1/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2/* ***** BEGIN LICENSE BLOCK *****
3 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 *
5 * The contents of this file are subject to the Mozilla Public License Version
6 * 1.1 (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 * http://www.mozilla.org/MPL/
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 *
15 * The Original Code is Mozilla Communicator client code.
16 *
17 * The Initial Developer of the Original Code is
18 * Netscape Communications Corporation.
19 * Portions created by the Initial Developer are Copyright (C) 1998
20 * the Initial Developer. All Rights Reserved.
21 *
22 * Contributor(s):
23 *
24 * Alternatively, the contents of this file may be used under the terms of
25 * either the GNU General Public License Version 2 or later (the "GPL"), or
26 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
27 * in which case the provisions of the GPL or the LGPL are applicable instead
28 * of those above. If you wish to allow use of your version of this file only
29 * under the terms of either the GPL or the LGPL, and not to allow others to
30 * use your version of this file under the terms of the MPL, indicate your
31 * decision by deleting the provisions above and replace them with the notice
32 * and other provisions required by the GPL or the LGPL. If you do not delete
33 * the provisions above, a recipient may use your version of this file under
34 * the terms of any one of the MPL, the GPL or the LGPL.
35 *
36 * ***** END LICENSE BLOCK ***** */
37
38#ifndef GIFImageReader_h
39#define GIFImageReader_h
40
41// Define ourselves as the clientPtr.  Mozilla just hacked their C++ callback class into this old C decoder,
42// so we will too.
43#include "GIFImageDecoder.h"
44
45#define MAX_LZW_BITS          12
46#define MAX_BITS            4097 /* 2^MAX_LZW_BITS+1 */
47#define MAX_COLORS           256
48#define MAX_HOLD_SIZE        256
49
50const int cLoopCountNotSeen = -2;
51
52/* gif2.h
53   The interface for the GIF87/89a decoder.
54*/
55// List of possible parsing states
56typedef enum {
57    gif_type,
58    gif_global_header,
59    gif_global_colormap,
60    gif_image_start,
61    gif_image_header,
62    gif_image_colormap,
63    gif_image_body,
64    gif_lzw_start,
65    gif_lzw,
66    gif_sub_block,
67    gif_extension,
68    gif_control_extension,
69    gif_consume_block,
70    gif_skip_block,
71    gif_done,
72    gif_oom,
73    gif_error,
74    gif_comment_extension,
75    gif_application_extension,
76    gif_netscape_extension_block,
77    gif_consume_netscape_extension,
78    gif_consume_comment
79} gstate;
80
81struct GIFFrameReader {
82    /* LZW decoder state machine */
83    unsigned char *stackp;              /* Current stack pointer */
84    int datasize;
85    int codesize;
86    int codemask;
87    int clear_code;             /* Codeword used to trigger dictionary reset */
88    int avail;                  /* Index of next available slot in dictionary */
89    int oldcode;
90    unsigned char firstchar;
91    int bits;                   /* Number of unread bits in "datum" */
92    int datum;                /* 32-bit input buffer */
93
94    /* Output state machine */
95    int ipass;                  /* Interlace pass; Ranges 1-4 if interlaced. */
96    unsigned int rows_remaining;        /* Rows remaining to be output */
97    unsigned int irow;                  /* Current output row, starting at zero */
98    unsigned char *rowbuf;              /* Single scanline temporary buffer */
99    unsigned char *rowend;              /* Pointer to end of rowbuf */
100    unsigned char *rowp;                /* Current output pointer */
101
102    /* Parameters for image frame currently being decoded */
103    unsigned int x_offset, y_offset;    /* With respect to "screen" origin */
104    unsigned int height, width;
105    int tpixel;                 /* Index of transparent pixel */
106    WebCore::RGBA32Buffer::FrameDisposalMethod disposal_method;   /* Restore to background, leave in place, etc.*/
107    unsigned char *local_colormap;    /* Per-image colormap */
108    int local_colormap_size;    /* Size of local colormap array. */
109
110    bool is_local_colormap_defined : 1;
111    bool progressive_display : 1;    /* If TRUE, do Haeberli interlace hack */
112    bool interlaced : 1;             /* TRUE, if scanlines arrive interlaced order */
113    bool is_transparent : 1;         /* TRUE, if tpixel is valid */
114
115    unsigned delay_time;        /* Display time, in milliseconds,
116                                   for this image in a multi-image GIF */
117
118
119    unsigned short*  prefix;          /* LZW decoding tables */
120    unsigned char*   suffix;          /* LZW decoding tables */
121    unsigned char*   stack;           /* Base of LZW decoder stack */
122
123
124    GIFFrameReader() {
125        stackp = 0;
126        datasize = codesize = codemask = clear_code = avail = oldcode = 0;
127        firstchar = 0;
128        bits = datum = 0;
129        ipass = 0;
130        rows_remaining = irow = 0;
131        rowbuf = rowend = rowp = 0;
132
133        x_offset = y_offset = width = height = 0;
134        tpixel = 0;
135        disposal_method = WebCore::RGBA32Buffer::DisposeNotSpecified;
136
137        local_colormap = 0;
138        local_colormap_size = 0;
139        is_local_colormap_defined = progressive_display = is_transparent = interlaced = false;
140
141        delay_time = 0;
142
143        prefix = 0;
144        suffix = stack = 0;
145    }
146
147    ~GIFFrameReader() {
148        delete []rowbuf;
149        delete []local_colormap;
150        delete []prefix;
151        delete []suffix;
152        delete []stack;
153    }
154};
155
156struct GIFImageReader {
157    WebCore::GIFImageDecoder* clientptr;
158    /* Parsing state machine */
159    gstate state;                      /* Current decoder master state */
160    unsigned bytes_to_consume;         /* Number of bytes to accumulate */
161    unsigned bytes_in_hold;            /* bytes accumulated so far*/
162    unsigned char hold[MAX_HOLD_SIZE]; /* Accumulation buffer */
163    unsigned char* global_colormap;    /* (3* MAX_COLORS in size) Default colormap if local not supplied, 3 bytes for each color  */
164
165     /* Global (multi-image) state */
166    int screen_bgcolor;         /* Logical screen background color */
167    int version;                /* Either 89 for GIF89 or 87 for GIF87 */
168    unsigned screen_width;       /* Logical screen width & height */
169    unsigned screen_height;
170    int global_colormap_size;   /* Size of global colormap array. */
171    unsigned images_decoded;    /* Counts completed frames for animated GIFs */
172    int images_count;           /* Counted all frames seen so far (including incomplete frames) */
173    int loop_count;             /* Netscape specific extension block to control
174                                   the number of animation loops a GIF renders. */
175
176    // Not really global, but convenient to locate here.
177    int count;                  /* Remaining # bytes in sub-block */
178
179    GIFFrameReader* frame_reader;
180
181    GIFImageReader(WebCore::GIFImageDecoder* client = 0) {
182        clientptr = client;
183        state = gif_type;
184        bytes_to_consume = 6;
185        bytes_in_hold = 0;
186        frame_reader = 0;
187        global_colormap = 0;
188
189        screen_bgcolor = version = 0;
190        screen_width = screen_height = 0;
191        global_colormap_size = images_decoded = images_count = 0;
192        loop_count = cLoopCountNotSeen;
193        count = 0;
194    }
195
196    ~GIFImageReader() {
197        close();
198    }
199
200    void close() {
201        delete []global_colormap;
202        global_colormap = 0;
203        delete frame_reader;
204        frame_reader = 0;
205    }
206
207    bool read(const unsigned char * buf, unsigned int numbytes,
208              WebCore::GIFImageDecoder::GIFQuery query = WebCore::GIFImageDecoder::GIFFullQuery, unsigned haltAtFrame = -1);
209
210private:
211    bool output_row();
212    bool do_lzw(const unsigned char *q);
213};
214
215#endif
216