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... *
5 * Written by Gershon Elber, Jun. 1989 *
6 * Hacks by Eric S. Raymond, Sep. 1992 *
7 * and Jareth Hein, Jan. 1998 *
8 *******************************************************************************
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 ******************************************************************************/
17 #ifndef INCLUDED_gifrlib_h_
18 #define INCLUDED_gifrlib_h_
32 #define GIF_FILE_BUFFER_SIZE 16384 /* Files uses bigger buffers than usual. */
34 typedef int GifBooleanType;
35 typedef unsigned char GifPixelType;
36 typedef unsigned char *GifRowType;
37 typedef unsigned char GifByteType;
39 #define VoidPtr void *
41 typedef struct GifColorType {
42 GifByteType Red, Green, Blue;
45 typedef struct ColorMapObject {
48 GifColorType *Colors; /* on malloc(3) heap */
51 typedef struct GifImageDesc {
52 int Left, Top, Width, Height, /* Current image dimensions. */
53 Interlace; /* Sequential/Interlaced lines. */
54 ColorMapObject *ColorMap; /* The local color map */
57 /* I/O operations. If you roll your own, they need to be semantically equivilent to
58 fread/fwrite, with an additional paramater to hold data local to your method. */
59 typedef size_t(*Gif_rw_func) (GifByteType * buffer, size_t size,
61 /* Finish up stream. Non-zero return indicates failure */
62 typedef int (*Gif_close_func) (VoidPtr close_data);
63 /* Error handling function */
64 typedef void (*Gif_error_func) (const char *string, VoidPtr error_data);
66 typedef struct GifFileType {
67 int SWidth, SHeight, /* Screen dimensions. */
68 SColorResolution, /* How many colors can we generate? */
69 SBackGroundColor; /* I hope you understand this one... */
70 ColorMapObject *SColorMap; /* NULL if it doesn't exist. */
71 int ImageCount; /* Number of current image */
72 GifImageDesc Image; /* Block describing current image */
73 struct SavedImage *SavedImages; /* Use this to accumulate file state */
74 VoidPtr Private; /* Don't mess with this! */
75 VoidPtr GifIO; /* Contains all information for I/O */
79 UNDEFINED_RECORD_TYPE,
80 SCREEN_DESC_RECORD_TYPE,
81 IMAGE_DESC_RECORD_TYPE, /* Begin with ',' */
82 EXTENSION_RECORD_TYPE, /* Begin with '!' */
83 TERMINATE_RECORD_TYPE /* Begin with ';' */
86 /******************************************************************************
87 * GIF89 extension function codes *
88 ******************************************************************************/
90 #define COMMENT_EXT_FUNC_CODE 0xfe /* comment */
91 #define GRAPHICS_EXT_FUNC_CODE 0xf9 /* graphics control */
92 #define PLAINTEXT_EXT_FUNC_CODE 0x01 /* plaintext */
93 #define APPLICATION_EXT_FUNC_CODE 0xff /* application block */
95 /******************************************************************************
96 * IO related routines. Defined in gif_io.c *
97 ******************************************************************************/
98 GifFileType *GifSetup(void);
99 void GifFree(GifFileType * GifFile);
100 void GifSetReadFunc(GifFileType * GifFile, Gif_rw_func func, VoidPtr data);
101 void GifSetWriteFunc(GifFileType * GifFile, Gif_rw_func func, VoidPtr data);
102 void GifSetCloseFunc(GifFileType * GifFile, Gif_close_func func, VoidPtr data);
104 /******************************************************************************
105 * O.K., here are the routines one can access in order to decode GIF file: *
106 ******************************************************************************/
108 void DGifOpenFileName(GifFileType * GifFile, const char *GifFileName);
109 void DGifOpenFileHandle(GifFileType * GifFile, int GifFileHandle);
110 void DGifInitRead(GifFileType * GifFile);
111 void DGifSlurp(GifFileType * GifFile);
112 void DGifGetScreenDesc(GifFileType * GifFile);
113 void DGifGetRecordType(GifFileType * GifFile, GifRecordType * GifType);
114 void DGifGetImageDesc(GifFileType * GifFile);
115 void DGifGetLine(GifFileType * GifFile, GifPixelType * GifLine, int GifLineLen);
116 void DGifGetPixel(GifFileType * GifFile, GifPixelType GifPixel);
117 void DGifGetComment(GifFileType * GifFile, char *GifComment);
118 void DGifGetExtension(GifFileType * GifFile, int *GifExtCode,
119 GifByteType ** GifExtension);
120 void DGifGetExtensionNext(GifFileType * GifFile, GifByteType ** GifExtension);
121 void DGifGetCode(GifFileType * GifFile, int *GifCodeSize,
122 GifByteType ** GifCodeBlock);
123 void DGifGetCodeNext(GifFileType * GifFile, GifByteType ** GifCodeBlock);
124 void DGifGetLZCodes(GifFileType * GifFile, int *GifCode);
125 int DGifCloseFile(GifFileType * GifFile);
127 #define D_GIF_ERR_OPEN_FAILED 101 /* And DGif possible errors. */
128 #define D_GIF_ERR_READ_FAILED 102
129 #define D_GIF_ERR_NOT_GIF_FILE 103
130 #define D_GIF_ERR_NO_SCRN_DSCR 104
131 #define D_GIF_ERR_NO_IMAG_DSCR 105
132 #define D_GIF_ERR_NO_COLOR_MAP 106
133 #define D_GIF_ERR_WRONG_RECORD 107
134 #define D_GIF_ERR_DATA_TOO_BIG 108
135 #define GIF_ERR_NOT_ENOUGH_MEM 109
136 #define D_GIF_ERR_NOT_ENOUGH_MEM 109
137 #define D_GIF_ERR_CLOSE_FAILED 110
138 #define D_GIF_ERR_NOT_READABLE 111
139 #define D_GIF_ERR_IMAGE_DEFECT 112
140 #define D_GIF_ERR_EOF_TOO_SOON 113
142 /******************************************************************************
143 * O.K., here are the error routines *
144 ******************************************************************************/
145 extern void GifSetErrorFunc(GifFileType * GifFile, Gif_error_func func,
147 extern void GifSetWarningFunc(GifFileType * GifFile, Gif_error_func func,
149 extern void GifInternError(GifFileType * GifFile, int errnum);
150 extern void GifInternWarning(GifFileType * GifFile, int errnum);
151 extern void GifError(GifFileType * GifFile, const char *err_str);
152 extern void GifWarning(GifFileType * GifFile, const char *err_str);
154 /*****************************************************************************
156 * Everything below this point is new after version 1.2, supporting `slurp
157 * mode' for doing I/O in two big belts with all the image-bashing in core.
159 *****************************************************************************/
161 /******************************************************************************
162 * Support for the in-core structures allocation (slurp mode). *
163 ******************************************************************************/
165 /* This is the in-core version of an extension record */
168 GifByteType *Bytes; /* on malloc(3) heap */
171 /* This holds an image header, its unpacked raster bits, and extensions */
172 typedef struct SavedImage {
173 GifImageDesc ImageDesc;
175 GifPixelType *RasterBits; /* on malloc(3) heap */
178 int ExtensionBlockCount;
179 ExtensionBlock *ExtensionBlocks; /* on malloc(3) heap */
182 extern void ApplyTranslation(SavedImage * Image, GifPixelType Translation[]);
184 extern void MakeExtension(SavedImage * New, int Function);
185 extern int AddExtensionBlock(SavedImage * New, int Length, GifByteType * data);
186 extern void FreeExtension(SavedImage * Image);
188 extern SavedImage *MakeSavedImage(GifFileType * GifFile, SavedImage * CopyFrom);
189 extern void FreeSavedImages(GifFileType * GifFile);
191 /* Common defines used by encode/decode functions */
193 #define COMMENT_EXT_FUNC_CODE 0xfe /* Extension function code for comment. */
194 #define GIF_STAMP "GIFVER" /* First chars in file - GIF stamp. */
195 #define GIF_STAMP_LEN sizeof(GIF_STAMP) - 1
196 #define GIF_VERSION_POS 3 /* Version first character in stamp. */
197 #define GIF87_STAMP "GIF87a" /* First chars in file - GIF stamp. */
198 #define GIF89_STAMP "GIF89a" /* First chars in file - GIF stamp. */
200 #define LZ_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
203 #define FILE_STATE_READ 0x01
204 #define FILE_STATE_WRITE 0x01
205 #define FILE_STATE_SCREEN 0x02
206 #define FILE_STATE_IMAGE 0x04
208 #define FLUSH_OUTPUT 4096 /* Impossible code, to signal flush. */
209 #define FIRST_CODE 4097 /* Impossible code, to signal first. */
210 #define NO_SUCH_CODE 4098 /* Impossible code, to signal empty. */
212 #define IS_READABLE(Private) (!(Private->FileState & FILE_STATE_READ))
213 #define IS_WRITEABLE(Private) (Private->FileState & FILE_STATE_WRITE)
215 typedef struct GifFilePrivateType {
216 int FileState, 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;
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;
246 typedef struct GifStdIODataType {
251 /* Install StdIO funcs on FILE into GifFile */
252 void GifStdIOInit(GifFileType * GifFile, FILE * file, int filehandle);
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);
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);
264 ColorMapObject *MakeMapObject(int ColorCount, GifColorType * ColorMap);
265 void FreeMapObject(ColorMapObject * Object);
267 #endif /* INCLUDED_gifrlib_h_ */