As discussed a while ago, decoding GIF images is not considered a Unisys

LZW patent violation so we can distribute read-only GIF support with
our bundled GD2.  The patent also expires in 2003, which is quickly
approaching, so we can roll in write support soon unless things change.

4 files changed, 580 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index 4005ef1a02..edad7386fe 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,7 @@
 PHP 4                                                                      NEWS
 |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
 ? ? ??? 2002, Version 4.3.0
+- Read-only GIF support for bundled GD2 library (Rasmus)
 - Make the glue argument to implode() optional, if it is not specified
   default to using "". (Sterling)
 - Fixed fields argument to contain correct info for xslt_set_error_handler.
diff --git a/ext/gd/config.m4 b/ext/gd/config.m4
index 0edec76c33..569eb9849e 100644
--- a/ext/gd/config.m4
+++ b/ext/gd/config.m4
@@ -243,7 +243,7 @@ if test "$PHP_GD" = "php"; then
         libgd/gd_io_file.c libgd/gd_ss.c libgd/gd_io_ss.c libgd/gd_png.c libgd/gd_jpeg.c \
 		libgd/gdxpm.c libgd/gdfontt.c libgd/gdfonts.c libgd/gdfontmb.c libgd/gdfontl.c \
 		libgd/gdfontg.c libgd/gdtables.c libgd/gdft.c libgd/gdcache.c libgd/gdkanji.c \
-		libgd/wbmp.c libgd/gd_wbmp.c libgd/gdhelpers.c libgd/gd_topal.c"
+		libgd/wbmp.c libgd/gd_wbmp.c libgd/gdhelpers.c libgd/gd_topal.c libgd/gd_gif_in.c"
 
 dnl check for fabsf and floorf which are available since C99
   AC_CHECK_FUNCS(fabsf floorf)
@@ -273,6 +273,7 @@ dnl These are always available with bundled library
   AC_DEFINE(HAVE_GD_GD2,              1, [ ])
   AC_DEFINE(HAVE_GD_PNG,              1, [ ])
   AC_DEFINE(HAVE_GD_BUNDLED,          1, [ ])
+  AC_DEFINE(HAVE_GD_GIF_READ,          1, [ ])
 
 dnl Make sure the libgd/ is first in the include path
   GDLIB_CFLAGS="-DHAVE_LIBPNG"
diff --git a/ext/gd/libgd/gd.h b/ext/gd/libgd/gd.h
index 4c8fb90fe9..d0ca82b278 100644
--- a/ext/gd/libgd/gd.h
+++ b/ext/gd/libgd/gd.h
@@ -376,6 +376,10 @@ void gdImageJpegCtx(gdImagePtr im, gdIOCtx *out, int quality);
 /* Best to free this memory with gdFree(), not free() */
 void *gdImageJpegPtr(gdImagePtr im, int *size, int quality);
 
+gdImagePtr gdImageCreateFromGif(FILE *fd);
+gdImagePtr gdImageCreateFromGifCtx(gdIOCtxPtr in);
+gdImagePtr gdImageCreateFromGifSource(gdSourcePtr in);
+
 /* A custom data sink. For backwards compatibility. Use
 	gdIOCtx instead. */
 /* The sink function must return -1 on error, otherwise the number
diff --git a/ext/gd/libgd/gd_gif_in.c b/ext/gd/libgd/gd_gif_in.c
new file mode 100644
index 0000000000..e600b80470
--- /dev/null
+++ b/ext/gd/libgd/gd_gif_in.c
@@ -0,0 +1,573 @@
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+#include <stdlib.h>
+#include "gd.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 gdImageCreateFromGifSource(gdSourcePtr inSource)
+{
+        gdIOCtx         *in = gdNewSSCtx(inSource, NULL);
+        gdImagePtr      im;
+
+        im = gdImageCreateFromGifCtx(in);
+
+        in->free(in);
+
+        return im;
+}
+
+gdImagePtr
+gdImageCreateFromGif(FILE *fdFile)
+{
+        gdIOCtx		*fd = gdNewFileCtx(fdFile);
+        gdImagePtr    	im = 0;
+
+        im = gdImageCreateFromGifCtx(fd);
+
+        fd->free(fd);
+
+        return im;
+}
+
+gdImagePtr
+gdImageCreateFromGifCtx(gdIOCtxPtr fd)
+{
+/* 1.4       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 */
+       }
+}
+