/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 8 -*- */ /* GdkPixbuf library - GIF image loader * * Copyright (C) 1999 Mark Crichton * Copyright (C) 1999 The Free Software Foundation * * Authors: Jonathan Blandford * Adapted from the gimp gif filter written by Adam Moss * 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 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 * Lesser General Public License for more details. * * 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. * * 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. * */ #include #include #include #include #include "gdk-pixbuf-private.h" #include "gdk-pixbuf-io.h" #include "io-gif-animation.h" #undef DUMP_IMAGE_DETAILS #define MAXCOLORMAPSIZE 256 #define MAX_LZW_BITS 12 #define INTERLACE 0x40 #define LOCALCOLORMAP 0x80 #define BitSet(byte, bit) (((byte) & (bit)) == (bit)) #define LM_to_uint(a,b) (((b)<<8)|(a)) 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 { int transparent; int delay_time; int input_flag; int disposal; }; typedef struct _GifContext GifContext; struct _GifContext { int state; /* really only relevant for progressive loading */ unsigned int width; unsigned int height; gboolean has_global_cmap; CMap global_color_map; gint global_colormap_size; unsigned int global_bit_pixel; unsigned int global_color_resolution; unsigned int background_index; gboolean frame_cmap_active; CMap frame_color_map; gint frame_colormap_size; unsigned int frame_bit_pixel; unsigned int aspect_ratio; GdkPixbuf *pixbuf; GdkPixbufGifAnim *animation; GdkPixbufFrame *frame; Gif89 gif89; /* stuff per frame. */ 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; gpointer user_data; guchar *buf; guint ptr; guint size; guint amount_needed; /* 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 *); #ifdef IO_GIFDEBUG static int count = 0; #endif /* Returns TRUE if read is OK, * FALSE if more memory is needed. */ static int gif_read (GifContext *context, guchar *buffer, size_t len) { 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); if (!retval && ferror (context->file)) g_set_error (context->error, G_FILE_ERROR, g_file_error_from_errno (errno), _("Failure reading GIF: %s"), strerror (errno)); #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; } /* Changes the stage to be GIF_GET_COLORMAP */ static void gif_set_get_colormap (GifContext *context) { context->global_colormap_size = 0; context->state = GIF_GET_COLORMAP; } static void gif_set_get_colormap2 (GifContext *context) { context->frame_colormap_size = 0; context->state = GIF_GET_COLORMAP2; } static gint gif_get_colormap (GifContext *context) { unsigned char rgb[3]; while (context->global_colormap_size < context->global_bit_pixel) { if (!gif_read (context, rgb, sizeof (rgb))) { return -1; } context->global_color_map[0][context->global_colormap_size] = rgb[0]; context->global_color_map[1][context->global_colormap_size] = rgb[1]; context->global_color_map[2][context->global_colormap_size] = rgb[2]; if (context->global_colormap_size == context->background_index) { context->animation->bg_red = rgb[0]; context->animation->bg_green = rgb[1]; context->animation->bg_blue = rgb[2]; } context->global_colormap_size ++; } return 0; } static gint gif_get_colormap2 (GifContext *context) { unsigned char rgb[3]; while (context->frame_colormap_size < context->frame_bit_pixel) { if (!gif_read (context, rgb, sizeof (rgb))) { return -1; } context->frame_color_map[0][context->frame_colormap_size] = rgb[0]; context->frame_color_map[1][context->frame_colormap_size] = rgb[1]; context->frame_color_map[2][context->frame_colormap_size] = rgb[2]; context->frame_colormap_size ++; } 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 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; } } if (context->block_count == 0) if (empty_block) { *empty_block = TRUE; return 0; } if (!gif_read (context, buf, context->block_count)) { return -1; } return 0; } 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 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->frame == NULL) { /* I only want to set the transparency if I haven't * created the frame 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; */ if (!gif_read (context, &context->block_count, 1)) { /*g_message (_("GIF: error in getting DataBlock size\n"));*/ return -1; } ZeroDataBlock = context->block_count == 0; if ((context->block_count != 0) && (!gif_read (context, buf, context->block_count))) { /*g_message (_("GIF: error in reading DataBlock\n"));*/ return -1; } 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 gif_lzw_fill_buffer (GifContext *context) { gint retval; 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?)")); return -2; } /* 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 (context->block_count == 0) context->code_done = TRUE; 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 = context->code_curbit, j = 0; j < code_size; ++i, ++j) ret |= ((context->block_buf[i / 8] & (1 << (i % 8))) != 0) << j; context->code_curbit += code_size; return ret; } static void set_gif_lzw_clear_code (GifContext *context) { context->state = GIF_LZW_CLEAR_CODE; context->lzw_code_pending = -1; } static int gif_lzw_clear_code (GifContext *context) { gint code; code = get_code (context, context->lzw_code_size); if (code == -3) return -0; context->lzw_firstcode = context->lzw_oldcode = code; context->lzw_code_pending = code; context->state = GIF_GET_LZW; return 0; } static int lzw_read_byte (GifContext *context) { int code, incode; gint retval; gint my_retval; register int i; if (context->lzw_code_pending != -1) { retval = context->lzw_code_pending; context->lzw_code_pending = -1; return retval; } if (context->lzw_fresh) { context->lzw_fresh = FALSE; do { 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 (context->lzw_sp > context->lzw_stack) { my_retval = *--(context->lzw_sp); return my_retval; } 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_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]; /*g_error (" DID WE EVER EVER GET HERE\n");*/ g_warning ("Unhandled Case. If you have an image that causes this, let me know.\n"); if (ZeroDataBlock) { return -2; } while ((count = GetDataBlock (context, buf)) > 0) ; if (count != 0) { /*g_print (_("GIF: missing EOD in data stream (common occurence)"));*/ return -2; } } incode = code; if (code >= context->lzw_max_code) { *(context->lzw_sp)++ = context->lzw_firstcode; code = context->lzw_oldcode; } 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 = context->lzw_table[0][code]; } *(context->lzw_sp)++ = context->lzw_firstcode = context->lzw_table[1][code]; 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; } } context->lzw_oldcode = incode; if (context->lzw_sp > context->lzw_stack) { my_retval = *--(context->lzw_sp); return my_retval; } } return code; } static void gif_set_get_lzw (GifContext *context) { context->state = GIF_GET_LZW; context->draw_xpos = 0; context->draw_ypos = 0; context->draw_pass = 0; } static void gif_fill_in_pixels (GifContext *context, guchar *dest, gint offset, guchar v) { guchar *pixel = NULL; guchar (*cmap)[MAXCOLORMAPSIZE]; if (context->frame_cmap_active) cmap = context->frame_color_map; else cmap = context->global_color_map; if (context->gif89.transparent != -1) { pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 4; *pixel = cmap [0][(guchar) v]; *(pixel+1) = cmap [1][(guchar) v]; *(pixel+2) = cmap [2][(guchar) v]; *(pixel+3) = (guchar) ((v == context->gif89.transparent) ? 0 : 255); } else { pixel = dest + (context->draw_ypos + offset) * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_xpos * 3; *pixel = cmap [0][(guchar) v]; *(pixel+1) = cmap [1][(guchar) v]; *(pixel+2) = cmap [2][(guchar) v]; } } /* 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; } } 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->frame == NULL) { context->frame = g_new (GdkPixbufFrame, 1); context->frame->composited = NULL; context->frame->revert = NULL; context->frame->pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, TRUE, 8, context->frame_len, context->frame_height); context->frame->x_offset = context->x_offset; context->frame->y_offset = context->y_offset; context->frame->need_recomposite = TRUE; /* GIF delay is in hundredths, we want thousandths */ context->frame->delay_time = context->gif89.delay_time * 10; context->frame->elapsed = context->animation->total_time; context->animation->total_time += context->frame->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->bg_transparent = (context->gif89.transparent == context->background_index); { /* Update animation size */ int w, h; context->animation->n_frames ++; context->animation->frames = g_list_append (context->animation->frames, context->frame); w = context->frame->x_offset + gdk_pixbuf_get_width (context->frame->pixbuf); h = context->frame->y_offset + gdk_pixbuf_get_height (context->frame->pixbuf); if (w > context->animation->width) context->animation->width = w; if (h > context->animation->height) context->animation->height = h; } /* Only call prepare_func for the first frame */ if (context->animation->frames->next == NULL) { if (context->prepare_func) (* context->prepare_func) (context->frame->pixbuf, GDK_PIXBUF_ANIMATION (context->animation), context->user_data); } else { /* Otherwise init frame with last frame */ GList *link; GdkPixbufFrame *prev_frame; link = g_list_find (context->animation->frames, context->frame); prev_frame = link->prev->data; gdk_pixbuf_gif_anim_frame_composite (context->animation, prev_frame); gdk_pixbuf_copy_area (prev_frame->composited, context->frame->x_offset, context->frame->y_offset, gdk_pixbuf_get_width (context->frame->pixbuf), gdk_pixbuf_get_height (context->frame->pixbuf), context->frame->pixbuf, 0, 0); } } dest = gdk_pixbuf_get_pixels (context->frame->pixbuf); bound_flag = FALSE; lower_bound = upper_bound = context->draw_ypos; first_pass = context->draw_pass; while (TRUE) { guchar (*cmap)[MAXCOLORMAPSIZE]; if (context->frame_cmap_active) cmap = context->frame_color_map; else cmap = context->global_color_map; v = lzw_read_byte (context); if (v < 0) { goto finished_data; } bound_flag = TRUE; g_assert (gdk_pixbuf_get_has_alpha (context->frame->pixbuf)); temp = dest + context->draw_ypos * gdk_pixbuf_get_rowstride (context->frame->pixbuf) + context->draw_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 : 255); 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: context->draw_ypos += 8; break; case 2: context->draw_ypos += 4; break; case 3: context->draw_ypos += 2; break; } if (context->draw_ypos >= context->frame_height) { context->draw_pass++; switch (context->draw_pass) { case 1: context->draw_ypos = 4; break; case 2: context->draw_ypos = 2; break; case 3: context->draw_ypos = 1; break; default: goto done; } } } else { 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 (context->draw_ypos >= context->frame_height) break; } done: context->state = GIF_GET_NEXT_STEP; v = 0; finished_data: if (bound_flag) context->frame->need_recomposite = TRUE; if (bound_flag && context->update_func) { if (lower_bound <= upper_bound && first_pass == context->draw_pass) { (* context->update_func) (context->frame->pixbuf, 0, lower_bound, gdk_pixbuf_get_width (context->frame->pixbuf), upper_bound - lower_bound, context->user_data); } else { if (lower_bound <= upper_bound) { (* context->update_func) (context->frame->pixbuf, context->frame->x_offset, context->frame->y_offset, gdk_pixbuf_get_width (context->frame->pixbuf), gdk_pixbuf_get_height (context->frame->pixbuf), context->user_data); } else { (* context->update_func) (context->frame->pixbuf, context->frame->x_offset, context->frame->y_offset, gdk_pixbuf_get_width (context->frame->pixbuf), upper_bound, context->user_data); (* context->update_func) (context->frame->pixbuf, context->frame->x_offset, lower_bound + context->frame->y_offset, gdk_pixbuf_get_width (context->frame->pixbuf), gdk_pixbuf_get_height (context->frame->pixbuf), context->user_data); } } } if (context->state == GIF_GET_NEXT_STEP) { /* Will be freed with context->animation, we are just * marking that we're done with it (no current frame) */ context->frame = NULL; context->frame_cmap_active = FALSE; } return v; } static void gif_set_prepare_lzw (GifContext *context) { context->state = GIF_PREPARE_LZW; context->lzw_code_pending = -1; } static int gif_prepare_lzw (GifContext *context) { gint i; 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; } /* needs 13 bytes to proceed. */ static gint gif_init (GifContext *context) { unsigned char buf[16]; char version[4]; 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 */ 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); version[3] = '\0'; if ((strcmp (version, "87a") != 0) && (strcmp (version, "89a") != 0)) { /* bad version number, not '87a' or '89a' */ 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 (!gif_read (context, buf, 7)) { /* Failed to read screen descriptor, error set */ return -1; } context->width = LM_to_uint (buf[0], buf[1]); context->height = LM_to_uint (buf[2], buf[3]); /* The 4th byte is * high bit: whether to use the background index * next 3: color resolution * next: whether colormap is sorted by priority of allocation * last 3: size of colormap */ context->global_bit_pixel = 2 << (buf[4] & 0x07); context->global_color_resolution = (((buf[4] & 0x70) >> 3) + 1); context->has_global_cmap = (buf[4] & 0x80) != 0; context->background_index = buf[5]; context->aspect_ratio = buf[6]; /* Use background of transparent black as default, though if * one isn't set explicitly no one should ever use it. */ context->animation->bg_red = 0; context->animation->bg_green = 0; context->animation->bg_blue = 0; if (context->has_global_cmap) { gif_set_get_colormap (context); } else { context->state = GIF_GET_NEXT_STEP; } #ifdef DUMP_IMAGE_DETAILS g_print (">Image width: %d height: %d global_cmap: %d background: %d\n", context->width, context->height, context->has_global_cmap, context->background_index); #endif return 0; } static void gif_set_get_frame_info (GifContext *context) { context->state = GIF_GET_FRAME_INFO; } 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->y_offset) > context->height) || ((context->frame_len + context->x_offset) > context->width)) { /* All frames must fit in the image bounds */ context->state = GIF_DONE; g_set_error (context->error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, _("GIF image contained a frame appearing outside the image bounds.")); return -2; } if (context->animation->frames == NULL && context->gif89.disposal == 3) { /* First frame can't have "revert to previous" as its * dispose mode. */ context->state = GIF_DONE; g_set_error (context->error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, _("First frame of GIF image had 'revert to previous' as its disposal mode.")); return -2; } #ifdef DUMP_IMAGE_DETAILS g_print (">width: %d height: %d xoffset: %d yoffset: %d disposal: %d delay: %d transparent: %d\n", context->frame_len, context->frame_height, context->x_offset, context->y_offset, context->gif89.disposal, context->gif89.delay_time, context->gif89.transparent); #endif context->frame_interlace = BitSet (buf[8], INTERLACE); if (BitSet (buf[8], LOCALCOLORMAP)) { #ifdef DUMP_IMAGE_DETAILS g_print (">has local colormap\n"); #endif /* 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->frame_cmap_active = TRUE; context->frame_bit_pixel = 1 << ((buf[8] & 0x07) + 1); gif_set_get_colormap2 (context); return 0; } if (!context->has_global_cmap) { context->state = GIF_DONE; g_set_error (context->error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, _("GIF image has no global colormap, and a frame inside it has no local colormap.")); return -2; } 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 */ /* 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 == '!') { /* Check the extention */ gif_set_get_extension (context); return 0; } /* look for frame */ if (c != ',') { /* Not a valid start character */ continue; } /* load the frame */ gif_set_get_frame_info (context); return 0; } } #define LOG(x) static gint gif_main_loop (GifContext *context) { gint retval = 0; do { switch (context->state) { case GIF_START: LOG("start\n"); retval = gif_init (context); break; case GIF_GET_COLORMAP: LOG("get_colormap\n"); retval = gif_get_colormap (context); if (retval == 0) context->state = GIF_GET_NEXT_STEP; break; case GIF_GET_NEXT_STEP: LOG("next_step\n"); retval = gif_get_next_step (context); break; case GIF_GET_FRAME_INFO: LOG("frame_info\n"); retval = gif_get_frame_info (context); break; case GIF_GET_EXTENTION: LOG("get_extension\n"); retval = gif_get_extension (context); if (retval == 0) context->state = GIF_GET_NEXT_STEP; break; case GIF_GET_COLORMAP2: LOG("get_colormap2\n"); retval = gif_get_colormap2 (context); if (retval == 0) gif_set_prepare_lzw (context); break; case GIF_PREPARE_LZW: LOG("prepare_lzw\n"); retval = gif_prepare_lzw (context); break; case GIF_LZW_FILL_BUFFER: LOG("fill_buffer\n"); retval = gif_lzw_fill_buffer (context); break; case GIF_LZW_CLEAR_CODE: LOG("clear_code\n"); retval = gif_lzw_clear_code (context); break; case GIF_GET_LZW: LOG("get_lzw\n"); retval = gif_get_lzw (context); break; case GIF_DONE: LOG("done\n"); 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->animation = g_object_new (GDK_TYPE_PIXBUF_GIF_ANIM, NULL); context->frame = NULL; context->file = NULL; context->state = GIF_START; context->prepare_func = NULL; context->update_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 */ static 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; if (gif_main_loop (context) == -1 || context->animation->frames == NULL) { if (context->error && *(context->error) == NULL) g_set_error (context->error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, _("GIF file was missing some data (perhaps it was truncated somehow?)")); } pixbuf = gdk_pixbuf_animation_get_static_image (GDK_PIXBUF_ANIMATION (context->animation)); if (pixbuf) g_object_ref (G_OBJECT (pixbuf)); g_object_unref (G_OBJECT (context->animation)); g_free (context->buf); g_free (context); return pixbuf; } static gpointer gdk_pixbuf__gif_image_begin_load (ModulePreparedNotifyFunc prepare_func, ModuleUpdatedNotifyFunc update_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->user_data = user_data; return (gpointer) context; } static gboolean gdk_pixbuf__gif_image_stop_load (gpointer data, GError **error) { GifContext *context = (GifContext *) data; gboolean retval = TRUE; if (context->state != GIF_DONE) { g_set_error (error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, _("GIF image was truncated or incomplete.")); retval = FALSE; } g_object_unref (G_OBJECT (context->animation)); g_free (context->buf); g_free (context); return retval; } static gboolean gdk_pixbuf__gif_image_load_increment (gpointer data, const 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 = (guchar*) buf; /* very dubious const cast */ 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 { context->buf = g_realloc (context->buf, context->size + size); memcpy (context->buf + context->size, buf, size); context->size += size; } } 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; } static 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->file = file; if (gif_main_loop (context) == -1 || context->animation->frames == NULL) { if (context->error && *(context->error) == NULL) g_set_error (context->error, GDK_PIXBUF_ERROR, GDK_PIXBUF_ERROR_CORRUPT_IMAGE, _("GIF file was missing some data (perhaps it was truncated somehow?)")); g_object_unref (G_OBJECT (context->animation)); context->animation = NULL; } if (context->animation) animation = GDK_PIXBUF_ANIMATION (context->animation); else animation = NULL; if (context->error && *(context->error)) g_print ("%s\n", (*(context->error))->message); g_free (context->buf); g_free (context); return animation; } void gdk_pixbuf__gif_fill_vtable (GdkPixbufModule *module) { module->load = gdk_pixbuf__gif_image_load; module->begin_load = gdk_pixbuf__gif_image_begin_load; module->stop_load = gdk_pixbuf__gif_image_stop_load; module->load_increment = gdk_pixbuf__gif_image_load_increment; module->load_animation = gdk_pixbuf__gif_image_load_animation; }