gecko-dev/modules/libpr0n/decoders/GIF2.h

139 lines
5.6 KiB
C

/* -*- 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 MAX_LZW_BITS 12
#define MAX_BITS 4097 /* 2^MAX_LZW_BITS+1 */
#define MAX_COLORS 256
#define MAX_HOLD_SIZE 256
enum { GIF_TRAILER = 0x3B }; //';'
enum { GIF_IMAGE_SEPARATOR = 0x2C }; //','
enum { GIF_EXTENSION_INTRODUCER = 0x21 }; //'!'
enum { GIF_GRAPHIC_CONTROL_LABEL = 0xF9 };
enum { GIF_COMMENT_LABEL = 0xFE };
enum { GIF_PLAIN_TEXT_LABEL = 0x01 };
enum { GIF_APPLICATION_EXTENSION_LABEL = 0xFF };
/* 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_error,
gif_comment_extension,
gif_application_extension,
gif_netscape_extension_block,
gif_consume_netscape_extension,
gif_consume_comment
} gstate;
/* A GIF decoder's state */
typedef struct gif_struct {
/* Parsing state machine */
gstate state; /* Curent decoder master state */
PRUint32 bytes_to_consume; /* Number of bytes to accumulate */
PRUint32 bytes_in_hold; /* bytes accumulated so far*/
/* LZW decoder state machine */
PRUint8 *stackp; /* Current stack pointer */
int datasize;
int codesize;
int codemask;
int avail; /* Index of next available slot in dictionary */
int oldcode;
PRUint8 firstchar;
int count; /* Remaining # bytes in sub-block */
int bits; /* Number of unread bits in "datum" */
int32 datum; /* 32-bit input buffer */
/* Output state machine */
int ipass; /* Interlace pass; Ranges 1-4 if interlaced. */
PRUintn rows_remaining; /* Rows remaining to be output */
PRUintn irow; /* Current output row, starting at zero */
PRUint8 *rowp; /* Current output pointer */
/* Parameters for image frame currently being decoded*/
PRUintn x_offset, y_offset; /* With respect to "screen" origin */
PRUintn height, width;
int tpixel; /* Index of transparent pixel */
PRInt32 disposal_method; /* Restore to background, leave in place, etc.*/
PRUint32 *local_colormap; /* Per-image colormap */
int local_colormap_size; /* Size of local colormap array. */
PRUint32 delay_time; /* Display time, in milliseconds,
for this image in a multi-image GIF */
/* Global (multi-image) state */
int version; /* Either 89 for GIF89 or 87 for GIF87 */
PRUintn screen_width; /* Logical screen width & height */
PRUintn screen_height;
PRUint32 global_colormap_depth; /* Depth of global colormap array. */
int images_decoded; /* Counts images for multi-part GIFs */
int loop_count; /* Netscape specific extension block to control
the number of animation loops a GIF renders. */
PRPackedBool progressive_display; /* If TRUE, do Haeberli interlace hack */
PRPackedBool interlaced; /* TRUE, if scanlines arrive interlaced order */
PRPackedBool is_transparent; /* TRUE, if tpixel is valid */
PRUint16 prefix[MAX_BITS]; /* LZW decoding tables */
PRUint8 hold[MAX_HOLD_SIZE]; /* Accumulation buffer */
PRUint32 global_colormap[MAX_COLORS]; /* Default colormap if local not supplied */
PRUint8 suffix[MAX_BITS]; /* LZW decoding tables */
PRUint8 stack[MAX_BITS]; /* Base of LZW decoder stack */
} gif_struct;
#endif