diff options
author | pierre <none@none> | 2006-04-05 15:35:09 +0000 |
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committer | pierre <none@none> | 2006-04-05 15:35:09 +0000 |
commit | 0b6804ee481a635e192f47ac811197e96fa05ecd (patch) | |
tree | 6b27a42482c143d2b70fb1157e55e847838f7318 /src/gd_gif_in.c | |
parent | 3d209b2ed96d2386b70cba65aaec6755654abc60 (diff) | |
download | libgd-0b6804ee481a635e192f47ac811197e96fa05ecd.tar.gz |
- sync to 1.5.0GD_1_5_0
Diffstat (limited to 'src/gd_gif_in.c')
-rw-r--r-- | src/gd_gif_in.c | 562 |
1 files changed, 562 insertions, 0 deletions
diff --git a/src/gd_gif_in.c b/src/gd_gif_in.c new file mode 100644 index 0000000..c95e4cb --- /dev/null +++ b/src/gd_gif_in.c @@ -0,0 +1,562 @@ +#include <stdio.h> +#include <math.h> +#include <string.h> +#include <stdlib.h> +#include "gd.h" +#include "io.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 + +static struct { + int transparent; + int delayTime; + int inputFlag; + int disposal; +} Gif89 = { -1, -1, -1, 0 }; + +static int ReadColorMap (gdIOCtx *fd, int number, unsigned char (*buffer)[256]); +static int DoExtension (gdIOCtx *fd, int label, int *Transparent); +static int GetDataBlock (gdIOCtx *fd, unsigned char *buf); +static int GetCode (gdIOCtx *fd, int code_size, int flag); +static int LWZReadByte (gdIOCtx *fd, int flag, int input_code_size); + +static void ReadImage (gdImagePtr im, gdIOCtx *fd, int len, int height, unsigned char (*cmap)[256], int interlace); /*1.4//, int ignore); */ + +int ZeroDataBlock; + +gdImagePtr +gdImageCreateFromGif(FILE *fdFile) +{ + gdIOCtx *fd = gdNewFileCtx(fdFile); + gdImagePtr im = 0; + + im = gdImageCreateFromGifCtx(fd); + + fd->free(fd); + + return im; +} + +gdImagePtr +gdImageCreateFromGifCtx(gdIOCtxPtr fd) +{ + int imageNumber; + int BitPixel; + int ColorResolution; + int Background; + int AspectRatio; + int Transparent = (-1); + unsigned char buf[16]; + unsigned char c; + unsigned char ColorMap[3][MAXCOLORMAPSIZE]; + unsigned char localColorMap[3][MAXCOLORMAPSIZE]; + int imw, imh; + int useGlobalColormap; + int bitPixel; + int i; + /*1.4//int imageCount = 0; */ + char version[4]; + + gdImagePtr im = 0; + ZeroDataBlock = FALSE; + + /*1.4//imageNumber = 1; */ + if (! ReadOK(fd,buf,6)) { + return 0; + } + if (strncmp((char *)buf,"GIF",3) != 0) { + return 0; + } + strncpy(version, (char *)buf + 3, 3); + version[3] = '\0'; + + if ((strcmp(version, "87a") != 0) && (strcmp(version, "89a") != 0)) { + return 0; + } + if (! ReadOK(fd,buf,7)) { + return 0; + } + BitPixel = 2<<(buf[4]&0x07); + ColorResolution = (int) (((buf[4]&0x70)>>3)+1); + Background = buf[5]; + AspectRatio = buf[6]; + + if (BitSet(buf[4], LOCALCOLORMAP)) { /* Global Colormap */ + if (ReadColorMap(fd, BitPixel, ColorMap)) { + return 0; + } + } + for (;;) { + 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); + 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); + + imw = LM_to_uint(buf[4],buf[5]); + imh = LM_to_uint(buf[6],buf[7]); + if (!(im = gdImageCreate(imw, imh))) { + return 0; + } + im->interlace = BitSet(buf[8], INTERLACE); + if (! useGlobalColormap) { + if (ReadColorMap(fd, bitPixel, localColorMap)) { + return 0; + } + ReadImage(im, fd, imw, imh, localColorMap, + BitSet(buf[8], INTERLACE)); + /*1.4//imageCount != imageNumber); */ + } else { + ReadImage(im, fd, imw, imh, + ColorMap, + BitSet(buf[8], INTERLACE)); + /*1.4//imageCount != imageNumber); */ + } + if (Transparent != (-1)) { + gdImageColorTransparent(im, Transparent); + } + goto terminated; + } + +terminated: + /* Terminator before any image was declared! */ + if (!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) +{ + static unsigned char buf[256]; + + switch (label) { + case 0xf9: /* Graphic Control Extension */ + (void) GetDataBlock(fd, (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) + *Transparent = buf[3]; + + while (GetDataBlock(fd, (unsigned char*) buf) != 0) + ; + return FALSE; + default: + break; + } + while (GetDataBlock(fd, (unsigned char*) buf) != 0) + ; + + return FALSE; +} + +static int +GetDataBlock_(gdIOCtx *fd, unsigned char *buf) +{ + unsigned char count; + + if (! ReadOK(fd,&count,1)) { + return -1; + } + + ZeroDataBlock = count == 0; + + if ((count != 0) && (! ReadOK(fd, buf, count))) { + return -1; + } + + return count; +} + +static int +GetDataBlock(gdIOCtx *fd, unsigned char *buf) +{ + int rv; + int i; + + rv = GetDataBlock_(fd,buf); + if (VERBOSE) + { printf("[GetDataBlock returning %d",rv); + if (rv > 0) + { printf(":"); + for (i=0;i<rv;i++) printf(" %02x",buf[i]); + } + printf("]\n"); + } + return(rv); +} + +static int +GetCode_(gdIOCtx *fd, 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) { + /* Oh well */ + } + return -1; + } + buf[0] = buf[last_byte-2]; + buf[1] = buf[last_byte-1]; + + if ((count = GetDataBlock(fd, &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 +GetCode(gdIOCtx *fd, int code_size, int flag) +{ + int rv; + + rv = GetCode_(fd,code_size,flag); + if (VERBOSE) printf("[GetCode(,%d,%d) returning %d]\n",code_size,flag,rv); + return(rv); +} + +#define STACK_SIZE ((1<<(MAX_LWZ_BITS))*2) +static int +LWZReadByte_(gdIOCtx *fd, 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[STACK_SIZE], *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(fd, 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(fd, code_size, FALSE); + } while (firstcode == clear_code); + return firstcode; + } + + if (sp > stack) + return *--sp; + + while ((code = GetCode(fd, 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(fd, code_size, FALSE); + return firstcode; + } else if (code == end_code) { + int count; + unsigned char buf[260]; + + if (ZeroDataBlock) + return -2; + + while ((count = GetDataBlock(fd, buf)) > 0) + ; + + if (count != 0) + return -2; + } + + incode = code; + + if (sp == (stack + STACK_SIZE)) { + /* Bad compressed data stream */ + return -1; + } + + if (code >= max_code) { + *sp++ = firstcode; + code = oldcode; + } + + while (code >= clear_code) { + if (sp == (stack + STACK_SIZE)) { + /* Bad compressed data stream */ + return -1; + } + *sp++ = table[1][code]; + if (code == table[0][code]) { + /* Oh well */ + } + 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 int +LWZReadByte(gdIOCtx *fd, int flag, int input_code_size) +{ + int rv; + + rv = LWZReadByte_(fd,flag,input_code_size); + 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) /*1.4//, int ignore) */ +{ + unsigned char c; + int v; + int xpos = 0, ypos = 0, pass = 0; + int i; + /* 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; + /* + ** Initialize the Compression routines + */ + if (! ReadOK(fd,&c,1)) { + return; + } + if (LWZReadByte(fd, TRUE, c) < 0) { + return; + } + + /* + ** If this is an "uninteresting picture" ignore it. + ** REMOVED For 1.4 + */ + /*if (ignore) { */ + /* while (LWZReadByte(fd, FALSE, c) >= 0) */ + /* ; */ + /* return; */ + /*} */ + + while ((v = LWZReadByte(fd,FALSE,c)) >= 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,FALSE,c)>=0) { + /* Ignore extra */ + } +} + |