--- /dev/null
+/*
+ * Gif extracting routines - derived from libungif
+ *
+ * Portions Copyright 2006 Mike McCormack
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
+ */
+
+/*
+ * Original copyright notice:
+ *
+ * The GIFLIB distribution is Copyright (c) 1997 Eric S. Raymond
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ */
+
+
+/******************************************************************************
+ * "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).
+ *****************************************************************************/
+
+#include "wincodecs_private.h"
+
+#include "ungif.h"
+
+static void *ungif_alloc( size_t sz )
+{
+ return HeapAlloc( GetProcessHeap(), 0, sz );
+}
+
+static void *ungif_calloc( size_t num, size_t sz )
+{
+ return HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY, num*sz );
+}
+
+static void *ungif_realloc( void *ptr, size_t sz )
+{
+ return HeapReAlloc( GetProcessHeap(), 0, ptr, sz );
+}
+
+static void ungif_free( void *ptr )
+{
+ HeapFree( GetProcessHeap(), 0, ptr );
+}
+
+#define LZ_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
+#define LZ_BITS 12
+
+#define NO_SUCH_CODE 4098 /* Impossible code, to signal empty. */
+
+typedef struct GifFilePrivateType {
+ GifWord BitsPerPixel, /* Bits per pixel (Codes uses at least this + 1). */
+ ClearCode, /* The CLEAR LZ code. */
+ EOFCode, /* The EOF LZ code. */
+ RunningCode, /* The next code algorithm can generate. */
+ RunningBits, /* The number of bits required to represent RunningCode. */
+ MaxCode1, /* 1 bigger than max. possible code, in RunningBits bits. */
+ LastCode, /* The code before the current code. */
+ CrntCode, /* Current algorithm code. */
+ StackPtr, /* For character stack (see below). */
+ CrntShiftState; /* Number of bits in CrntShiftDWord. */
+ unsigned long CrntShiftDWord; /* For bytes decomposition into codes. */
+ unsigned long PixelCount; /* Number of pixels in image. */
+ InputFunc Read; /* function to read gif input (TVT) */
+ GifByteType Buf[256]; /* Compressed input is buffered here. */
+ GifByteType Stack[LZ_MAX_CODE]; /* Decoded pixels are stacked here. */
+ GifByteType Suffix[LZ_MAX_CODE + 1]; /* So we can trace the codes. */
+ GifPrefixType Prefix[LZ_MAX_CODE + 1];
+} GifFilePrivateType;
+
+/* avoid extra function call in case we use fread (TVT) */
+#define READ(_gif,_buf,_len) \
+ ((GifFilePrivateType*)_gif->Private)->Read(_gif,_buf,_len)
+
+static int DGifGetWord(GifFileType *GifFile, GifWord *Word);
+static int DGifSetupDecompress(GifFileType *GifFile);
+static int DGifDecompressLine(GifFileType *GifFile, GifPixelType *Line, int LineLen);
+static int DGifGetPrefixChar(const GifPrefixType *Prefix, int Code, int ClearCode);
+static int DGifDecompressInput(GifFileType *GifFile, int *Code);
+static int DGifBufferedInput(GifFileType *GifFile, GifByteType *Buf,
+ GifByteType *NextByte);
+
+static int DGifGetExtensionNext(GifFileType * GifFile, GifByteType ** GifExtension);
+static int DGifGetCodeNext(GifFileType * GifFile, GifByteType ** GifCodeBlock);
+
+/******************************************************************************
+ * Miscellaneous utility functions
+ *****************************************************************************/
+
+/* return smallest bitfield size n will fit in */
+static int
+BitSize(int n) {
+
+ register int i;
+
+ for (i = 1; i <= 8; i++)
+ if ((1 << i) >= n)
+ break;
+ return (i);
+}
+
+/******************************************************************************
+ * Color map object functions
+ *****************************************************************************/
+
+/*
+ * Allocate a color map of given size; initialize with contents of
+ * ColorMap if that pointer is non-NULL.
+ */
+static ColorMapObject *
+MakeMapObject(int ColorCount,
+ const GifColorType * ColorMap) {
+
+ ColorMapObject *Object;
+
+ /*** FIXME: Our ColorCount has to be a power of two. Is it necessary to
+ * make the user know that or should we automatically round up instead? */
+ if (ColorCount != (1 << BitSize(ColorCount))) {
+ return NULL;
+ }
+
+ Object = ungif_alloc(sizeof(ColorMapObject));
+ if (Object == NULL) {
+ return NULL;
+ }
+
+ Object->Colors = ungif_calloc(ColorCount, sizeof(GifColorType));
+ if (Object->Colors == NULL) {
+ ungif_free(Object);
+ return NULL;
+ }
+
+ Object->ColorCount = ColorCount;
+ Object->BitsPerPixel = BitSize(ColorCount);
+
+ if (ColorMap) {
+ memcpy(Object->Colors, ColorMap, ColorCount * sizeof(GifColorType));
+ }
+
+ return (Object);
+}
+
+/*
+ * Free a color map object
+ */
+static void
+FreeMapObject(ColorMapObject * Object) {
+
+ if (Object != NULL) {
+ ungif_free(Object->Colors);
+ ungif_free(Object);
+ /*** FIXME:
+ * When we are willing to break API we need to make this function
+ * FreeMapObject(ColorMapObject **Object)
+ * and do this assignment to NULL here:
+ * *Object = NULL;
+ */
+ }
+}
+
+static int
+AddExtensionBlock(Extensions *New,
+ int Len,
+ const unsigned char ExtData[]) {
+
+ ExtensionBlock *ep;
+
+ if (New->ExtensionBlocks == NULL)
+ New->ExtensionBlocks = ungif_alloc(sizeof(ExtensionBlock));
+ else
+ New->ExtensionBlocks = ungif_realloc(New->ExtensionBlocks,
+ sizeof(ExtensionBlock) *
+ (New->ExtensionBlockCount + 1));
+
+ if (New->ExtensionBlocks == NULL)
+ return (GIF_ERROR);
+
+ ep = &New->ExtensionBlocks[New->ExtensionBlockCount++];
+
+ ep->ByteCount=Len + 3;
+ ep->Bytes = ungif_alloc(ep->ByteCount + 3);
+ if (ep->Bytes == NULL)
+ return (GIF_ERROR);
+
+ /* Extension Header */
+ ep->Bytes[0] = 0x21;
+ ep->Bytes[1] = New->Function;
+ ep->Bytes[2] = Len;
+
+ if (ExtData) {
+ memcpy(ep->Bytes + 3, ExtData, Len);
+ ep->Function = New->Function;
+ }
+
+ return (GIF_OK);
+}
+
+static int
+AppendExtensionBlock(Extensions *New,
+ int Len,
+ const unsigned char ExtData[])
+{
+ ExtensionBlock *ep;
+
+ if (New->ExtensionBlocks == NULL)
+ return (GIF_ERROR);
+
+ ep = &New->ExtensionBlocks[New->ExtensionBlockCount - 1];
+
+ ep->Bytes = ungif_realloc(ep->Bytes, ep->ByteCount + Len + 1);
+ if (ep->Bytes == NULL)
+ return (GIF_ERROR);
+
+ ep->Bytes[ep->ByteCount] = Len;
+
+ if (ExtData)
+ memcpy(ep->Bytes + ep->ByteCount + 1, ExtData, Len);
+
+ ep->ByteCount += Len + 1;
+
+ return (GIF_OK);
+}
+
+static void
+FreeExtension(Extensions *Extensions)
+{
+ ExtensionBlock *ep;
+
+ if ((Extensions == NULL) || (Extensions->ExtensionBlocks == NULL)) {
+ return;
+ }
+ for (ep = Extensions->ExtensionBlocks;
+ ep < (Extensions->ExtensionBlocks + Extensions->ExtensionBlockCount); ep++)
+ ungif_free(ep->Bytes);
+ ungif_free(Extensions->ExtensionBlocks);
+ Extensions->ExtensionBlocks = NULL;
+}
+
+/******************************************************************************
+ * Image block allocation functions
+******************************************************************************/
+
+static void
+FreeSavedImages(GifFileType * GifFile) {
+
+ SavedImage *sp;
+
+ if ((GifFile == NULL) || (GifFile->SavedImages == NULL)) {
+ return;
+ }
+ for (sp = GifFile->SavedImages;
+ sp < GifFile->SavedImages + GifFile->ImageCount; sp++) {
+ if (sp->ImageDesc.ColorMap) {
+ FreeMapObject(sp->ImageDesc.ColorMap);
+ sp->ImageDesc.ColorMap = NULL;
+ }
+
+ ungif_free(sp->RasterBits);
+
+ if (sp->Extensions.ExtensionBlocks)
+ FreeExtension(&sp->Extensions);
+ }
+ ungif_free(GifFile->SavedImages);
+ GifFile->SavedImages=NULL;
+}
+
+/******************************************************************************
+ * This routine should be called before any other DGif calls. Note that
+ * this routine is called automatically from DGif file open routines.
+ *****************************************************************************/
+static int
+DGifGetScreenDesc(GifFileType * GifFile) {
+
+ int i, BitsPerPixel, SortFlag;
+ GifByteType Buf[3];
+
+ /* Put the screen descriptor into the file: */
+ if (DGifGetWord(GifFile, &GifFile->SWidth) == GIF_ERROR ||
+ DGifGetWord(GifFile, &GifFile->SHeight) == GIF_ERROR)
+ return GIF_ERROR;
+
+ if (READ(GifFile, Buf, 3) != 3) {
+ return GIF_ERROR;
+ }
+ GifFile->SColorResolution = (((Buf[0] & 0x70) + 1) >> 4) + 1;
+ SortFlag = (Buf[0] & 0x08) != 0;
+ BitsPerPixel = (Buf[0] & 0x07) + 1;
+ GifFile->SBackGroundColor = Buf[1];
+ GifFile->SAspectRatio = Buf[2];
+ if (Buf[0] & 0x80) { /* Do we have global color map? */
+
+ GifFile->SColorMap = MakeMapObject(1 << BitsPerPixel, NULL);
+ if (GifFile->SColorMap == NULL) {
+ return GIF_ERROR;
+ }
+
+ /* Get the global color map: */
+ GifFile->SColorMap->SortFlag = SortFlag;
+ for (i = 0; i < GifFile->SColorMap->ColorCount; i++) {
+ if (READ(GifFile, Buf, 3) != 3) {
+ FreeMapObject(GifFile->SColorMap);
+ GifFile->SColorMap = NULL;
+ return GIF_ERROR;
+ }
+ GifFile->SColorMap->Colors[i].Red = Buf[0];
+ GifFile->SColorMap->Colors[i].Green = Buf[1];
+ GifFile->SColorMap->Colors[i].Blue = Buf[2];
+ }
+ } else {
+ GifFile->SColorMap = NULL;
+ }
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * This routine should be called before any attempt to read an image.
+ *****************************************************************************/
+static int
+DGifGetRecordType(GifFileType * GifFile,
+ GifRecordType * Type) {
+
+ GifByteType Buf;
+
+ if (READ(GifFile, &Buf, 1) != 1) {
+ /* Wine-specific behavior: Native accepts broken GIF files that have no
+ * terminator, so we match this by treating EOF as a terminator. */
+ *Type = TERMINATE_RECORD_TYPE;
+ return GIF_OK;
+ }
+
+ 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;
+ return GIF_ERROR;
+ }
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * This routine should be called before any attempt to read an image.
+ * Note it is assumed the Image desc. header (',') has been read.
+ *****************************************************************************/
+static int
+DGifGetImageDesc(GifFileType * GifFile) {
+
+ int i, BitsPerPixel, SortFlag;
+ GifByteType Buf[3];
+ GifFilePrivateType *Private = GifFile->Private;
+ SavedImage *sp;
+
+ if (DGifGetWord(GifFile, &GifFile->Image.Left) == GIF_ERROR ||
+ DGifGetWord(GifFile, &GifFile->Image.Top) == GIF_ERROR ||
+ DGifGetWord(GifFile, &GifFile->Image.Width) == GIF_ERROR ||
+ DGifGetWord(GifFile, &GifFile->Image.Height) == GIF_ERROR)
+ return GIF_ERROR;
+ if (READ(GifFile, Buf, 1) != 1) {
+ return GIF_ERROR;
+ }
+ BitsPerPixel = (Buf[0] & 0x07) + 1;
+ SortFlag = (Buf[0] & 0x20) != 0;
+ GifFile->Image.Interlace = (Buf[0] & 0x40);
+ if (Buf[0] & 0x80) { /* Does this image have local color map? */
+
+ FreeMapObject(GifFile->Image.ColorMap);
+
+ GifFile->Image.ColorMap = MakeMapObject(1 << BitsPerPixel, NULL);
+ if (GifFile->Image.ColorMap == NULL) {
+ return GIF_ERROR;
+ }
+
+ /* Get the image local color map: */
+ GifFile->Image.ColorMap->SortFlag = SortFlag;
+ for (i = 0; i < GifFile->Image.ColorMap->ColorCount; i++) {
+ if (READ(GifFile, Buf, 3) != 3) {
+ FreeMapObject(GifFile->Image.ColorMap);
+ GifFile->Image.ColorMap = NULL;
+ return GIF_ERROR;
+ }
+ GifFile->Image.ColorMap->Colors[i].Red = Buf[0];
+ GifFile->Image.ColorMap->Colors[i].Green = Buf[1];
+ GifFile->Image.ColorMap->Colors[i].Blue = Buf[2];
+ }
+ } else if (GifFile->Image.ColorMap) {
+ FreeMapObject(GifFile->Image.ColorMap);
+ GifFile->Image.ColorMap = NULL;
+ }
+
+ if (GifFile->SavedImages) {
+ if ((GifFile->SavedImages = ungif_realloc(GifFile->SavedImages,
+ sizeof(SavedImage) *
+ (GifFile->ImageCount + 1))) == NULL) {
+ return GIF_ERROR;
+ }
+ } else {
+ if ((GifFile->SavedImages = ungif_alloc(sizeof(SavedImage))) == NULL) {
+ return GIF_ERROR;
+ }
+ }
+
+ sp = &GifFile->SavedImages[GifFile->ImageCount];
+ sp->ImageDesc = GifFile->Image;
+ if (GifFile->Image.ColorMap != NULL) {
+ sp->ImageDesc.ColorMap = MakeMapObject(
+ GifFile->Image.ColorMap->ColorCount,
+ GifFile->Image.ColorMap->Colors);
+ if (sp->ImageDesc.ColorMap == NULL) {
+ return GIF_ERROR;
+ }
+ sp->ImageDesc.ColorMap->SortFlag = GifFile->Image.ColorMap->SortFlag;
+ }
+ sp->RasterBits = NULL;
+ sp->Extensions.ExtensionBlockCount = 0;
+ sp->Extensions.ExtensionBlocks = NULL;
+
+ GifFile->ImageCount++;
+
+ Private->PixelCount = (long)GifFile->Image.Width *
+ (long)GifFile->Image.Height;
+
+ DGifSetupDecompress(GifFile); /* Reset decompress algorithm parameters. */
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * Get one full scanned line (Line) of length LineLen from GIF file.
+ *****************************************************************************/
+static int
+DGifGetLine(GifFileType * GifFile,
+ GifPixelType * Line,
+ int LineLen) {
+
+ GifByteType *Dummy;
+ GifFilePrivateType *Private = GifFile->Private;
+
+ if (!LineLen)
+ LineLen = GifFile->Image.Width;
+
+ if ((Private->PixelCount -= LineLen) > 0xffff0000UL) {
+ return GIF_ERROR;
+ }
+
+ if (DGifDecompressLine(GifFile, Line, LineLen) == GIF_OK) {
+ 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
+ if (DGifGetCodeNext(GifFile, &Dummy) == GIF_ERROR)
+ {
+ WARN("GIF is not properly terminated\n");
+ break;
+ }
+ while (Dummy != NULL) ;
+ }
+ return GIF_OK;
+ } else
+ return GIF_ERROR;
+}
+
+/******************************************************************************
+ * Get an extension block (see GIF manual) from gif file. This routine only
+ * returns the first data block, and DGifGetExtensionNext should be 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.
+ *****************************************************************************/
+static int
+DGifGetExtension(GifFileType * GifFile,
+ int *ExtCode,
+ GifByteType ** Extension) {
+
+ GifByteType Buf;
+
+ if (READ(GifFile, &Buf, 1) != 1) {
+ return GIF_ERROR;
+ }
+ *ExtCode = Buf;
+
+ return DGifGetExtensionNext(GifFile, Extension);
+}
+
+/******************************************************************************
+ * Get a following extension block (see GIF manual) from gif file. This
+ * routine should be called until NULL Extension is returned.
+ * The Extension should NOT be freed by the user (not dynamically allocated).
+ *****************************************************************************/
+static int
+DGifGetExtensionNext(GifFileType * GifFile,
+ GifByteType ** Extension) {
+
+ GifByteType Buf;
+ GifFilePrivateType *Private = GifFile->Private;
+
+ if (READ(GifFile, &Buf, 1) != 1) {
+ return GIF_ERROR;
+ }
+ if (Buf > 0) {
+ *Extension = Private->Buf; /* Use private unused buffer. */
+ (*Extension)[0] = Buf; /* Pascal strings notation (pos. 0 is len.). */
+ if (READ(GifFile, &((*Extension)[1]), Buf) != Buf) {
+ return GIF_ERROR;
+ }
+ } else
+ *Extension = NULL;
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * Get 2 bytes (word) from the given file:
+ *****************************************************************************/
+static int
+DGifGetWord(GifFileType * GifFile,
+ GifWord *Word) {
+
+ unsigned char c[2];
+
+ if (READ(GifFile, c, 2) != 2) {
+ return GIF_ERROR;
+ }
+
+ *Word = (((unsigned int)c[1]) << 8) + c[0];
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * 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).
+ *****************************************************************************/
+static int
+DGifGetCodeNext(GifFileType * GifFile,
+ GifByteType ** CodeBlock) {
+
+ GifByteType Buf;
+ GifFilePrivateType *Private = GifFile->Private;
+
+ if (READ(GifFile, &Buf, 1) != 1) {
+ return GIF_ERROR;
+ }
+
+ if (Buf > 0) {
+ *CodeBlock = Private->Buf; /* Use private unused buffer. */
+ (*CodeBlock)[0] = Buf; /* Pascal strings notation (pos. 0 is len.). */
+ if (READ(GifFile, &((*CodeBlock)[1]), Buf) != Buf) {
+ return GIF_ERROR;
+ }
+ } else {
+ *CodeBlock = NULL;
+ Private->Buf[0] = 0; /* Make sure the buffer is empty! */
+ Private->PixelCount = 0; /* And local info. indicate image read. */
+ }
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * Setup the LZ decompression for this image:
+ *****************************************************************************/
+static int
+DGifSetupDecompress(GifFileType * GifFile) {
+
+ int i, BitsPerPixel;
+ GifByteType CodeSize;
+ GifPrefixType *Prefix;
+ GifFilePrivateType *Private = GifFile->Private;
+
+ READ(GifFile, &CodeSize, 1); /* 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;
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * 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 int
+DGifDecompressLine(GifFileType * GifFile,
+ GifPixelType * Line,
+ int LineLen) {
+
+ int i = 0;
+ int j, CrntCode, EOFCode, ClearCode, CrntPrefix, LastCode, StackPtr;
+ GifByteType *Stack, *Suffix;
+ GifPrefixType *Prefix;
+ GifFilePrivateType *Private = GifFile->Private;
+
+ StackPtr = Private->StackPtr;
+ Prefix = Private->Prefix;
+ Suffix = Private->Suffix;
+ Stack = Private->Stack;
+ EOFCode = Private->EOFCode;
+ ClearCode = Private->ClearCode;
+ LastCode = Private->LastCode;
+
+ if (StackPtr != 0) {
+ /* Let pop the stack off before continuing to read the gif file: */
+ while (StackPtr != 0 && i < LineLen)
+ Line[i++] = Stack[--StackPtr];
+ }
+
+ while (i < LineLen) { /* Decode LineLen items. */
+ if (DGifDecompressInput(GifFile, &CrntCode) == GIF_ERROR)
+ return GIF_ERROR;
+
+ 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) {
+ return GIF_ERROR;
+ }
+ 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 {
+ /* It's a 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 {
+ /* It's a code 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
+ * order (that's what stack is good for!) for 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 {
+ return GIF_ERROR;
+ }
+ } else
+ CrntPrefix = CrntCode;
+
+ /* Now (if image is O.K.) we should not get a 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 cannot
+ * 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) {
+ return GIF_ERROR;
+ }
+ /* 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;
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * 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(const GifPrefixType *Prefix,
+ int Code,
+ int ClearCode) {
+
+ int i = 0;
+
+ while (Code > ClearCode && i++ <= LZ_MAX_CODE)
+ Code = Prefix[Code];
+ return Code;
+}
+
+/******************************************************************************
+ * The LZ decompression input routine:
+ * This routine is responsible for the decompression of the bit stream from
+ * 8 bits (bytes) packets, into the real codes.
+ * Returns GIF_OK if read successfully.
+ *****************************************************************************/
+static int
+DGifDecompressInput(GifFileType * GifFile,
+ int *Code) {
+
+ GifFilePrivateType *Private = GifFile->Private;
+
+ GifByteType NextByte;
+ static const unsigned short CodeMasks[] = {
+ 0x0000, 0x0001, 0x0003, 0x0007,
+ 0x000f, 0x001f, 0x003f, 0x007f,
+ 0x00ff, 0x01ff, 0x03ff, 0x07ff,
+ 0x0fff
+ };
+ /* The image can't contain more than LZ_BITS per code. */
+ if (Private->RunningBits > LZ_BITS) {
+ return GIF_ERROR;
+ }
+
+ while (Private->CrntShiftState < Private->RunningBits) {
+ /* Needs to get more bytes from input stream for next code: */
+ if (DGifBufferedInput(GifFile, Private->Buf, &NextByte) == GIF_ERROR) {
+ return GIF_ERROR;
+ }
+ 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 cannot fit into RunningBits bits, must raise its size. Note
+ * however that codes above 4095 are used for special signaling.
+ * If we're using LZ_BITS bits already and we're at the max code, just
+ * keep using the table as it is, don't increment Private->RunningCode.
+ */
+ if (Private->RunningCode < LZ_MAX_CODE + 2 &&
+ ++Private->RunningCode > Private->MaxCode1 &&
+ Private->RunningBits < LZ_BITS) {
+ Private->MaxCode1 <<= 1;
+ Private->RunningBits++;
+ }
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * 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) and returns GIF_OK if successful.
+ *****************************************************************************/
+static int
+DGifBufferedInput(GifFileType * GifFile,
+ GifByteType * Buf,
+ GifByteType * NextByte) {
+
+ if (Buf[0] == 0) {
+ /* Needs to read the next buffer - this one is empty: */
+ if (READ(GifFile, Buf, 1) != 1) {
+ return GIF_ERROR;
+ }
+ /* There shouldn't be any empty data blocks here as the LZW spec
+ * says the LZW termination code should come first. Therefore we
+ * shouldn't be inside this routine at that point.
+ */
+ if (Buf[0] == 0) {
+ return GIF_ERROR;
+ }
+ if (READ(GifFile, &Buf[1], Buf[0]) != Buf[0]) {
+ return GIF_ERROR;
+ }
+ *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]--;
+ }
+
+ return GIF_OK;
+}
+
+/******************************************************************************
+ * 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().
+ ******************************************************************************/
+int
+DGifSlurp(GifFileType * GifFile) {
+
+ int ImageSize;
+ GifRecordType RecordType;
+ SavedImage *sp;
+ GifByteType *ExtData;
+ Extensions temp_save;
+
+ temp_save.ExtensionBlocks = NULL;
+ temp_save.ExtensionBlockCount = 0;
+
+ do {
+ if (DGifGetRecordType(GifFile, &RecordType) == GIF_ERROR)
+ return (GIF_ERROR);
+
+ switch (RecordType) {
+ case IMAGE_DESC_RECORD_TYPE:
+ if (DGifGetImageDesc(GifFile) == GIF_ERROR)
+ return (GIF_ERROR);
+
+ sp = &GifFile->SavedImages[GifFile->ImageCount - 1];
+ ImageSize = sp->ImageDesc.Width * sp->ImageDesc.Height;
+
+ sp->RasterBits = ungif_alloc(ImageSize * sizeof(GifPixelType));
+ if (sp->RasterBits == NULL) {
+ return GIF_ERROR;
+ }
+ if (DGifGetLine(GifFile, sp->RasterBits, ImageSize) ==
+ GIF_ERROR)
+ return (GIF_ERROR);
+ if (temp_save.ExtensionBlocks) {
+ sp->Extensions.ExtensionBlocks = temp_save.ExtensionBlocks;
+ sp->Extensions.ExtensionBlockCount = temp_save.ExtensionBlockCount;
+
+ temp_save.ExtensionBlocks = NULL;
+ temp_save.ExtensionBlockCount = 0;
+
+ /* FIXME: The following is wrong. It is left in only for
+ * backwards compatibility. Someday it should go away. Use
+ * the sp->ExtensionBlocks->Function variable instead. */
+ sp->Extensions.Function = sp->Extensions.ExtensionBlocks[0].Function;
+ }
+ break;
+
+ case EXTENSION_RECORD_TYPE:
+ {
+ int Function;
+ Extensions *Extensions;
+
+ if (DGifGetExtension(GifFile, &Function, &ExtData) == GIF_ERROR)
+ return (GIF_ERROR);
+
+ if (GifFile->ImageCount || Function == GRAPHICS_EXT_FUNC_CODE)
+ Extensions = &temp_save;
+ else
+ Extensions = &GifFile->Extensions;
+
+ Extensions->Function = Function;
+
+ if (ExtData)
+ {
+ /* Create an extension block with our data */
+ if (AddExtensionBlock(Extensions, ExtData[0], &ExtData[1]) == GIF_ERROR)
+ return (GIF_ERROR);
+ }
+ else /* Empty extension block */
+ {
+ if (AddExtensionBlock(Extensions, 0, NULL) == GIF_ERROR)
+ return (GIF_ERROR);
+ }
+
+ while (ExtData != NULL) {
+ int Len;
+ GifByteType *Data;
+
+ if (DGifGetExtensionNext(GifFile, &ExtData) == GIF_ERROR)
+ return (GIF_ERROR);
+
+ if (ExtData)
+ {
+ Len = ExtData[0];
+ Data = &ExtData[1];
+ }
+ else
+ {
+ Len = 0;
+ Data = NULL;
+ }
+
+ if (AppendExtensionBlock(Extensions, Len, Data) == GIF_ERROR)
+ return (GIF_ERROR);
+ }
+ break;
+ }
+
+ case TERMINATE_RECORD_TYPE:
+ break;
+
+ default: /* Should be trapped by DGifGetRecordType */
+ break;
+ }
+ } while (RecordType != TERMINATE_RECORD_TYPE);
+
+ /* Just in case the Gif has an extension block without an associated
+ * image... (Should we save this into a savefile structure with no image
+ * instead? Have to check if the present writing code can handle that as
+ * well.... */
+ if (temp_save.ExtensionBlocks)
+ FreeExtension(&temp_save);
+
+ return (GIF_OK);
+}
+
+/******************************************************************************
+ * GifFileType constructor with user supplied input function (TVT)
+ *****************************************************************************/
+GifFileType *
+DGifOpen(void *userData,
+ InputFunc readFunc) {
+
+ unsigned char Buf[GIF_STAMP_LEN + 1];
+ GifFileType *GifFile;
+ GifFilePrivateType *Private;
+
+ GifFile = ungif_alloc(sizeof(GifFileType));
+ if (GifFile == NULL) {
+ return NULL;
+ }
+
+ memset(GifFile, '\0', sizeof(GifFileType));
+
+ Private = ungif_alloc(sizeof(GifFilePrivateType));
+ if (!Private) {
+ ungif_free(GifFile);
+ return NULL;
+ }
+
+ GifFile->Private = (void*)Private;
+
+ Private->Read = readFunc; /* TVT */
+ GifFile->UserData = userData; /* TVT */
+
+ /* Lets see if this is a GIF file: */
+ if (READ(GifFile, Buf, GIF_STAMP_LEN) != GIF_STAMP_LEN) {
+ ungif_free(Private);
+ ungif_free(GifFile);
+ return NULL;
+ }
+
+ /* The GIF Version number is ignored at this time. Maybe we should do
+ * something more useful with it. */
+ Buf[GIF_STAMP_LEN] = 0;
+ if (memcmp(GIF_STAMP, Buf, GIF_VERSION_POS) != 0) {
+ ungif_free(Private);
+ ungif_free(GifFile);
+ return NULL;
+ }
+
+ if (DGifGetScreenDesc(GifFile) == GIF_ERROR) {
+ ungif_free(Private);
+ ungif_free(GifFile);
+ return NULL;
+ }
+
+ return GifFile;
+}
+
+/******************************************************************************
+ * This routine should be called last, to close the GIF file.
+ *****************************************************************************/
+int
+DGifCloseFile(GifFileType * GifFile) {
+
+ GifFilePrivateType *Private;
+
+ if (GifFile == NULL)
+ return GIF_ERROR;
+
+ Private = GifFile->Private;
+
+ if (GifFile->Image.ColorMap) {
+ FreeMapObject(GifFile->Image.ColorMap);
+ GifFile->Image.ColorMap = NULL;
+ }
+
+ if (GifFile->SColorMap) {
+ FreeMapObject(GifFile->SColorMap);
+ GifFile->SColorMap = NULL;
+ }
+
+ ungif_free(Private);
+ Private = NULL;
+
+ if (GifFile->SavedImages) {
+ FreeSavedImages(GifFile);
+ GifFile->SavedImages = NULL;
+ }
+
+ FreeExtension(&GifFile->Extensions);
+
+ ungif_free(GifFile);
+
+ return GIF_OK;
+}
projects / reactos.git / blobdiff