Aditya Barve
This is a code which generates the various zoomed versions of an image stored in an SD card and displays it on a Nokia LCD based on the keys pressed on a capacitive touch pad.
Dependencies: FatFileSystem mbed
Fork of
Lab3
by 
Martin Sturm
Diff: picojpeg/picojpeg.c
- Revision:
- 0:c546b51ecf0b
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/picojpeg/picojpeg.c Tue Oct 11 01:24:18 2011 +0000
@@ -0,0 +1,1736 @@
+//------------------------------------------------------------------------------
+// picojpeg v1.0 - Public domain, Rich Geldreich <richgel99@gmail.com>
+// Last modified Nov. 27, 2010
+//------------------------------------------------------------------------------
+#include "picojpeg.h"
+//------------------------------------------------------------------------------
+typedef unsigned char uint8;
+typedef unsigned short uint16;
+typedef signed char int8;
+typedef signed short int16;
+//------------------------------------------------------------------------------
+// Change as needed - the PJPG_MAX_WIDTH/PJPG_MAX_HEIGHT checks are only present
+// to quickly detect bogus files.
+#define PJPG_MAX_WIDTH 16384
+#define PJPG_MAX_HEIGHT 16384
+
+#define PJPG_MAXCOMPSINSCAN 3
+//------------------------------------------------------------------------------
+typedef enum
+{
+ M_SOF0 = 0xC0,
+ M_SOF1 = 0xC1,
+ M_SOF2 = 0xC2,
+ M_SOF3 = 0xC3,
+
+ M_SOF5 = 0xC5,
+ M_SOF6 = 0xC6,
+ M_SOF7 = 0xC7,
+
+ M_JPG = 0xC8,
+ M_SOF9 = 0xC9,
+ M_SOF10 = 0xCA,
+ M_SOF11 = 0xCB,
+
+ M_SOF13 = 0xCD,
+ M_SOF14 = 0xCE,
+ M_SOF15 = 0xCF,
+
+ M_DHT = 0xC4,
+
+ M_DAC = 0xCC,
+
+ M_RST0 = 0xD0,
+ M_RST1 = 0xD1,
+ M_RST2 = 0xD2,
+ M_RST3 = 0xD3,
+ M_RST4 = 0xD4,
+ M_RST5 = 0xD5,
+ M_RST6 = 0xD6,
+ M_RST7 = 0xD7,
+
+ M_SOI = 0xD8,
+ M_EOI = 0xD9,
+ M_SOS = 0xDA,
+ M_DQT = 0xDB,
+ M_DNL = 0xDC,
+ M_DRI = 0xDD,
+ M_DHP = 0xDE,
+ M_EXP = 0xDF,
+
+ M_APP0 = 0xE0,
+ M_APP15 = 0xEF,
+
+ M_JPG0 = 0xF0,
+ M_JPG13 = 0xFD,
+ M_COM = 0xFE,
+
+ M_TEM = 0x01,
+
+ M_ERROR = 0x100
+} JPEG_MARKER;
+
+#define RST0 0xD0
+//------------------------------------------------------------------------------
+const int8 ZAG[] =
+{
+ 0, 1, 8, 16, 9, 2, 3, 10,
+ 17, 24, 32, 25, 18, 11, 4, 5,
+ 12, 19, 26, 33, 40, 48, 41, 34,
+ 27, 20, 13, 6, 7, 14, 21, 28,
+ 35, 42, 49, 56, 57, 50, 43, 36,
+ 29, 22, 15, 23, 30, 37, 44, 51,
+ 58, 59, 52, 45, 38, 31, 39, 46,
+ 53, 60, 61, 54, 47, 55, 62, 63,
+};
+//------------------------------------------------------------------------------
+// 128 bytes
+static int16 gCoeffBuf[8*8];
+
+// 8*8*4 bytes * 3 = 768
+static uint8 gMCUBufR[256];
+static uint8 gMCUBufG[256];
+static uint8 gMCUBufB[256];
+
+// 256 bytes
+static int16 gQuant0[8*8];
+static int16 gQuant1[8*8];
+
+// 6 bytes
+static int16 gLastDC[3];
+
+typedef struct HuffTableT
+{
+ uint16 mMinCode[16];
+ uint16 mMaxCode[16];
+ uint8 mValPtr[16];
+} HuffTable;
+
+// DC - 192
+static HuffTable gHuffTab0;
+
+static uint8 gHuffVal0[16];
+
+static HuffTable gHuffTab1;
+static uint8 gHuffVal1[16];
+
+// AC - 672
+static HuffTable gHuffTab2;
+static uint8 gHuffVal2[256];
+
+static HuffTable gHuffTab3;
+static uint8 gHuffVal3[256];
+
+static uint8 gValidHuffTables;
+static uint8 gValidQuantTables;
+
+static uint8 gTemFlag;
+#define MAX_IN_BUF_SIZE 256
+static uint8 gInBuf[MAX_IN_BUF_SIZE];
+static uint8 gInBufOfs;
+static uint8 gInBufLeft;
+
+static uint16 gBitBuf;
+static uint8 gBitsLeft;
+//------------------------------------------------------------------------------
+static uint16 gImageXSize;
+static uint16 gImageYSize;
+static uint8 gCompsInFrame;
+static uint8 gCompIdent[3];
+static uint8 gCompHSamp[3];
+static uint8 gCompVSamp[3];
+static uint8 gCompQuant[3];
+
+static uint16 gRestartInterval;
+static uint16 gNextRestartNum;
+static uint16 gRestartsLeft;
+
+static uint8 gCompsInScan;
+static uint8 gCompList[3];
+static uint8 gCompDCTab[3]; // 0,1
+static uint8 gCompACTab[3]; // 0,1
+
+static pjpeg_scan_type_t gScanType;
+
+static uint8 gMaxBlocksPerMCU;
+static uint8 gMaxMCUXSize;
+static uint8 gMaxMCUYSize;
+static uint16 gMaxMCUSPerRow;
+static uint16 gMaxMCUSPerCol;
+static uint16 gNumMCUSRemaining;
+static uint8 gMCUOrg[6];
+
+static pjpeg_need_bytes_callback_t g_pNeedBytesCallback;
+static void *g_pCallback_data;
+//------------------------------------------------------------------------------
+static uint8 fillInBuf(void)
+{
+ unsigned char status;
+
+ // Reserve a few bytes at the beginning of the buffer for putting back ("stuffing") chars.
+ gInBufOfs = 4;
+ gInBufLeft = 0;
+
+ status = (*g_pNeedBytesCallback)(gInBuf + gInBufOfs, MAX_IN_BUF_SIZE - gInBufOfs, &gInBufLeft, g_pCallback_data);
+ if (status)
+ return status;
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 getChar(void)
+{
+ if (!gInBufLeft)
+ {
+ fillInBuf();
+ if (!gInBufLeft)
+ {
+ gTemFlag = ~gTemFlag;
+ return gTemFlag ? 0xFF : 0xD9;
+ }
+ }
+
+ gInBufLeft--;
+ return gInBuf[gInBufOfs++];
+}
+//------------------------------------------------------------------------------
+static void stuffChar(uint8 i)
+{
+ gInBufOfs--;
+ gInBuf[gInBufOfs] = i;
+ gInBufLeft++;
+}
+//------------------------------------------------------------------------------
+static uint8 getOctet(uint8 FFCheck)
+{
+ uint8 c = getChar();
+
+ if ((FFCheck) && (c == 0xFF))
+ {
+ uint8 n = getChar();
+
+ if (n)
+ {
+ stuffChar(n);
+ stuffChar(0xFF);
+ }
+ }
+
+ return c;
+}
+//------------------------------------------------------------------------------
+static uint16 getBits(uint8 numBits, uint8 FFCheck)
+{
+ uint8 origBits = numBits;
+ uint16 ret = gBitBuf;
+
+ if (numBits > 8)
+ {
+ numBits -= 8;
+
+ gBitBuf <<= gBitsLeft;
+
+ gBitBuf |= getOctet(FFCheck);
+
+ gBitBuf <<= (8 - gBitsLeft);
+
+ ret = (ret & 0xFF00) | (gBitBuf >> 8);
+ }
+
+ if (gBitsLeft < numBits)
+ {
+ gBitBuf <<= gBitsLeft;
+
+ gBitBuf |= getOctet(FFCheck);
+
+ gBitBuf <<= (numBits - gBitsLeft);
+
+ gBitsLeft = 8 - (numBits - gBitsLeft);
+ }
+ else
+ {
+ gBitsLeft = (uint8)(gBitsLeft - numBits);
+ gBitBuf <<= numBits;
+ }
+
+ return ret >> (16 - origBits);
+}
+//------------------------------------------------------------------------------
+static uint16 getBits1(uint8 numBits)
+{
+ return getBits(numBits, 0);
+}
+//------------------------------------------------------------------------------
+static uint16 getBits2(uint8 numBits)
+{
+ return getBits(numBits, 1);
+}
+//------------------------------------------------------------------------------
+static uint8 getBit(void)
+{
+ uint8 ret = 0;
+ if (gBitBuf & 0x8000)
+ ret = 1;
+
+ if (!gBitsLeft)
+ {
+ gBitBuf |= getOctet(1);
+
+ gBitsLeft += 8;
+ }
+
+ gBitsLeft--;
+ gBitBuf <<= 1;
+
+ return ret;
+}
+//------------------------------------------------------------------------------
+static uint16 getExtendTest(uint8 i)
+{
+ switch (i)
+ {
+ case 0: return 0;
+ case 1: return 0x0001;
+ case 2: return 0x0002;
+ case 3: return 0x0004;
+ case 4: return 0x0008;
+ case 5: return 0x0010;
+ case 6: return 0x0020;
+ case 7: return 0x0040;
+ case 8: return 0x0080;
+ case 9: return 0x0100;
+ case 10: return 0x0200;
+ case 11: return 0x0400;
+ case 12: return 0x0800;
+ case 13: return 0x1000;
+ case 14: return 0x2000;
+ case 15: return 0x4000;
+ default: return 0;
+ }
+}
+//------------------------------------------------------------------------------
+static int16 getExtendOffset(uint8 i)
+{
+ switch (i)
+ {
+ case 0: return 0;
+ case 1: return ((-1)<<1) + 1;
+ case 2: return ((-1)<<2) + 1;
+ case 3: return ((-1)<<3) + 1;
+ case 4: return ((-1)<<4) + 1;
+ case 5: return ((-1)<<5) + 1;
+ case 6: return ((-1)<<6) + 1;
+ case 7: return ((-1)<<7) + 1;
+ case 8: return ((-1)<<8) + 1;
+ case 9: return ((-1)<<9) + 1;
+ case 10: return ((-1)<<10) + 1;
+ case 11: return ((-1)<<11) + 1;
+ case 12: return ((-1)<<12) + 1;
+ case 13: return ((-1)<<13) + 1;
+ case 14: return ((-1)<<14) + 1;
+ case 15: return ((-1)<<15) + 1;
+ default: return 0;
+ }
+};
+//------------------------------------------------------------------------------
+static int16 huffExtend(uint16 x, uint8 s)
+{
+ return ((x < getExtendTest(s)) ? ((int16)x + getExtendOffset(s)) : (int16)x);
+}
+//------------------------------------------------------------------------------
+static uint8 huffDecode(const HuffTable* pHuffTable, const uint8* pHuffVal)
+{
+ uint8 i = 0;
+ uint8 j;
+ uint16 code = getBit();
+
+ for ( ; ; )
+ {
+ uint16 maxCode;
+
+ if (i == 16)
+ return 0;
+
+ maxCode = pHuffTable->mMaxCode[i];
+ if ((code <= maxCode) && (maxCode != 0xFFFF))
+ break;
+
+ i++;
+ code <<= 1;
+ code |= getBit();
+ }
+
+ j = pHuffTable->mValPtr[i];
+ j = (uint8)(j + (code - pHuffTable->mMinCode[i]));
+
+ return pHuffVal[j];
+}
+//------------------------------------------------------------------------------
+static void huffCreate(const uint8* pBits, HuffTable* pHuffTable)
+{
+ uint8 i = 0;
+ uint8 j = 0;
+
+ uint16 code = 0;
+
+ for ( ; ; )
+ {
+ uint8 num = pBits[i];
+
+ if (!num)
+ {
+ pHuffTable->mMinCode[i] = 0x0000;
+ pHuffTable->mMaxCode[i] = 0xFFFF;
+ pHuffTable->mValPtr[i] = 0;
+ }
+ else
+ {
+ pHuffTable->mMinCode[i] = code;
+ pHuffTable->mMaxCode[i] = code + num - 1;
+ pHuffTable->mValPtr[i] = j;
+
+ j = (uint8)(j + num);
+
+ code = (uint16)(code + num);
+ }
+
+ code <<= 1;
+
+ i++;
+ if (i > 15)
+ break;
+ }
+}
+//------------------------------------------------------------------------------
+static HuffTable* getHuffTable(uint8 index)
+{
+ // 0-1 = DC
+ // 2-3 = AC
+ switch (index)
+ {
+ case 0: return &gHuffTab0;
+ case 1: return &gHuffTab1;
+ case 2: return &gHuffTab2;
+ case 3: return &gHuffTab3;
+ default: return 0;
+ }
+}
+//------------------------------------------------------------------------------
+static uint8* getHuffVal(uint8 index)
+{
+ // 0-1 = DC
+ // 2-3 = AC
+ switch (index)
+ {
+ case 0: return gHuffVal0;
+ case 1: return gHuffVal1;
+ case 2: return gHuffVal2;
+ case 3: return gHuffVal3;
+ default: return 0;
+ }
+}
+//------------------------------------------------------------------------------
+static uint16 getMaxHuffCodes(uint8 index)
+{
+ return (index < 2) ? 12 : 255;
+}
+//------------------------------------------------------------------------------
+static uint8 readDHTMarker(void)
+{
+ uint8 bits[16];
+ uint16 left = getBits1(16);
+
+ if (left < 2)
+ return PJPG_BAD_DHT_MARKER;
+
+ left -= 2;
+
+ while (left)
+ {
+ uint8 i, tableIndex, index;
+ uint8* pHuffVal;
+ HuffTable* pHuffTable;
+ uint16 count, totalRead;
+
+ index = (uint8)getBits1(8);
+
+ if ( ((index & 0xF) > 1) || ((index & 0xF0) > 0x10) )
+ return PJPG_BAD_DHT_INDEX;
+
+ tableIndex = ((index >> 3) & 2) + (index & 1);
+
+ pHuffTable = getHuffTable(tableIndex);
+ pHuffVal = getHuffVal(tableIndex);
+
+ gValidHuffTables |= (1 << tableIndex);
+
+ count = 0;
+ for (i = 0; i <= 15; i++)
+ {
+ uint8 n = (uint8)getBits1(8);
+ bits[i] = n;
+ count = (uint16)(count + n);
+ }
+
+ if (count > getMaxHuffCodes(tableIndex))
+ return PJPG_BAD_DHT_COUNTS;
+
+ for (i = 0; i < count; i++)
+ pHuffVal[i] = (uint8)getBits1(8);
+
+ totalRead = 1 + 16 + count;
+
+ if (left < totalRead)
+ return PJPG_BAD_DHT_MARKER;
+
+ left = (uint16)(left - totalRead);
+
+ huffCreate(bits, pHuffTable);
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static void createWinogradQuant(int16* pQuant);
+
+static uint8 readDQTMarker(void)
+{
+ uint16 left = getBits1(16);
+
+ if (left < 2)
+ return PJPG_BAD_DQT_MARKER;
+
+ left -= 2;
+
+ while (left)
+ {
+ uint8 i;
+ uint8 n = (uint8)getBits1(8);
+ uint8 prec = n >> 4;
+ uint16 totalRead;
+
+ n &= 0x0F;
+
+ if (n > 1)
+ return PJPG_BAD_DQT_TABLE;
+
+ gValidQuantTables |= (n ? 2 : 1);
+
+ // read quantization entries, in zag order
+ for (i = 0; i < 64; i++)
+ {
+ uint16 temp = getBits1(8);
+
+ if (prec)
+ temp = (temp << 8) + getBits1(8);
+
+ if (n)
+ gQuant1[i] = (int16)temp;
+ else
+ gQuant0[i] = (int16)temp;
+ }
+
+ createWinogradQuant(n ? gQuant1 : gQuant0);
+
+ totalRead = 64 + 1;
+
+ if (prec)
+ totalRead += 64;
+
+ if (left < totalRead)
+ return PJPG_BAD_DQT_LENGTH;
+
+ left = (uint16)(left - totalRead);
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 readSOFMarker(void)
+{
+ uint8 i;
+ uint16 left = getBits1(16);
+
+ if (getBits1(8) != 8)
+ return PJPG_BAD_PRECISION;
+
+ gImageYSize = getBits1(16);
+
+ if ((!gImageYSize) || (gImageYSize > PJPG_MAX_HEIGHT))
+ return PJPG_BAD_HEIGHT;
+
+ gImageXSize = getBits1(16);
+
+ if ((!gImageXSize) || (gImageXSize > PJPG_MAX_WIDTH))
+ return PJPG_BAD_WIDTH;
+
+ gCompsInFrame = (uint8)getBits1(8);
+
+ if (gCompsInFrame > 3)
+ return PJPG_TOO_MANY_COMPONENTS;
+
+ if (left != (gCompsInFrame + gCompsInFrame + gCompsInFrame + 8))
+ return PJPG_BAD_SOF_LENGTH;
+
+ for (i = 0; i < gCompsInFrame; i++)
+ {
+ gCompIdent[i] = (uint8)getBits1(8);
+ gCompHSamp[i] = (uint8)getBits1(4);
+ gCompVSamp[i] = (uint8)getBits1(4);
+ gCompQuant[i] = (uint8)getBits1(8);
+
+ if (gCompQuant[i] > 1)
+ return PJPG_UNSUPPORTED_QUANT_TABLE;
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+// Used to skip unrecognized markers.
+static uint8 skipVariableMarker(void)
+{
+ uint16 left = getBits1(16);
+
+ if (left < 2)
+ return PJPG_BAD_VARIABLE_MARKER;
+
+ left -= 2;
+
+ while (left)
+ {
+ getBits1(8);
+ left--;
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+// Read a define restart interval (DRI) marker.
+static uint8 readDRIMarker(void)
+{
+ if (getBits1(16) != 4)
+ return PJPG_BAD_DRI_LENGTH;
+
+ gRestartInterval = getBits1(16);
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+// Read a start of scan (SOS) marker.
+static uint8 readSOSMarker(void)
+{
+ uint8 i;
+ uint16 left = getBits1(16);
+ uint8 spectral_start, spectral_end, successive_high, successive_low;
+
+ gCompsInScan = (uint8)getBits1(8);
+
+ left -= 3;
+
+ if ( (left != (gCompsInScan + gCompsInScan + 3)) || (gCompsInScan < 1) || (gCompsInScan > PJPG_MAXCOMPSINSCAN) )
+ return PJPG_BAD_SOS_LENGTH;
+
+ for (i = 0; i < gCompsInScan; i++)
+ {
+ uint8 cc = (uint8)getBits1(8);
+ uint8 c = (uint8)getBits1(8);
+ uint8 ci;
+
+ left -= 2;
+
+ for (ci = 0; ci < gCompsInFrame; ci++)
+ if (cc == gCompIdent[ci])
+ break;
+
+ if (ci >= gCompsInFrame)
+ return PJPG_BAD_SOS_COMP_ID;
+
+ gCompList[i] = ci;
+ gCompDCTab[ci] = (c >> 4) & 15;
+ gCompACTab[ci] = (c & 15);
+ }
+
+ spectral_start = (uint8)getBits1(8);
+ spectral_end = (uint8)getBits1(8);
+ successive_high = (uint8)getBits1(4);
+ successive_low = (uint8)getBits1(4);
+
+ left -= 3;
+
+ while (left)
+ {
+ getBits1(8);
+ left--;
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 nextMarker(void)
+{
+ uint8 c;
+ uint8 bytes = 0;
+
+ do
+ {
+ do
+ {
+ bytes++;
+
+ c = (uint8)getBits1(8);
+
+ } while (c != 0xFF);
+
+ do
+ {
+ c = (uint8)getBits1(8);
+
+ } while (c == 0xFF);
+
+ } while (c == 0);
+
+ // If bytes > 0 here, there where extra bytes before the marker (not good).
+
+ return c;
+}
+//------------------------------------------------------------------------------
+// Process markers. Returns when an SOFx, SOI, EOI, or SOS marker is
+// encountered.
+static uint8 processMarkers(uint8* pMarker)
+{
+ for ( ; ; )
+ {
+ uint8 c = nextMarker();
+
+ switch (c)
+ {
+ case M_SOF0:
+ case M_SOF1:
+ case M_SOF2:
+ case M_SOF3:
+ case M_SOF5:
+ case M_SOF6:
+ case M_SOF7:
+ // case M_JPG:
+ case M_SOF9:
+ case M_SOF10:
+ case M_SOF11:
+ case M_SOF13:
+ case M_SOF14:
+ case M_SOF15:
+ case M_SOI:
+ case M_EOI:
+ case M_SOS:
+ {
+ *pMarker = c;
+ return 0;
+ }
+ case M_DHT:
+ {
+ readDHTMarker();
+ break;
+ }
+ // Sorry, no arithmitic support at this time. Dumb patents!
+ case M_DAC:
+ {
+ return PJPG_NO_ARITHMITIC_SUPPORT;
+ }
+ case M_DQT:
+ {
+ readDQTMarker();
+ break;
+ }
+ case M_DRI:
+ {
+ readDRIMarker();
+ break;
+ }
+ //case M_APP0: /* no need to read the JFIF marker */
+
+ case M_JPG:
+ case M_RST0: /* no parameters */
+ case M_RST1:
+ case M_RST2:
+ case M_RST3:
+ case M_RST4:
+ case M_RST5:
+ case M_RST6:
+ case M_RST7:
+ case M_TEM:
+ {
+ return PJPG_UNEXPECTED_MARKER;
+ }
+ default: /* must be DNL, DHP, EXP, APPn, JPGn, COM, or RESn or APP0 */
+ {
+ skipVariableMarker();
+ break;
+ }
+ }
+ }
+// return 0;
+}
+//------------------------------------------------------------------------------
+// Finds the start of image (SOI) marker.
+static uint8 locateSOIMarker(void)
+{
+ uint16 bytesleft;
+
+ uint8 lastchar = (uint8)getBits1(8);
+
+ uint8 thischar = (uint8)getBits1(8);
+
+ /* ok if it's a normal JPEG file without a special header */
+
+ if ((lastchar == 0xFF) && (thischar == M_SOI))
+ return 0;
+
+ bytesleft = 4096; //512;
+
+ for ( ; ; )
+ {
+ if (--bytesleft == 0)
+ return PJPG_NOT_JPEG;
+
+ lastchar = thischar;
+
+ thischar = (uint8)getBits1(8);
+
+ if (lastchar == 0xFF)
+ {
+ if (thischar == M_SOI)
+ break;
+ else if (thischar == M_EOI) //getBits1 will keep returning M_EOI if we read past the end
+ return PJPG_NOT_JPEG;
+ }
+ }
+
+ /* Check the next character after marker: if it's not 0xFF, it can't
+ be the start of the next marker, so the file is bad */
+
+ thischar = (uint8)((gBitBuf >> 8) & 0xFF);
+
+ if (thischar != 0xFF)
+ return PJPG_NOT_JPEG;
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+// Find a start of frame (SOF) marker.
+static uint8 locateSOFMarker(void)
+{
+ uint8 c;
+
+ uint8 status = locateSOIMarker();
+ if (status)
+ return status;
+
+ status = processMarkers(&c);
+ if (status)
+ return status;
+
+ switch (c)
+ {
+ case M_SOF2:
+ {
+ return PJPG_UNSUPPORTED_MODE;
+ }
+ case M_SOF0: /* baseline DCT */
+ {
+ status = readSOFMarker();
+ if (status)
+ return status;
+
+ break;
+ }
+ case M_SOF9:
+ {
+ return PJPG_NO_ARITHMITIC_SUPPORT;
+ }
+ case M_SOF1: /* extended sequential DCT */
+ default:
+ {
+ return PJPG_UNSUPPORTED_MARKER;
+ }
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+// Find a start of scan (SOS) marker.
+static uint8 locateSOSMarker(uint8* pFoundEOI)
+{
+ uint8 c;
+ uint8 status;
+
+ *pFoundEOI = 0;
+
+ status = processMarkers(&c);
+ if (status)
+ return status;
+
+ if (c == M_EOI)
+ {
+ *pFoundEOI = 1;
+ return 0;
+ }
+ else if (c != M_SOS)
+ return PJPG_UNEXPECTED_MARKER;
+
+ return readSOSMarker();
+}
+//------------------------------------------------------------------------------
+static uint8 init(void)
+{
+ gImageXSize = 0;
+ gImageYSize = 0;
+ gCompsInFrame = 0;
+ gRestartInterval = 0;
+ gCompsInScan = 0;
+ gValidHuffTables = 0;
+ gValidQuantTables = 0;
+ gTemFlag = 0;
+ gInBufOfs = 0;
+ gInBufLeft = 0;
+ gBitBuf = 0;
+ gBitsLeft = 8;
+
+ getBits1(8);
+ getBits1(8);
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+// This method throws back into the stream any bytes that where read
+// into the bit buffer during initial marker scanning.
+static void fixInBuffer(void)
+{
+ /* In case any 0xFF's where pulled into the buffer during marker scanning */
+
+ if (gBitsLeft > 0)
+ stuffChar((uint8)gBitBuf);
+
+ stuffChar((uint8)(gBitBuf >> 8));
+
+ gBitsLeft = 8;
+ getBits2(8);
+ getBits2(8);
+}
+//------------------------------------------------------------------------------
+// Restart interval processing.
+static uint8 processRestart(void)
+{
+ // Let's scan a little bit to find the marker, but not _too_ far.
+ // 1536 is a "fudge factor" that determines how much to scan.
+ uint16 i;
+ uint8 c = 0;
+
+ for (i = 1536; i > 0; i--)
+ if (getChar() == 0xFF)
+ break;
+
+ if (i == 0)
+ return PJPG_BAD_RESTART_MARKER;
+
+ for ( ; i > 0; i--)
+ if ((c = getChar()) != 0xFF)
+ break;
+
+ if (i == 0)
+ return PJPG_BAD_RESTART_MARKER;
+
+ // Is it the expected marker? If not, something bad happened.
+ if (c != (gNextRestartNum + M_RST0))
+ return PJPG_BAD_RESTART_MARKER;
+
+ // Reset each component's DC prediction values.
+ gLastDC[0] = 0;
+ gLastDC[1] = 0;
+ gLastDC[2] = 0;
+
+ gRestartsLeft = gRestartInterval;
+
+ gNextRestartNum = (gNextRestartNum + 1) & 7;
+
+ // Get the bit buffer going again...
+
+ gBitsLeft = 8;
+ getBits2(8);
+ getBits2(8);
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 findEOI(void)
+{
+ uint8 c;
+ uint8 status;
+
+ // Prime the bit buffer
+ gBitsLeft = 8;
+ getBits1(8);
+ getBits1(8);
+
+ // The next marker _should_ be EOI
+ status = processMarkers(&c);
+ if (status)
+ return status;
+
+ //gTotalBytesRead -= in_buf_left;
+ if (c != M_EOI)
+ return PJPG_UNEXPECTED_MARKER;
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 checkHuffTables(void)
+{
+ uint8 i;
+
+ for (i = 0; i < gCompsInScan; i++)
+ {
+ uint8 compDCTab = gCompDCTab[gCompList[i]];
+ uint8 compACTab = gCompACTab[gCompList[i]] + 2;
+
+ if ( ((gValidHuffTables & (1 << compDCTab)) == 0) ||
+ ((gValidHuffTables & (1 << compACTab)) == 0) )
+ return PJPG_UNDEFINED_HUFF_TABLE;
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 checkQuantTables(void)
+{
+ uint8 i;
+
+ for (i = 0; i < gCompsInScan; i++)
+ {
+ uint8 compQuantMask = gCompQuant[gCompList[i]] ? 2 : 1;
+
+ if ((gValidQuantTables & compQuantMask) == 0)
+ return PJPG_UNDEFINED_QUANT_TABLE;
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 initScan(void)
+{
+ uint8 foundEOI;
+ uint8 status = locateSOSMarker(&foundEOI);
+ if (status)
+ return status;
+ if (foundEOI)
+ return PJPG_UNEXPECTED_MARKER;
+
+ status = checkHuffTables();
+ if (status)
+ return status;
+
+ status = checkQuantTables();
+ if (status)
+ return status;
+
+ gLastDC[0] = 0;
+ gLastDC[1] = 0;
+ gLastDC[2] = 0;
+
+ if (gRestartInterval)
+ {
+ gRestartsLeft = gRestartInterval;
+ gNextRestartNum = 0;
+ }
+
+ fixInBuffer();
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+static uint8 initFrame(void)
+{
+ if (gCompsInFrame == 1)
+ {
+ if ((gCompHSamp[0] != 1) || (gCompVSamp[0] != 1))
+ return PJPG_UNSUPPORTED_SAMP_FACTORS;
+
+ gScanType = PJPG_GRAYSCALE;
+
+ gMaxBlocksPerMCU = 1;
+ gMCUOrg[0] = 0;
+
+ gMaxMCUXSize = 8;
+ gMaxMCUYSize = 8;
+ }
+ else if (gCompsInFrame == 3)
+ {
+ if ( ((gCompHSamp[1] != 1) || (gCompVSamp[1] != 1)) ||
+ ((gCompHSamp[2] != 1) || (gCompVSamp[2] != 1)) )
+ return PJPG_UNSUPPORTED_SAMP_FACTORS;
+
+ if ((gCompHSamp[0] == 1) && (gCompVSamp[0] == 1))
+ {
+ gScanType = PJPG_YH1V1;
+
+ gMaxBlocksPerMCU = 3;
+ gMCUOrg[0] = 0;
+ gMCUOrg[1] = 1;
+ gMCUOrg[2] = 2;
+
+ gMaxMCUXSize = 8;
+ gMaxMCUYSize = 8;
+ }
+ else if ((gCompHSamp[0] == 2) && (gCompVSamp[0] == 2))
+ {
+ gScanType = PJPG_YH2V2;
+
+ gMaxBlocksPerMCU = 6;
+ gMCUOrg[0] = 0;
+ gMCUOrg[1] = 0;
+ gMCUOrg[2] = 0;
+ gMCUOrg[3] = 0;
+ gMCUOrg[4] = 1;
+ gMCUOrg[5] = 2;
+
+ gMaxMCUXSize = 16;
+ gMaxMCUYSize = 16;
+ }
+ else
+ return PJPG_UNSUPPORTED_SAMP_FACTORS;
+ }
+ else
+ return PJPG_UNSUPPORTED_COLORSPACE;
+
+ gMaxMCUSPerRow = (gImageXSize + (gMaxMCUXSize - 1)) >> ((gMaxMCUXSize == 8) ? 3 : 4);
+ gMaxMCUSPerCol = (gImageYSize + (gMaxMCUYSize - 1)) >> ((gMaxMCUYSize == 8) ? 3 : 4);
+
+ gNumMCUSRemaining = gMaxMCUSPerRow * gMaxMCUSPerCol;
+
+ return 0;
+}
+/*----------------------------------------------------------------------------*/
+#define DCT_SCALE_BITS 7
+
+#define DCT_SCALE (1U << DCT_SCALE_BITS)
+
+#define DESCALE(x) (((x) + (1U << (DCT_SCALE_BITS - 1))) >> DCT_SCALE_BITS)
+
+#define WFIX(x) ((x) * DCT_SCALE + 0.5f)
+
+#define WINOGRAD_QUANT_SCALE_BITS 10
+
+const uint8 gWinogradQuant[] =
+{
+ 128, 178, 178, 167, 246, 167, 151, 232,
+ 232, 151, 128, 209, 219, 209, 128, 101,
+ 178, 197, 197, 178, 101, 69, 139, 167,
+ 177, 167, 139, 69, 35, 96, 131, 151,
+ 151, 131, 96, 35, 49, 91, 118, 128,
+ 118, 91, 49, 46, 81, 101, 101, 81,
+ 46, 42, 69, 79, 69, 42, 35, 54,
+ 54, 35, 28, 37, 28, 19, 19, 10,
+};
+
+static void createWinogradQuant(int16* pQuant)
+{
+ uint8 i;
+
+ for (i = 0; i < 64; i++)
+ {
+ long x = pQuant[i];
+ x *= gWinogradQuant[i];
+ pQuant[i] = (int16)((x + (1 << (WINOGRAD_QUANT_SCALE_BITS - DCT_SCALE_BITS - 1))) >> (WINOGRAD_QUANT_SCALE_BITS - DCT_SCALE_BITS));
+ }
+}
+
+// 1/cos(4*pi/16)
+// 362, 256+106
+#define b1 362
+
+// 1/cos(6*pi/16)
+// 669, 256+256+157
+#define b2 669
+
+// 1/cos(4*pi/16)
+// 362, 256+106
+#define b3 362
+
+// 1/cos(2*pi/16)
+// 277, 256+21
+#define b4 277
+
+// 1/(cos(2*pi/16) + cos(6*pi/16))
+// 196, 196
+#define b5 196
+
+static int16 imul_b1_b3(int16 w)
+{
+ long x = (w * 362L);
+ x += 128L;
+ return (int16)(x >> 8);
+}
+
+static int16 imul_b2(int16 w)
+{
+ long x = (w * 669L);
+ x += 128L;
+ return (int16)(x >> 8);
+}
+
+static int16 imul_b4(int16 w)
+{
+ long x = (w * 277L);
+ x += 128L;
+ return (int16)(x >> 8);
+}
+
+static int16 imul_b5(int16 w)
+{
+ long x = (w * 196L);
+ x += 128L;
+ return (int16)(x >> 8);
+}
+
+static uint8 clamp(int16 s)
+{
+ if ((uint16)s > 255U)
+ {
+ if (s < 0)
+ return 0;
+ else if (s > 255)
+ return 255;
+ }
+
+ return (uint8)s;
+}
+
+static void idctRows(void)
+{
+ uint8 i;
+ int16* pSrc = gCoeffBuf;
+
+ for (i = 0; i < 8; i++)
+ {
+ int16 src4 = *(pSrc+5);
+ int16 src7 = *(pSrc+3);
+ int16 x4 = src4 - src7;
+ int16 x7 = src4 + src7;
+
+ int16 src5 = *(pSrc+1);
+ int16 src6 = *(pSrc+7);
+ int16 x5 = src5 + src6;
+ int16 x6 = src5 - src6;
+
+ int16 tmp1 = imul_b5(x4 - x6);
+ int16 stg26 = imul_b4(x6) - tmp1;
+
+ int16 x24 = tmp1 - imul_b2(x4);
+
+ int16 x15 = x5 - x7;
+ int16 x17 = x5 + x7;
+
+ int16 tmp2 = stg26 - x17;
+ int16 tmp3 = imul_b1_b3(x15) - tmp2;
+ int16 x44 = tmp3 + x24;
+
+ int16 src0 = *(pSrc+0);
+ int16 src1 = *(pSrc+4);
+ int16 x30 = src0 + src1;
+ int16 x31 = src0 - src1;
+
+ int16 src2 = *(pSrc+2);
+ int16 src3 = *(pSrc+6);
+ int16 x12 = src2 - src3;
+ int16 x13 = src2 + src3;
+
+ int16 x32 = imul_b1_b3(x12) - x13;
+
+ int16 x40 = x30 + x13;
+ int16 x43 = x30 - x13;
+ int16 x41 = x31 + x32;
+ int16 x42 = x31 - x32;
+
+ *(pSrc+0) = x40 + x17;
+ *(pSrc+1) = x41 + tmp2;
+ *(pSrc+2) = x42 + tmp3;
+ *(pSrc+3) = x43 - x44;
+ *(pSrc+4) = x43 + x44;
+ *(pSrc+5) = x42 - tmp3;
+ *(pSrc+6) = x41 - tmp2;
+ *(pSrc+7) = x40 - x17;
+
+ pSrc += 8;
+ }
+}
+
+static void idctCols(void)
+{
+ uint8 i;
+
+ int16* pSrc = gCoeffBuf;
+
+ for (i = 0; i < 8; i++)
+ {
+ int16 src4 = *(pSrc+5*8);
+ int16 src7 = *(pSrc+3*8);
+ int16 x4 = src4 - src7;
+ int16 x7 = src4 + src7;
+
+ int16 src5 = *(pSrc+1*8);
+ int16 src6 = *(pSrc+7*8);
+ int16 x5 = src5 + src6;
+ int16 x6 = src5 - src6;
+
+ int16 tmp1 = imul_b5(x4 - x6);
+ int16 stg26 = imul_b4(x6) - tmp1;
+
+ int16 x24 = tmp1 - imul_b2(x4);
+
+ int16 x15 = x5 - x7;
+ int16 x17 = x5 + x7;
+
+ int16 tmp2 = stg26 - x17;
+ int16 tmp3 = imul_b1_b3(x15) - tmp2;
+ int16 x44 = tmp3 + x24;
+
+ int16 src0 = *(pSrc+0*8);
+ int16 src1 = *(pSrc+4*8);
+ int16 x30 = src0 + src1;
+ int16 x31 = src0 - src1;
+
+ int16 src2 = *(pSrc+2*8);
+ int16 src3 = *(pSrc+6*8);
+ int16 x12 = src2 - src3;
+ int16 x13 = src2 + src3;
+
+ int16 x32 = imul_b1_b3(x12) - x13;
+
+ int16 x40 = x30 + x13;
+ int16 x43 = x30 - x13;
+ int16 x41 = x31 + x32;
+ int16 x42 = x31 - x32;
+
+ *(pSrc+0*8) = clamp(DESCALE(x40 + x17) + 128);
+ *(pSrc+1*8) = clamp(DESCALE(x41 + tmp2) + 128);
+ *(pSrc+2*8) = clamp(DESCALE(x42 + tmp3) + 128);
+ *(pSrc+3*8) = clamp(DESCALE(x43 - x44) + 128);
+ *(pSrc+4*8) = clamp(DESCALE(x43 + x44) + 128);
+ *(pSrc+5*8) = clamp(DESCALE(x42 - tmp3) + 128);
+ *(pSrc+6*8) = clamp(DESCALE(x41 - tmp2) + 128);
+ *(pSrc+7*8) = clamp(DESCALE(x40 - x17) + 128);
+
+ pSrc++;
+ }
+}
+
+/*----------------------------------------------------------------------------*/
+static uint8 addAndClamp(uint8 a, int16 b)
+{
+ b = a + b;
+
+ if ((uint16)b > 255U)
+ {
+ if (b < 0)
+ return 0;
+ else if (b > 255)
+ return 255;
+ }
+
+ return (uint8)b;
+}
+/*----------------------------------------------------------------------------*/
+static uint8 subAndClamp(uint8 a, int16 b)
+{
+ b = a - b;
+
+ if ((uint16)b > 255U)
+ {
+ if (b < 0)
+ return 0;
+ else if (b > 255)
+ return 255;
+ }
+
+ return (uint8)b;
+}
+/*----------------------------------------------------------------------------*/
+// 103/256
+//R = Y + 1.402 (Cr-128)
+
+// 88/256, 183/256
+//G = Y - 0.34414 (Cb-128) - 0.71414 (Cr-128)
+
+// 198/256
+//B = Y + 1.772 (Cb-128)
+/*----------------------------------------------------------------------------*/
+static void upsampleCb(uint8 srcOfs, uint8 dstOfs)
+{
+ // Cb - affects G and B
+ uint8 x, y;
+ int16* pSrc = gCoeffBuf + srcOfs;
+ uint8* pDstG = gMCUBufG + dstOfs;
+ uint8* pDstB = gMCUBufB + dstOfs;
+ for (y = 0; y < 4; y++)
+ {
+ for (x = 0; x < 4; x++)
+ {
+ uint8 cb = (uint8)*pSrc++;
+ int16 cbG, cbB;
+
+ cbG = ((cb * 88U) >> 8U) - 44U;
+ pDstG[0] = subAndClamp(pDstG[0], cbG);
+ pDstG[1] = subAndClamp(pDstG[1], cbG);
+ pDstG[8] = subAndClamp(pDstG[8], cbG);
+ pDstG[9] = subAndClamp(pDstG[9], cbG);
+
+ cbB = (cb + ((cb * 198U) >> 8U)) - 227U;
+ pDstB[0] = addAndClamp(pDstB[0], cbB);
+ pDstB[1] = addAndClamp(pDstB[1], cbB);
+ pDstB[8] = addAndClamp(pDstB[8], cbB);
+ pDstB[9] = addAndClamp(pDstB[9], cbB);
+
+ pDstG += 2;
+ pDstB += 2;
+ }
+
+ pSrc = pSrc - 4 + 8;
+ pDstG = pDstG - 8 + 16;
+ pDstB = pDstB - 8 + 16;
+ }
+}
+/*----------------------------------------------------------------------------*/
+// 103/256
+//R = Y + 1.402 (Cr-128)
+
+// 88/256, 183/256
+//G = Y - 0.34414 (Cb-128) - 0.71414 (Cr-128)
+
+// 198/256
+//B = Y + 1.772 (Cb-128)
+/*----------------------------------------------------------------------------*/
+static void upsampleCr(uint8 srcOfs, uint8 dstOfs)
+{
+ // Cr - affects R and G
+ uint8 x, y;
+ int16* pSrc = gCoeffBuf + srcOfs;
+ uint8* pDstR = gMCUBufR + dstOfs;
+ uint8* pDstG = gMCUBufG + dstOfs;
+ for (y = 0; y < 4; y++)
+ {
+ for (x = 0; x < 4; x++)
+ {
+ uint8 cr = (uint8)*pSrc++;
+ int16 crR, crG;
+
+ crR = (cr + ((cr * 103U) >> 8U)) - 179;
+ pDstR[0] = addAndClamp(pDstR[0], crR);
+ pDstR[1] = addAndClamp(pDstR[1], crR);
+ pDstR[8] = addAndClamp(pDstR[8], crR);
+ pDstR[9] = addAndClamp(pDstR[9], crR);
+
+ crG = ((cr * 183U) >> 8U) - 91;
+ pDstG[0] = subAndClamp(pDstG[0], crG);
+ pDstG[1] = subAndClamp(pDstG[1], crG);
+ pDstG[8] = subAndClamp(pDstG[8], crG);
+ pDstG[9] = subAndClamp(pDstG[9], crG);
+
+ pDstR += 2;
+ pDstG += 2;
+ }
+
+ pSrc = pSrc - 4 + 8;
+ pDstR = pDstR - 8 + 16;
+ pDstG = pDstG - 8 + 16;
+ }
+}
+/*----------------------------------------------------------------------------*/
+static void copyY(uint8 dstOfs)
+{
+ uint8 i;
+ uint8* pRDst = gMCUBufR + dstOfs;
+ uint8* pGDst = gMCUBufG + dstOfs;
+ uint8* pBDst = gMCUBufB + dstOfs;
+ int16* pSrc = gCoeffBuf;
+
+ for (i = 64; i > 0; i--)
+ {
+ uint8 c = (uint8)*pSrc++;
+
+ *pRDst++ = c;
+ *pGDst++ = c;
+ *pBDst++ = c;
+ }
+}
+/*----------------------------------------------------------------------------*/
+static void convertCb(uint8 dstOfs)
+{
+ uint8 i;
+ uint8* pDstG = gMCUBufG + dstOfs;
+ uint8* pDstB = gMCUBufB + dstOfs;
+ int16* pSrc = gCoeffBuf;
+
+ for (i = 64; i > 0; i--)
+ {
+ uint8 cb = (uint8)*pSrc++;
+ int16 cbG, cbB;
+
+ cbG = ((cb * 88U) >> 8U) - 44U;
+ *pDstG++ = subAndClamp(pDstG[0], cbG);
+
+ cbB = (cb + ((cb * 198U) >> 8U)) - 227U;
+ *pDstB++ = addAndClamp(pDstB[0], cbB);
+ }
+}
+/*----------------------------------------------------------------------------*/
+static void convertCr(uint8 dstOfs)
+{
+ uint8 i;
+ uint8* pDstR = gMCUBufR + dstOfs;
+ uint8* pDstG = gMCUBufG + dstOfs;
+ int16* pSrc = gCoeffBuf;
+
+ for (i = 64; i > 0; i--)
+ {
+ uint8 cr = (uint8)*pSrc++;
+ int16 crR, crG;
+
+ crR = (cr + ((cr * 103U) >> 8U)) - 179;
+ *pDstR++ = addAndClamp(pDstR[0], crR);
+
+ crG = ((cr * 183U) >> 8U) - 91;
+ *pDstG++ = subAndClamp(pDstG[0], crG);
+ }
+}
+/*----------------------------------------------------------------------------*/
+static void transformBlock(uint8 mcuBlock)
+{
+ idctRows();
+ idctCols();
+
+ switch (gScanType)
+ {
+ case PJPG_GRAYSCALE:
+ {
+ copyY(0);
+ break;
+ }
+ case PJPG_YH1V1:
+ {
+ switch (mcuBlock)
+ {
+ case 0:
+ {
+ copyY(0);
+ break;
+ }
+ case 1:
+ {
+ convertCb(0);
+ break;
+ }
+ case 2:
+ {
+ convertCr(0);
+ break;
+ }
+ }
+
+ break;
+ }
+ case PJPG_YH2V2:
+ {
+ switch (mcuBlock)
+ {
+ case 0:
+ {
+ copyY(0);
+ break;
+ }
+ case 1:
+ {
+ copyY(64);
+ break;
+ }
+ case 2:
+ {
+ copyY(128);
+ break;
+ }
+ case 3:
+ {
+ copyY(192);
+ break;
+ }
+ case 4:
+ {
+ upsampleCb(0, 0);
+ upsampleCb(4, 64);
+ upsampleCb(4*8, 128);
+ upsampleCb(4+4*8, 192);
+ break;
+ }
+ case 5:
+ {
+ upsampleCr(0, 0);
+ upsampleCr(4, 64);
+ upsampleCr(4*8, 128);
+ upsampleCr(4+4*8, 192);
+ break;
+ }
+ }
+ }
+ }
+}
+//------------------------------------------------------------------------------
+static uint8 decodeNextMCU(void)
+{
+ uint8 status;
+ uint8 mcuBlock;
+
+ if (gRestartInterval)
+ {
+ if (gRestartsLeft == 0)
+ {
+ status = processRestart();
+ if (status)
+ return status;
+ }
+ gRestartsLeft--;
+ }
+
+ for (mcuBlock = 0; mcuBlock < gMaxBlocksPerMCU; mcuBlock++)
+ {
+ uint8 componentID = gMCUOrg[mcuBlock];
+ uint8 compQuant = gCompQuant[componentID];
+ uint8 compDCTab = gCompDCTab[componentID];
+ uint8 numExtraBits, compACTab, k;
+ const int16* pQ = compQuant ? gQuant1 : gQuant0;
+ uint16 r, dc;
+
+ uint8 s = huffDecode(compDCTab ? &gHuffTab1 : &gHuffTab0, compDCTab ? gHuffVal1 : gHuffVal0);
+
+ r = 0;
+ numExtraBits = s & 0xF;
+ if (numExtraBits)
+ r = getBits2(numExtraBits);
+ dc = huffExtend(r, s);
+
+ dc = dc + gLastDC[componentID];
+ gLastDC[componentID] = dc;
+
+ gCoeffBuf[0] = dc * pQ[0];
+
+ compACTab = gCompACTab[componentID];
+
+ for (k = 1; k < 64; k++)
+ {
+ uint16 extraBits;
+
+ s = huffDecode(compACTab ? &gHuffTab3 : &gHuffTab2, compACTab ? gHuffVal3 : gHuffVal2);
+
+ extraBits = 0;
+ numExtraBits = s & 0xF;
+ if (numExtraBits)
+ extraBits = getBits2(numExtraBits);
+
+ r = s >> 4;
+ s &= 15;
+
+ if (s)
+ {
+ int16 ac;
+
+ if (r)
+ {
+ if ((k + r) > 63)
+ return PJPG_DECODE_ERROR;
+
+ while (r)
+ {
+ gCoeffBuf[ZAG[k++]] = 0;
+ r--;
+ }
+ }
+
+ ac = huffExtend(extraBits, s);
+
+ gCoeffBuf[ZAG[k]] = ac * pQ[k];
+ }
+ else
+ {
+ if (r == 15)
+ {
+ if ((k + 16) > 64)
+ return PJPG_DECODE_ERROR;
+
+ for (r = 16; r > 0; r--)
+ gCoeffBuf[ZAG[k++]] = 0;
+
+ k--; // - 1 because the loop counter is k
+ }
+ else
+ break;
+ }
+ }
+
+ while (k < 64)
+ gCoeffBuf[ZAG[k++]] = 0;
+
+ transformBlock(mcuBlock);
+ }
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+unsigned char pjpeg_decode_mcu(void)
+{
+ uint8 status;
+
+ if (!gNumMCUSRemaining)
+ return PJPG_NO_MORE_BLOCKS;
+
+ status = decodeNextMCU();
+ if (status)
+ return status;
+
+ gNumMCUSRemaining--;
+
+ return 0;
+}
+//------------------------------------------------------------------------------
+unsigned char pjpeg_decode_init(pjpeg_image_info_t *pInfo, pjpeg_need_bytes_callback_t pNeed_bytes_callback, void *pCallback_data)
+{
+ uint8 status;
+
+ g_pNeedBytesCallback = pNeed_bytes_callback;
+ g_pCallback_data = pCallback_data;
+
+ status = init();
+ if (status)
+ return status;
+
+ status = locateSOFMarker();
+ if (status)
+ return status;
+
+ status = initFrame();
+ if (status)
+ return status;
+
+ status = initScan();
+ if (status)
+ return status;
+
+ pInfo->m_width = gImageXSize;
+ pInfo->m_height = gImageYSize;
+ pInfo->m_comps = gCompsInFrame;
+ pInfo->m_scanType = gScanType;
+ pInfo->m_MCUSPerRow = gMaxMCUSPerRow;
+ pInfo->m_MCUSPerCol = gMaxMCUSPerCol;
+ pInfo->m_MCUWidth = gMaxMCUXSize;
+ pInfo->m_MCUHeight = gMaxMCUYSize;
+ pInfo->m_pMCUBufR = gMCUBufR;
+ pInfo->m_pMCUBufG = gMCUBufG;
+ pInfo->m_pMCUBufB = gMCUBufB;
+
+ return 0;
+}