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DEFINITIONS
This source file includes following definitions.
- set_verbose
- gdImageCreateFromGifSource
- gdImageCreateFromGif
- gdImageCreateFromGifCtx
- ReadColorMap
- DoExtension
- GetDataBlock_
- GetDataBlock
- GetCode_
- GetCode
- LWZReadByte_
- LWZReadByte
- ReadImage
#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>
#include "gd.h"
#include "php.h"
/* Used only when debugging GIF compression code */
/* #define DEBUGGING_ENVARS */
#ifdef DEBUGGING_ENVARS
static int verbose_set = 0;
static int verbose;
#define VERBOSE (verbose_set?verbose:set_verbose())
static int set_verbose(void)
{
verbose = !!getenv("GIF_VERBOSE");
verbose_set = 1;
return(verbose);
}
#else
#define VERBOSE 0
#endif
#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) (gdGetBuf(buffer, len, file) > 0)
#define LM_to_uint(a,b) (((b)<<8)|(a))
/* We may eventually want to use this information, but def it out for now */
#if 0
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;
} GifScreen;
#endif
#if 0
static struct {
int transparent;
int delayTime;
int inputFlag;
int disposal;
} Gif89 = { -1, -1, -1, 0 };
#endif
#define STACK_SIZE ((1<<(MAX_LWZ_BITS))*2)
typedef struct {
unsigned char buf[280];
int curbit, lastbit, done, last_byte;
} CODE_STATIC_DATA;
typedef struct {
int fresh;
int code_size, set_code_size;
int max_code, max_code_size;
int firstcode, oldcode;
int clear_code, end_code;
int table[2][(1<< MAX_LWZ_BITS)];
int stack[STACK_SIZE], *sp;
CODE_STATIC_DATA scd;
} LZW_STATIC_DATA;
static int ReadColorMap (gdIOCtx *fd, int number, unsigned char (*buffer)[256]);
static int DoExtension (gdIOCtx *fd, int label, int *Transparent, int *ZeroDataBlockP);
static int GetDataBlock (gdIOCtx *fd, unsigned char *buf, int *ZeroDataBlockP);
static int GetCode (gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag, int *ZeroDataBlockP);
static int LWZReadByte (gdIOCtx *fd, LZW_STATIC_DATA *sd, char flag, int input_code_size, int *ZeroDataBlockP);
static void ReadImage (gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned char (*cmap)[256], int interlace, int *ZeroDataBlockP); /*1.4//, int ignore); */
gdImagePtr gdImageCreateFromGifSource(gdSourcePtr inSource) /* {{{ */
{
gdIOCtx *in = gdNewSSCtx(inSource, NULL);
gdImagePtr im;
im = gdImageCreateFromGifCtx(in);
in->gd_free(in);
return im;
}
/* }}} */
gdImagePtr gdImageCreateFromGif(FILE *fdFile) /* {{{ */
{
gdIOCtx *fd = gdNewFileCtx(fdFile);
gdImagePtr im = 0;
im = gdImageCreateFromGifCtx(fd);
fd->gd_free(fd);
return im;
}
/* }}} */
gdImagePtr gdImageCreateFromGifCtx(gdIOCtxPtr fd) /* {{{ */
{
int BitPixel;
#if 0
int ColorResolution;
int Background;
int AspectRatio;
#endif
int Transparent = (-1);
unsigned char buf[16];
unsigned char c;
unsigned char ColorMap[3][MAXCOLORMAPSIZE];
unsigned char localColorMap[3][MAXCOLORMAPSIZE];
int imw, imh, screen_width, screen_height;
int gif87a, useGlobalColormap;
int bitPixel;
int i;
/*1.4//int imageCount = 0; */
int ZeroDataBlock = FALSE;
int haveGlobalColormap;
gdImagePtr im = 0;
/*1.4//imageNumber = 1; */
if (! ReadOK(fd,buf,6)) {
return 0;
}
if (strncmp((char *)buf,"GIF",3) != 0) {
return 0;
}
if (memcmp((char *)buf+3, "87a", 3) == 0) {
gif87a = 1;
} else if (memcmp((char *)buf+3, "89a", 3) == 0) {
gif87a = 0;
} else {
return 0;
}
if (! ReadOK(fd,buf,7)) {
return 0;
}
BitPixel = 2<<(buf[4]&0x07);
#if 0
ColorResolution = (int) (((buf[4]&0x70)>>3)+1);
Background = buf[5];
AspectRatio = buf[6];
#endif
screen_width = imw = LM_to_uint(buf[0],buf[1]);
screen_height = imh = LM_to_uint(buf[2],buf[3]);
haveGlobalColormap = BitSet(buf[4], LOCALCOLORMAP); /* Global Colormap */
if (haveGlobalColormap) {
if (ReadColorMap(fd, BitPixel, ColorMap)) {
return 0;
}
}
for (;;) {
int top, left;
int width, height;
if (! ReadOK(fd,&c,1)) {
return 0;
}
if (c == ';') { /* GIF terminator */
goto terminated;
}
if (c == '!') { /* Extension */
if (! ReadOK(fd,&c,1)) {
return 0;
}
DoExtension(fd, c, &Transparent, &ZeroDataBlock);
continue;
}
if (c != ',') { /* Not a valid start character */
continue;
}
/*1.4//++imageCount; */
if (! ReadOK(fd,buf,9)) {
return 0;
}
useGlobalColormap = ! BitSet(buf[8], LOCALCOLORMAP);
bitPixel = 1<<((buf[8]&0x07)+1);
left = LM_to_uint(buf[0], buf[1]);
top = LM_to_uint(buf[2], buf[3]);
width = LM_to_uint(buf[4], buf[5]);
height = LM_to_uint(buf[6], buf[7]);
if (left + width > screen_width || top + height > screen_height) {
if (VERBOSE) {
printf("Frame is not confined to screen dimension.\n");
}
return 0;
}
if (!(im = gdImageCreate(width, height))) {
return 0;
}
im->interlace = BitSet(buf[8], INTERLACE);
if (!useGlobalColormap) {
if (ReadColorMap(fd, bitPixel, localColorMap)) {
gdImageDestroy(im);
return 0;
}
ReadImage(im, fd, width, height, localColorMap,
BitSet(buf[8], INTERLACE), &ZeroDataBlock);
} else {
if (!haveGlobalColormap) {
gdImageDestroy(im);
return 0;
}
ReadImage(im, fd, width, height,
ColorMap,
BitSet(buf[8], INTERLACE), &ZeroDataBlock);
}
if (Transparent != (-1)) {
gdImageColorTransparent(im, Transparent);
}
goto terminated;
}
terminated:
/* Terminator before any image was declared! */
if (!im) {
return 0;
}
if (!im->colorsTotal) {
gdImageDestroy(im);
return 0;
}
/* Check for open colors at the end, so
we can reduce colorsTotal and ultimately
BitsPerPixel */
for (i=((im->colorsTotal-1)); (i>=0); i--) {
if (im->open[i]) {
im->colorsTotal--;
} else {
break;
}
}
return im;
}
/* }}} */
static int ReadColorMap(gdIOCtx *fd, int number, unsigned char (*buffer)[256]) /* {{{ */
{
int i;
unsigned char rgb[3];
for (i = 0; i < number; ++i) {
if (! ReadOK(fd, rgb, sizeof(rgb))) {
return TRUE;
}
buffer[CM_RED][i] = rgb[0] ;
buffer[CM_GREEN][i] = rgb[1] ;
buffer[CM_BLUE][i] = rgb[2] ;
}
return FALSE;
}
/* }}} */
static int
DoExtension(gdIOCtx *fd, int label, int *Transparent, int *ZeroDataBlockP)
{
unsigned char buf[256];
switch (label) {
case 0xf9: /* Graphic Control Extension */
memset(buf, 0, 4); /* initialize a few bytes in the case the next function fails */
(void) GetDataBlock(fd, (unsigned char*) buf, ZeroDataBlockP);
#if 0
Gif89.disposal = (buf[0] >> 2) & 0x7;
Gif89.inputFlag = (buf[0] >> 1) & 0x1;
Gif89.delayTime = LM_to_uint(buf[1],buf[2]);
#endif
if ((buf[0] & 0x1) != 0)
*Transparent = buf[3];
while (GetDataBlock(fd, (unsigned char*) buf, ZeroDataBlockP) > 0);
return FALSE;
default:
break;
}
while (GetDataBlock(fd, (unsigned char*) buf, ZeroDataBlockP) > 0)
;
return FALSE;
}
/* }}} */
static int
GetDataBlock_(gdIOCtx *fd, unsigned char *buf, int *ZeroDataBlockP)
{
unsigned char count;
if (! ReadOK(fd,&count,1)) {
return -1;
}
*ZeroDataBlockP = count == 0;
if ((count != 0) && (! ReadOK(fd, buf, count))) {
return -1;
}
return count;
}
/* }}} */
static int
GetDataBlock(gdIOCtx *fd, unsigned char *buf, int *ZeroDataBlockP)
{
int rv;
int i;
rv = GetDataBlock_(fd,buf, ZeroDataBlockP);
if (VERBOSE) {
char *tmp = NULL;
if (rv > 0) {
tmp = safe_emalloc(3 * rv, sizeof(char), 1);
for (i=0;i<rv;i++) {
sprintf(&tmp[3*sizeof(char)*i], " %02x", buf[i]);
}
} else {
tmp = estrdup("");
}
php_gd_error_ex(E_NOTICE, "[GetDataBlock returning %d: %s]", rv, tmp);
efree(tmp);
}
return(rv);
}
/* }}} */
static int
GetCode_(gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag, int *ZeroDataBlockP)
{
int i, j, ret;
unsigned char count;
if (flag) {
scd->curbit = 0;
scd->lastbit = 0;
scd->last_byte = 0;
scd->done = FALSE;
return 0;
}
if ( (scd->curbit + code_size) >= scd->lastbit) {
if (scd->done) {
if (scd->curbit >= scd->lastbit) {
/* Oh well */
}
return -1;
}
scd->buf[0] = scd->buf[scd->last_byte-2];
scd->buf[1] = scd->buf[scd->last_byte-1];
if ((count = GetDataBlock(fd, &scd->buf[2], ZeroDataBlockP)) <= 0)
scd->done = TRUE;
scd->last_byte = 2 + count;
scd->curbit = (scd->curbit - scd->lastbit) + 16;
scd->lastbit = (2+count)*8 ;
}
ret = 0;
for (i = scd->curbit, j = 0; j < code_size; ++i, ++j)
ret |= ((scd->buf[ i / 8 ] & (1 << (i % 8))) != 0) << j;
scd->curbit += code_size;
return ret;
}
static int
GetCode(gdIOCtx *fd, CODE_STATIC_DATA *scd, int code_size, int flag, int *ZeroDataBlockP)
{
int rv;
rv = GetCode_(fd, scd, code_size,flag, ZeroDataBlockP);
if (VERBOSE) printf("[GetCode(,%d,%d) returning %d]\n",code_size,flag,rv);
return(rv);
}
/* }}} */
static int
LWZReadByte_(gdIOCtx *fd, LZW_STATIC_DATA *sd, char flag, int input_code_size, int *ZeroDataBlockP)
{
int code, incode, i;
if (flag) {
sd->set_code_size = input_code_size;
sd->code_size = sd->set_code_size+1;
sd->clear_code = 1 << sd->set_code_size ;
sd->end_code = sd->clear_code + 1;
sd->max_code_size = 2*sd->clear_code;
sd->max_code = sd->clear_code+2;
GetCode(fd, &sd->scd, 0, TRUE, ZeroDataBlockP);
sd->fresh = TRUE;
for (i = 0; i < sd->clear_code; ++i) {
sd->table[0][i] = 0;
sd->table[1][i] = i;
}
for (; i < (1<<MAX_LWZ_BITS); ++i)
sd->table[0][i] = sd->table[1][0] = 0;
sd->sp = sd->stack;
return 0;
} else if (sd->fresh) {
sd->fresh = FALSE;
do {
sd->firstcode = sd->oldcode =
GetCode(fd, &sd->scd, sd->code_size, FALSE, ZeroDataBlockP);
} while (sd->firstcode == sd->clear_code);
return sd->firstcode;
}
if (sd->sp > sd->stack)
return *--sd->sp;
while ((code = GetCode(fd, &sd->scd, sd->code_size, FALSE, ZeroDataBlockP)) >= 0) {
if (code == sd->clear_code) {
for (i = 0; i < sd->clear_code; ++i) {
sd->table[0][i] = 0;
sd->table[1][i] = i;
}
for (; i < (1<<MAX_LWZ_BITS); ++i)
sd->table[0][i] = sd->table[1][i] = 0;
sd->code_size = sd->set_code_size+1;
sd->max_code_size = 2*sd->clear_code;
sd->max_code = sd->clear_code+2;
sd->sp = sd->stack;
sd->firstcode = sd->oldcode =
GetCode(fd, &sd->scd, sd->code_size, FALSE, ZeroDataBlockP);
return sd->firstcode;
} else if (code == sd->end_code) {
int count;
unsigned char buf[260];
if (*ZeroDataBlockP)
return -2;
while ((count = GetDataBlock(fd, buf, ZeroDataBlockP)) > 0)
;
if (count != 0)
return -2;
}
incode = code;
if (sd->sp == (sd->stack + STACK_SIZE)) {
/* Bad compressed data stream */
return -1;
}
if (code >= sd->max_code) {
*sd->sp++ = sd->firstcode;
code = sd->oldcode;
}
while (code >= sd->clear_code) {
if (sd->sp == (sd->stack + STACK_SIZE)) {
/* Bad compressed data stream */
return -1;
}
*sd->sp++ = sd->table[1][code];
if (code == sd->table[0][code]) {
/* Oh well */
}
code = sd->table[0][code];
}
*sd->sp++ = sd->firstcode = sd->table[1][code];
if ((code = sd->max_code) <(1<<MAX_LWZ_BITS)) {
sd->table[0][code] = sd->oldcode;
sd->table[1][code] = sd->firstcode;
++sd->max_code;
if ((sd->max_code >= sd->max_code_size) &&
(sd->max_code_size < (1<<MAX_LWZ_BITS))) {
sd->max_code_size *= 2;
++sd->code_size;
}
}
sd->oldcode = incode;
if (sd->sp > sd->stack)
return *--sd->sp;
}
return code;
}
/* }}} */
static int
LWZReadByte(gdIOCtx *fd, LZW_STATIC_DATA *sd, char flag, int input_code_size, int *ZeroDataBlockP)
{
int rv;
rv = LWZReadByte_(fd, sd, flag, input_code_size, ZeroDataBlockP);
if (VERBOSE) printf("[LWZReadByte(,%d,%d) returning %d]\n",flag,input_code_size,rv);
return(rv);
}
/* }}} */
static void
ReadImage(gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned char (*cmap)[256], int interlace, int *ZeroDataBlockP) /*1.4//, int ignore) */
{
unsigned char c;
int v;
int xpos = 0, ypos = 0, pass = 0;
int i;
LZW_STATIC_DATA sd;
/*
** Initialize the Compression routines
*/
if (! ReadOK(fd,&c,1)) {
return;
}
if (c > MAX_LWZ_BITS) {
return;
}
/* Stash the color map into the image */
for (i=0; (i<gdMaxColors); i++) {
im->red[i] = cmap[CM_RED][i];
im->green[i] = cmap[CM_GREEN][i];
im->blue[i] = cmap[CM_BLUE][i];
im->open[i] = 1;
}
/* Many (perhaps most) of these colors will remain marked open. */
im->colorsTotal = gdMaxColors;
if (LWZReadByte(fd, &sd, TRUE, c, ZeroDataBlockP) < 0) {
return;
}
/*
** If this is an "uninteresting picture" ignore it.
** REMOVED For 1.4
*/
/*if (ignore) { */
/* while (LWZReadByte(fd, &sd, FALSE, c) >= 0) */
/* ; */
/* return; */
/*} */
while ((v = LWZReadByte(fd, &sd, FALSE, c, ZeroDataBlockP)) >= 0) {
if (v >= gdMaxColors) {
v = 0;
}
/* This how we recognize which colors are actually used. */
if (im->open[v]) {
im->open[v] = 0;
}
gdImageSetPixel(im, xpos, ypos, v);
++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:
if (LWZReadByte(fd, &sd, FALSE, c, ZeroDataBlockP) >=0) {
/* Ignore extra */
}
}
/* }}} */