--- /dev/null
+/******************************************************************************
+* "Gif-Lib" - Yet another gif library. *
+* *
+* Written by: Gershon Elber IBM PC Ver 1.1, Aug. 1990 *
+*******************************************************************************
+* The kernel of the GIF Decoding process can be found here. *
+*******************************************************************************
+* History: *
+* 16 Jun 89 - Version 1.0 by Gershon Elber. *
+* 3 Sep 90 - Version 1.1 by Gershon Elber (Support for Gif89, Unique names). *
+* 19 Feb 98 - Version 1.2 by Jareth Hein (Support for user specified I/O) *
+******************************************************************************/
+
+#ifdef __MSDOS__
+#include <io.h>
+#include <alloc.h>
+#include <stdlib.h>
+#include <sys\stat.h>
+#else
+#include <sys/types.h>
+#include <sys/stat.h>
+#endif /* __MSDOS__ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#endif
+
+#include "gifrlib.h"
+
+#define PROGRAM_NAME "GIFLIB"
+
+
+static void DGifGetWord(GifFileType *GifFile, int *Word);
+static void DGifSetupDecompress(GifFileType *GifFile);
+static void DGifDecompressLine(GifFileType *GifFile, GifPixelType *Line,
+ int LineLen);
+static int DGifGetPrefixChar(unsigned int *Prefix, int Code, int ClearCode);
+static void DGifDecompressInput(GifFileType *GifFile, int *Code);
+static void DGifBufferedInput(GifFileType *GifFile, GifByteType *NextByte);
+
+/******************************************************************************
+* Open a new gif file for read, given by its name. *
+* Returns GifFileType pointer dynamically allocated which serves as the gif *
+* info record. *
+******************************************************************************/
+void DGifOpenFileName(GifFileType *GifFile, const char *FileName)
+{
+ FILE *f;
+
+ if ((f = fopen(FileName,
+#ifdef __MSDOS__
+ "rb"
+#else
+ "r"
+#endif /* __MSDOS__ */
+ )) == NULL)
+ GifInternError(GifFile, D_GIF_ERR_OPEN_FAILED);
+
+ GifStdIOInit(GifFile, f, -1);
+ DGifInitRead(GifFile);
+}
+
+/******************************************************************************
+* Update a new gif file, given its file handle. *
+* Returns GifFileType pointer dynamically allocated which serves as the gif *
+* info record. *
+******************************************************************************/
+void DGifOpenFileHandle(GifFileType *GifFile, int FileHandle)
+{
+ FILE *f;
+
+#ifdef __MSDOS__
+ setmode(FileHandle, O_BINARY); /* Make sure it is in binary mode. */
+ f = fdopen(FileHandle, "rb"); /* Make it into a stream: */
+ setvbuf(f, NULL, _IOFBF, GIF_FILE_BUFFER_SIZE);/* And inc. stream buffer.*/
+#else
+ f = fdopen(FileHandle, "r"); /* Make it into a stream: */
+#endif /* __MSDOS__ */
+
+ GifStdIOInit(GifFile, f, -1);
+ DGifInitRead(GifFile);
+}
+
+/******************************************************************************
+* Update a new gif file, given its file handle. *
+* Returns GifFileType pointer dynamically allocated which serves as the gif *
+* info record. _GifError is cleared if succesfull. *
+******************************************************************************/
+void DGifInitRead(GifFileType *GifFile)
+{
+ GifByteType Buf[GIF_STAMP_LEN+1];
+ GifFilePrivateType *Private;
+
+ if ((Private = (GifFilePrivateType *) malloc(sizeof(GifFilePrivateType)))
+ == NULL) {
+ GifInternError(GifFile, D_GIF_ERR_NOT_ENOUGH_MEM);
+ }
+ memset(Private, '\0', sizeof(GifFilePrivateType));
+ GifFile->Private = (VoidPtr) Private;
+
+ Private->FileState = 0; /* Make sure bit 0 = 0 (File open for read). */
+
+ /* Lets see if this is a GIF file: */
+ GifRead(Buf, GIF_STAMP_LEN, GifFile);
+
+ /* The GIF Version number is ignored at this time. Maybe we should do */
+ /* something more useful with it. */
+ Buf[GIF_STAMP_LEN] = 0;
+ if (strncmp(GIF_STAMP, Buf, GIF_VERSION_POS) != 0) {
+ GifInternError(GifFile, D_GIF_ERR_NOT_GIF_FILE);
+ }
+
+ DGifGetScreenDesc(GifFile);
+}
+
+/******************************************************************************
+* This routine should be called before any other DGif calls. Note that *
+* this routine is called automatically from DGif file open routines. *
+******************************************************************************/
+void DGifGetScreenDesc(GifFileType *GifFile)
+{
+ int i, BitsPerPixel;
+ GifByteType Buf[3];
+ GifFilePrivateType *Private = (GifFilePrivateType*) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ /* Put the screen descriptor into the file: */
+ DGifGetWord(GifFile, &GifFile->SWidth);
+ DGifGetWord(GifFile, &GifFile->SHeight);
+
+ GifRead(Buf, 3, GifFile);
+ GifFile->SColorResolution = (((Buf[0] & 0x70) + 1) >> 4) + 1;
+ BitsPerPixel = (Buf[0] & 0x07) + 1;
+ GifFile->SBackGroundColor = Buf[1];
+ if (Buf[0] & 0x80) { /* Do we have global color map? */
+
+ GifFile->SColorMap = MakeMapObject(1 << BitsPerPixel, NULL);
+
+ /* Get the global color map: */
+ for (i = 0; i < GifFile->SColorMap->ColorCount; i++) {
+ GifRead(Buf, 3, GifFile);
+ GifFile->SColorMap->Colors[i].Red = Buf[0];
+ GifFile->SColorMap->Colors[i].Green = Buf[1];
+ GifFile->SColorMap->Colors[i].Blue = Buf[2];
+ }
+ } else {
+ /* We should always have a colormap */
+ GifFile->SColorMap = MakeMapObject(2, NULL);
+ GifFile->SColorMap->Colors[0].Red = 0;
+ GifFile->SColorMap->Colors[0].Green = 0;
+ GifFile->SColorMap->Colors[0].Blue = 0;
+ GifFile->SColorMap->Colors[1].Red = 0xff;
+ GifFile->SColorMap->Colors[1].Green = 0xff;
+ GifFile->SColorMap->Colors[1].Blue = 0xff;
+ }
+}
+
+/******************************************************************************
+* This routine should be called before any attemp to read an image. *
+******************************************************************************/
+void DGifGetRecordType(GifFileType *GifFile, GifRecordType *Type)
+{
+ GifByteType Buf;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ GifRead(&Buf, 1, GifFile);
+
+ switch (Buf) {
+ case ',':
+ *Type = IMAGE_DESC_RECORD_TYPE;
+ break;
+ case '!':
+ *Type = EXTENSION_RECORD_TYPE;
+ break;
+ case ';':
+ *Type = TERMINATE_RECORD_TYPE;
+ break;
+ default:
+ *Type = UNDEFINED_RECORD_TYPE;
+ GifInternError(GifFile, D_GIF_ERR_WRONG_RECORD);
+ }
+}
+
+/******************************************************************************
+* This routine should be called before any attemp to read an image. *
+* Note it is assumed the Image desc. header (',') has been read. *
+******************************************************************************/
+void DGifGetImageDesc(GifFileType *GifFile)
+{
+ int i, BitsPerPixel;
+ GifByteType Buf[3];
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ DGifGetWord(GifFile, &GifFile->Image.Left);
+ DGifGetWord(GifFile, &GifFile->Image.Top);
+ DGifGetWord(GifFile, &GifFile->Image.Width);
+ DGifGetWord(GifFile, &GifFile->Image.Height);
+
+ GifRead(Buf, 1, GifFile);
+ BitsPerPixel = (Buf[0] & 0x07) + 1;
+ GifFile->Image.Interlace = (Buf[0] & 0x40);
+ if (Buf[0] & 0x80) { /* Does this image have local color map? */
+
+ if (GifFile->Image.ColorMap && GifFile->SavedImages == NULL)
+ FreeMapObject(GifFile->Image.ColorMap);
+
+ GifFile->Image.ColorMap = MakeMapObject(1 << BitsPerPixel, NULL);
+
+ /* Get the image local color map: */
+ for (i = 0; i < GifFile->Image.ColorMap->ColorCount; i++) {
+ GifRead(Buf, 3, GifFile);
+ GifFile->Image.ColorMap->Colors[i].Red = Buf[0];
+ GifFile->Image.ColorMap->Colors[i].Green = Buf[1];
+ GifFile->Image.ColorMap->Colors[i].Blue = Buf[2];
+ }
+ }
+
+ if (GifFile->SavedImages) {
+ SavedImage *sp;
+
+ if ((GifFile->SavedImages = (SavedImage *)realloc(GifFile->SavedImages,
+ sizeof(SavedImage) * (GifFile->ImageCount + 1))) == NULL) {
+ GifInternError(GifFile, D_GIF_ERR_NOT_ENOUGH_MEM);
+ }
+
+ sp = &GifFile->SavedImages[GifFile->ImageCount];
+ memcpy(&sp->ImageDesc, &GifFile->Image, sizeof(GifImageDesc));
+ if (GifFile->Image.ColorMap)
+ {
+ sp->ImageDesc.ColorMap =
+ MakeMapObject (GifFile->Image.ColorMap->ColorCount,
+ GifFile->Image.ColorMap->Colors);
+ }
+ sp->RasterBits = (GifPixelType *)NULL;
+ sp->ExtensionBlockCount = 0;
+ sp->ExtensionBlocks = (ExtensionBlock *)NULL;
+ }
+
+ GifFile->ImageCount++;
+
+ Private->PixelCount = (long) GifFile->Image.Width *
+ (long) GifFile->Image.Height;
+
+ DGifSetupDecompress(GifFile); /* Reset decompress algorithm parameters. */
+}
+
+/******************************************************************************
+* Get one full scanned line (Line) of length LineLen from GIF file. *
+******************************************************************************/
+void DGifGetLine(GifFileType *GifFile, GifPixelType *Line, int LineLen)
+{
+ GifByteType *Dummy;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ if (!LineLen) LineLen = GifFile->Image.Width;
+
+#if defined(__MSDOS__) || defined(__GNUC__)
+ if ((Private->PixelCount -= LineLen) > 0xffff0000UL)
+#else
+ if ((Private->PixelCount -= LineLen) > 0xffff0000)
+#endif /* __MSDOS__ */
+ {
+ GifInternError(GifFile, D_GIF_ERR_DATA_TOO_BIG);
+ }
+
+ DGifDecompressLine(GifFile, Line, LineLen);
+ if (Private->PixelCount == 0) {
+ /* We probably would not be called any more, so lets clean */
+ /* everything before we return: need to flush out all rest of */
+ /* image until empty block (size 0) detected. We use GetCodeNext.*/
+ do
+ DGifGetCodeNext(GifFile, &Dummy);
+ while (Dummy != NULL);
+ }
+}
+
+/******************************************************************************
+* Put one pixel (Pixel) into GIF file. *
+******************************************************************************/
+void DGifGetPixel(GifFileType *GifFile, GifPixelType Pixel)
+{
+ GifByteType *Dummy;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+#if defined(__MSDOS__) || defined(__GNUC__)
+ if (--Private->PixelCount > 0xffff0000UL)
+#else
+ if (--Private->PixelCount > 0xffff0000)
+#endif /* __MSDOS__ */
+ {
+ GifInternError(GifFile, D_GIF_ERR_DATA_TOO_BIG);
+ }
+
+ DGifDecompressLine(GifFile, &Pixel, 1);
+ if (Private->PixelCount == 0) {
+ /* We probably would not be called any more, so lets clean */
+ /* everything before we return: need to flush out all rest of */
+ /* image until empty block (size 0) detected. We use GetCodeNext.*/
+ do
+ DGifGetCodeNext(GifFile, &Dummy);
+ while (Dummy != NULL);
+ }
+}
+
+/******************************************************************************
+* Get an extension block (see GIF manual) from gif file. This routine only *
+* returns the first data block, and DGifGetExtensionNext shouldbe called *
+* after this one until NULL extension is returned. *
+* The Extension should NOT be freed by the user (not dynamically allocated).*
+* Note it is assumed the Extension desc. header ('!') has been read. *
+******************************************************************************/
+void DGifGetExtension(GifFileType *GifFile, int *ExtCode,
+ GifByteType **Extension)
+{
+ GifByteType Buf;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ GifRead(&Buf, 1, GifFile);
+ *ExtCode = Buf;
+
+ DGifGetExtensionNext(GifFile, Extension);
+}
+
+/******************************************************************************
+* Get a following extension block (see GIF manual) from gif file. This *
+* routine sould be called until NULL Extension is returned. *
+* The Extension should NOT be freed by the user (not dynamically allocated).*
+******************************************************************************/
+void DGifGetExtensionNext(GifFileType *GifFile, GifByteType **Extension)
+{
+ GifByteType Buf;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ GifRead(&Buf, 1, GifFile);
+ if (Buf > 0) {
+ *Extension = Private->Buf; /* Use private unused buffer. */
+ (*Extension)[0] = Buf; /* Pascal strings notation (pos. 0 is len.). */
+ GifRead(&((*Extension)[1]), Buf, GifFile);
+ }
+ else
+ *Extension = NULL;
+}
+
+/******************************************************************************
+* This routine should be called second to last, to close the GIF file. *
+******************************************************************************/
+int DGifCloseFile(GifFileType *GifFile)
+{
+ GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
+
+ if (GifFile == NULL) return -1;
+
+ if (!IS_READABLE(Private))
+ {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ if (GifClose (GifFile))
+ {
+ GifInternError(GifFile, D_GIF_ERR_CLOSE_FAILED);
+ }
+ return 0;
+}
+
+/******************************************************************************
+* Get 2 bytes (word) from the given file: *
+******************************************************************************/
+static void DGifGetWord(GifFileType *GifFile, int *Word)
+{
+ unsigned char c[2];
+
+ GifRead(c, 2, GifFile);
+
+ *Word = (((unsigned int) c[1]) << 8) + c[0];
+}
+
+/******************************************************************************
+* Get the image code in compressed form. his routine can be called if the *
+* information needed to be piped out as is. Obviously this is much faster *
+* than decoding and encoding again. This routine should be followed by calls *
+* to DGifGetCodeNext, until NULL block is returned. *
+* The block should NOT be freed by the user (not dynamically allocated). *
+******************************************************************************/
+void DGifGetCode(GifFileType *GifFile, int *CodeSize, GifByteType **CodeBlock)
+{
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ *CodeSize = Private->BitsPerPixel;
+
+ DGifGetCodeNext(GifFile, CodeBlock);
+}
+
+/******************************************************************************
+* Continue to get the image code in compressed form. This routine should be *
+* called until NULL block is returned. *
+* The block should NOT be freed by the user (not dynamically allocated). *
+******************************************************************************/
+void DGifGetCodeNext(GifFileType *GifFile, GifByteType **CodeBlock)
+{
+ GifByteType Buf;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ GifRead(&Buf, 1, GifFile);
+
+ if (Buf > 0) {
+ *CodeBlock = Private->Buf; /* Use private unused buffer. */
+ (*CodeBlock)[0] = Buf; /* Pascal strings notation (pos. 0 is len.). */
+ GifRead(&((*CodeBlock)[1]), Buf, GifFile);
+ }
+ else {
+ *CodeBlock = NULL;
+ Private->Buf[0] = 0; /* Make sure the buffer is empty! */
+ Private->PixelCount = 0; /* And local info. indicate image read. */
+ }
+
+}
+
+/******************************************************************************
+* Setup the LZ decompression for this image: *
+******************************************************************************/
+static void DGifSetupDecompress(GifFileType *GifFile)
+{
+ int i, BitsPerPixel;
+ GifByteType CodeSize;
+ unsigned int *Prefix;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ GifRead(&CodeSize, 1, GifFile); /* Read Code size from file. */
+ BitsPerPixel = CodeSize;
+
+ Private->Buf[0] = 0; /* Input Buffer empty. */
+ Private->BitsPerPixel = BitsPerPixel;
+ Private->ClearCode = (1 << BitsPerPixel);
+ Private->EOFCode = Private->ClearCode + 1;
+ Private->RunningCode = Private->EOFCode + 1;
+ Private->RunningBits = BitsPerPixel + 1; /* Number of bits per code. */
+ Private->MaxCode1 = 1 << Private->RunningBits; /* Max. code + 1. */
+ Private->StackPtr = 0; /* No pixels on the pixel stack. */
+ Private->LastCode = NO_SUCH_CODE;
+ Private->CrntShiftState = 0; /* No information in CrntShiftDWord. */
+ Private->CrntShiftDWord = 0;
+
+ Prefix = Private->Prefix;
+ for (i = 0; i <= LZ_MAX_CODE; i++) Prefix[i] = NO_SUCH_CODE;
+}
+
+/******************************************************************************
+* The LZ decompression routine: *
+* This version decompress the given gif file into Line of length LineLen. *
+* This routine can be called few times (one per scan line, for example), in *
+* order the complete the whole image. *
+******************************************************************************/
+static void DGifDecompressLine(GifFileType *GifFile, GifPixelType *Line,
+ int LineLen)
+{
+ int i = 0, j, CrntCode, EOFCode, ClearCode, CrntPrefix, LastCode, StackPtr;
+ GifByteType *Stack, *Suffix;
+ unsigned int *Prefix;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ StackPtr = Private->StackPtr;
+ Prefix = Private->Prefix;
+ Suffix = Private->Suffix;
+ Stack = Private->Stack;
+ EOFCode = Private->EOFCode;
+ ClearCode = Private->ClearCode;
+ LastCode = Private->LastCode;
+
+ CrntPrefix = 0;
+ if (StackPtr != 0) {
+ /* Let pop the stack off before continueing to read the gif file: */
+ while (StackPtr != 0 && i < LineLen) Line[i++] = Stack[--StackPtr];
+ }
+
+ while (i < LineLen) { /* Decode LineLen items. */
+ DGifDecompressInput(GifFile, &CrntCode);
+
+ if (CrntCode == EOFCode) {
+ /* Note however that usually we will not be here as we will stop */
+ /* decoding as soon as we got all the pixel, or EOF code will */
+ /* not be read at all, and DGifGetLine/Pixel clean everything. */
+ if (i != LineLen - 1 || Private->PixelCount != 0) {
+ GifInternError(GifFile, D_GIF_ERR_EOF_TOO_SOON);
+ }
+ i++;
+ }
+ else if (CrntCode == ClearCode) {
+ /* We need to start over again: */
+ for (j = 0; j <= LZ_MAX_CODE; j++) Prefix[j] = NO_SUCH_CODE;
+ Private->RunningCode = Private->EOFCode + 1;
+ Private->RunningBits = Private->BitsPerPixel + 1;
+ Private->MaxCode1 = 1 << Private->RunningBits;
+ LastCode = Private->LastCode = NO_SUCH_CODE;
+ }
+ else {
+ /* Its regular code - if in pixel range simply add it to output */
+ /* stream, otherwise trace to codes linked list until the prefix */
+ /* is in pixel range: */
+ if (CrntCode < ClearCode) {
+ /* This is simple - its pixel scalar, so add it to output: */
+ Line[i++] = CrntCode;
+ }
+ else {
+ /* Its a code to needed to be traced: trace the linked list */
+ /* until the prefix is a pixel, while pushing the suffix */
+ /* pixels on our stack. If we done, pop the stack in reverse */
+ /* (thats what stack is good for!) order to output. */
+ if (Prefix[CrntCode] == NO_SUCH_CODE) {
+ /* Only allowed if CrntCode is exactly the running code: */
+ /* In that case CrntCode = XXXCode, CrntCode or the */
+ /* prefix code is last code and the suffix char is */
+ /* exactly the prefix of last code! */
+ if (CrntCode == Private->RunningCode - 2) {
+ CrntPrefix = LastCode;
+ Suffix[Private->RunningCode - 2] =
+ Stack[StackPtr++] = DGifGetPrefixChar(Prefix,
+ LastCode, ClearCode);
+ }
+ else {
+ GifInternError(GifFile, D_GIF_ERR_IMAGE_DEFECT);
+ }
+ }
+ else
+ CrntPrefix = CrntCode;
+
+ /* Now (if image is O.K.) we should not get an NO_SUCH_CODE */
+ /* During the trace. As we might loop forever, in case of */
+ /* defective image, we count the number of loops we trace */
+ /* and stop if we got LZ_MAX_CODE. obviously we can not */
+ /* loop more than that. */
+ j = 0;
+ while (j++ <= LZ_MAX_CODE &&
+ CrntPrefix > ClearCode &&
+ CrntPrefix <= LZ_MAX_CODE) {
+ Stack[StackPtr++] = Suffix[CrntPrefix];
+ CrntPrefix = Prefix[CrntPrefix];
+ }
+ if (j >= LZ_MAX_CODE || CrntPrefix > LZ_MAX_CODE) {
+ GifInternError(GifFile, D_GIF_ERR_IMAGE_DEFECT);
+ }
+ /* Push the last character on stack: */
+ Stack[StackPtr++] = CrntPrefix;
+
+ /* Now lets pop all the stack into output: */
+ while (StackPtr != 0 && i < LineLen)
+ Line[i++] = Stack[--StackPtr];
+ }
+ if (LastCode != NO_SUCH_CODE) {
+ Prefix[Private->RunningCode - 2] = LastCode;
+
+ if (CrntCode == Private->RunningCode - 2) {
+ /* Only allowed if CrntCode is exactly the running code: */
+ /* In that case CrntCode = XXXCode, CrntCode or the */
+ /* prefix code is last code and the suffix char is */
+ /* exactly the prefix of last code! */
+ Suffix[Private->RunningCode - 2] =
+ DGifGetPrefixChar(Prefix, LastCode, ClearCode);
+ }
+ else {
+ Suffix[Private->RunningCode - 2] =
+ DGifGetPrefixChar(Prefix, CrntCode, ClearCode);
+ }
+ }
+ LastCode = CrntCode;
+ }
+ }
+
+ Private->LastCode = LastCode;
+ Private->StackPtr = StackPtr;
+}
+
+/******************************************************************************
+* Routine to trace the Prefixes linked list until we get a prefix which is *
+* not code, but a pixel value (less than ClearCode). Returns that pixel value.*
+* If image is defective, we might loop here forever, so we limit the loops to *
+* the maximum possible if image O.k. - LZ_MAX_CODE times. *
+******************************************************************************/
+static int DGifGetPrefixChar(unsigned int *Prefix, int Code, int ClearCode)
+{
+ int i = 0;
+
+ while (Code > ClearCode && i++ <= LZ_MAX_CODE) Code = Prefix[Code];
+ return Code;
+}
+
+/******************************************************************************
+* Interface for accessing the LZ codes directly. Set Code to the real code *
+* (12bits), or to -1 if EOF code is returned. *
+******************************************************************************/
+void DGifGetLZCodes(GifFileType *GifFile, int *Code)
+{
+ GifByteType *CodeBlock;
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+
+ if (!IS_READABLE(Private)) {
+ /* This file was NOT open for reading: */
+ GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
+ }
+
+ DGifDecompressInput(GifFile, Code);
+
+ if (*Code == Private->EOFCode) {
+ /* Skip rest of codes (hopefully only NULL terminating block): */
+ do
+ DGifGetCodeNext(GifFile, &CodeBlock);
+ while (CodeBlock != NULL);
+
+ *Code = -1;
+ }
+ else if (*Code == Private->ClearCode) {
+ /* We need to start over again: */
+ Private->RunningCode = Private->EOFCode + 1;
+ Private->RunningBits = Private->BitsPerPixel + 1;
+ Private->MaxCode1 = 1 << Private->RunningBits;
+ }
+}
+
+/******************************************************************************
+* The LZ decompression input routine: *
+* This routine is responsable for the decompression of the bit stream from *
+* 8 bits (bytes) packets, into the real codes. *
+* Returns GIF_OK if read succesfully. *
+******************************************************************************/
+static void DGifDecompressInput(GifFileType *GifFile, int *Code)
+{
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+ GifByteType NextByte;
+ static unsigned int CodeMasks[] = {
+ 0x0000, 0x0001, 0x0003, 0x0007,
+ 0x000f, 0x001f, 0x003f, 0x007f,
+ 0x00ff, 0x01ff, 0x03ff, 0x07ff,
+ 0x0fff
+ };
+
+ while (Private->CrntShiftState < Private->RunningBits) {
+ /* Needs to get more bytes from input stream for next code: */
+ DGifBufferedInput(GifFile, &NextByte);
+ Private->CrntShiftDWord |=
+ ((unsigned long) NextByte) << Private->CrntShiftState;
+ Private->CrntShiftState += 8;
+ }
+ *Code = Private->CrntShiftDWord & CodeMasks[Private->RunningBits];
+
+ Private->CrntShiftDWord >>= Private->RunningBits;
+ Private->CrntShiftState -= Private->RunningBits;
+
+ /* If code cannt fit into RunningBits bits, must raise its size. Note */
+ /* however that codes above 4095 are used for special signaling. */
+ if (++Private->RunningCode > Private->MaxCode1 &&
+ Private->RunningBits < LZ_BITS) {
+ Private->MaxCode1 <<= 1;
+ Private->RunningBits++;
+ }
+}
+
+/******************************************************************************
+* This routines read one gif data block at a time and buffers it internally *
+* so that the decompression routine could access it. *
+* The routine returns the next byte from its internal buffer (or read next *
+* block in if buffer empty) *
+******************************************************************************/
+static void DGifBufferedInput(GifFileType *GifFile, GifByteType *NextByte)
+{
+ GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
+ GifByteType *Buf = Private->Buf;
+
+ if (Buf[0] == 0) {
+ /* Needs to read the next buffer - this one is empty: */
+ GifRead(Buf, 1, GifFile);
+ GifRead((Buf + 1), Buf[0], GifFile);
+ *NextByte = Buf[1];
+ Buf[1] = 2; /* We use now the second place as last char read! */
+ Buf[0]--;
+ }
+ else {
+ *NextByte = Buf[Buf[1]++];
+ Buf[0]--;
+ }
+}
+
+/******************************************************************************
+* This routine reads an entire GIF into core, hanging all its state info off *
+* the GifFileType pointer. Call DGifOpenFileName() or DGifOpenFileHandle() *
+* first to initialize I/O. Its inverse is EGifSpew(). *
+******************************************************************************/
+void DGifSlurp(GifFileType *GifFile)
+{
+ int ImageSize;
+ GifRecordType RecordType;
+ SavedImage *sp;
+ GifByteType *ExtData;
+
+ /* Some versions of malloc dislike 0-length requests */
+ GifFile->SavedImages = (SavedImage *)malloc(sizeof(SavedImage));
+ memset(GifFile->SavedImages, 0, sizeof(SavedImage));
+ sp = &GifFile->SavedImages[0];
+
+ do {
+ DGifGetRecordType(GifFile, &RecordType);
+
+ switch (RecordType) {
+ case IMAGE_DESC_RECORD_TYPE:
+ DGifGetImageDesc(GifFile);
+
+ sp = &GifFile->SavedImages[GifFile->ImageCount-1];
+ ImageSize = sp->ImageDesc.Width * sp->ImageDesc.Height;
+
+ sp->RasterBits
+ = (GifPixelType*) malloc(ImageSize * sizeof(GifPixelType));
+
+ DGifGetLine(GifFile, sp->RasterBits, ImageSize);
+ break;
+
+ case EXTENSION_RECORD_TYPE:
+ DGifGetExtension(GifFile,&sp->Function,&ExtData);
+
+ do {
+ if (AddExtensionBlock(sp, ExtData[0], ExtData+1) == GIF_ERROR)
+ GifInternError(GifFile, D_GIF_ERR_NOT_ENOUGH_MEM);
+ DGifGetExtensionNext(GifFile, &ExtData);
+ } while (ExtData != NULL);
+ break;
+
+ case TERMINATE_RECORD_TYPE:
+ break;
+
+ default: /* Should be trapped by DGifGetRecordType */
+ break;
+ }
+ } while (RecordType != TERMINATE_RECORD_TYPE);
+}
+
+/******************************************************************************
+* Extension record functions *
+******************************************************************************/
+
+void MakeExtension(SavedImage *New, int Function)
+{
+ New->Function = Function;
+ /*
+ * Someday we might have to deal with multiple extensions.
+ */
+}
+
+int AddExtensionBlock(SavedImage *New, int Len, GifByteType *data)
+{
+ int size;
+ ExtensionBlock *ep;
+
+ if (New->ExtensionBlocks == NULL)
+ New->ExtensionBlocks = (ExtensionBlock *)malloc(sizeof(ExtensionBlock));
+ else
+ New->ExtensionBlocks =
+ (ExtensionBlock *)realloc(New->ExtensionBlocks,
+ sizeof(ExtensionBlock) * (New->ExtensionBlockCount + 1));
+
+ if (New->ExtensionBlocks == NULL)
+ return(GIF_ERROR);
+
+ ep = &New->ExtensionBlocks[New->ExtensionBlockCount++];
+ ep->ByteCount = Len;
+ size = Len * sizeof(GifByteType);
+ ep->Bytes = (GifByteType *)malloc(size);
+ memcpy(ep->Bytes, data, size);
+ return(GIF_OK);
+}
+
+void FreeExtension(SavedImage *Image)
+{
+ ExtensionBlock *ep;
+
+ for (ep = Image->ExtensionBlocks;
+ ep < Image->ExtensionBlocks + Image->ExtensionBlockCount;
+ ep++)
+ (void) free((char *)ep->Bytes);
+ free((char *)Image->ExtensionBlocks);
+ Image->ExtensionBlocks = NULL;
+}
+
+/******************************************************************************
+* Image block allocation functions *
+******************************************************************************/
+SavedImage *MakeSavedImage(GifFileType *GifFile, SavedImage *CopyFrom)
+/*
+ * Append an image block to the SavedImages array
+ */
+{
+ SavedImage *sp;
+
+ if (GifFile->SavedImages == NULL)
+ GifFile->SavedImages = (SavedImage *)malloc(sizeof(SavedImage));
+ else
+ GifFile->SavedImages = (SavedImage *)realloc(GifFile->SavedImages,
+ sizeof(SavedImage) * (GifFile->ImageCount+1));
+
+ if (GifFile->SavedImages == NULL)
+ return((SavedImage *)NULL);
+ else
+ {
+ sp = &GifFile->SavedImages[GifFile->ImageCount++];
+ memset((char *)sp, '\0', sizeof(SavedImage));
+
+ if (CopyFrom)
+ {
+ memcpy((char *)sp, CopyFrom, sizeof(SavedImage));
+
+ /*
+ * Make our own allocated copies of the heap fields in the
+ * copied record. This guards against potential aliasing
+ * problems.
+ */
+
+ /* first, the local color map */
+ if (sp->ImageDesc.ColorMap)
+ sp->ImageDesc.ColorMap =
+ MakeMapObject(CopyFrom->ImageDesc.ColorMap->ColorCount,
+ CopyFrom->ImageDesc.ColorMap->Colors);
+
+ /* next, the raster */
+ sp->RasterBits = (char *)malloc(sizeof(GifPixelType)
+ * CopyFrom->ImageDesc.Height
+ * CopyFrom->ImageDesc.Width);
+ memcpy(sp->RasterBits,
+ CopyFrom->RasterBits,
+ sizeof(GifPixelType)
+ * CopyFrom->ImageDesc.Height
+ * CopyFrom->ImageDesc.Width);
+
+ /* finally, the extension blocks */
+ if (sp->ExtensionBlocks)
+ {
+ sp->ExtensionBlocks
+ = (ExtensionBlock*)malloc(sizeof(ExtensionBlock)
+ * CopyFrom->ExtensionBlockCount);
+ memcpy(sp->ExtensionBlocks,
+ CopyFrom->ExtensionBlocks,
+ sizeof(ExtensionBlock)
+ * CopyFrom->ExtensionBlockCount);
+
+ /*
+ * For the moment, the actual blocks can take their
+ * chances with free(). We'll fix this later.
+ */
+ }
+ }
+
+ return(sp);
+ }
+}
+
+void FreeSavedImages(GifFileType *GifFile)
+{
+ SavedImage *sp;
+
+ for (sp = GifFile->SavedImages;
+ sp < GifFile->SavedImages + GifFile->ImageCount;
+ sp++)
+ {
+ if (sp->ImageDesc.ColorMap)
+ FreeMapObject(sp->ImageDesc.ColorMap);
+
+ if (sp->RasterBits)
+ free((char *)sp->RasterBits);
+
+ if (sp->ExtensionBlocks)
+ FreeExtension(sp);
+ }
+ free((char *) GifFile->SavedImages);
+}
+
+/******************************************************************************
+* Miscellaneous utility functions *
+******************************************************************************/
+
+int BitSize(int n)
+/* return smallest bitfield size n will fit in */
+{
+ register int i;
+
+ for (i = 1; i <= 8; i++)
+ if ((1 << i) >= n)
+ break;
+ return(i);
+}
+
+/******************************************************************************
+* Color map object functions *
+******************************************************************************/
+
+ColorMapObject *MakeMapObject(int ColorCount, GifColorType *ColorMap)
+/*
+ * Allocate a color map of given size; initialize with contents of
+ * ColorMap if that pointer is non-NULL.
+ */
+{
+ ColorMapObject *Object;
+
+ if (ColorCount != (1 << BitSize(ColorCount)))
+ return((ColorMapObject *)NULL);
+
+ Object = (ColorMapObject *)malloc(sizeof(ColorMapObject));
+ if (Object == (ColorMapObject *)NULL)
+ return((ColorMapObject *)NULL);
+
+ Object->Colors = (GifColorType *)calloc(ColorCount, sizeof(GifColorType));
+ if (Object->Colors == (GifColorType *)NULL)
+ return((ColorMapObject *)NULL);
+
+ Object->ColorCount = ColorCount;
+ Object->BitsPerPixel = BitSize(ColorCount);
+
+ if (ColorMap)
+ memcpy((char *)Object->Colors,
+ (char *)ColorMap, ColorCount * sizeof(GifColorType));
+
+ return(Object);
+}
+
+void FreeMapObject(ColorMapObject *Object)
+/*
+ * Free a color map object
+ */
+{
+ free(Object->Colors);
+ free(Object);
+}
projects / chise / xemacs-chise.git.1 / blobdiff