kolibrios/contrib/sdk/sources/SDL-1.2.2/SDL_image/IMG_gif.c

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/*
IMGLIB: An example image loading library for use with SDL
Copyright (C) 1999 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Sam Lantinga
5635-34 Springhouse Dr.
Pleasanton, CA 94588 (USA)
slouken@devolution.com
*/
/* This is a GIF image file loading framework */
#include <stdio.h>
#include <string.h>
#include "SDL_image.h"
#ifdef LOAD_GIF
/* See if an image is contained in a data source */
int IMG_isGIF(SDL_RWops *src)
{
int is_GIF;
char magic[6];
is_GIF = 0;
if ( SDL_RWread(src, magic, 6, 1) ) {
if ( (strncmp(magic, "GIF", 3) == 0) &&
((memcmp(magic + 3, "87a", 3) == 0) ||
(memcmp(magic + 3, "89a", 3) == 0)) ) {
is_GIF = 1;
}
}
return(is_GIF);
}
/* Code from here to end of file has been adapted from XPaint: */
/* +-------------------------------------------------------------------+ */
/* | Copyright 1990, 1991, 1993 David Koblas. | */
/* | Copyright 1996 Torsten Martinsen. | */
/* | Permission to use, copy, modify, and distribute this software | */
/* | and its documentation for any purpose and without fee is hereby | */
/* | granted, provided that the above copyright notice appear in all | */
/* | copies and that both that copyright notice and this permission | */
/* | notice appear in supporting documentation. This software is | */
/* | provided "as is" without express or implied warranty. | */
/* +-------------------------------------------------------------------+ */
/* Adapted for use in SDL by Sam Lantinga -- 7/20/98 */
#define USED_BY_SDL
#include <stdio.h>
#include <string.h>
#ifdef USED_BY_SDL
/* Changes to work with SDL:
Include SDL header file
Use SDL_Surface rather than xpaint Image structure
Define SDL versions of RWSetMsg(), ImageNewCmap() and ImageSetCmap()
*/
#include "SDL.h"
#define Image SDL_Surface
#define RWSetMsg IMG_SetError
#define ImageNewCmap(w, h, s) SDL_AllocSurface(SDL_SWSURFACE,w,h,8,0,0,0,0)
#define ImageSetCmap(s, i, R, G, B) do { \
s->format->palette->colors[i].r = R; \
s->format->palette->colors[i].g = G; \
s->format->palette->colors[i].b = B; \
} while (0)
/* * * * * */
#else
/* Original XPaint sources */
#include "image.h"
#include "rwTable.h"
#define SDL_RWops FILE
#define SDL_RWclose fclose
#endif /* USED_BY_SDL */
#define MAXCOLORMAPSIZE 256
#define TRUE 1
#define FALSE 0
#define CM_RED 0
#define CM_GREEN 1
#define CM_BLUE 2
#define MAX_LWZ_BITS 12
#define INTERLACE 0x40
#define LOCALCOLORMAP 0x80
#define BitSet(byte, bit) (((byte) & (bit)) == (bit))
#define ReadOK(file,buffer,len) SDL_RWread(file, buffer, len, 1)
#define LM_to_uint(a,b) (((b)<<8)|(a))
static struct {
unsigned int Width;
unsigned int Height;
unsigned char ColorMap[3][MAXCOLORMAPSIZE];
unsigned int BitPixel;
unsigned int ColorResolution;
unsigned int Background;
unsigned int AspectRatio;
int GrayScale;
} GifScreen;
static struct {
int transparent;
int delayTime;
int inputFlag;
int disposal;
} Gif89;
static int ReadColorMap(SDL_RWops * src, int number,
unsigned char buffer[3][MAXCOLORMAPSIZE], int *flag);
static int DoExtension(SDL_RWops * src, int label);
static int GetDataBlock(SDL_RWops * src, unsigned char *buf);
static int GetCode(SDL_RWops * src, int code_size, int flag);
static int LWZReadByte(SDL_RWops * src, int flag, int input_code_size);
static Image *ReadImage(SDL_RWops * src, int len, int height, int,
unsigned char cmap[3][MAXCOLORMAPSIZE],
int gray, int interlace, int ignore);
Image *
IMG_LoadGIF_RW(SDL_RWops *src)
{
unsigned char buf[16];
unsigned char c;
unsigned char localColorMap[3][MAXCOLORMAPSIZE];
int grayScale;
int useGlobalColormap;
int bitPixel;
int imageCount = 0;
char version[4];
int imageNumber = 1;
Image *image = NULL;
if ( src == NULL ) {
goto done;
}
if (!ReadOK(src, buf, 6)) {
RWSetMsg("error reading magic number");
goto done;
}
if (strncmp((char *) buf, "GIF", 3) != 0) {
RWSetMsg("not a GIF file");
goto done;
}
strncpy(version, (char *) buf + 3, 3);
version[3] = '\0';
if ((strcmp(version, "87a") != 0) && (strcmp(version, "89a") != 0)) {
RWSetMsg("bad version number, not '87a' or '89a'");
goto done;
}
Gif89.transparent = -1;
Gif89.delayTime = -1;
Gif89.inputFlag = -1;
Gif89.disposal = 0;
if (!ReadOK(src, buf, 7)) {
RWSetMsg("failed to read screen descriptor");
goto done;
}
GifScreen.Width = LM_to_uint(buf[0], buf[1]);
GifScreen.Height = LM_to_uint(buf[2], buf[3]);
GifScreen.BitPixel = 2 << (buf[4] & 0x07);
GifScreen.ColorResolution = (((buf[4] & 0x70) >> 3) + 1);
GifScreen.Background = buf[5];
GifScreen.AspectRatio = buf[6];
if (BitSet(buf[4], LOCALCOLORMAP)) { /* Global Colormap */
if (ReadColorMap(src, GifScreen.BitPixel, GifScreen.ColorMap,
&GifScreen.GrayScale)) {
RWSetMsg("error reading global colormap");
goto done;
}
}
do {
if (!ReadOK(src, &c, 1)) {
RWSetMsg("EOF / read error on image data");
goto done;
}
if (c == ';') { /* GIF terminator */
if (imageCount < imageNumber) {
RWSetMsg("only %d image%s found in file",
imageCount, imageCount > 1 ? "s" : "");
goto done;
}
}
if (c == '!') { /* Extension */
if (!ReadOK(src, &c, 1)) {
RWSetMsg("EOF / read error on extention function code");
goto done;
}
DoExtension(src, c);
continue;
}
if (c != ',') { /* Not a valid start character */
continue;
}
++imageCount;
if (!ReadOK(src, buf, 9)) {
RWSetMsg("couldn't read left/top/width/height");
goto done;
}
useGlobalColormap = !BitSet(buf[8], LOCALCOLORMAP);
bitPixel = 1 << ((buf[8] & 0x07) + 1);
if (!useGlobalColormap) {
if (ReadColorMap(src, bitPixel, localColorMap, &grayScale)) {
RWSetMsg("error reading local colormap");
goto done;
}
image = ReadImage(src, LM_to_uint(buf[4], buf[5]),
LM_to_uint(buf[6], buf[7]),
bitPixel, localColorMap, grayScale,
BitSet(buf[8], INTERLACE),
imageCount != imageNumber);
} else {
image = ReadImage(src, LM_to_uint(buf[4], buf[5]),
LM_to_uint(buf[6], buf[7]),
GifScreen.BitPixel, GifScreen.ColorMap,
GifScreen.GrayScale, BitSet(buf[8], INTERLACE),
imageCount != imageNumber);
}
} while (image == NULL);
#ifdef USED_BY_SDL
if ( Gif89.transparent > 0 ) {
SDL_SetColorKey(image, SDL_SRCCOLORKEY, Gif89.transparent);
}
#endif
done:
return image;
}
static int
ReadColorMap(SDL_RWops *src, int number,
unsigned char buffer[3][MAXCOLORMAPSIZE], int *gray)
{
int i;
unsigned char rgb[3];
int flag;
flag = TRUE;
for (i = 0; i < number; ++i) {
if (!ReadOK(src, rgb, sizeof(rgb))) {
RWSetMsg("bad colormap");
return 1;
}
buffer[CM_RED][i] = rgb[0];
buffer[CM_GREEN][i] = rgb[1];
buffer[CM_BLUE][i] = rgb[2];
flag &= (rgb[0] == rgb[1] && rgb[1] == rgb[2]);
}
#if 0
if (flag)
*gray = (number == 2) ? PBM_TYPE : PGM_TYPE;
else
*gray = PPM_TYPE;
#else
*gray = 0;
#endif
return FALSE;
}
static int
DoExtension(SDL_RWops *src, int label)
{
static unsigned char buf[256];
char *str;
switch (label) {
case 0x01: /* Plain Text Extension */
str = "Plain Text Extension";
break;
case 0xff: /* Application Extension */
str = "Application Extension";
break;
case 0xfe: /* Comment Extension */
str = "Comment Extension";
while (GetDataBlock(src, (unsigned char *) buf) != 0);
return FALSE;
case 0xf9: /* Graphic Control Extension */
str = "Graphic Control Extension";
(void) GetDataBlock(src, (unsigned char *) buf);
Gif89.disposal = (buf[0] >> 2) & 0x7;
Gif89.inputFlag = (buf[0] >> 1) & 0x1;
Gif89.delayTime = LM_to_uint(buf[1], buf[2]);
if ((buf[0] & 0x1) != 0)
Gif89.transparent = buf[3];
while (GetDataBlock(src, (unsigned char *) buf) != 0);
return FALSE;
default:
str = (char *)buf;
sprintf(str, "UNKNOWN (0x%02x)", label);
break;
}
while (GetDataBlock(src, (unsigned char *) buf) != 0);
return FALSE;
}
static int ZeroDataBlock = FALSE;
static int
GetDataBlock(SDL_RWops *src, unsigned char *buf)
{
unsigned char count;
if (!ReadOK(src, &count, 1)) {
/* pm_message("error in getting DataBlock size" ); */
return -1;
}
ZeroDataBlock = count == 0;
if ((count != 0) && (!ReadOK(src, buf, count))) {
/* pm_message("error in reading DataBlock" ); */
return -1;
}
return count;
}
static int
GetCode(SDL_RWops *src, int code_size, int flag)
{
static unsigned char buf[280];
static int curbit, lastbit, done, last_byte;
int i, j, ret;
unsigned char count;
if (flag) {
curbit = 0;
lastbit = 0;
done = FALSE;
return 0;
}
if ((curbit + code_size) >= lastbit) {
if (done) {
if (curbit >= lastbit)
RWSetMsg("ran off the end of my bits");
return -1;
}
buf[0] = buf[last_byte - 2];
buf[1] = buf[last_byte - 1];
if ((count = GetDataBlock(src, &buf[2])) == 0)
done = TRUE;
last_byte = 2 + count;
curbit = (curbit - lastbit) + 16;
lastbit = (2 + count) * 8;
}
ret = 0;
for (i = curbit, j = 0; j < code_size; ++i, ++j)
ret |= ((buf[i / 8] & (1 << (i % 8))) != 0) << j;
curbit += code_size;
return ret;
}
static int
LWZReadByte(SDL_RWops *src, int flag, int input_code_size)
{
static int fresh = FALSE;
int code, incode;
static int code_size, set_code_size;
static int max_code, max_code_size;
static int firstcode, oldcode;
static int clear_code, end_code;
static int table[2][(1 << MAX_LWZ_BITS)];
static int stack[(1 << (MAX_LWZ_BITS)) * 2], *sp;
register int i;
if (flag) {
set_code_size = input_code_size;
code_size = set_code_size + 1;
clear_code = 1 << set_code_size;
end_code = clear_code + 1;
max_code_size = 2 * clear_code;
max_code = clear_code + 2;
GetCode(src, 0, TRUE);
fresh = TRUE;
for (i = 0; i < clear_code; ++i) {
table[0][i] = 0;
table[1][i] = i;
}
for (; i < (1 << MAX_LWZ_BITS); ++i)
table[0][i] = table[1][0] = 0;
sp = stack;
return 0;
} else if (fresh) {
fresh = FALSE;
do {
firstcode = oldcode = GetCode(src, code_size, FALSE);
} while (firstcode == clear_code);
return firstcode;
}
if (sp > stack)
return *--sp;
while ((code = GetCode(src, code_size, FALSE)) >= 0) {
if (code == clear_code) {
for (i = 0; i < clear_code; ++i) {
table[0][i] = 0;
table[1][i] = i;
}
for (; i < (1 << MAX_LWZ_BITS); ++i)
table[0][i] = table[1][i] = 0;
code_size = set_code_size + 1;
max_code_size = 2 * clear_code;
max_code = clear_code + 2;
sp = stack;
firstcode = oldcode = GetCode(src, code_size, FALSE);
return firstcode;
} else if (code == end_code) {
int count;
unsigned char buf[260];
if (ZeroDataBlock)
return -2;
while ((count = GetDataBlock(src, buf)) > 0);
if (count != 0) {
/*
* pm_message("missing EOD in data stream (common occurence)");
*/
}
return -2;
}
incode = code;
if (code >= max_code) {
*sp++ = firstcode;
code = oldcode;
}
while (code >= clear_code) {
*sp++ = table[1][code];
if (code == table[0][code])
RWSetMsg("circular table entry BIG ERROR");
code = table[0][code];
}
*sp++ = firstcode = table[1][code];
if ((code = max_code) < (1 << MAX_LWZ_BITS)) {
table[0][code] = oldcode;
table[1][code] = firstcode;
++max_code;
if ((max_code >= max_code_size) &&
(max_code_size < (1 << MAX_LWZ_BITS))) {
max_code_size *= 2;
++code_size;
}
}
oldcode = incode;
if (sp > stack)
return *--sp;
}
return code;
}
static Image *
ReadImage(SDL_RWops * src, int len, int height, int cmapSize,
unsigned char cmap[3][MAXCOLORMAPSIZE],
int gray, int interlace, int ignore)
{
Image *image;
unsigned char c;
int i, v;
int xpos = 0, ypos = 0, pass = 0;
/*
** Initialize the compression routines
*/
if (!ReadOK(src, &c, 1)) {
RWSetMsg("EOF / read error on image data");
return NULL;
}
if (LWZReadByte(src, TRUE, c) < 0) {
RWSetMsg("error reading image");
return NULL;
}
/*
** If this is an "uninteresting picture" ignore it.
*/
if (ignore) {
while (LWZReadByte(src, FALSE, c) >= 0);
return NULL;
}
image = ImageNewCmap(len, height, cmapSize);
for (i = 0; i < cmapSize; i++)
ImageSetCmap(image, i, cmap[CM_RED][i],
cmap[CM_GREEN][i], cmap[CM_BLUE][i]);
while ((v = LWZReadByte(src, FALSE, c)) >= 0) {
#ifdef USED_BY_SDL
((Uint8 *)image->pixels)[xpos + ypos * image->pitch] = v;
#else
image->data[xpos + ypos * len] = v;
#endif
++xpos;
if (xpos == len) {
xpos = 0;
if (interlace) {
switch (pass) {
case 0:
case 1:
ypos += 8;
break;
case 2:
ypos += 4;
break;
case 3:
ypos += 2;
break;
}
if (ypos >= height) {
++pass;
switch (pass) {
case 1:
ypos = 4;
break;
case 2:
ypos = 2;
break;
case 3:
ypos = 1;
break;
default:
goto fini;
}
}
} else {
++ypos;
}
}
if (ypos >= height)
break;
}
fini:
return image;
}
#else
/* See if an image is contained in a data source */
int IMG_isGIF(SDL_RWops *src)
{
return(0);
}
/* Load a GIF type image from an SDL datasource */
SDL_Surface *IMG_LoadGIF_RW(SDL_RWops *src)
{
return(NULL);
}
#endif /* LOAD_GIF */