/******************************************************************************
* "Gif-Lib" - Yet another gif library.
*
* Written by: Gershon Elber Ver 1.1, Aug. 1990
******************************************************************************
* The kernel of the GIF Encoding process can be found here.
******************************************************************************
* History:
* 14 Jun 89 - Version 1.0 by Gershon Elber.
* 3 Sep 90 - Version 1.1 by Gershon Elber (Support for Gif89, Unique names).
* 26 Jun 96 - Version 3.0 by Eric S. Raymond (Full GIF89 support)
*****************************************************************************/
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#if (defined (__MSDOS__) || defined(WINDOWS32)) && !defined(__DJGPP__) && !defined(__GNUC__)
#include <io.h>
#include <sys\stat.h>
#else
#include <sys/types.h>
#include <sys/stat.h>
#endif /* __MSDOS__ */
#include "gif_lib.h"
#include "gif_lib_private.h"
/* Masks given codes to BitsPerPixel, to make sure all codes are in range: */
/*@+charint@*/
static const GifPixelType CodeMask[] = {
0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff
};
/*@-charint@*/
static char GifVersionPrefix[GIF_STAMP_LEN + 1];
#define WRITE(_gif,_buf,_len) \
(((GifFilePrivateType*)_gif->Private)->Write ? \
((GifFilePrivateType*)_gif->Private)->Write(_gif,_buf,_len) : \
fwrite(_buf, 1, (size_t)_len, ((GifFilePrivateType*)_gif->Private)->File))
static int EGifPutWord(int Word, GifFileType * GifFile);
static int EGifSetupCompress(GifFileType * GifFile);
static int EGifCompressLine(GifFileType * GifFile, GifPixelType * Line,
int LineLen);
static int EGifCompressOutput(GifFileType * GifFile, int Code);
static int EGifBufferedOutput(GifFileType * GifFile, GifByteType * Buf,
int c);
/******************************************************************************
* Open a new gif file for write, given by its name. If TestExistance then
* if the file exists this routines fails (returns NULL).
* Returns GifFileType pointer dynamically allocated which serves as the gif
* info record. _GifError is cleared if succesfull.
*****************************************************************************/
GifFileType *
EGifOpenFileName(const char *FileName,
bool TestExistance) {
int FileHandle;
GifFileType *GifFile;
if (TestExistance)
FileHandle = open(FileName, O_WRONLY | O_CREAT | O_EXCL,
S_IREAD | S_IWRITE);
else
FileHandle = open(FileName, O_WRONLY | O_CREAT | O_TRUNC,
S_IREAD | S_IWRITE);
if (FileHandle == -1) {
_GifError = E_GIF_ERR_OPEN_FAILED;
return NULL;
}
GifFile = EGifOpenFileHandle(FileHandle);
if (GifFile == (GifFileType *) NULL)
close(FileHandle);
return GifFile;
}
/******************************************************************************
* Update a new gif file, given its file handle, which must be opened for
* write in binary mode.
* Returns GifFileType pointer dynamically allocated which serves as the gif
* info record. _GifError is cleared if succesfull.
*****************************************************************************/
GifFileType *
EGifOpenFileHandle(int FileHandle) {
GifFileType *GifFile;
GifFilePrivateType *Private;
FILE *f;
GifFile = (GifFileType *) malloc(sizeof(GifFileType));
if (GifFile == NULL) {
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return NULL;
}
memset(GifFile, '\0', sizeof(GifFileType));
Private = (GifFilePrivateType *)malloc(sizeof(GifFilePrivateType));
if (Private == NULL) {
free(GifFile);
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return NULL;
}
if ((Private->HashTable = _InitHashTable()) == NULL) {
free(GifFile);
free(Private);
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return NULL;
}
#if defined(__MSDOS__) || defined(WINDOWS32) || defined(_OPEN_BINARY)
setmode(FileHandle, O_BINARY); /* Make sure it is in binary mode. */
#endif /* __MSDOS__ */
f = fdopen(FileHandle, "wb"); /* Make it into a stream: */
/* MSDOS and Windows32 requires this, no reason not to do it under Unix */
setvbuf(f, NULL, _IOFBF, GIF_FILE_BUFFER_SIZE); /* And inc. stream
* buffer. */
GifFile->Private = (void *)Private;
Private->FileHandle = FileHandle;
Private->File = f;
Private->FileState = FILE_STATE_WRITE;
Private->Write = (OutputFunc) 0; /* No user write routine (MRB) */
GifFile->UserData = (void *)NULL; /* No user write handle (MRB) */
_GifError = 0;
return GifFile;
}
/******************************************************************************
* Output constructor that takes user supplied output function.
* Basically just a copy of EGifOpenFileHandle. (MRB)
*****************************************************************************/
GifFileType *
EGifOpen(void *userData,
OutputFunc writeFunc) {
GifFileType *GifFile;
GifFilePrivateType *Private;
GifFile = (GifFileType *)malloc(sizeof(GifFileType));
if (GifFile == NULL) {
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return NULL;
}
memset(GifFile, '\0', sizeof(GifFileType));
Private = (GifFilePrivateType *)malloc(sizeof(GifFilePrivateType));
if (Private == NULL) {
free(GifFile);
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return NULL;
}
Private->HashTable = _InitHashTable();
if (Private->HashTable == NULL) {
free (GifFile);
free (Private);
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return NULL;
}
GifFile->Private = (void *)Private;
Private->FileHandle = 0;
Private->File = (FILE *) 0;
Private->FileState = FILE_STATE_WRITE;
Private->Write = writeFunc; /* User write routine (MRB) */
GifFile->UserData = userData; /* User write handle (MRB) */
_GifError = 0;
return GifFile;
}
/******************************************************************************
* Routine to set current GIF version. All files open for write will be
* using this version until next call to this routine. Version consists of
* 3 characters as "87a" or "89a". No test is made to validate the version.
*****************************************************************************/
void
EGifSetGifVersion(const char *Version) {
strncpy(GifVersionPrefix, GIF_STAMP, GIF_STAMP_LEN);
strncpy(GifVersionPrefix + GIF_VERSION_POS, Version, 3);
}
/******************************************************************************
* This routine should be called before any other EGif calls, immediately
* follows the GIF file openning.
*****************************************************************************/
int
EGifPutScreenDesc(GifFileType * GifFile,
int Width,
int Height,
int ColorRes,
int BackGround,
const ColorMapObject * ColorMap) {
GifByteType Buf[3];
GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
char *write_version;
int i, j;
if (Private->FileState & FILE_STATE_SCREEN) {
/* If already has screen descriptor - something is wrong! */
_GifError = E_GIF_ERR_HAS_SCRN_DSCR;
return GIF_ERROR;
}
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
/* Bulletproofing - always write GIF89 if we need to */
Private->gif89 = false;
for (i = 0; i < GifFile->ImageCount; i++) {
for (j = 0; j < GifFile->SavedImages[i].ExtensionBlockCount; j++) {
int function =
GifFile->SavedImages[i].ExtensionBlocks[j].Function;
if (function == COMMENT_EXT_FUNC_CODE
|| function == GRAPHICS_EXT_FUNC_CODE
|| function == PLAINTEXT_EXT_FUNC_CODE
|| function == APPLICATION_EXT_FUNC_CODE)
Private->gif89 = true;
}
}
/*
* Older versions of the library didn't compute which version
* the image's extension blocks require here, but rather in EGifSpew(),
* and it was done in a non-thread-safe way. The default for sequential
* writes was GIF87 but you could override it with EGifSetGifVersion.
* This new code lets you shoot yourself in the foot if you really
* want to, but defaults to the oldest version that will carry the
* extensions.
*/
if (GifVersionPrefix[0] != '\0')
write_version = GifVersionPrefix;
else if (Private->gif89)
write_version = GIF89_STAMP;
else
write_version = GIF87_STAMP;
/* First write the version prefix into the file. */
if (WRITE(GifFile, (unsigned char *)write_version,
strlen(write_version)) != strlen(write_version)) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
GifFile->SWidth = Width;
GifFile->SHeight = Height;
GifFile->SColorResolution = ColorRes;
GifFile->SBackGroundColor = BackGround;
if (ColorMap) {
GifFile->SColorMap = MakeMapObject(ColorMap->ColorCount,
ColorMap->Colors);
if (GifFile->SColorMap == NULL) {
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return GIF_ERROR;
}
} else
GifFile->SColorMap = NULL;
/*
* Put the logical screen descriptor into the file:
*/
/* Logical Screen Descriptor: Dimensions */
EGifPutWord(Width, GifFile);
EGifPutWord(Height, GifFile);
/* Logical Screen Descriptor: Packed Fields */
/* Note: We have actual size of the color table default to the largest
* possible size (7+1 == 8 bits) because the decoder can use it to decide
* how to display the files.
*/
Buf[0] = (ColorMap ? 0x80 : 0x00) | /* Yes/no global colormap */
((ColorRes - 1) << 4) | /* Bits allocated to each primary color */
(ColorMap ? ColorMap->BitsPerPixel - 1 : 0x07 ); /* Actual size of the
color table. */
Buf[1] = BackGround; /* Index into the ColorTable for background color */
Buf[2] = 0; /* Pixel Aspect Ratio */
WRITE(GifFile, Buf, 3);
/* If we have Global color map - dump it also: */
if (ColorMap != NULL) {
int i;
for (i = 0; i < ColorMap->ColorCount; i++) {
/* Put the ColorMap out also: */
Buf[0] = ColorMap->Colors[i].Red;
Buf[1] = ColorMap->Colors[i].Green;
Buf[2] = ColorMap->Colors[i].Blue;
if (WRITE(GifFile, Buf, 3) != 3) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
}
}
/* Mark this file as has screen descriptor, and no pixel written yet: */
Private->FileState |= FILE_STATE_SCREEN;
return GIF_OK;
}
/******************************************************************************
* This routine should be called before any attempt to dump an image - any
* call to any of the pixel dump routines.
*****************************************************************************/
int
EGifPutImageDesc(GifFileType * GifFile,
int Left,
int Top,
int Width,
int Height,
bool Interlace,
const ColorMapObject * ColorMap) {
GifByteType Buf[3];
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (Private->FileState & FILE_STATE_IMAGE &&
#if defined(__MSDOS__) || defined(WINDOWS32) || defined(__GNUC__)
Private->PixelCount > 0xffff0000UL) {
#else
Private->PixelCount > 0xffff0000) {
#endif /* __MSDOS__ */
/* If already has active image descriptor - something is wrong! */
_GifError = E_GIF_ERR_HAS_IMAG_DSCR;
return GIF_ERROR;
}
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
GifFile->Image.Left = Left;
GifFile->Image.Top = Top;
GifFile->Image.Width = Width;
GifFile->Image.Height = Height;
GifFile->Image.Interlace = Interlace;
if (ColorMap) {
GifFile->Image.ColorMap = MakeMapObject(ColorMap->ColorCount,
ColorMap->Colors);
if (GifFile->Image.ColorMap == NULL) {
_GifError = E_GIF_ERR_NOT_ENOUGH_MEM;
return GIF_ERROR;
}
} else {
GifFile->Image.ColorMap = NULL;
}
/* Put the image descriptor into the file: */
Buf[0] = ','; /* Image seperator character. */
WRITE(GifFile, Buf, 1);
EGifPutWord(Left, GifFile);
EGifPutWord(Top, GifFile);
EGifPutWord(Width, GifFile);
EGifPutWord(Height, GifFile);
Buf[0] = (ColorMap ? 0x80 : 0x00) |
(Interlace ? 0x40 : 0x00) |
(ColorMap ? ColorMap->BitsPerPixel - 1 : 0);
WRITE(GifFile, Buf, 1);
/* If we have Global color map - dump it also: */
if (ColorMap != NULL) {
int i;
for (i = 0; i < ColorMap->ColorCount; i++) {
/* Put the ColorMap out also: */
Buf[0] = ColorMap->Colors[i].Red;
Buf[1] = ColorMap->Colors[i].Green;
Buf[2] = ColorMap->Colors[i].Blue;
if (WRITE(GifFile, Buf, 3) != 3) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
}
}
if (GifFile->SColorMap == NULL && GifFile->Image.ColorMap == NULL) {
_GifError = E_GIF_ERR_NO_COLOR_MAP;
return GIF_ERROR;
}
/* Mark this file as has screen descriptor: */
Private->FileState |= FILE_STATE_IMAGE;
Private->PixelCount = (long)Width *(long)Height;
EGifSetupCompress(GifFile); /* Reset compress algorithm parameters. */
return GIF_OK;
}
/******************************************************************************
* Put one full scanned line (Line) of length LineLen into GIF file.
*****************************************************************************/
int
EGifPutLine(GifFileType * GifFile,
GifPixelType * Line,
int LineLen) {
int i;
GifPixelType Mask;
GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
if (!LineLen)
LineLen = GifFile->Image.Width;
if (Private->PixelCount < (unsigned)LineLen) {
_GifError = E_GIF_ERR_DATA_TOO_BIG;
return GIF_ERROR;
}
Private->PixelCount -= LineLen;
/* Make sure the codes are not out of bit range, as we might generate
* wrong code (because of overflow when we combine them) in this case: */
Mask = CodeMask[Private->BitsPerPixel];
for (i = 0; i < LineLen; i++)
Line[i] &= Mask;
return EGifCompressLine(GifFile, Line, LineLen);
}
/******************************************************************************
* Put one pixel (Pixel) into GIF file.
*****************************************************************************/
int
EGifPutPixel(GifFileType * GifFile,
GifPixelType Pixel) {
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
if (Private->PixelCount == 0) {
_GifError = E_GIF_ERR_DATA_TOO_BIG;
return GIF_ERROR;
}
--Private->PixelCount;
/* Make sure the code is not out of bit range, as we might generate
* wrong code (because of overflow when we combine them) in this case: */
Pixel &= CodeMask[Private->BitsPerPixel];
return EGifCompressLine(GifFile, &Pixel, 1);
}
/******************************************************************************
* Put a comment into GIF file using the GIF89 comment extension block.
*****************************************************************************/
int
EGifPutComment(GifFileType * GifFile,
const char *Comment) {
unsigned int length = strlen(Comment);
char *buf;
length = strlen(Comment);
if (length <= 255) {
return EGifPutExtension(GifFile, COMMENT_EXT_FUNC_CODE,
length, Comment);
} else {
buf = (char *)Comment;
if (EGifPutExtensionFirst(GifFile, COMMENT_EXT_FUNC_CODE, 255, buf)
== GIF_ERROR) {
return GIF_ERROR;
}
length -= 255;
buf = buf + 255;
/* Break the comment into 255 byte sub blocks */
while (length > 255) {
if (EGifPutExtensionNext(GifFile, 0, 255, buf) == GIF_ERROR) {
return GIF_ERROR;
}
buf = buf + 255;
length -= 255;
}
/* Output any partial block and the clear code. */
if (length > 0) {
if (EGifPutExtensionLast(GifFile, 0, length, buf) == GIF_ERROR) {
return GIF_ERROR;
}
} else {
if (EGifPutExtensionLast(GifFile, 0, 0, NULL) == GIF_ERROR) {
return GIF_ERROR;
}
}
}
return GIF_OK;
}
/******************************************************************************
* Put a first extension block (see GIF manual) into gif file. Here more
* extensions can be dumped using EGifPutExtensionNext until
* EGifPutExtensionLast is invoked.
*****************************************************************************/
int
EGifPutExtensionFirst(GifFileType * GifFile,
int ExtCode,
int ExtLen,
const void *Extension) {
GifByteType Buf[3];
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
if (ExtCode == 0) {
WRITE(GifFile, (GifByteType *)&ExtLen, 1);
} else {
Buf[0] = '!';
Buf[1] = ExtCode;
Buf[2] = ExtLen;
WRITE(GifFile, Buf, 3);
}
WRITE(GifFile, Extension, ExtLen);
return GIF_OK;
}
/******************************************************************************
* Put a middle extension block (see GIF manual) into gif file.
*****************************************************************************/
int
EGifPutExtensionNext(GifFileType * GifFile,
int ExtCode,
int ExtLen,
const void *Extension) {
GifByteType Buf;
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
Buf = ExtLen;
WRITE(GifFile, &Buf, 1);
WRITE(GifFile, Extension, ExtLen);
return GIF_OK;
}
/******************************************************************************
* Put a last extension block (see GIF manual) into gif file.
*****************************************************************************/
int
EGifPutExtensionLast(GifFileType * GifFile,
int ExtCode,
int ExtLen,
const void *Extension) {
GifByteType Buf;
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
/* If we are given an extension sub-block output it now. */
if (ExtLen > 0) {
Buf = ExtLen;
WRITE(GifFile, &Buf, 1);
WRITE(GifFile, Extension, ExtLen);
}
/* Write the block terminator */
Buf = 0;
WRITE(GifFile, &Buf, 1);
return GIF_OK;
}
/******************************************************************************
* Put an extension block (see GIF manual) into gif file.
* Warning: This function is only useful for Extension blocks that have at
* most one subblock. Extensions with more than one subblock need to use the
* EGifPutExtension{First,Next,Last} functions instead.
*****************************************************************************/
int
EGifPutExtension(GifFileType * GifFile,
int ExtCode,
int ExtLen,
const void *Extension) {
GifByteType Buf[3];
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
if (ExtCode == 0)
WRITE(GifFile, (GifByteType *)&ExtLen, 1);
else {
Buf[0] = '!'; /* Extension Introducer 0x21 */
Buf[1] = ExtCode; /* Extension Label */
Buf[2] = ExtLen; /* Extension length */
WRITE(GifFile, Buf, 3);
}
WRITE(GifFile, Extension, ExtLen);
Buf[0] = 0;
WRITE(GifFile, Buf, 1);
return GIF_OK;
}
/******************************************************************************
* Put the image code in compressed form. This 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 EGifPutCodeNext, until NULL block is given.
* The block should NOT be freed by the user (not dynamically allocated).
*****************************************************************************/
int
EGifPutCode(GifFileType * GifFile,
int CodeSize,
const GifByteType * CodeBlock) {
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
/* No need to dump code size as Compression set up does any for us: */
/*
* Buf = CodeSize;
* if (WRITE(GifFile, &Buf, 1) != 1) {
* _GifError = E_GIF_ERR_WRITE_FAILED;
* return GIF_ERROR;
* }
*/
return EGifPutCodeNext(GifFile, CodeBlock);
}
/******************************************************************************
* Continue to put the image code in compressed form. This routine should be
* called with blocks of code as read via DGifGetCode/DGifGetCodeNext. If
* given buffer pointer is NULL, empty block is written to mark end of code.
*****************************************************************************/
int
EGifPutCodeNext(GifFileType * GifFile,
const GifByteType * CodeBlock) {
GifByteType Buf;
GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
if (CodeBlock != NULL) {
if (WRITE(GifFile, CodeBlock, CodeBlock[0] + 1)
!= (unsigned)(CodeBlock[0] + 1)) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
} else {
Buf = 0;
if (WRITE(GifFile, &Buf, 1) != 1) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
Private->PixelCount = 0; /* And local info. indicate image read. */
}
return GIF_OK;
}
/******************************************************************************
* This routine should be called last, to close GIF file.
*****************************************************************************/
int
EGifCloseFile(GifFileType * GifFile) {
GifByteType Buf;
GifFilePrivateType *Private;
FILE *File;
if (GifFile == NULL)
return GIF_ERROR;
Private = (GifFilePrivateType *) GifFile->Private;
if (Private == NULL)
return GIF_ERROR;
if (!IS_WRITEABLE(Private)) {
/* This file was NOT open for writing: */
_GifError = E_GIF_ERR_NOT_WRITEABLE;
return GIF_ERROR;
}
File = Private->File;
Buf = ';';
WRITE(GifFile, &Buf, 1);
if (GifFile->Image.ColorMap) {
FreeMapObject(GifFile->Image.ColorMap);
GifFile->Image.ColorMap = NULL;
}
if (GifFile->SColorMap) {
FreeMapObject(GifFile->SColorMap);
GifFile->SColorMap = NULL;
}
if (Private) {
if (Private->HashTable) {
free((char *) Private->HashTable);
}
free((char *) Private);
}
free(GifFile);
if (File && fclose(File) != 0) {
_GifError = E_GIF_ERR_CLOSE_FAILED;
return GIF_ERROR;
}
return GIF_OK;
}
/******************************************************************************
* Put 2 bytes (word) into the given file:
*****************************************************************************/
static int
EGifPutWord(int Word,
GifFileType * GifFile) {
unsigned char c[2];
c[0] = Word & 0xff;
c[1] = (Word >> 8) & 0xff;
if (WRITE(GifFile, c, 2) == 2)
return GIF_OK;
else
return GIF_ERROR;
}
/******************************************************************************
* Setup the LZ compression for this image:
*****************************************************************************/
static int
EGifSetupCompress(GifFileType * GifFile) {
int BitsPerPixel;
GifByteType Buf;
GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
/* Test and see what color map to use, and from it # bits per pixel: */
if (GifFile->Image.ColorMap)
BitsPerPixel = GifFile->Image.ColorMap->BitsPerPixel;
else if (GifFile->SColorMap)
BitsPerPixel = GifFile->SColorMap->BitsPerPixel;
else {
_GifError = E_GIF_ERR_NO_COLOR_MAP;
return GIF_ERROR;
}
Buf = BitsPerPixel = (BitsPerPixel < 2 ? 2 : BitsPerPixel);
WRITE(GifFile, &Buf, 1); /* Write the Code size to file. */
Private->Buf[0] = 0; /* Nothing was output yet. */
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->CrntCode = FIRST_CODE; /* Signal that this is first one! */
Private->CrntShiftState = 0; /* No information in CrntShiftDWord. */
Private->CrntShiftDWord = 0;
/* Clear hash table and send Clear to make sure the decoder do the same. */
_ClearHashTable(Private->HashTable);
if (EGifCompressOutput(GifFile, Private->ClearCode) == GIF_ERROR) {
_GifError = E_GIF_ERR_DISK_IS_FULL;
return GIF_ERROR;
}
return GIF_OK;
}
/******************************************************************************
* The LZ compression routine:
* This version compresses the given buffer Line of length LineLen.
* This routine can be called a few times (one per scan line, for example), in
* order to complete the whole image.
******************************************************************************/
static int
EGifCompressLine(GifFileType * GifFile,
GifPixelType * Line,
int LineLen) {
int i = 0, CrntCode, NewCode;
unsigned long NewKey;
GifPixelType Pixel;
GifHashTableType *HashTable;
GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
HashTable = Private->HashTable;
if (Private->CrntCode == FIRST_CODE) /* Its first time! */
CrntCode = Line[i++];
else
CrntCode = Private->CrntCode; /* Get last code in compression. */
while (i < LineLen) { /* Decode LineLen items. */
Pixel = Line[i++]; /* Get next pixel from stream. */
/* Form a new unique key to search hash table for the code combines
* CrntCode as Prefix string with Pixel as postfix char.
*/
NewKey = (((uint32_t) CrntCode) << 8) + Pixel;
if ((NewCode = _ExistsHashTable(HashTable, NewKey)) >= 0) {
/* This Key is already there, or the string is old one, so
* simple take new code as our CrntCode:
*/
CrntCode = NewCode;
} else {
/* Put it in hash table, output the prefix code, and make our
* CrntCode equal to Pixel.
*/
if (EGifCompressOutput(GifFile, CrntCode) == GIF_ERROR) {
_GifError = E_GIF_ERR_DISK_IS_FULL;
return GIF_ERROR;
}
CrntCode = Pixel;
/* If however the HashTable if full, we send a clear first and
* Clear the hash table.
*/
if (Private->RunningCode >= LZ_MAX_CODE) {
/* Time to do some clearance: */
if (EGifCompressOutput(GifFile, Private->ClearCode)
== GIF_ERROR) {
_GifError = E_GIF_ERR_DISK_IS_FULL;
return GIF_ERROR;
}
Private->RunningCode = Private->EOFCode + 1;
Private->RunningBits = Private->BitsPerPixel + 1;
Private->MaxCode1 = 1 << Private->RunningBits;
_ClearHashTable(HashTable);
} else {
/* Put this unique key with its relative Code in hash table: */
_InsertHashTable(HashTable, NewKey, Private->RunningCode++);
}
}
}
/* Preserve the current state of the compression algorithm: */
Private->CrntCode = CrntCode;
if (Private->PixelCount == 0) {
/* We are done - output last Code and flush output buffers: */
if (EGifCompressOutput(GifFile, CrntCode) == GIF_ERROR) {
_GifError = E_GIF_ERR_DISK_IS_FULL;
return GIF_ERROR;
}
if (EGifCompressOutput(GifFile, Private->EOFCode) == GIF_ERROR) {
_GifError = E_GIF_ERR_DISK_IS_FULL;
return GIF_ERROR;
}
if (EGifCompressOutput(GifFile, FLUSH_OUTPUT) == GIF_ERROR) {
_GifError = E_GIF_ERR_DISK_IS_FULL;
return GIF_ERROR;
}
}
return GIF_OK;
}
/******************************************************************************
* The LZ compression output routine:
* This routine is responsible for the compression of the bit stream into
* 8 bits (bytes) packets.
* Returns GIF_OK if written succesfully.
*****************************************************************************/
static int
EGifCompressOutput(GifFileType * GifFile,
int Code) {
GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
int retval = GIF_OK;
if (Code == FLUSH_OUTPUT) {
while (Private->CrntShiftState > 0) {
/* Get Rid of what is left in DWord, and flush it. */
if (EGifBufferedOutput(GifFile, Private->Buf,
Private->CrntShiftDWord & 0xff) == GIF_ERROR)
retval = GIF_ERROR;
Private->CrntShiftDWord >>= 8;
Private->CrntShiftState -= 8;
}
Private->CrntShiftState = 0; /* For next time. */
if (EGifBufferedOutput(GifFile, Private->Buf,
FLUSH_OUTPUT) == GIF_ERROR)
retval = GIF_ERROR;
} else {
Private->CrntShiftDWord |= ((long)Code) << Private->CrntShiftState;
Private->CrntShiftState += Private->RunningBits;
while (Private->CrntShiftState >= 8) {
/* Dump out full bytes: */
if (EGifBufferedOutput(GifFile, Private->Buf,
Private->CrntShiftDWord & 0xff) == GIF_ERROR)
retval = GIF_ERROR;
Private->CrntShiftDWord >>= 8;
Private->CrntShiftState -= 8;
}
}
/* 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 && Code <= 4095) {
Private->MaxCode1 = 1 << ++Private->RunningBits;
}
return retval;
}
/******************************************************************************
* This routines buffers the given characters until 255 characters are ready
* to be output. If Code is equal to -1 the buffer is flushed (EOF).
* The buffer is Dumped with first byte as its size, as GIF format requires.
* Returns GIF_OK if written succesfully.
*****************************************************************************/
static int
EGifBufferedOutput(GifFileType * GifFile,
GifByteType * Buf,
int c) {
if (c == FLUSH_OUTPUT) {
/* Flush everything out. */
if (Buf[0] != 0
&& WRITE(GifFile, Buf, Buf[0] + 1) != (unsigned)(Buf[0] + 1)) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
/* Mark end of compressed data, by an empty block (see GIF doc): */
Buf[0] = 0;
if (WRITE(GifFile, Buf, 1) != 1) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
} else {
if (Buf[0] == 255) {
/* Dump out this buffer - it is full: */
if (WRITE(GifFile, Buf, Buf[0] + 1) != (unsigned)(Buf[0] + 1)) {
_GifError = E_GIF_ERR_WRITE_FAILED;
return GIF_ERROR;
}
Buf[0] = 0;
}
Buf[++Buf[0]] = c;
}
return GIF_OK;
}
/******************************************************************************
* This routine writes to disk an in-core representation of a GIF previously
* created by DGifSlurp().
*****************************************************************************/
int
EGifSpew(GifFileType * GifFileOut) {
int i, j;
int bOff; /* Block Offset for adding sub blocks in Extensions */
if (EGifPutScreenDesc(GifFileOut,
GifFileOut->SWidth,
GifFileOut->SHeight,
GifFileOut->SColorResolution,
GifFileOut->SBackGroundColor,
GifFileOut->SColorMap) == GIF_ERROR) {
return (GIF_ERROR);
}
for (i = 0; i < GifFileOut->ImageCount; i++) {
SavedImage *sp = &GifFileOut->SavedImages[i];
int SavedHeight = sp->ImageDesc.Height;
int SavedWidth = sp->ImageDesc.Width;
ExtensionBlock *ep;
/* this allows us to delete images by nuking their rasters */
if (sp->RasterBits == NULL)
continue;
if (sp->ExtensionBlocks) {
for (j = 0; j < sp->ExtensionBlockCount; j++) {
ep = &sp->ExtensionBlocks[j];
if (j == sp->ExtensionBlockCount - 1 || (ep+1)->Function != 0) {
/*** FIXME: Must check whether outputting
* <ExtLen><Extension> is ever valid or if we should just
* drop anything with a 0 for the Function. (And whether
* we should drop here or in EGifPutExtension)
*/
if (EGifPutExtension(GifFileOut,
(ep->Function != 0) ? ep->Function : '\0',
ep->ByteCount,
ep->Bytes) == GIF_ERROR) {
return (GIF_ERROR);
}
} else {
EGifPutExtensionFirst(GifFileOut, ep->Function, ep->ByteCount, ep->Bytes);
for (bOff = j+1; bOff < sp->ExtensionBlockCount; bOff++) {
ep = &sp->ExtensionBlocks[bOff];
if (ep->Function != 0) {
break;
}
EGifPutExtensionNext(GifFileOut, 0,
ep->ByteCount, ep->Bytes);
}
EGifPutExtensionLast(GifFileOut, 0, 0, NULL);
j = bOff-1;
}
}
}
if (EGifPutImageDesc(GifFileOut,
sp->ImageDesc.Left,
sp->ImageDesc.Top,
SavedWidth,
SavedHeight,
sp->ImageDesc.Interlace,
sp->ImageDesc.ColorMap) == GIF_ERROR)
return (GIF_ERROR);
for (j = 0; j < SavedHeight; j++) {
if (EGifPutLine(GifFileOut,
sp->RasterBits + j * SavedWidth,
SavedWidth) == GIF_ERROR)
return (GIF_ERROR);
}
}
if (EGifCloseFile(GifFileOut) == GIF_ERROR)
return (GIF_ERROR);
return (GIF_OK);
}