]> Pileus Git - ~andy/gtk/blobdiff - gdk-pixbuf/io-gif.c
Adopt to new prototypes for unicode,locale,filename conversion functions.
[~andy/gtk] / gdk-pixbuf / io-gif.c
index d3bbcbfedfc164e87d40299a9d66666447deb217..e61f41fb879577a23a140fbff9d78618cd70e294 100644 (file)
@@ -5,54 +5,93 @@
  *
  * Authors: Jonathan Blandford <jrb@redhat.com>
  *          Adapted from the gimp gif filter written by Adam Moss <adam@gimp.org>
- *          Gimp work based on earlier work by ......
+ *          Gimp work based on earlier work.
  *          Permission to relicense under the LGPL obtained.
  *
  * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public
+ * modify it under the terms of the GNU Lesser 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.
+ * Lesser General Public License for more details.
  *
- * You should have received a copy of the GNU Library General Public
+ * You should have received a copy of the GNU Lesser General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
 
+/* This loader is very hairy code.
+ *
+ * The main loop was not designed for incremental loading, so when it was hacked
+ * in it got a bit messy.  Basicly, every function is written to expect a failed
+ * read_gif, and lets you call it again assuming that the bytes are there.
+ *
+ * A note on Animations:
+ * Currently, it doesn't correctly read the different colormap per frame.  This
+ * needs implementing sometime.
+ *
+ * Return vals.
+ * Unless otherwise specified, these are the return vals for most functions:
+ *
+ *  0 -> success
+ * -1 -> more bytes needed.
+ * -2 -> failure; abort the load
+ * -3 -> control needs to be passed back to the main loop
+ *        \_ (most of the time returning 0 will get this, but not always)
+ *
+ * >1 -> for functions that get a guchar, the char will be returned.
+ *
+ * -jrb (11/03/1999)
+ */
+
+/*
+ * If you have any images that crash this code, please, please let me know and
+ * send them to me.
+ *                                            <jrb@redhat.com>
+ */
+
+\f
+
 #include <config.h>
 #include <stdio.h>
-#include <glib.h>
-#include <gif_lib.h>
 #include <string.h>
-#include "gdk-pixbuf.h"
+#include "gdk-pixbuf-private.h"
 #include "gdk-pixbuf-io.h"
-\f
 
+\f
 
 #define MAXCOLORMAPSIZE  256
-
-#define CM_RED           0
-#define CM_GREEN         1
-#define CM_BLUE          2
-
-#define MAX_LWZ_BITS     12
+#define MAX_LZW_BITS     12
 
 #define INTERLACE          0x40
 #define LOCALCOLORMAP      0x80
 #define BitSet(byte, bit)  (((byte) & (bit)) == (bit))
-#define ReadOK(file,buffer,len) (fread(buffer, len, 1, file) != 0)
 #define LM_to_uint(a,b)         (((b)<<8)|(a))
 
-#define GRAYSCALE        1
-#define COLOR            2
+\f
 
 typedef unsigned char CMap[3][MAXCOLORMAPSIZE];
 
+/* Possible states we can be in. */
+enum {
+       GIF_START,
+       GIF_GET_COLORMAP,
+       GIF_GET_NEXT_STEP,
+       GIF_GET_FRAME_INFO,
+       GIF_GET_EXTENTION,
+       GIF_GET_COLORMAP2,
+       GIF_PREPARE_LZW,
+       GIF_LZW_FILL_BUFFER,
+       GIF_LZW_CLEAR_CODE,
+       GIF_GET_LZW,
+       GIF_DONE,
+};
+
+
 typedef struct _Gif89 Gif89;
 struct _Gif89
 {
@@ -65,421 +104,822 @@ struct _Gif89
 typedef struct _GifContext GifContext;
 struct _GifContext
 {
+       int state; /* really only relevant for progressive loading */
        unsigned int width;
        unsigned int height;
        CMap color_map;
+       CMap frame_color_map;
        unsigned int bit_pixel;
        unsigned int color_resolution;
        unsigned int background;
        unsigned int aspect_ratio;
-       int gray_scale;
        GdkPixbuf *pixbuf;
+       GdkPixbufAnimation *animation;
+       GdkPixbufFrame *frame;
        Gif89 gif89;
+
+       /* stuff per frame.  As we only support the first one, not so
+        * relevant.  But still needed */
+       int frame_len;
+       int frame_height;
+       int frame_interlace;
+       int x_offset;
+       int y_offset;
+
+       /* Static read only */
+       FILE *file;
+
+       /* progressive read, only. */
+       ModulePreparedNotifyFunc prepare_func;
+       ModuleUpdatedNotifyFunc update_func;
+       ModuleFrameDoneNotifyFunc frame_done_func;
+       ModuleAnimationDoneNotifyFunc anim_done_func;
+       gpointer user_data;
+       guchar *buf;
+       guint ptr;
+       guint size;
+       guint amount_needed;
+
+       /* colormap context */
+       gint colormap_index;
+       gint colormap_flag;
+
+       /* extension context */
+       guchar extension_label;
+       guchar extension_flag;
+
+       /* get block context */
+       guchar block_count;
+       guchar block_buf[280];
+       gint block_ptr;
+
+       int old_state; /* used by lzw_fill buffer */
+       /* get_code context */
+       int code_curbit;
+       int code_lastbit;
+       int code_done;
+       int code_last_byte;
+       int lzw_code_pending;
+
+       /* lzw context */
+       gint lzw_fresh;
+       gint lzw_code_size;
+       guchar lzw_set_code_size;
+       gint lzw_max_code;
+       gint lzw_max_code_size;
+       gint lzw_firstcode;
+       gint lzw_oldcode;
+       gint lzw_clear_code;
+       gint lzw_end_code;
+       gint *lzw_sp;
+
+       gint lzw_table[2][(1 << MAX_LZW_BITS)];
+       gint lzw_stack[(1 << (MAX_LZW_BITS)) * 2 + 1];
+
+       /* painting context */
+       gint draw_xpos;
+       gint draw_ypos;
+       gint draw_pass;
+
+        /* error pointer */
+        GError **error;
 };
 
+static int GetDataBlock (GifContext *, unsigned char *);
 
-int verbose = FALSE;
-int showComment = TRUE;
-char *globalcomment = NULL;
-gint globalusecomment = TRUE;
-
-static int ReadColorMap (FILE *, int, CMap, int *);
-static int DoExtension (FILE *file, GifContext *context, int label);
-static int GetDataBlock (FILE *, unsigned char *);
-static int GetCode (FILE *, int, int);
-static int LWZReadByte (FILE *, int, int);
-
-static void ReadImage (FILE *file,
-                      GifContext *context, 
-                      int   len,
-                      int   height,
-                      CMap  cmap,
-                      int   ncols,
-                      int   format,
-                      int   interlace,
-                      int   number,
-                      guint   leftpos,
-                      guint   toppos);
+\f
 
+#ifdef IO_GIFDEBUG
+static int count = 0;
+#endif
+
+/* Returns TRUE if read is OK,
+ * FALSE if more memory is needed. */
 static int
-ReadColorMap (FILE *file,
-             int   number,
-             CMap  buffer,
-             int  *format)
+gif_read (GifContext *context, guchar *buffer, size_t len)
 {
-       int i;
-       unsigned char rgb[3];
-       int flag;
+       gint retval;
+#ifdef IO_GIFDEBUG
+       gint i;
+#endif
+       if (context->file) {
+#ifdef IO_GIFDEBUG
+               count += len;
+               g_print ("Fsize :%d\tcount :%d\t", len, count);
+#endif
+               retval = (fread(buffer, len, 1, context->file) != 0);                
+#ifdef IO_GIFDEBUG
+               if (len < 100) {
+                       for (i = 0; i < len; i++)
+                               g_print ("%d ", buffer[i]);
+               }
+               g_print ("\n");
+#endif
+                
+               return retval;
+       } else {
+#ifdef IO_GIFDEBUG
+/*             g_print ("\tlooking for %d bytes.  size == %d, ptr == %d\n", len, context->size, context->ptr); */
+#endif
+               if ((context->size - context->ptr) >= len) {
+#ifdef IO_GIFDEBUG
+                       count += len;
+#endif
+                       memcpy (buffer, context->buf + context->ptr, len);
+                       context->ptr += len;
+                       context->amount_needed = 0;
+#ifdef IO_GIFDEBUG
+                       g_print ("Psize :%d\tcount :%d\t", len, count);
+                       if (len < 100) {
+                               for (i = 0; i < len; i++)
+                                       g_print ("%d ", buffer[i]);
+                       }
+                       g_print ("\n");
+#endif
+                       return TRUE;
+               }
+               context->amount_needed = len - (context->size - context->ptr);
+       }
+       return 0;
+}
 
-       flag = TRUE;
+/* Changes the stage to be GIF_GET_COLORMAP */
+static void
+gif_set_get_colormap (GifContext *context)
+{
+       context->colormap_flag = TRUE;
+       context->colormap_index = 0;
+       context->state = GIF_GET_COLORMAP;
+}
 
-       for (i = 0; i < number; ++i) {
-               if (!ReadOK (file, rgb, sizeof (rgb))) {
+static void
+gif_set_get_colormap2 (GifContext *context)
+{
+       context->colormap_flag = TRUE;
+       context->colormap_index = 0;
+       context->state = GIF_GET_COLORMAP2;
+}
+
+static gint
+gif_get_colormap (GifContext *context)
+{
+       unsigned char rgb[3];
+
+       while (context->colormap_index < context->bit_pixel) {
+               if (!gif_read (context, rgb, sizeof (rgb))) {
                        /*g_message (_("GIF: bad colormap\n"));*/
-                       return TRUE;
+                       return -1;
                }
 
-               buffer[CM_RED][i] = rgb[0];
-               buffer[CM_GREEN][i] = rgb[1];
-               buffer[CM_BLUE][i] = rgb[2];
+               context->color_map[0][context->colormap_index] = rgb[0];
+               context->color_map[1][context->colormap_index] = rgb[1];
+               context->color_map[2][context->colormap_index] = rgb[2];
 
-               flag &= (rgb[0] == rgb[1] && rgb[1] == rgb[2]);
+               context->colormap_flag &= (rgb[0] == rgb[1] && rgb[1] == rgb[2]);
+               context->colormap_index ++;
        }
 
-       *format = (flag) ? GRAYSCALE : COLOR;
-
-       return FALSE;
+       return 0;
 }
 
+/*
+ * in order for this function to work, we need to perform some black magic.
+ * We want to return -1 to let the calling function know, as before, that it needs
+ * more bytes.  If we return 0, we were able to successfully read all block->count bytes.
+ * Problem is, we don't want to reread block_count every time, so we check to see if
+ * context->block_count is 0 before we read in the function.
+ *
+ * As a result, context->block_count MUST be 0 the first time the get_data_block is called
+ * within a context, and cannot be 0 the second time it's called.
+ */
+
 static int
-DoExtension (FILE *file, GifContext *context, int label)
-{
-       static guchar buf[256];
-
-       switch (label) {
-       case 0xf9:                      /* Graphic Control Extension */
-               (void) GetDataBlock (file, (unsigned char *) buf);
-               context->gif89.disposal = (buf[0] >> 2) & 0x7;
-               context->gif89.input_flag = (buf[0] >> 1) & 0x1;
-               context->gif89.delay_time = LM_to_uint (buf[1], buf[2]);
-               if (context->pixbuf == NULL) {
-                       /* I only want to set the transparency if I haven't
-                        * created the pixbuf yet. */
-                       if ((buf[0] & 0x1) != 0)
-                               context->gif89.transparent = buf[3];
-                       else
-                               context->gif89.transparent = -1;
+get_data_block (GifContext *context,
+               unsigned char *buf,
+               gint *empty_block)
+{
+
+       if (context->block_count == 0) {
+               if (!gif_read (context, &context->block_count, 1)) {
+                       return -1;
                }
-               while (GetDataBlock (file, (unsigned char *) buf) != 0)
-                       ;
-               return FALSE;
-               break;
-       default:
-               /* Unhandled extension */
-               break;
        }
 
-       while (GetDataBlock (file, (unsigned char *) buf) != 0)
-               ;
+       if (context->block_count == 0)
+               if (empty_block) {
+                       *empty_block = TRUE;
+                       return 0;
+               }
+
+       if (!gif_read (context, buf, context->block_count)) {
+               return -1;
+       }
 
-       return FALSE;
+       return 0;
 }
 
-int ZeroDataBlock = FALSE;
+static void
+gif_set_get_extension (GifContext *context)
+{
+       context->state = GIF_GET_EXTENTION;
+       context->extension_flag = TRUE;
+       context->extension_label = 0;
+       context->block_count = 0;
+       context->block_ptr = 0;
+}
 
 static int
-GetDataBlock (FILE          *file,
+gif_get_extension (GifContext *context)
+{
+       gint retval;
+       gint empty_block = FALSE;
+
+       if (context->extension_flag) {
+               if (context->extension_label == 0) {
+                       /* I guess bad things can happen if we have an extension of 0 )-: */
+                       /* I should look into this sometime */
+                       if (!gif_read (context, & context->extension_label , 1)) {
+                               return -1;
+                       }
+               }
+
+               switch (context->extension_label) {
+               case 0xf9:                      /* Graphic Control Extension */
+                       retval = get_data_block (context, (unsigned char *) context->block_buf, NULL);
+                       if (retval != 0)
+                               return retval;
+                       if (context->pixbuf == NULL) {
+                               /* I only want to set the transparency if I haven't
+                                * created the pixbuf yet. */
+                               context->gif89.disposal = (context->block_buf[0] >> 2) & 0x7;
+                               context->gif89.input_flag = (context->block_buf[0] >> 1) & 0x1;
+                               context->gif89.delay_time = LM_to_uint (context->block_buf[1], context->block_buf[2]);
+                               
+                               if ((context->block_buf[0] & 0x1) != 0) {
+                                       context->gif89.transparent = context->block_buf[3];
+                               } else {
+                                       context->gif89.transparent = -1;
+                               }
+                       }
+
+                       /* Now we've successfully loaded this one, we continue on our way */
+                       context->block_count = 0;
+                       context->extension_flag = FALSE;
+               default:
+                       /* Unhandled extension */
+                       break;
+               }
+       }
+       /* read all blocks, until I get an empty block, in case there was an extension I didn't know about. */
+       do {
+               retval = get_data_block (context, (unsigned char *) context->block_buf, &empty_block);
+               if (retval != 0)
+                       return retval;
+               context->block_count = 0;
+       } while (!empty_block);
+
+       return 0;
+}
+
+static int ZeroDataBlock = FALSE;
+
+static int
+GetDataBlock (GifContext *context,
              unsigned char *buf)
 {
-       unsigned char count;
+/*     unsigned char count; */
 
-       if (!ReadOK (file, &count, 1)) {
+       if (!gif_read (context, &context->block_count, 1)) {
                /*g_message (_("GIF: error in getting DataBlock size\n"));*/
                return -1;
        }
 
-       ZeroDataBlock = count == 0;
+       ZeroDataBlock = context->block_count == 0;
 
-       if ((count != 0) && (!ReadOK (file, buf, count))) {
+       if ((context->block_count != 0) && (!gif_read (context, buf, context->block_count))) {
                /*g_message (_("GIF: error in reading DataBlock\n"));*/
                return -1;
        }
 
-       return count;
+       return context->block_count;
+}
+
+
+static void
+gif_set_lzw_fill_buffer (GifContext *context)
+{
+       context->block_count = 0;
+       context->old_state = context->state;
+       context->state = GIF_LZW_FILL_BUFFER;
 }
 
 static int
-GetCode (FILE *file,
-        int   code_size,
-        int   flag)
+gif_lzw_fill_buffer (GifContext *context)
 {
-       static unsigned char buf[280];
-       static int curbit, lastbit, done, last_byte;
-       int i, j, ret;
-       unsigned char count;
+       gint retval;
 
-       if (flag) {
-               curbit = 0;
-               lastbit = 0;
-               done = FALSE;
-               return 0;
-       }
+       if (context->code_done) {
+               if (context->code_curbit >= context->code_lastbit) {
+                        g_set_error (context->error,
+                                     GDK_PIXBUF_ERROR,
+                                     GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                     _("GIF file was missing some data (perhaps it was truncated somehow?)"));
 
-       if ((curbit + code_size) >= lastbit){
-               if (done) {
-                       if (curbit >= lastbit) {
-                               /*g_message (_("GIF: ran off the end of by bits\n"));*/
-                               return -1;
-                       }
-                       return -1;
+                       return -2;
                }
-               buf[0] = buf[last_byte - 2];
-               buf[1] = buf[last_byte - 1];
+                /* Is this supposed to be an error or what? */
+               /* g_message ("trying to read more data after we've done stuff\n"); */
+                g_set_error (context->error,
+                             GDK_PIXBUF_ERROR,
+                             GDK_PIXBUF_ERROR_FAILED,
+                             _("Internal error in the GIF loader (%s)"),
+                             G_STRLOC);
+                
+               return -2;
+       }
+
+       context->block_buf[0] = context->block_buf[context->code_last_byte - 2];
+       context->block_buf[1] = context->block_buf[context->code_last_byte - 1];
+
+       retval = get_data_block (context, &context->block_buf[2], NULL);
+
+       if (retval == -1)
+               return -1;
 
-               if ((count = GetDataBlock (file, &buf[2])) == 0)
-                       done = TRUE;
+       if (context->block_count == 0)
+               context->code_done = TRUE;
 
-               last_byte = 2 + count;
-               curbit = (curbit - lastbit) + 16;
-               lastbit = (2 + count) * 8;
+       context->code_last_byte = 2 + context->block_count;
+       context->code_curbit = (context->code_curbit - context->code_lastbit) + 16;
+       context->code_lastbit = (2 + context->block_count) * 8;
+
+       context->state = context->old_state;
+       return 0;
+}
+
+static int
+get_code (GifContext *context,
+         int   code_size)
+{
+       int i, j, ret;
+
+       if ((context->code_curbit + code_size) >= context->code_lastbit){
+               gif_set_lzw_fill_buffer (context);
+               return -3;
        }
 
        ret = 0;
-       for (i = curbit, j = 0; j < code_size; ++i, ++j)
-               ret |= ((buf[i / 8] & (1 << (i % 8))) != 0) << j;
+       for (i = context->code_curbit, j = 0; j < code_size; ++i, ++j)
+               ret |= ((context->block_buf[i / 8] & (1 << (i % 8))) != 0) << j;
 
-       curbit += code_size;
+       context->code_curbit += code_size;
 
        return ret;
 }
 
-static int
-LWZReadByte (FILE *file,
-            int   flag,
-            int   input_code_size)
+
+static void
+set_gif_lzw_clear_code (GifContext *context)
 {
-       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;
+       context->state = GIF_LZW_CLEAR_CODE;
+       context->lzw_code_pending = -1;
+}
 
-       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;
+static int
+gif_lzw_clear_code (GifContext *context)
+{
+       gint code;
 
-               GetCode (file, 0, TRUE);
+       code = get_code (context, context->lzw_code_size);
+       if (code == -3)
+               return -0;
 
-               fresh = TRUE;
+       context->lzw_firstcode = context->lzw_oldcode = code;
+       context->lzw_code_pending = code;
+       context->state = GIF_GET_LZW;
+       return 0;
+}
 
-               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;
+static int
+lzw_read_byte (GifContext *context)
+{
+       int code, incode;
+       gint retval;
+       gint my_retval;
+       register int i;
 
-               sp = stack;
+       if (context->lzw_code_pending != -1) {
+               retval = context->lzw_code_pending;
+               context->lzw_code_pending = -1;
+               return retval;
+       }
 
-               return 0;
-       } else if (fresh) {
-               fresh = FALSE;
+       if (context->lzw_fresh) {
+               context->lzw_fresh = FALSE;
                do {
-                       firstcode = oldcode = GetCode (file, code_size, FALSE);
-               } while (firstcode == clear_code);
-               return firstcode;
+                       retval = get_code (context, context->lzw_code_size);
+                       if (retval < 0) {
+                               return retval;
+                       }
+
+                       context->lzw_firstcode = context->lzw_oldcode = retval;
+               } while (context->lzw_firstcode == context->lzw_clear_code);
+               return context->lzw_firstcode;
        }
 
-       if (sp > stack)
-               return *--sp;
+       if (context->lzw_sp > context->lzw_stack) {
+               my_retval = *--(context->lzw_sp);
+               return my_retval;
+       }
 
-       while ((code = GetCode (file, code_size, FALSE)) >= 0) {
-               if (code == clear_code) {
-                       for (i = 0; i < clear_code; ++i) {
-                               table[0][i] = 0;
-                               table[1][i] = i;
+       while ((code = get_code (context, context->lzw_code_size)) >= 0) {
+               if (code == context->lzw_clear_code) {
+                       for (i = 0; i < context->lzw_clear_code; ++i) {
+                               context->lzw_table[0][i] = 0;
+                               context->lzw_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 (file, code_size, FALSE);
-                       return firstcode;
-               } else if (code == end_code) {
+                       for (; i < (1 << MAX_LZW_BITS); ++i)
+                               context->lzw_table[0][i] = context->lzw_table[1][i] = 0;
+                       context->lzw_code_size = context->lzw_set_code_size + 1;
+                       context->lzw_max_code_size = 2 * context->lzw_clear_code;
+                       context->lzw_max_code = context->lzw_clear_code + 2;
+                       context->lzw_sp = context->lzw_stack;
+
+                       set_gif_lzw_clear_code (context);
+                       return -3;
+               } else if (code == context->lzw_end_code) {
                        int count;
                        unsigned char buf[260];
 
-                       if (ZeroDataBlock)
+                       /*g_error (" DID WE EVER EVER GET HERE\n");*/
+                       g_warning ("Unhandled Case.  If you have an image that causes this, let me <jrb@redhat.com> know.\n");
+
+                       if (ZeroDataBlock) {
                                return -2;
+                       }
 
-                       while ((count = GetDataBlock (file, buf)) > 0)
+                       while ((count = GetDataBlock (context, buf)) > 0)
                                ;
 
-                       if (count != 0)
+                       if (count != 0) {
                                /*g_print (_("GIF: missing EOD in data stream (common occurence)"));*/
-                       return -2;
+                               return -2;
+                       }
                }
 
                incode = code;
 
-               if (code >= max_code) {
-                       *sp++ = firstcode;
-                       code = oldcode;
+               if (code >= context->lzw_max_code) {
+                       *(context->lzw_sp)++ = context->lzw_firstcode;
+                       code = context->lzw_oldcode;
                }
 
-               while (code >= clear_code) {
-                       *sp++ = table[1][code];
-                       if (code == table[0][code]) {
-                               /*g_message (_("GIF: circular table entry BIG ERROR\n"));*/
-                               /*gimp_quit ();*/
-                               return -1;
+               while (code >= context->lzw_clear_code) {
+                       *(context->lzw_sp)++ = context->lzw_table[1][code];
+
+                       if (code == context->lzw_table[0][code]) {
+                                g_set_error (context->error,
+                                             GDK_PIXBUF_ERROR,
+                                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                                             _("Circular table entry in GIF file"));
+                               return -2;
                        }
-                       code = table[0][code];
+                       code = context->lzw_table[0][code];
                }
 
-               *sp++ = firstcode = table[1][code];
+               *(context->lzw_sp)++ = context->lzw_firstcode = context->lzw_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;
+               if ((code = context->lzw_max_code) < (1 << MAX_LZW_BITS)) {
+                       context->lzw_table[0][code] = context->lzw_oldcode;
+                       context->lzw_table[1][code] = context->lzw_firstcode;
+                       ++context->lzw_max_code;
+                       if ((context->lzw_max_code >= context->lzw_max_code_size) &&
+                           (context->lzw_max_code_size < (1 << MAX_LZW_BITS))) {
+                               context->lzw_max_code_size *= 2;
+                               ++context->lzw_code_size;
                        }
                }
 
-               oldcode = incode;
+               context->lzw_oldcode = incode;
 
-               if (sp > stack)
-                       return *--sp;
+               if (context->lzw_sp > context->lzw_stack) {
+                       my_retval = *--(context->lzw_sp);
+                       return my_retval;
+               }
        }
        return code;
 }
 
 static void
-ReadImage (FILE *file,
-          GifContext *context, 
-          int   len,
-          int   height,
-          CMap  cmap,
-          int   ncols,
-          int   format,
-          int   interlace,
-          int   number,
-          guint   leftpos,
-          guint   toppos)
+gif_set_get_lzw (GifContext *context)
 {
-       guchar *dest, *temp;
-       guchar c;
-       gint xpos = 0, ypos = 0, pass = 0;
-       gint v;
+       context->state = GIF_GET_LZW;
+       context->draw_xpos = 0;
+       context->draw_ypos = 0;
+       context->draw_pass = 0;
+}
 
-       /*
-       **  Initialize the Compression routines
-       */
-       if (!ReadOK (file, &c, 1)) {
-               /*g_message (_("GIF: EOF / read error on image data\n"));*/
-               return;
+static void
+gif_fill_in_pixels (GifContext *context, guchar *dest, gint offset, guchar v)
+{
+       guchar *pixel = NULL;
+
+       if (context->gif89.transparent != -1) {
+               pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->pixbuf) + context->draw_xpos * 4;
+               *pixel = context->color_map [0][(guchar) v];
+               *(pixel+1) = context->color_map [1][(guchar) v];
+               *(pixel+2) = context->color_map [2][(guchar) v];
+               *(pixel+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 65535);
+       } else {
+               pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->pixbuf) + context->draw_xpos * 3;
+               *pixel = context->color_map [0][(guchar) v];
+               *(pixel+1) = context->color_map [1][(guchar) v];
+               *(pixel+2) = context->color_map [2][(guchar) v];
        }
+}
+
 
-       g_print ("c = %d\n", c);
-       if (LWZReadByte (file, TRUE, c) < 0) {
-               /*g_message (_("GIF: error while reading\n"));*/
-               return;
+/* only called if progressive and interlaced */
+static void
+gif_fill_in_lines (GifContext *context, guchar *dest, guchar v)
+{
+       switch (context->draw_pass) {
+       case 0:
+               if (context->draw_ypos > 4) {
+                       gif_fill_in_pixels (context, dest, -4, v);
+                       gif_fill_in_pixels (context, dest, -3, v);
+               }
+               if (context->draw_ypos < (context->frame_height - 4)) {
+                       gif_fill_in_pixels (context, dest, 3, v);
+                       gif_fill_in_pixels (context, dest, 4, v);
+               }
+               /* we don't need a break here.  We draw the outer pixels first, then the
+                * inner ones, then the innermost ones.  case 0 needs to draw all 3 bands.
+                * case 1, just the last two, and case 2 just draws the last one*/
+       case 1:
+               if (context->draw_ypos > 2)
+                       gif_fill_in_pixels (context, dest, -2, v);
+               if (context->draw_ypos < (context->frame_height - 2))
+                       gif_fill_in_pixels (context, dest, 2, v);
+               /* no break as above. */
+       case 2:
+               if (context->draw_ypos > 1)
+                       gif_fill_in_pixels (context, dest, -1, v);
+               if (context->draw_ypos < (context->frame_height - 1))
+                       gif_fill_in_pixels (context, dest, 1, v);
+       case 3:
+       default:
+               break;
        }
+}
 
-       context->pixbuf = gdk_pixbuf_new (ART_PIX_RGB,
-                                         context->gif89.transparent,
-                                         8,
-                                         context->width,
-                                         context->height);
+static int
+gif_get_lzw (GifContext *context)
+{
+       guchar *dest, *temp;
+       gint lower_bound, upper_bound; /* bounds for emitting the area_updated signal */
+       gboolean bound_flag;
+       gint first_pass; /* bounds for emitting the area_updated signal */
+       gint v;
 
+       if (context->pixbuf == NULL) {
+               context->pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB,
+                                                 context->gif89.transparent != -1,
+                                                 8,
+                                                 context->frame_len,
+                                                 context->frame_height);
+
+               if (context->prepare_func)
+                       (* context->prepare_func) (context->pixbuf, context->user_data);
+               if (context->animation || context->frame_done_func || context->anim_done_func) {
+                       context->frame = g_new (GdkPixbufFrame, 1);
+                       context->frame->x_offset = context->x_offset;
+                       context->frame->y_offset = context->y_offset;;
+                       context->frame->delay_time = context->gif89.delay_time;
+                       switch (context->gif89.disposal) {
+                       case 0:
+                       case 1:
+                               context->frame->action = GDK_PIXBUF_FRAME_RETAIN;
+                               break;
+                       case 2:
+                               context->frame->action = GDK_PIXBUF_FRAME_DISPOSE;
+                               break;
+                       case 3:
+                               context->frame->action = GDK_PIXBUF_FRAME_REVERT;
+                               break;
+                       default:
+                               context->frame->action = GDK_PIXBUF_FRAME_RETAIN;
+                               break;
+                       }
+                       context->frame->pixbuf = context->pixbuf;
+                       if (context->animation) {
+                               int w,h;
+                               context->animation->n_frames ++;
+                               context->animation->frames = g_list_append (context->animation->frames, context->frame);
+                               w = gdk_pixbuf_get_width (context->pixbuf);
+                               h = gdk_pixbuf_get_height (context->pixbuf);
+                               if (w > context->animation->width)
+                                       context->animation->width = w;
+                               if (h > context->animation->height)
+                                       context->animation->height = h;
+                       }
+               }
+       }
        dest = gdk_pixbuf_get_pixels (context->pixbuf);
-       while ((v = LWZReadByte (file, FALSE, c)) >= 0) {
-//             g_print ("in inner loop: xpos = %d, ypos = %d\n", xpos, ypos);
-               if (context->gif89.transparent) {
-                       temp = dest + (ypos * len + xpos) * 4;
-                       *temp = cmap [0][(guchar) v];
-                       *(temp+1) = cmap [1][(guchar) v];
-                       *(temp+2) = cmap [2][(guchar) v];
-                       *(temp+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 65535);
+
+       bound_flag = FALSE;
+       lower_bound = upper_bound = context->draw_ypos;
+       first_pass = context->draw_pass;
+
+       while (TRUE) {
+               v = lzw_read_byte (context);
+               if (v < 0) {
+                       goto finished_data;
+               }
+               bound_flag = TRUE;
+
+               if (context->gif89.transparent != -1) {
+                       temp = dest + context->draw_ypos * gdk_pixbuf_get_rowstride (context->pixbuf) + context->draw_xpos * 4;
+                       *temp = context->color_map [0][(guchar) v];
+                       *(temp+1) = context->color_map [1][(guchar) v];
+                       *(temp+2) = context->color_map [2][(guchar) v];
+                       *(temp+3) = (guchar) ((v == context->gif89.transparent) ? 0 : -1);
                } else {
-                       temp = dest + (ypos * len + xpos) * 3;
-                       *temp = cmap [0][(guchar) v];
-                       *(temp+1) = cmap [1][(guchar) v];
-                       *(temp+2) = cmap [2][(guchar) v];
+                       temp = dest + context->draw_ypos * gdk_pixbuf_get_rowstride (context->pixbuf) + context->draw_xpos * 3;
+                       *temp = context->color_map [0][(guchar) v];
+                       *(temp+1) = context->color_map [1][(guchar) v];
+                       *(temp+2) = context->color_map [2][(guchar) v];
                }
 
-               xpos++;
-               if (xpos == len) {
-                       xpos = 0;
-                       if (interlace) {
-                               switch (pass) {
+               if (context->prepare_func && context->frame_interlace)
+                       gif_fill_in_lines (context, dest, v);
+
+               context->draw_xpos++;
+
+               if (context->draw_xpos == context->frame_len) {
+                       context->draw_xpos = 0;
+                       if (context->frame_interlace) {
+                               switch (context->draw_pass) {
                                case 0:
                                case 1:
-                                       ypos += 8;
+                                       context->draw_ypos += 8;
                                        break;
                                case 2:
-                                       ypos += 4;
+                                       context->draw_ypos += 4;
                                        break;
                                case 3:
-                                       ypos += 2;
+                                       context->draw_ypos += 2;
                                        break;
                                }
 
-                               if (ypos >= height) {
-                                       pass++;
-                                       switch (pass) {
+                               if (context->draw_ypos >= context->frame_height) {
+                                       context->draw_pass++;
+                                       switch (context->draw_pass) {
                                        case 1:
-                                               ypos = 4;
+                                               context->draw_ypos = 4;
                                                break;
                                        case 2:
-                                               ypos = 2;
+                                               context->draw_ypos = 2;
                                                break;
                                        case 3:
-                                               ypos = 1;
+                                               context->draw_ypos = 1;
                                                break;
                                        default:
-                                               goto fini;
+                                               goto done;
                                        }
                                }
                        } else {
-                               ypos++;
+                               context->draw_ypos++;
                        }
+                       if (context->draw_pass != first_pass) {
+                               if (context->draw_ypos > lower_bound) {
+                                       lower_bound = 0;
+                                       upper_bound = context->frame_height;
+                               } else {
+
+                               }
+                       } else
+                               upper_bound = context->draw_ypos;
                }
-               if (ypos >= height)
+               if (context->draw_ypos >= context->frame_height)
                        break;
        }
+ done:
+       /* we got enough data. there may be more (ie, newer layers) but we can quit now */
+       if (context->animation || context->frame_done_func || context->anim_done_func) {
+               context->state = GIF_GET_NEXT_STEP;
+       } else
+               context->state = GIF_DONE;
+       v = 0;
+ finished_data:
+       if (bound_flag && context->update_func) {
+               if (lower_bound <= upper_bound && first_pass == context->draw_pass) {
+                       (* context->update_func)
+                               (context->pixbuf,
+                                0, lower_bound,
+                                gdk_pixbuf_get_width (context->pixbuf),
+                                upper_bound - lower_bound,
+                                context->user_data);
+               } else {
+                       if (lower_bound <= upper_bound) {
+                               (* context->update_func)
+                                       (context->pixbuf,
+                                        0, 0,
+                                        gdk_pixbuf_get_width (context->pixbuf),
+                                        gdk_pixbuf_get_height (context->pixbuf),
+                                        context->user_data);
+                       } else {
+                               (* context->update_func)
+                                       (context->pixbuf,
+                                        0, 0,
+                                        gdk_pixbuf_get_width (context->pixbuf),
+                                        upper_bound,
+                                        context->user_data);
+                               (* context->update_func)
+                                       (context->pixbuf,
+                                        0, lower_bound,
+                                        gdk_pixbuf_get_width (context->pixbuf),
+                                        gdk_pixbuf_get_height (context->pixbuf),
+                                        context->user_data);
+                       }
+               }
+       }
 
- fini:
-       ypos = 0;
-/*     while (ReadOK (file, &c, 1) >= 0)
-       ypos++;
-       g_print ("ypos%d\n", ypos);*/
-/*
-       if (LWZReadByte (file, FALSE, c) >= 0)
-               g_print ("GIF: too much input data, ignoring extra...\n");
-*/
+       if ((context->animation || context->frame_done_func || context->anim_done_func)
+           && context->state == GIF_GET_NEXT_STEP) {
+               if (context->frame_done_func)
+                       (* context->frame_done_func) (context->frame,
+                                                     context->user_data);
+               if (context->frame_done_func)
+                       gdk_pixbuf_unref (context->pixbuf);
+               context->pixbuf = NULL;
+               context->frame = NULL;
+       }
+       
+       return v;
 }
 
-/* Shared library entry point */
-GdkPixbuf *
-image_load (FILE *file)
+static void
+gif_set_prepare_lzw (GifContext *context)
 {
-       unsigned char buf[16];
-       unsigned char c;
-       CMap localColorMap;
-       int useGlobalColormap;
-       int bitPixel;
-       int imageCount = 0;
-       char version[4];
-       GifContext *context;
+       context->state = GIF_PREPARE_LZW;
+       context->lzw_code_pending = -1;
+}
+static int
+gif_prepare_lzw (GifContext *context)
+{
+       gint i;
 
-       g_return_val_if_fail (file != NULL, NULL);
+       if (!gif_read (context, &(context->lzw_set_code_size), 1)) {
+               /*g_message (_("GIF: EOF / read error on image data\n"));*/
+               return -1;
+       }
+
+       context->lzw_code_size = context->lzw_set_code_size + 1;
+       context->lzw_clear_code = 1 << context->lzw_set_code_size;
+       context->lzw_end_code = context->lzw_clear_code + 1;
+       context->lzw_max_code_size = 2 * context->lzw_clear_code;
+       context->lzw_max_code = context->lzw_clear_code + 2;
+       context->lzw_fresh = TRUE;
+       context->code_curbit = 0;
+       context->code_lastbit = 0;
+       context->code_last_byte = 0;
+       context->code_done = FALSE;
+
+       for (i = 0; i < context->lzw_clear_code; ++i) {
+               context->lzw_table[0][i] = 0;
+               context->lzw_table[1][i] = i;
+       }
+       for (; i < (1 << MAX_LZW_BITS); ++i)
+               context->lzw_table[0][i] = context->lzw_table[1][0] = 0;
+
+       context->lzw_sp = context->lzw_stack;
+       gif_set_get_lzw (context);
+
+       return 0;
+}
 
-       context = g_new (GifContext, 1);
+/* needs 13 bytes to proceed. */
+static gint
+gif_init (GifContext *context)
+{
+       unsigned char buf[16];
+       char version[4];
 
-       if (!ReadOK (file, buf, 6)) {
-               /* Unable to read magic number */
-               return NULL;
+       if (!gif_read (context, buf, 6)) {
+               /* Unable to read magic number,
+                 * gif_read() should have set error
+                 */
+               return -1;
        }
 
        if (strncmp ((char *) buf, "GIF", 3) != 0) {
                /* Not a GIF file */
-               return NULL;
+                g_set_error (context->error,
+                             GDK_PIXBUF_ERROR,
+                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                             _("File does not appear to be a GIF file"));
+               return -1;
        }
 
        strncpy (version, (char *) buf + 3, 3);
@@ -487,13 +927,18 @@ image_load (FILE *file)
 
        if ((strcmp (version, "87a") != 0) && (strcmp (version, "89a") != 0)) {
                /* bad version number, not '87a' or '89a' */
-               return NULL;
+                g_set_error (context->error,
+                             GDK_PIXBUF_ERROR,
+                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                             _("Version %s of the GIF file format is not supported"),
+                             version);
+               return -1;
        }
 
        /* read the screen descriptor */
-       if (!ReadOK (file, buf, 7)) {
-               /* Failed to read screen descriptor */
-               return NULL;
+       if (!gif_read (context, buf, 7)) {
+               /* Failed to read screen descriptor, error set */
+               return -1;
        }
 
        context->width = LM_to_uint (buf[0], buf[1]);
@@ -502,86 +947,328 @@ image_load (FILE *file)
        context->color_resolution = (((buf[4] & 0x70) >> 3) + 1);
        context->background = buf[5];
        context->aspect_ratio = buf[6];
-       context->pixbuf = NULL;
 
        if (BitSet (buf[4], LOCALCOLORMAP)) {
-               /* Global Colormap */
-               if (ReadColorMap (file, context->bit_pixel,
-                                 context->color_map,
-                                 &context->gray_scale)) {
-                       g_free (context);
-                       return NULL;
-               }
+               gif_set_get_colormap (context);
+       } else {
+               context->state = GIF_GET_NEXT_STEP;
        }
+       return 0;
+}
+
+static void
+gif_set_get_frame_info (GifContext *context)
+{
+       context->state = GIF_GET_FRAME_INFO;
+}
 
-       if (context->aspect_ratio != 0 && context->aspect_ratio != 49) {
-               /*g_message (_("GIF: warning - non-square pixels\n"));*/
+static gint
+gif_get_frame_info (GifContext *context)
+{
+       unsigned char buf[9];
+       if (!gif_read (context, buf, 9)) {
+               return -1;
+       }
+       /* Okay, we got all the info we need.  Lets record it */
+       context->frame_len = LM_to_uint (buf[4], buf[5]);
+       context->frame_height = LM_to_uint (buf[6], buf[7]);
+       context->x_offset = LM_to_uint (buf[0], buf[1]);
+       context->y_offset = LM_to_uint (buf[2], buf[3]);
+
+       if (context->frame_height > context->height) {
+               /* we don't want to resize things.  So we exit */
+               context->state = GIF_DONE;
+
+                g_set_error (context->error,
+                             GDK_PIXBUF_ERROR,
+                             GDK_PIXBUF_ERROR_CORRUPT_IMAGE,
+                             _("GIF animation contained a frame with an incorrect size"));
+                
+               return -2;
        }
 
-       for (;;) {
-               g_print ("in loop\n");
-               if (!ReadOK (file, &c, 1)) {
-                       /*g_message (_("GIF: EOF / read error on image data\n"));*/
-                       return context->pixbuf;
-               }
+       context->frame_interlace = BitSet (buf[8], INTERLACE);
+       if (BitSet (buf[8], LOCALCOLORMAP)) {
+               /* Does this frame have it's own colormap. */
+               /* really only relevant when looking at the first frame
+                * of an animated gif. */
+               /* if it does, we need to re-read in the colormap,
+                * the gray_scale, and the bit_pixel */
+               context->bit_pixel = 1 << ((buf[8] & 0x07) + 1);
+               gif_set_get_colormap2 (context);
+               return 0;
+       }
+       gif_set_prepare_lzw (context);
+       return 0;
+
+}
 
+static gint
+gif_get_next_step (GifContext *context)
+{
+       unsigned char c;
+       while (TRUE) {
+               if (!gif_read (context, &c, 1)) {
+                       return -1;
+               }
                if (c == ';') {
                        /* GIF terminator */
-                       return context->pixbuf;
+                       /* hmm.  Not 100% sure what to do about this.  Should
+                        * i try to return a blank image instead? */
+                       context->state = GIF_DONE;
+                       return 0;
                }
 
                if (c == '!') {
-                       /* Extension */
-                       if (!ReadOK (file, &c, 1)) {
-                               /*g_message (_("GIF: EOF / read error on extension function code\n"));*/
-                               return context->pixbuf; /* will be -1 if failed on first image! */
-                       }
-                       DoExtension (file, context, c);
-                       continue;
+                       /* Check the extention */
+                       gif_set_get_extension (context);
+                       return 0;
                }
 
+               /* look for frame */
                if (c != ',') {
                        /* Not a valid start character */
-                       /*g_message (_("GIF: bogus character 0x%02x, ignoring\n"), (int) c);*/
                        continue;
                }
+               /* load the frame */
+               gif_set_get_frame_info (context);
+               return 0;
+       }
+}
 
-               ++imageCount;
 
-               if (!ReadOK (file, buf, 9)) {
-                       /*g_message (_("GIF: couldn't read left/top/width/height\n"));*/
-                       return context->pixbuf; /* will be -1 if failed on first image! */
-               }
+static gint
+gif_main_loop (GifContext *context)
+{
+       gint retval = 0;
+
+       do {
+               switch (context->state) {
+               case GIF_START:
+                       retval = gif_init (context);
+                       break;
 
-               useGlobalColormap = !BitSet (buf[8], LOCALCOLORMAP);
+               case GIF_GET_COLORMAP:
+                       retval = gif_get_colormap (context);
+                       if (retval == 0)
+                               context->state = GIF_GET_NEXT_STEP;
+                       break;
 
-               bitPixel = 1 << ((buf[8] & 0x07) + 1);
+               case GIF_GET_NEXT_STEP:
+                       retval = gif_get_next_step (context);
+                       break;
 
-               if (!useGlobalColormap) {
-                       if (ReadColorMap (file, bitPixel, localColorMap, &context->gray_scale)) {
-                               /*g_message (_("GIF: error reading local colormap\n"));*/
-                               return context->pixbuf; /* will be -1 if failed on first image! */
-                       }
-                       ReadImage (file, context, LM_to_uint (buf[4], buf[5]),
-                                  LM_to_uint (buf[6], buf[7]),
-                                  localColorMap, bitPixel,
-                                  context->gray_scale,
-                                  BitSet (buf[8], INTERLACE), imageCount,
-                                  (guint) LM_to_uint (buf[0], buf[1]),
-                                  (guint) LM_to_uint (buf[2], buf[3]));
+               case GIF_GET_FRAME_INFO:
+                       retval = gif_get_frame_info (context);
+                       break;
+
+               case GIF_GET_EXTENTION:
+                       retval = gif_get_extension (context);
+                       if (retval == 0)
+                               context->state = GIF_GET_NEXT_STEP;
+                       break;
+
+               case GIF_GET_COLORMAP2:
+                       retval = gif_get_colormap (context);
+                       if (retval == 0)
+                               gif_set_prepare_lzw (context);
+                       break;
+
+               case GIF_PREPARE_LZW:
+                       retval = gif_prepare_lzw (context);
+                       break;
+
+               case GIF_LZW_FILL_BUFFER:
+                       retval = gif_lzw_fill_buffer (context);
+                       break;
+
+               case GIF_LZW_CLEAR_CODE:
+                       retval = gif_lzw_clear_code (context);
+                       break;
+
+               case GIF_GET_LZW:
+                       retval = gif_get_lzw (context);
+                       break;
+
+               case GIF_DONE:
+               default:
+                       retval = 0;
+                       goto done;
+               };
+       } while ((retval == 0) || (retval == -3));
+ done:
+       return retval;
+}
+
+static GifContext *
+new_context (void)
+{
+       GifContext *context;
+
+       context = g_new0 (GifContext, 1);
+
+       context->pixbuf = NULL;
+       context->file = NULL;
+       context->state = GIF_START;
+       context->prepare_func = NULL;
+       context->update_func = NULL;
+       context->frame_done_func = NULL;
+       context->anim_done_func = NULL;
+       context->user_data = NULL;
+       context->buf = NULL;
+       context->amount_needed = 0;
+       context->gif89.transparent = -1;
+       context->gif89.delay_time = -1;
+       context->gif89.input_flag = -1;
+       context->gif89.disposal = -1;
+
+       return context;
+}
+/* Shared library entry point */
+GdkPixbuf *
+gdk_pixbuf__gif_image_load (FILE *file, GError **error)
+{
+       GifContext *context;
+       GdkPixbuf *pixbuf;
+
+       g_return_val_if_fail (file != NULL, NULL);
+
+       context = new_context ();
+       context->file = file;
+        context->error = error;
+        
+       gif_main_loop (context);
+
+       pixbuf = context->pixbuf;
+       g_free (context);
+       return pixbuf;
+}
+
+gpointer
+gdk_pixbuf__gif_image_begin_load (ModulePreparedNotifyFunc prepare_func,
+                                 ModuleUpdatedNotifyFunc update_func,
+                                 ModuleFrameDoneNotifyFunc frame_done_func,
+                                 ModuleAnimationDoneNotifyFunc anim_done_func,
+                                 gpointer user_data,
+                                  GError **error)
+{
+       GifContext *context;
+
+#ifdef IO_GIFDEBUG
+       count = 0;
+#endif
+       context = new_context ();
+        context->error = error;
+       context->prepare_func = prepare_func;
+       context->update_func = update_func;
+       context->frame_done_func = frame_done_func;
+       context->anim_done_func = anim_done_func;
+       context->user_data = user_data;
+
+       return (gpointer) context;
+}
+
+void
+gdk_pixbuf__gif_image_stop_load (gpointer data)
+{
+       GifContext *context = (GifContext *) data;
+
+       /* FIXME: free the animation data */
+
+       if (context->pixbuf)
+               gdk_pixbuf_unref (context->pixbuf);
+       if (context->animation)
+               gdk_pixbuf_animation_unref (context->animation);
+/*     g_free (context->buf);*/
+       g_free (context);
+}
+
+gboolean
+gdk_pixbuf__gif_image_load_increment (gpointer data, guchar *buf, guint size,
+                                      GError **error)
+{
+       gint retval;
+       GifContext *context = (GifContext *) data;
+
+        context->error = error;
+        
+       if (context->amount_needed == 0) {
+               /* we aren't looking for some bytes. */
+               /* we can use buf now, but we don't want to keep it around at all.
+                * it will be gone by the end of the call. */
+               context->buf = buf;
+               context->ptr = 0;
+               context->size = size;
+       } else {
+               /* we need some bytes */
+               if (size < context->amount_needed) {
+                       context->amount_needed -= size;
+                       /* copy it over and return */
+                       memcpy (context->buf + context->size, buf, size);
+                       context->size += size;
+                       return TRUE;
+               } else if (size == context->amount_needed) {
+                       memcpy (context->buf + context->size, buf, size);
+                       context->size += size;
                } else {
-                       ReadImage (file, context, LM_to_uint (buf[4], buf[5]),
-                                  LM_to_uint (buf[6], buf[7]),
-                                  context->color_map, context->bit_pixel,
-                                  context->gray_scale,
-                                  BitSet (buf[8], INTERLACE), imageCount,
-                                  (guint) LM_to_uint (buf[0], buf[1]),
-                                  (guint) LM_to_uint (buf[2], buf[3]));
+                       context->buf = g_realloc (context->buf, context->size + size);
+                       memcpy (context->buf + context->size, buf, size);
+                       context->size += size;
                }
        }
 
-       return context->pixbuf;
+       retval = gif_main_loop (context);
+
+       if (retval == -2)
+               return FALSE;
+       if (retval == -1) {
+               /* we didn't have enough memory */
+               /* prepare for the next image_load_increment */
+               if (context->buf == buf) {
+                       g_assert (context->size == size);
+                       context->buf = (guchar *)g_new (guchar, context->amount_needed + (context->size - context->ptr));
+                       memcpy (context->buf, buf + context->ptr, context->size - context->ptr);
+               } else {
+                       /* copy the left overs to the begining of the buffer */
+                       /* and realloc the memory */
+                       memmove (context->buf, context->buf + context->ptr, context->size - context->ptr);
+                       context->buf = g_realloc (context->buf, context->amount_needed + (context->size - context->ptr));
+               }
+               context->size = context->size - context->ptr;
+               context->ptr = 0;
+       } else {
+               /* we are prolly all done */
+               if (context->buf == buf)
+                       context->buf = NULL;
+       }
+       return TRUE;
 }
 
+GdkPixbufAnimation *
+gdk_pixbuf__gif_image_load_animation (FILE *file,
+                                      GError **error)
+{
+       GifContext *context;
+       GdkPixbufAnimation *animation;
+
+       g_return_val_if_fail (file != NULL, NULL);
 
+       context = new_context ();
 
+        context->error = error;
+        
+       context->animation = g_object_new (GDK_TYPE_PIXBUF_ANIMATION, NULL);
+
+       context->animation->n_frames = 0;
+       context->animation->frames = NULL;
+       context->animation->width = 0;
+       context->animation->height = 0;
+       context->file = file;
+
+       gif_main_loop (context);
+
+       animation = context->animation;
+       g_free (context);
+       return animation;
+}