b 67 the data.
destinyXfate 2:0e2ef1edf01b 68 */
destinyXfate 2:0e2ef1edf01b 69
destinyXfate 2:0e2ef1edf01b 70 #define NEAR_BUF_SIZE 1024
destinyXfate 2:0e2ef1edf01b 71 #define MIN(a,b) (a <= b ? a : b)
destinyXfate 2:0e2ef1edf01b 72
destinyXfate 2:0e2ef1edf01b 73 static void PNGAPI
destinyXfate 2:0e2ef1edf01b 74 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
destinyXfate 2:0e2ef1edf01b 75 {
destinyXfate 2:0e2ef1edf01b 76 int check;
destinyXfate 2:0e2ef1edf01b 77 png_byte *n_data;
destinyXfate 2:0e2ef1edf01b 78 png_FILE_p io_ptr;
destinyXfate 2:0e2ef1edf01b 79
destinyXfate 2:0e2ef1edf01b 80 if(png_ptr == NULL) return;
destinyXfate 2:0e2ef1edf01b 81 /* Check if data really is near. If so, use usual code. */
destinyXfate 2:0e2ef1edf01b 82 n_data = (png_byte *)CVT_PTR_NOCHECK(data);
destinyXfate 2:0e2ef1edf01b 83 io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
destinyXfate 2:0e2ef1edf01b 84 if ((png_bytep)n_data == data)
destinyXfate 2:0e2ef1edf01b 85 {
destinyXfate 2:0e2ef1edf01b 86 #if defined(_WIN32_WCE)
destinyXfate 2:0e2ef1edf01b 87 if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
destinyXfate 2:0e2ef1edf01b 88 check = 0;
destinyXfate 2:0e2ef1edf01b 89 #else
destinyXfate 2:0e2ef1edf01b 90 check = fread(n_data, 1, length, io_ptr);
destinyXfate 2:0e2ef1edf01b 91 #endif
destinyXfate 2:0e2ef1edf01b 92 }
destinyXfate 2:0e2ef1edf01b 93 else
destinyXfate 2:0e2ef1edf01b 94 {
destinyXfate 2:0e2ef1edf01b 95 png_byte buf[NEAR_BUF_SIZE];
destinyXfate 2:0e2ef1edf01b 96 png_size_t read, remaining, err;
destinyXfate 2:0e2ef1edf01b 97 check = 0;
destinyXfate 2:0e2ef1edf01b 98 remaining = length;
destinyXfate 2:0e2ef1edf01b 99 do
destinyXfate 2:0e2ef1edf01b 100 {
destinyXfate 2:0e2ef1edf01b 101 read = MIN(NEAR_BUF_SIZE, remaining);
destinyXfate 2:0e2ef1edf01b 102 #if defined(_WIN32_WCE)
destinyXfate 2:0e2ef1edf01b 103 if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
destinyXfate 2:0e2ef1edf01b 104 err = 0;
destinyXfate 2:0e2ef1edf01b 105 #else
destinyXfate 2:0e2ef1edf01b 106 err = fread(buf, (png_size_t)1, read, io_ptr);
destinyXfate 2:0e2ef1edf01b 107 #endif
destinyXfate 2:0e2ef1edf01b 108 png_memcpy(data, buf, read); /* copy far buffer to near buffer */
destinyXfate 2:0e2ef1edf01b 109 if(err != read)
destinyXfate 2:0e2ef1edf01b 110 break;
destinyXfate 2:0e2ef1edf01b 111 else
destinyXfate 2:0e2ef1edf01b 112 check += err;
destinyXfate 2:0e2ef1edf01b 113 data += read;
destinyXfate 2:0e2ef1edf01b 114 remaining -= read;
destinyXfate 2:0e2ef1edf01b 115 }
destinyXfate 2:0e2ef1edf01b 116 while (remaining != 0);
destinyXfate 2:0e2ef1edf01b 117 }
destinyXfate 2:0e2ef1edf01b 118 if ((png_uint_32)check != (png_uint_32)length)
destinyXfate 2:0e2ef1edf01b 119 png_error(png_ptr, "read Error");
destinyXfate 2:0e2ef1edf01b 120 }
destinyXfate 2:0e2ef1edf01b 121 #endif
destinyXfate 2:0e2ef1edf01b 122 #endif
destinyXfate 2:0e2ef1edf01b 123
destinyXfate 2:0e2ef1edf01b 124 /* This function allows the application to supply a new input function
destinyXfate 2:0e2ef1edf01b 125 for libpng if standard C streams aren't being used.
destinyXfate 2:0e2ef1edf01b 126
destinyXfate 2:0e2ef1edf01b 127 This function takes as its arguments:
destinyXfate 2:0e2ef1edf01b 128 png_ptr - pointer to a png input data structure
destinyXfate 2:0e2ef1edf01b 129 io_ptr - pointer to user supplied structure containing info about
destinyXfate 2:0e2ef1edf01b 130 the input functions. May be NULL.
destinyXfate 2:0e2ef1edf01b 131 read_data_fn - pointer to a new input function that takes as its
destinyXfate 2:0e2ef1edf01b 132 arguments a pointer to a png_struct, a pointer to
destinyXfate 2:0e2ef1edf01b 133 a location where input data can be stored, and a 32-bit
destinyXfate 2:0e2ef1edf01b 134 unsigned int that is the number of bytes to be read.
destinyXfate 2:0e2ef1edf01b 135 To exit and output any fatal error messages the new write
destinyXfate 2:0e2ef1edf01b 136 function should call png_error(png_ptr, "Error msg"). */
destinyXfate 2:0e2ef1edf01b 137 void PNGAPI
destinyXfate 2:0e2ef1edf01b 138 png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
destinyXfate 2:0e2ef1edf01b 139 png_rw_ptr read_data_fn)
destinyXfate 2:0e2ef1edf01b 140 {
destinyXfate 2:0e2ef1edf01b 141 if(png_ptr == NULL) return;
destinyXfate 2:0e2ef1edf01b 142 png_ptr->io_ptr = io_ptr;
destinyXfate 2:0e2ef1edf01b 143
destinyXfate 2:0e2ef1edf01b 144 #if !defined(PNG_NO_STDIO)
destinyXfate 2:0e2ef1edf01b 145 if (read_data_fn != NULL)
destinyXfate 2:0e2ef1edf01b 146 png_ptr->read_data_fn = read_data_fn;
destinyXfate 2:0e2ef1edf01b 147 else
destinyXfate 2:0e2ef1edf01b 148 png_ptr->read_data_fn = png_default_read_data;
destinyXfate 2:0e2ef1edf01b 149 #else
destinyXfate 2:0e2ef1edf01b 150 png_ptr->read_data_fn = read_data_fn;
destinyXfate 2:0e2ef1edf01b 151 #endif
destinyXfate 2:0e2ef1edf01b 152
destinyXfate 2:0e2ef1edf01b 153 /* It is an error to write to a read device */
destinyXfate 2:0e2ef1edf01b 154 if (png_ptr->write_data_fn != NULL)
destinyXfate 2:0e2ef1edf01b 155 {
destinyXfate 2:0e2ef1edf01b 156 png_ptr->write_data_fn = NULL;
destinyXfate 2:0e2ef1edf01b 157 png_warning(png_ptr,
destinyXfate 2:0e2ef1edf01b 158 "It's an error to set both read_data_fn and write_data_fn in the ");
destinyXfate 2:0e2ef1edf01b 159 png_warning(png_ptr,
destinyXfate 2:0e2ef1edf01b 160 "same structure. Resetting write_data_fn to NULL.");
destinyXfate 2:0e2ef1edf01b 161 }
destinyXfate 2:0e2ef1edf01b 162
destinyXfate 2:0e2ef1edf01b 163 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
destinyXfate 2:0e2ef1edf01b 164 png_ptr->output_flush_fn = NULL;
destinyXfate 2:0e2ef1edf01b 165 #endif
destinyXfate 2:0e2ef1edf01b 166 }
destinyXfate 2:0e2ef1edf01b 167 #endif /* PNG_READ_SUPPORTED */
destinyXfate 2:0e2ef1edf01b 168