/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is Mozilla Communicator client code. * * The Initial Developer of the Original Code is * Netscape Communications Corporation. * Portions created by the Initial Developer are Copyright (C) 1998 * the Initial Developer. All Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the terms of * either the GNU General Public License Version 2 or later (the "GPL"), or * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ #ifndef _GIF_H_ #define _GIF_H_ // Define ourselves as the clientPtr. Mozilla just hacked their C++ callback class into this old C decoder, // so we will too. #include "GIFImageDecoder.h" #define MAX_LZW_BITS 12 #define MAX_BITS 4097 /* 2^MAX_LZW_BITS+1 */ #define MAX_COLORS 256 #define MAX_HOLD_SIZE 256 /* gif2.h The interface for the GIF87/89a decoder. */ // List of possible parsing states typedef enum { gif_type, gif_global_header, gif_global_colormap, gif_image_start, gif_image_header, gif_image_colormap, gif_image_body, gif_lzw_start, gif_lzw, gif_sub_block, gif_extension, gif_control_extension, gif_consume_block, gif_skip_block, gif_done, gif_oom, gif_error, gif_comment_extension, gif_application_extension, gif_netscape_extension_block, gif_consume_netscape_extension, gif_consume_comment } gstate; /* "Disposal" method indicates how the image should be handled in the framebuffer before the subsequent image is displayed. */ typedef enum { DISPOSE_NOT_SPECIFIED = 0, DISPOSE_KEEP = 1, /* Leave it in the framebuffer */ DISPOSE_OVERWRITE_BGCOLOR = 2, /* Overwrite with background color */ DISPOSE_OVERWRITE_PREVIOUS = 3 /* Save-under */ } gdispose; struct GIFFrameReader { /* LZW decoder state machine */ unsigned char *stackp; /* Current stack pointer */ int datasize; int codesize; int codemask; int clear_code; /* Codeword used to trigger dictionary reset */ int avail; /* Index of next available slot in dictionary */ int oldcode; unsigned char firstchar; int bits; /* Number of unread bits in "datum" */ int datum; /* 32-bit input buffer */ /* Output state machine */ int ipass; /* Interlace pass; Ranges 1-4 if interlaced. */ unsigned int rows_remaining; /* Rows remaining to be output */ unsigned int irow; /* Current output row, starting at zero */ unsigned char *rowbuf; /* Single scanline temporary buffer */ unsigned char *rowend; /* Pointer to end of rowbuf */ unsigned char *rowp; /* Current output pointer */ /* Parameters for image frame currently being decoded */ unsigned int x_offset, y_offset; /* With respect to "screen" origin */ unsigned int height, width; int tpixel; /* Index of transparent pixel */ gdispose disposal_method; /* Restore to background, leave in place, etc.*/ unsigned char *local_colormap; /* Per-image colormap */ int local_colormap_size; /* Size of local colormap array. */ bool is_local_colormap_defined : 1; bool progressive_display : 1; /* If TRUE, do Haeberli interlace hack */ bool interlaced : 1; /* TRUE, if scanlines arrive interlaced order */ bool is_transparent : 1; /* TRUE, if tpixel is valid */ unsigned delay_time; /* Display time, in milliseconds, for this image in a multi-image GIF */ unsigned short* prefix; /* LZW decoding tables */ unsigned char* suffix; /* LZW decoding tables */ unsigned char* stack; /* Base of LZW decoder stack */ GIFFrameReader() { stackp = 0; datasize = codesize = codemask = clear_code = avail = oldcode = 0; firstchar = 0; bits = datum = 0; ipass = 0; rows_remaining = irow = 0; rowbuf = rowend = rowp = 0; x_offset = y_offset = width = height = 0; tpixel = 0; disposal_method = DISPOSE_NOT_SPECIFIED; local_colormap = 0; local_colormap_size = 0; is_local_colormap_defined = progressive_display = is_transparent = interlaced = false; delay_time = 0; prefix = 0; suffix = stack = 0; } ~GIFFrameReader() { delete []rowbuf; delete []local_colormap; delete []prefix; delete []suffix; delete []stack; } }; struct GIFImageReader { WebCore::GIFImageDecoder* clientptr; /* Parsing state machine */ gstate state; /* Current decoder master state */ unsigned bytes_to_consume; /* Number of bytes to accumulate */ unsigned bytes_in_hold; /* bytes accumulated so far*/ unsigned char hold[MAX_HOLD_SIZE]; /* Accumulation buffer */ unsigned char* global_colormap; /* (3* MAX_COLORS in size) Default colormap if local not supplied, 3 bytes for each color */ /* Global (multi-image) state */ int screen_bgcolor; /* Logical screen background color */ int version; /* Either 89 for GIF89 or 87 for GIF87 */ unsigned screen_width; /* Logical screen width & height */ unsigned screen_height; int global_colormap_size; /* Size of global colormap array. */ int images_decoded; /* Counts completed frames for animated GIFs */ int images_count; /* Counted all frames seen so far (including incomplete frames) */ int loop_count; /* Netscape specific extension block to control the number of animation loops a GIF renders. */ // Not really global, but convenient to locate here. int count; /* Remaining # bytes in sub-block */ GIFFrameReader* frame_reader; GIFImageReader(WebCore::GIFImageDecoder* client = 0) { clientptr = client; state = gif_type; bytes_to_consume = 6; bytes_in_hold = 0; frame_reader = 0; global_colormap = 0; screen_bgcolor = version = 0; screen_width = screen_height = 0; global_colormap_size = images_decoded = images_count = 0; loop_count = -1; count = 0; } ~GIFImageReader() { close(); } void close() { delete []global_colormap; global_colormap = 0; delete frame_reader; frame_reader = 0; } bool read(const unsigned char * buf, unsigned int numbytes, WebCore::GIFImageDecoder::GIFQuery query = WebCore::GIFImageDecoder::GIFFullQuery, unsigned haltAtFrame = -1); private: void output_row(); int do_lzw(const unsigned char *q); }; #endif