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1 /******************************************************************************
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2 * In order to make life a little bit easier when using the GIF file format, *
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3 * this library was written, and which does all the dirty work... *
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4 * *
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5 * Written by Gershon Elber, Jun. 1989 *
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6 * Hacks by Eric S. Raymond, Sep. 1992 *
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7 * and Jareth Hein, Jan. 1998 *
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8 *******************************************************************************
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9 * History: *
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10 * 14 Jun 89 - Version 1.0 by Gershon Elber. *
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11 * 3 Sep 90 - Version 1.1 by Gershon Elber (Support for Gif89, Unique names). *
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12 * 15 Sep 90 - Version 2.0 by Eric S. Raymond (Changes to suoport GIF slurp) *
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13 * 26 Jun 96 - Version 3.0 by Eric S. Raymond (Full GIF89 support) *
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14 * 19 Jan 98 - Version 3.1 by Jareth Hein (Support for user-defined I/O). *
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15 ******************************************************************************/
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16
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17 #ifndef GIF_LIB_H
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18 #define GIF_LIB_H
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19
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20 #define GIF_ERROR 0
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21 #define GIF_OK 1
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22
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23 #ifndef TRUE
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24 #define TRUE 1
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25 #define FALSE 0
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26 #endif
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27
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28 #ifndef NULL
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29 #define NULL 0
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30 #endif /* NULL */
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31
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32 #define GIF_FILE_BUFFER_SIZE 16384 /* Files uses bigger buffers than usual. */
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33
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34 typedef int GifBooleanType;
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35 typedef unsigned char GifPixelType;
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36 typedef unsigned char * GifRowType;
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37 typedef unsigned char GifByteType;
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38
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39 #ifdef SYSV
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40 #define VoidPtr char *
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41 #else
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42 #define VoidPtr void *
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43 #endif /* SYSV */
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44
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45 typedef struct GifColorType {
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46 GifByteType Red, Green, Blue;
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47 } GifColorType;
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48
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49 typedef struct ColorMapObject
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50 {
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51 int ColorCount;
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52 int BitsPerPixel;
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53 GifColorType *Colors; /* on malloc(3) heap */
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54 }
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55 ColorMapObject;
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56
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57 typedef struct GifImageDesc {
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58 int Left, Top, Width, Height, /* Current image dimensions. */
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59 Interlace; /* Sequential/Interlaced lines. */
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60 ColorMapObject *ColorMap; /* The local color map */
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61 } GifImageDesc;
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62
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63 /* I/O operations. If you roll your own, they need to be semantically equivilent to
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64 fread/fwrite, with an additional paramater to hold data local to your method. */
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65 typedef size_t (*Gif_rw_func)(GifByteType *buffer, size_t size, VoidPtr method_data);
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66 /* Finish up stream. Non-zero return indicates failure */
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67 typedef int (*Gif_close_func)(VoidPtr close_data);
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68 /* Error handling function */
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69 typedef void (*Gif_error_func)(const char *string, VoidPtr error_data);
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70
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71 typedef struct GifFileType {
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72 int SWidth, SHeight, /* Screen dimensions. */
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73 SColorResolution, /* How many colors can we generate? */
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74 SBackGroundColor; /* I hope you understand this one... */
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75 ColorMapObject *SColorMap; /* NULL if it doesn't exist. */
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76 int ImageCount; /* Number of current image */
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77 GifImageDesc Image; /* Block describing current image */
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78 struct SavedImage *SavedImages; /* Use this to accumulate file state */
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79 VoidPtr Private; /* Don't mess with this! */
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80 VoidPtr GifIO; /* Contains all information for I/O */
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81 } GifFileType;
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82
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83 typedef enum {
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84 UNDEFINED_RECORD_TYPE,
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85 SCREEN_DESC_RECORD_TYPE,
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86 IMAGE_DESC_RECORD_TYPE, /* Begin with ',' */
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87 EXTENSION_RECORD_TYPE, /* Begin with '!' */
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88 TERMINATE_RECORD_TYPE /* Begin with ';' */
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89 } GifRecordType;
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90
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91 /******************************************************************************
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92 * GIF89 extension function codes *
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93 ******************************************************************************/
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94
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95 #define COMMENT_EXT_FUNC_CODE 0xfe /* comment */
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96 #define GRAPHICS_EXT_FUNC_CODE 0xf9 /* graphics control */
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97 #define PLAINTEXT_EXT_FUNC_CODE 0x01 /* plaintext */
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98 #define APPLICATION_EXT_FUNC_CODE 0xff /* application block */
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99
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100 /******************************************************************************
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101 * IO related routines. Defined in gif_io.c *
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102 ******************************************************************************/
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103 GifFileType *GifSetup(void);
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104 void GifFree(GifFileType *GifFile);
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105 void GifSetReadFunc (GifFileType *GifFile, Gif_rw_func func, VoidPtr data);
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106 void GifSetWriteFunc(GifFileType *GifFile, Gif_rw_func func, VoidPtr data);
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107 void GifSetCloseFunc(GifFileType *GifFile, Gif_close_func func, VoidPtr data);
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108
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109 /******************************************************************************
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110 * O.K., here are the routines one can access in order to decode GIF file: *
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111 ******************************************************************************/
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112
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113 void DGifOpenFileName(GifFileType *GifFile, const char *GifFileName);
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114 void DGifOpenFileHandle(GifFileType *GifFile, int GifFileHandle);
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115 void DGifInitRead(GifFileType *GifFile);
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116 void DGifSlurp(GifFileType *GifFile);
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117 void DGifGetScreenDesc(GifFileType *GifFile);
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118 void DGifGetRecordType(GifFileType *GifFile, GifRecordType *GifType);
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119 void DGifGetImageDesc(GifFileType *GifFile);
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120 void DGifGetLine(GifFileType *GifFile, GifPixelType *GifLine, int GifLineLen);
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121 void DGifGetPixel(GifFileType *GifFile, GifPixelType GifPixel);
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122 void DGifGetComment(GifFileType *GifFile, char *GifComment);
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123 void DGifGetExtension(GifFileType *GifFile, int *GifExtCode,
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124 GifByteType **GifExtension);
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125 void DGifGetExtensionNext(GifFileType *GifFile, GifByteType **GifExtension);
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126 void DGifGetCode(GifFileType *GifFile, int *GifCodeSize,
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127 GifByteType **GifCodeBlock);
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128 void DGifGetCodeNext(GifFileType *GifFile, GifByteType **GifCodeBlock);
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129 void DGifGetLZCodes(GifFileType *GifFile, int *GifCode);
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130 int DGifCloseFile(GifFileType *GifFile);
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131
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132 #define D_GIF_ERR_OPEN_FAILED 101 /* And DGif possible errors. */
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133 #define D_GIF_ERR_READ_FAILED 102
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134 #define D_GIF_ERR_NOT_GIF_FILE 103
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135 #define D_GIF_ERR_NO_SCRN_DSCR 104
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136 #define D_GIF_ERR_NO_IMAG_DSCR 105
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137 #define D_GIF_ERR_NO_COLOR_MAP 106
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138 #define D_GIF_ERR_WRONG_RECORD 107
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139 #define D_GIF_ERR_DATA_TOO_BIG 108
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140 #define GIF_ERR_NOT_ENOUGH_MEM 109
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141 #define D_GIF_ERR_NOT_ENOUGH_MEM 109
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142 #define D_GIF_ERR_CLOSE_FAILED 110
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143 #define D_GIF_ERR_NOT_READABLE 111
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144 #define D_GIF_ERR_IMAGE_DEFECT 112
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145 #define D_GIF_ERR_EOF_TOO_SOON 113
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146
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147 /******************************************************************************
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148 * O.K., here are the error routines *
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149 ******************************************************************************/
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150 extern void GifSetErrorFunc(GifFileType *GifFile, Gif_error_func func, VoidPtr data);
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151 extern void GifSetWarningFunc(GifFileType *GifFile, Gif_error_func func, VoidPtr data);
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152 extern void GifInternError(GifFileType *GifFile, int errnum);
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153 extern void GifInternWarning(GifFileType *GifFile, int errnum);
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154 extern void GifError(GifFileType *GifFile, const char *err_str);
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155 extern void GifWarning(GifFileType *GifFile, const char *err_str);
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156
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157 /*****************************************************************************
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158 *
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159 * Everything below this point is new after version 1.2, supporting `slurp
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160 * mode' for doing I/O in two big belts with all the image-bashing in core.
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161 *
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162 *****************************************************************************/
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163
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164 /******************************************************************************
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165 * Support for the in-core structures allocation (slurp mode). *
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166 ******************************************************************************/
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167
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168 /* This is the in-core version of an extension record */
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169 typedef struct {
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321
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170 int ByteCount;
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171 GifByteType *Bytes; /* on malloc(3) heap */
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308
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172 } ExtensionBlock;
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173
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174 /* This holds an image header, its unpacked raster bits, and extensions */
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175 typedef struct SavedImage {
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176 GifImageDesc ImageDesc;
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177
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321
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178 GifPixelType *RasterBits; /* on malloc(3) heap */
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308
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179
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180 int Function;
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181 int ExtensionBlockCount;
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182 ExtensionBlock *ExtensionBlocks; /* on malloc(3) heap */
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183 } SavedImage;
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184
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185 extern void ApplyTranslation(SavedImage *Image, GifPixelType Translation[]);
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186
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187 extern void MakeExtension(SavedImage *New, int Function);
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188 extern int AddExtensionBlock(SavedImage *New, int Length, GifByteType *data);
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189 extern void FreeExtension(SavedImage *Image);
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190
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191 extern SavedImage *MakeSavedImage(GifFileType *GifFile, SavedImage *CopyFrom);
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192 extern void FreeSavedImages(GifFileType *GifFile);
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193
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194 /* Common defines used by encode/decode functions */
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195
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196 #define COMMENT_EXT_FUNC_CODE 0xfe /* Extension function code for comment. */
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197 #define GIF_STAMP "GIFVER" /* First chars in file - GIF stamp. */
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198 #define GIF_STAMP_LEN sizeof(GIF_STAMP) - 1
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199 #define GIF_VERSION_POS 3 /* Version first character in stamp. */
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200 #define GIF87_STAMP "GIF87a" /* First chars in file - GIF stamp. */
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201 #define GIF89_STAMP "GIF89a" /* First chars in file - GIF stamp. */
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202
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203 #define LZ_MAX_CODE 4095 /* Biggest code possible in 12 bits. */
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204 #define LZ_BITS 12
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205
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206 #define FILE_STATE_READ 0x01
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207 #define FILE_STATE_WRITE 0x01
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208 #define FILE_STATE_SCREEN 0x02
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209 #define FILE_STATE_IMAGE 0x04
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210
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211 #define FLUSH_OUTPUT 4096 /* Impossible code, to signal flush. */
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212 #define FIRST_CODE 4097 /* Impossible code, to signal first. */
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213 #define NO_SUCH_CODE 4098 /* Impossible code, to signal empty. */
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214
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215 #define IS_READABLE(Private) (!(Private->FileState & FILE_STATE_READ))
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216 #define IS_WRITEABLE(Private) (Private->FileState & FILE_STATE_WRITE)
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217
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218 typedef struct GifFilePrivateType {
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219 int FileState,
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220 BitsPerPixel, /* Bits per pixel (Codes uses at list this + 1). */
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221 ClearCode, /* The CLEAR LZ code. */
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222 EOFCode, /* The EOF LZ code. */
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223 RunningCode, /* The next code algorithm can generate. */
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224 RunningBits,/* The number of bits required to represent RunningCode. */
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225 MaxCode1, /* 1 bigger than max. possible code, in RunningBits bits. */
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226 LastCode, /* The code before the current code. */
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227 CrntCode, /* Current algorithm code. */
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228 StackPtr, /* For character stack (see below). */
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229 CrntShiftState; /* Number of bits in CrntShiftDWord. */
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230 unsigned long CrntShiftDWord; /* For bytes decomposition into codes. */
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231 unsigned long PixelCount; /* Number of pixels in image. */
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232 GifByteType Buf[256]; /* Compressed input is buffered here. */
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233 GifByteType Stack[LZ_MAX_CODE]; /* Decoded pixels are stacked here. */
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234 GifByteType Suffix[LZ_MAX_CODE+1]; /* So we can trace the codes. */
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235 unsigned int Prefix[LZ_MAX_CODE+1];
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236 } GifFilePrivateType;
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237
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238 typedef struct GifIODataType {
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239 Gif_rw_func ReadFunc, WriteFunc; /* Pointers to the functions that will do the I/O */
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240 Gif_close_func CloseFunc;
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241 VoidPtr ReadFunc_data; /* data to be passed to the read function */
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242 VoidPtr WriteFunc_data; /* data to be passed to the write function */
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243 VoidPtr CloseFunc_data; /* data to be passed to the close function */
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244 Gif_error_func ErrorFunc; /* MUST NOT RETURN (use lng_jmp or exit)! */
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245 Gif_error_func WarningFunc; /* For warning messages (can be ignored) */
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246 VoidPtr ErrorFunc_data;
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247 VoidPtr WarningFunc_data;
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248 } GifIODataType;
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249
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250 typedef struct GifStdIODataType {
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251 FILE *File;
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252 int FileHandle;
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253 } GifStdIODataType;
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254
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255 /* Install StdIO funcs on FILE into GifFile */
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256 void GifStdIOInit(GifFileType *GifFile, FILE *file, int filehandle);
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257
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258 /* Error checking reads, writes and closes */
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259 void GifRead(GifByteType *buf, size_t size, GifFileType *GifFile);
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260 void GifWrite(GifByteType *buf, size_t size, GifFileType *GifFile);
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261 int GifClose(GifFileType *GifFile);
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262
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263 /* The default Read and Write functions for files */
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264 size_t GifStdRead(GifByteType *buf, size_t size, VoidPtr method_data);
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265 size_t GifStdWrite(GifByteType *buf, size_t size, VoidPtr method_data);
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266 int GifStdFileClose(VoidPtr method_data);
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267
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268 ColorMapObject *MakeMapObject(int ColorCount, GifColorType *ColorMap);
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269 void FreeMapObject(ColorMapObject *Object);
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270
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271
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272 #endif /* GIF_LIB_H */
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