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comparison src/gifrlib.h @ 428:3ecd8885ac67 r21-2-22

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date Mon, 13 Aug 2007 11:28:15 +0200
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1 /******************************************************************************
2 * In order to make life a little bit easier when using the GIF file format, *
3 * this library was written, and which does all the dirty work... *
4 * *
5 * Written by Gershon Elber, Jun. 1989 *
6 * Hacks by Eric S. Raymond, Sep. 1992 *
7 * and Jareth Hein, Jan. 1998 *
8 *******************************************************************************
9 * History: *
10 * 14 Jun 89 - Version 1.0 by Gershon Elber. *
11 * 3 Sep 90 - Version 1.1 by Gershon Elber (Support for Gif89, Unique names). *
12 * 15 Sep 90 - Version 2.0 by Eric S. Raymond (Changes to suoport GIF slurp) *
13 * 26 Jun 96 - Version 3.0 by Eric S. Raymond (Full GIF89 support) *
14 * 19 Jan 98 - Version 3.1 by Jareth Hein (Support for user-defined I/O). *
15 ******************************************************************************/
16
17 #ifndef GIF_LIB_H
18 #define GIF_LIB_H
19
20 #define GIF_ERROR 0
21 #define GIF_OK 1
22
23 #ifndef TRUE
24 #define TRUE 1
25 #define FALSE 0
26 #endif
27
28 #ifndef NULL
29 #define NULL 0
30 #endif /* NULL */
31
32 #define GIF_FILE_BUFFER_SIZE 16384 /* Files uses bigger buffers than usual. */
33
34 typedef int GifBooleanType;
35 typedef unsigned char GifPixelType;
36 typedef unsigned char * GifRowType;
37 typedef unsigned char GifByteType;
38
39 #define VoidPtr void *
40
41 typedef struct GifColorType {
42 GifByteType Red, Green, Blue;
43 } GifColorType;
44
45 typedef struct ColorMapObject
46 {
47 int ColorCount;
48 int BitsPerPixel;
49 GifColorType *Colors; /* on malloc(3) heap */
50 }
51 ColorMapObject;
52
53 typedef struct GifImageDesc {
54 int Left, Top, Width, Height, /* Current image dimensions. */
55 Interlace; /* Sequential/Interlaced lines. */
56 ColorMapObject *ColorMap; /* The local color map */
57 } GifImageDesc;
58
59 /* I/O operations. If you roll your own, they need to be semantically equivilent to
60 fread/fwrite, with an additional paramater to hold data local to your method. */
61 typedef size_t (*Gif_rw_func)(GifByteType *buffer, size_t size, VoidPtr method_data);
62 /* Finish up stream. Non-zero return indicates failure */
63 typedef int (*Gif_close_func)(VoidPtr close_data);
64 /* Error handling function */
65 typedef void (*Gif_error_func)(const char *string, VoidPtr error_data);
66
67 typedef struct GifFileType {
68 int SWidth, SHeight, /* Screen dimensions. */
69 SColorResolution, /* How many colors can we generate? */
70 SBackGroundColor; /* I hope you understand this one... */
71 ColorMapObject *SColorMap; /* NULL if it doesn't exist. */
72 int ImageCount; /* Number of current image */
73 GifImageDesc Image; /* Block describing current image */
74 struct SavedImage *SavedImages; /* Use this to accumulate file state */
75 VoidPtr Private; /* Don't mess with this! */
76 VoidPtr GifIO; /* Contains all information for I/O */
77 } GifFileType;
78
79 typedef enum {
80 UNDEFINED_RECORD_TYPE,
81 SCREEN_DESC_RECORD_TYPE,
82 IMAGE_DESC_RECORD_TYPE, /* Begin with ',' */
83 EXTENSION_RECORD_TYPE, /* Begin with '!' */
84 TERMINATE_RECORD_TYPE /* Begin with ';' */
85 } GifRecordType;
86
87 /******************************************************************************
88 * GIF89 extension function codes *
89 ******************************************************************************/
90
91 #define COMMENT_EXT_FUNC_CODE 0xfe /* comment */
92 #define GRAPHICS_EXT_FUNC_CODE 0xf9 /* graphics control */
93 #define PLAINTEXT_EXT_FUNC_CODE 0x01 /* plaintext */
94 #define APPLICATION_EXT_FUNC_CODE 0xff /* application block */
95
96 /******************************************************************************
97 * IO related routines. Defined in gif_io.c *
98 ******************************************************************************/
99 GifFileType *GifSetup(void);
100 void GifFree(GifFileType *GifFile);
101 void GifSetReadFunc (GifFileType *GifFile, Gif_rw_func func, VoidPtr data);
102 void GifSetWriteFunc(GifFileType *GifFile, Gif_rw_func func, VoidPtr data);
103 void GifSetCloseFunc(GifFileType *GifFile, Gif_close_func func, VoidPtr data);
104
105 /******************************************************************************
106 * O.K., here are the routines one can access in order to decode GIF file: *
107 ******************************************************************************/
108
109 void DGifOpenFileName(GifFileType *GifFile, const char *GifFileName);
110 void DGifOpenFileHandle(GifFileType *GifFile, int GifFileHandle);
111 void DGifInitRead(GifFileType *GifFile);
112 void DGifSlurp(GifFileType *GifFile);
113 void DGifGetScreenDesc(GifFileType *GifFile);
114 void DGifGetRecordType(GifFileType *GifFile, GifRecordType *GifType);
115 void DGifGetImageDesc(GifFileType *GifFile);
116 void DGifGetLine(GifFileType *GifFile, GifPixelType *GifLine, int GifLineLen);
117 void DGifGetPixel(GifFileType *GifFile, GifPixelType GifPixel);
118 void DGifGetComment(GifFileType *GifFile, char *GifComment);
119 void DGifGetExtension(GifFileType *GifFile, int *GifExtCode,
120 GifByteType **GifExtension);
121 void DGifGetExtensionNext(GifFileType *GifFile, GifByteType **GifExtension);
122 void DGifGetCode(GifFileType *GifFile, int *GifCodeSize,
123 GifByteType **GifCodeBlock);
124 void DGifGetCodeNext(GifFileType *GifFile, GifByteType **GifCodeBlock);
125 void DGifGetLZCodes(GifFileType *GifFile, int *GifCode);
126 int DGifCloseFile(GifFileType *GifFile);
127
128 #define D_GIF_ERR_OPEN_FAILED 101 /* And DGif possible errors. */
129 #define D_GIF_ERR_READ_FAILED 102
130 #define D_GIF_ERR_NOT_GIF_FILE 103
131 #define D_GIF_ERR_NO_SCRN_DSCR 104
132 #define D_GIF_ERR_NO_IMAG_DSCR 105
133 #define D_GIF_ERR_NO_COLOR_MAP 106
134 #define D_GIF_ERR_WRONG_RECORD 107
135 #define D_GIF_ERR_DATA_TOO_BIG 108
136 #define GIF_ERR_NOT_ENOUGH_MEM 109
137 #define D_GIF_ERR_NOT_ENOUGH_MEM 109
138 #define D_GIF_ERR_CLOSE_FAILED 110
139 #define D_GIF_ERR_NOT_READABLE 111
140 #define D_GIF_ERR_IMAGE_DEFECT 112
141 #define D_GIF_ERR_EOF_TOO_SOON 113
142
143 /******************************************************************************
144 * O.K., here are the error routines *
145 ******************************************************************************/
146 extern void GifSetErrorFunc(GifFileType *GifFile, Gif_error_func func, VoidPtr data);
147 extern void GifSetWarningFunc(GifFileType *GifFile, Gif_error_func func, VoidPtr data);
148 extern void GifInternError(GifFileType *GifFile, int errnum);
149 extern void GifInternWarning(GifFileType *GifFile, int errnum);
150 extern void GifError(GifFileType *GifFile, const char *err_str);
151 extern void GifWarning(GifFileType *GifFile, const char *err_str);
152
153 /*****************************************************************************
154 *
155 * Everything below this point is new after version 1.2, supporting `slurp
156 * mode' for doing I/O in two big belts with all the image-bashing in core.
157 *
158 *****************************************************************************/
159
160 /******************************************************************************
161 * Support for the in-core structures allocation (slurp mode). *
162 ******************************************************************************/
163
164 /* This is the in-core version of an extension record */
165 typedef struct {
166 int ByteCount;
167 GifByteType *Bytes; /* on malloc(3) heap */
168 } ExtensionBlock;
169
170 /* This holds an image header, its unpacked raster bits, and extensions */
171 typedef struct SavedImage {
172 GifImageDesc ImageDesc;
173
174 GifPixelType *RasterBits; /* on malloc(3) heap */
175
176 int Function;
177 int ExtensionBlockCount;
178 ExtensionBlock *ExtensionBlocks; /* on malloc(3) heap */
179 } SavedImage;
180
181 extern void ApplyTranslation(SavedImage *Image, GifPixelType Translation[]);
182
183 extern void MakeExtension(SavedImage *New, int Function);
184 extern int AddExtensionBlock(SavedImage *New, int Length, GifByteType *data);
185 extern void FreeExtension(SavedImage *Image);
186
187 extern SavedImage *MakeSavedImage(GifFileType *GifFile, SavedImage *CopyFrom);
188 extern void FreeSavedImages(GifFileType *GifFile);
189
190 /* Common defines used by encode/decode functions */
191
192 #define COMMENT_EXT_FUNC_CODE 0xfe /* Extension function code for comment. */
193 #define GIF_STAMP "GIFVER" /* First chars in file - GIF stamp. */
194 #define GIF_STAMP_LEN sizeof(GIF_STAMP) - 1
195 #define GIF_VERSION_POS 3 /* Version first character in stamp. */
196 #define GIF87_STAMP "GIF87a" /* First chars in file - GIF stamp. */
197 #define GIF89_STAMP "GIF89a" /* First chars in file - GIF stamp. */
198
199 #define LZ_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
200 #define LZ_BITS 12
201
202 #define FILE_STATE_READ 0x01
203 #define FILE_STATE_WRITE 0x01
204 #define FILE_STATE_SCREEN 0x02
205 #define FILE_STATE_IMAGE 0x04
206
207 #define FLUSH_OUTPUT 4096 /* Impossible code, to signal flush. */
208 #define FIRST_CODE 4097 /* Impossible code, to signal first. */
209 #define NO_SUCH_CODE 4098 /* Impossible code, to signal empty. */
210
211 #define IS_READABLE(Private) (!(Private->FileState & FILE_STATE_READ))
212 #define IS_WRITEABLE(Private) (Private->FileState & FILE_STATE_WRITE)
213
214 typedef struct GifFilePrivateType {
215 int FileState,
216 BitsPerPixel, /* Bits per pixel (Codes uses at list this + 1). */
217 ClearCode, /* The CLEAR LZ code. */
218 EOFCode, /* The EOF LZ code. */
219 RunningCode, /* The next code algorithm can generate. */
220 RunningBits,/* The number of bits required to represent RunningCode. */
221 MaxCode1, /* 1 bigger than max. possible code, in RunningBits bits. */
222 LastCode, /* The code before the current code. */
223 CrntCode, /* Current algorithm code. */
224 StackPtr, /* For character stack (see below). */
225 CrntShiftState; /* Number of bits in CrntShiftDWord. */
226 unsigned long CrntShiftDWord; /* For bytes decomposition into codes. */
227 unsigned long PixelCount; /* Number of pixels in image. */
228 GifByteType Buf[256]; /* Compressed input is buffered here. */
229 GifByteType Stack[LZ_MAX_CODE]; /* Decoded pixels are stacked here. */
230 GifByteType Suffix[LZ_MAX_CODE+1]; /* So we can trace the codes. */
231 unsigned int Prefix[LZ_MAX_CODE+1];
232 } GifFilePrivateType;
233
234 typedef struct GifIODataType {
235 Gif_rw_func ReadFunc, WriteFunc; /* Pointers to the functions that will do the I/O */
236 Gif_close_func CloseFunc;
237 VoidPtr ReadFunc_data; /* data to be passed to the read function */
238 VoidPtr WriteFunc_data; /* data to be passed to the write function */
239 VoidPtr CloseFunc_data; /* data to be passed to the close function */
240 Gif_error_func ErrorFunc; /* MUST NOT RETURN (use lng_jmp or exit)! */
241 Gif_error_func WarningFunc; /* For warning messages (can be ignored) */
242 VoidPtr ErrorFunc_data;
243 VoidPtr WarningFunc_data;
244 } GifIODataType;
245
246 typedef struct GifStdIODataType {
247 FILE *File;
248 int FileHandle;
249 } GifStdIODataType;
250
251 /* Install StdIO funcs on FILE into GifFile */
252 void GifStdIOInit(GifFileType *GifFile, FILE *file, int filehandle);
253
254 /* Error checking reads, writes and closes */
255 void GifRead(GifByteType *buf, size_t size, GifFileType *GifFile);
256 void GifWrite(GifByteType *buf, size_t size, GifFileType *GifFile);
257 int GifClose(GifFileType *GifFile);
258
259 /* The default Read and Write functions for files */
260 size_t GifStdRead(GifByteType *buf, size_t size, VoidPtr method_data);
261 size_t GifStdWrite(GifByteType *buf, size_t size, VoidPtr method_data);
262 int GifStdFileClose(VoidPtr method_data);
263
264 ColorMapObject *MakeMapObject(int ColorCount, GifColorType *ColorMap);
265 void FreeMapObject(ColorMapObject *Object);
266
267
268 #endif /* GIF_LIB_H */