/*****************************************************************************
* "Gif-Lib" - Yet another gif library.
*
* Written by: Gershon Elber Ver 0.1, Jun. 1989
* Extensively hacked by: Eric S. Raymond Ver 1.?, Sep 1992
*****************************************************************************
* GIF construction tools
*****************************************************************************
* History:
* 15 Sep 92 - Version 1.0 by Eric Raymond.
****************************************************************************/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "gif_lib.h"
#define MAX(x, y) (((x) > (y)) ? (x) : (y))
/******************************************************************************
* Miscellaneous utility functions
*****************************************************************************/
/* return smallest bitfield size n will fit in */
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.
*/
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 ((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);
}
/*
* Free a color map object
*/
void
FreeMapObject(ColorMapObject * Object) {
if (Object != NULL) {
free(Object->Colors);
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;
*/
}
}
#ifdef DEBUG
void
DumpColorMap(ColorMapObject * Object,
FILE * fp) {
if (Object) {
int i, j, Len = Object->ColorCount;
for (i = 0; i < Len; i += 4) {
for (j = 0; j < 4 && j < Len; j++) {
fprintf(fp, "%3d: %02x %02x %02x ", i + j,
Object->Colors[i + j].Red,
Object->Colors[i + j].Green,
Object->Colors[i + j].Blue);
}
fprintf(fp, "\n");
}
}
}
#endif /* DEBUG */
/*
* Compute the union of two given color maps and return it. If result can't
* fit into 256 colors, NULL is returned, the allocated union otherwise.
* ColorIn1 is copied as is to ColorUnion, while colors from ColorIn2 are
* copied iff they didn't exist before. ColorTransIn2 maps the old
* ColorIn2 into ColorUnion color map table.
*/
ColorMapObject *
UnionColorMap(const ColorMapObject * ColorIn1,
const ColorMapObject * ColorIn2,
GifPixelType ColorTransIn2[]) {
int i, j, CrntSlot, RoundUpTo, NewBitSize;
ColorMapObject *ColorUnion;
/*
* Allocate table which will hold the result for sure.
*/
ColorUnion = MakeMapObject(MAX(ColorIn1->ColorCount,
ColorIn2->ColorCount) * 2, NULL);
if (ColorUnion == NULL)
return (NULL);
/* Copy ColorIn1 to ColorUnionSize; */
/*** FIXME: What if there are duplicate entries into the colormap to begin
* with? */
for (i = 0; i < ColorIn1->ColorCount; i++)
ColorUnion->Colors[i] = ColorIn1->Colors[i];
CrntSlot = ColorIn1->ColorCount;
/*
* Potentially obnoxious hack:
*
* Back CrntSlot down past all contiguous {0, 0, 0} slots at the end
* of table 1. This is very useful if your display is limited to
* 16 colors.
*/
while (ColorIn1->Colors[CrntSlot - 1].Red == 0
&& ColorIn1->Colors[CrntSlot - 1].Green == 0
&& ColorIn1->Colors[CrntSlot - 1].Blue == 0)
CrntSlot--;
/* Copy ColorIn2 to ColorUnionSize (use old colors if they exist): */
for (i = 0; i < ColorIn2->ColorCount && CrntSlot <= 256; i++) {
/* Let's see if this color already exists: */
/*** FIXME: Will it ever occur that ColorIn2 will contain duplicate
* entries? So we should search from 0 to CrntSlot rather than
* ColorIn1->ColorCount?
*/
for (j = 0; j < ColorIn1->ColorCount; j++)
if (memcmp (&ColorIn1->Colors[j], &ColorIn2->Colors[i],
sizeof(GifColorType)) == 0)
break;
if (j < ColorIn1->ColorCount)
ColorTransIn2[i] = j; /* color exists in Color1 */
else {
/* Color is new - copy it to a new slot: */
ColorUnion->Colors[CrntSlot] = ColorIn2->Colors[i];
ColorTransIn2[i] = CrntSlot++;
}
}
if (CrntSlot > 256) {
FreeMapObject(ColorUnion);
return ((ColorMapObject *) NULL);
}
NewBitSize = BitSize(CrntSlot);
RoundUpTo = (1 << NewBitSize);
if (RoundUpTo != ColorUnion->ColorCount) {
register GifColorType *Map = ColorUnion->Colors;
/*
* Zero out slots up to next power of 2.
* We know these slots exist because of the way ColorUnion's
* start dimension was computed.
*/
for (j = CrntSlot; j < RoundUpTo; j++)
Map[j].Red = Map[j].Green = Map[j].Blue = 0;
/* perhaps we can shrink the map? */
if (RoundUpTo < ColorUnion->ColorCount)
ColorUnion->Colors = (GifColorType *)realloc(Map,
sizeof(GifColorType) * RoundUpTo);
}
ColorUnion->ColorCount = RoundUpTo;
ColorUnion->BitsPerPixel = NewBitSize;
return (ColorUnion);
}
/*
* Apply a given color translation to the raster bits of an image
*/
void
ApplyTranslation(SavedImage * Image,
GifPixelType Translation[]) {
register int i;
register int RasterSize = Image->ImageDesc.Height * Image->ImageDesc.Width;
for (i = 0; i < RasterSize; i++)
Image->RasterBits[i] = Translation[Image->RasterBits[i]];
}
/******************************************************************************
* Extension record functions
*****************************************************************************/
void
MakeExtension(SavedImage * New,
int Function) {
New->Function = Function;
/*** FIXME:
* Someday we might have to deal with multiple extensions.
* ??? Was this a note from Gershon or from me? Does the multiple
* extension blocks solve this or do we need multiple Functions? Or is
* this an obsolete function? (People should use AddExtensionBlock
* instead?)
* Looks like AddExtensionBlock needs to take the int Function argument
* then it can take the place of this function. Right now people have to
* use both. Fix AddExtensionBlock and add this to the deprecation list.
*/
}
int
AddExtensionBlock(SavedImage * New,
int Len,
unsigned char ExtData[]) {
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;
ep->Bytes = (char *)malloc(ep->ByteCount);
if (ep->Bytes == NULL)
return (GIF_ERROR);
if (ExtData) {
memcpy(ep->Bytes, ExtData, Len);
ep->Function = New->Function;
}
return (GIF_OK);
}
void
FreeExtension(SavedImage * Image)
{
ExtensionBlock *ep;
if ((Image == NULL) || (Image->ExtensionBlocks == NULL)) {
return;
}
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
******************************************************************************/
/* Private Function:
* Frees the last image in the GifFile->SavedImages array
*/
void
FreeLastSavedImage(GifFileType *GifFile) {
SavedImage *sp;
if ((GifFile == NULL) || (GifFile->SavedImages == NULL))
return;
/* Remove one SavedImage from the GifFile */
GifFile->ImageCount--;
sp = &GifFile->SavedImages[GifFile->ImageCount];
/* Deallocate its Colormap */
if (sp->ImageDesc.ColorMap) {
FreeMapObject(sp->ImageDesc.ColorMap);
sp->ImageDesc.ColorMap = NULL;
}
/* Deallocate the image data */
if (sp->RasterBits)
free((char *)sp->RasterBits);
/* Deallocate any extensions */
if (sp->ExtensionBlocks)
FreeExtension(sp);
/*** FIXME: We could realloc the GifFile->SavedImages structure but is
* there a point to it? Saves some memory but we'd have to do it every
* time. If this is used in FreeSavedImages then it would be inefficient
* (The whole array is going to be deallocated.) If we just use it when
* we want to free the last Image it's convenient to do it here.
*/
}
/*
* Append an image block to the SavedImages array
*/
SavedImage *
MakeSavedImage(GifFileType * GifFile,
const SavedImage * CopyFrom) {
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);
if (sp->ImageDesc.ColorMap == NULL) {
FreeLastSavedImage(GifFile);
return (SavedImage *)(NULL);
}
}
/* next, the raster */
sp->RasterBits = (unsigned char *)malloc(sizeof(GifPixelType) *
CopyFrom->ImageDesc.Height *
CopyFrom->ImageDesc.Width);
if (sp->RasterBits == NULL) {
FreeLastSavedImage(GifFile);
return (SavedImage *)(NULL);
}
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);
if (sp->ExtensionBlocks == NULL) {
FreeLastSavedImage(GifFile);
return (SavedImage *)(NULL);
}
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.
*** FIXME: [Better check this out... Toshio]
* 2004 May 27: Looks like this was an ESR note.
* It means the blocks are shallow copied from InFile to
* OutFile. However, I don't see that in this code....
* Did ESR fix it but never remove this note (And other notes
* in gifspnge?)
*/
}
}
return (sp);
}
}
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;
}
if (sp->RasterBits)
free((char *)sp->RasterBits);
if (sp->ExtensionBlocks)
FreeExtension(sp);
}
free((char *)GifFile->SavedImages);
GifFile->SavedImages=NULL;
}