1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /****************************************************************************
26
27 gif_lib_private.h - internal giflib routines and structures
28
29 ****************************************************************************/
30
31 #ifndef _GIF_LIB_PRIVATE_H
32 #define _GIF_LIB_PRIVATE_H
33
34 #include "gif_lib.h"
35 #include "gif_hash.h"
36
37 #define EXTENSION_INTRODUCER 0x21
38 #define DESCRIPTOR_INTRODUCER 0x2c
39 #define TERMINATOR_INTRODUCER 0x3b
40
41 #define LZ_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
42 #define LZ_BITS 12
43
44 #define FLUSH_OUTPUT 4096 /* Impossible code, to signal flush. */
45 #define FIRST_CODE 4097 /* Impossible code, to signal first. */
46 #define NO_SUCH_CODE 4098 /* Impossible code, to signal empty. */
47
48 #define FILE_STATE_WRITE 0x01
49 #define FILE_STATE_SCREEN 0x02
50 #define FILE_STATE_IMAGE 0x04
51 #define FILE_STATE_READ 0x08
52
53 #define IS_READABLE(Private) (Private->FileState & FILE_STATE_READ)
54 #define IS_WRITEABLE(Private) (Private->FileState & FILE_STATE_WRITE)
55
56 typedef struct GifFilePrivateType {
57 GifWord FileState, FileHandle, /* Where all this data goes to! */
58 BitsPerPixel, /* Bits per pixel (Codes uses at least this + 1). */
59 ClearCode, /* The CLEAR LZ code. */
60 EOFCode, /* The EOF LZ code. */
61 RunningCode, /* The next code algorithm can generate. */
62 RunningBits, /* The number of bits required to represent RunningCode. */
63 MaxCode1, /* 1 bigger than max. possible code, in RunningBits bits. */
64 LastCode, /* The code before the current code. */
65 CrntCode, /* Current algorithm code. */
66 StackPtr, /* For character stack (see below). */
67 CrntShiftState; /* Number of bits in CrntShiftDWord. */
68 unsigned long CrntShiftDWord; /* For bytes decomposition into codes. */
69 unsigned long PixelCount; /* Number of pixels in image. */
70 FILE *File; /* File as stream. */
71 InputFunc Read; /* function to read gif input (TVT) */
72 OutputFunc Write; /* function to write gif output (MRB) */
73 GifByteType Buf[256]; /* Compressed input is buffered here. */
74 GifByteType Stack[LZ_MAX_CODE]; /* Decoded pixels are stacked here. */
75 GifByteType Suffix[LZ_MAX_CODE + 1]; /* So we can trace the codes. */
76 GifPrefixType Prefix[LZ_MAX_CODE + 1];
77 GifHashTableType *HashTable;
78 bool gif89;
79 } GifFilePrivateType;
80
81 #endif /* _GIF_LIB_PRIVATE_H */
82
83 /* end */