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308
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1 /******************************************************************************
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2 * "Gif-Lib" - Yet another gif library. *
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3 * *
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4 * Written by: Gershon Elber IBM PC Ver 1.1, Aug. 1990 *
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5 *******************************************************************************
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6 * The kernel of the GIF Decoding process can be found here. *
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7 *******************************************************************************
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8 * History: *
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9 * 16 Jun 89 - Version 1.0 by Gershon Elber. *
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10 * 3 Sep 90 - Version 1.1 by Gershon Elber (Support for Gif89, Unique names). *
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11 * 19 Feb 98 - Version 1.2 by Jareth Hein (Support for user specified I/O) *
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12 ******************************************************************************/
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13
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14 #ifdef __MSDOS__
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15 #include <io.h>
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16 #include <alloc.h>
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17 #include <stdlib.h>
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18 #include <sys\stat.h>
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19 #else
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20 #include <sys/types.h>
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21 #include <sys/stat.h>
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22 #endif /* __MSDOS__ */
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23
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24 #include <stdio.h>
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25 #include <stdlib.h>
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26 #include <string.h>
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27
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28 #ifdef HAVE_FCNTL_H
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29 #include <fcntl.h>
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30 #endif
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31
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32 #include "gifrlib.h"
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33
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34 #define PROGRAM_NAME "GIFLIB"
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35
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36
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37 static void DGifGetWord(GifFileType *GifFile, int *Word);
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38 static void DGifSetupDecompress(GifFileType *GifFile);
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39 static void DGifDecompressLine(GifFileType *GifFile, GifPixelType *Line,
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40 int LineLen);
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41 static int DGifGetPrefixChar(unsigned int *Prefix, int Code, int ClearCode);
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42 static void DGifDecompressInput(GifFileType *GifFile, int *Code);
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43 static void DGifBufferedInput(GifFileType *GifFile, GifByteType *NextByte);
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44
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45 /******************************************************************************
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46 * Open a new gif file for read, given by its name. *
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47 * Returns GifFileType pointer dynamically allocated which serves as the gif *
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48 * info record. *
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49 ******************************************************************************/
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50 void DGifOpenFileName(GifFileType *GifFile, const char *FileName)
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51 {
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52 FILE *f;
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53
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54 if ((f = fopen(FileName,
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55 #ifdef __MSDOS__
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56 "rb"
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57 #else
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58 "r"
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59 #endif /* __MSDOS__ */
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60 )) == NULL)
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61 GifInternError(GifFile, D_GIF_ERR_OPEN_FAILED);
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62
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63 GifStdIOInit(GifFile, f, -1);
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64 DGifInitRead(GifFile);
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65 }
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66
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67 /******************************************************************************
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68 * Update a new gif file, given its file handle. *
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69 * Returns GifFileType pointer dynamically allocated which serves as the gif *
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70 * info record. *
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71 ******************************************************************************/
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72 void DGifOpenFileHandle(GifFileType *GifFile, int FileHandle)
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73 {
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74 FILE *f;
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75
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76 #ifdef __MSDOS__
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77 setmode(FileHandle, O_BINARY); /* Make sure it is in binary mode. */
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78 f = fdopen(FileHandle, "rb"); /* Make it into a stream: */
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79 setvbuf(f, NULL, _IOFBF, GIF_FILE_BUFFER_SIZE);/* And inc. stream buffer.*/
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80 #else
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81 f = fdopen(FileHandle, "r"); /* Make it into a stream: */
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82 #endif /* __MSDOS__ */
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83
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84 GifStdIOInit(GifFile, f, -1);
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85 DGifInitRead(GifFile);
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86 }
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87
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88 /******************************************************************************
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89 * Update a new gif file, given its file handle. *
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90 * Returns GifFileType pointer dynamically allocated which serves as the gif *
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91 * info record. _GifError is cleared if succesfull. *
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92 ******************************************************************************/
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93 void DGifInitRead(GifFileType *GifFile)
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94 {
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95 GifByteType Buf[GIF_STAMP_LEN+1];
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96 GifFilePrivateType *Private;
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97
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98 if ((Private = (GifFilePrivateType *) malloc(sizeof(GifFilePrivateType)))
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99 == NULL) {
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100 GifInternError(GifFile, D_GIF_ERR_NOT_ENOUGH_MEM);
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101 }
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102 memset(Private, '\0', sizeof(GifFilePrivateType));
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103 GifFile->Private = (VoidPtr) Private;
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104
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105 Private->FileState = 0; /* Make sure bit 0 = 0 (File open for read). */
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106
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107 /* Lets see if this is a GIF file: */
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108 GifRead(Buf, GIF_STAMP_LEN, GifFile);
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109
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110 /* The GIF Version number is ignored at this time. Maybe we should do */
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111 /* something more useful with it. */
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112 Buf[GIF_STAMP_LEN] = 0;
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321
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113 if (strncmp(GIF_STAMP, (const char *) Buf, GIF_VERSION_POS) != 0) {
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308
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114 GifInternError(GifFile, D_GIF_ERR_NOT_GIF_FILE);
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115 }
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116
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117 DGifGetScreenDesc(GifFile);
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118 }
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119
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120 /******************************************************************************
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121 * This routine should be called before any other DGif calls. Note that *
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122 * this routine is called automatically from DGif file open routines. *
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123 ******************************************************************************/
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124 void DGifGetScreenDesc(GifFileType *GifFile)
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125 {
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126 int i, BitsPerPixel;
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127 GifByteType Buf[3];
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128 GifFilePrivateType *Private = (GifFilePrivateType*) GifFile->Private;
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129
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130 if (!IS_READABLE(Private)) {
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131 /* This file was NOT open for reading: */
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132 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
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133 }
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134
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135 /* Put the screen descriptor into the file: */
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136 DGifGetWord(GifFile, &GifFile->SWidth);
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137 DGifGetWord(GifFile, &GifFile->SHeight);
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138
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139 GifRead(Buf, 3, GifFile);
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140 GifFile->SColorResolution = (((Buf[0] & 0x70) + 1) >> 4) + 1;
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141 BitsPerPixel = (Buf[0] & 0x07) + 1;
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142 GifFile->SBackGroundColor = Buf[1];
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143 if (Buf[0] & 0x80) { /* Do we have global color map? */
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144
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145 GifFile->SColorMap = MakeMapObject(1 << BitsPerPixel, NULL);
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146
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147 /* Get the global color map: */
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148 for (i = 0; i < GifFile->SColorMap->ColorCount; i++) {
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149 GifRead(Buf, 3, GifFile);
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150 GifFile->SColorMap->Colors[i].Red = Buf[0];
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151 GifFile->SColorMap->Colors[i].Green = Buf[1];
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152 GifFile->SColorMap->Colors[i].Blue = Buf[2];
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153 }
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154 } else {
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155 /* We should always have a colormap */
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156 GifFile->SColorMap = MakeMapObject(2, NULL);
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157 GifFile->SColorMap->Colors[0].Red = 0;
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158 GifFile->SColorMap->Colors[0].Green = 0;
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159 GifFile->SColorMap->Colors[0].Blue = 0;
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160 GifFile->SColorMap->Colors[1].Red = 0xff;
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161 GifFile->SColorMap->Colors[1].Green = 0xff;
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162 GifFile->SColorMap->Colors[1].Blue = 0xff;
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163 }
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164 }
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165
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166 /******************************************************************************
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167 * This routine should be called before any attemp to read an image. *
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168 ******************************************************************************/
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169 void DGifGetRecordType(GifFileType *GifFile, GifRecordType *Type)
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170 {
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171 GifByteType Buf;
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172 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
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173
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174 if (!IS_READABLE(Private)) {
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175 /* This file was NOT open for reading: */
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176 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
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177 }
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178
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179 GifRead(&Buf, 1, GifFile);
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180
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181 switch (Buf) {
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182 case ',':
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183 *Type = IMAGE_DESC_RECORD_TYPE;
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184 break;
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185 case '!':
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186 *Type = EXTENSION_RECORD_TYPE;
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187 break;
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188 case ';':
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189 *Type = TERMINATE_RECORD_TYPE;
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190 break;
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191 default:
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192 *Type = UNDEFINED_RECORD_TYPE;
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193 GifInternError(GifFile, D_GIF_ERR_WRONG_RECORD);
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194 }
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195 }
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196
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197 /******************************************************************************
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198 * This routine should be called before any attemp to read an image. *
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199 * Note it is assumed the Image desc. header (',') has been read. *
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200 ******************************************************************************/
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201 void DGifGetImageDesc(GifFileType *GifFile)
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202 {
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203 int i, BitsPerPixel;
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204 GifByteType Buf[3];
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205 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
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206
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207 if (!IS_READABLE(Private)) {
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208 /* This file was NOT open for reading: */
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209 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
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210 }
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211
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212 DGifGetWord(GifFile, &GifFile->Image.Left);
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213 DGifGetWord(GifFile, &GifFile->Image.Top);
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214 DGifGetWord(GifFile, &GifFile->Image.Width);
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215 DGifGetWord(GifFile, &GifFile->Image.Height);
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216
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217 GifRead(Buf, 1, GifFile);
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218 BitsPerPixel = (Buf[0] & 0x07) + 1;
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219 GifFile->Image.Interlace = (Buf[0] & 0x40);
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220 if (Buf[0] & 0x80) { /* Does this image have local color map? */
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221
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222 if (GifFile->Image.ColorMap && GifFile->SavedImages == NULL)
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223 FreeMapObject(GifFile->Image.ColorMap);
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224
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225 GifFile->Image.ColorMap = MakeMapObject(1 << BitsPerPixel, NULL);
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226
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227 /* Get the image local color map: */
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228 for (i = 0; i < GifFile->Image.ColorMap->ColorCount; i++) {
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229 GifRead(Buf, 3, GifFile);
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230 GifFile->Image.ColorMap->Colors[i].Red = Buf[0];
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231 GifFile->Image.ColorMap->Colors[i].Green = Buf[1];
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232 GifFile->Image.ColorMap->Colors[i].Blue = Buf[2];
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233 }
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234 }
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235
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236 if (GifFile->SavedImages) {
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237 SavedImage *sp;
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238
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239 if ((GifFile->SavedImages = (SavedImage *)realloc(GifFile->SavedImages,
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240 sizeof(SavedImage) * (GifFile->ImageCount + 1))) == NULL) {
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241 GifInternError(GifFile, D_GIF_ERR_NOT_ENOUGH_MEM);
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242 }
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243
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244 sp = &GifFile->SavedImages[GifFile->ImageCount];
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245 memcpy(&sp->ImageDesc, &GifFile->Image, sizeof(GifImageDesc));
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246 if (GifFile->Image.ColorMap)
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247 {
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248 sp->ImageDesc.ColorMap =
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249 MakeMapObject (GifFile->Image.ColorMap->ColorCount,
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250 GifFile->Image.ColorMap->Colors);
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251 }
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252 sp->RasterBits = (GifPixelType *)NULL;
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253 sp->ExtensionBlockCount = 0;
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254 sp->ExtensionBlocks = (ExtensionBlock *)NULL;
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255 }
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256
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257 GifFile->ImageCount++;
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258
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259 Private->PixelCount = (long) GifFile->Image.Width *
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260 (long) GifFile->Image.Height;
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261
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262 DGifSetupDecompress(GifFile); /* Reset decompress algorithm parameters. */
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263 }
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264
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265 /******************************************************************************
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266 * Get one full scanned line (Line) of length LineLen from GIF file. *
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267 ******************************************************************************/
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268 void DGifGetLine(GifFileType *GifFile, GifPixelType *Line, int LineLen)
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269 {
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270 GifByteType *Dummy;
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271 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
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272
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273 if (!IS_READABLE(Private)) {
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274 /* This file was NOT open for reading: */
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275 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
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276 }
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277
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278 if (!LineLen) LineLen = GifFile->Image.Width;
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279
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280 #if defined(__MSDOS__) || defined(__GNUC__)
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281 if ((Private->PixelCount -= LineLen) > 0xffff0000UL)
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282 #else
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283 if ((Private->PixelCount -= LineLen) > 0xffff0000)
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284 #endif /* __MSDOS__ */
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285 {
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286 GifInternError(GifFile, D_GIF_ERR_DATA_TOO_BIG);
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287 }
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288
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289 DGifDecompressLine(GifFile, Line, LineLen);
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290 if (Private->PixelCount == 0) {
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291 /* We probably would not be called any more, so lets clean */
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292 /* everything before we return: need to flush out all rest of */
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293 /* image until empty block (size 0) detected. We use GetCodeNext.*/
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294 do
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295 DGifGetCodeNext(GifFile, &Dummy);
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296 while (Dummy != NULL);
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297 }
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298 }
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299
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300 /******************************************************************************
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301 * Put one pixel (Pixel) into GIF file. *
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302 ******************************************************************************/
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303 void DGifGetPixel(GifFileType *GifFile, GifPixelType Pixel)
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304 {
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305 GifByteType *Dummy;
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306 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
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307
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308 if (!IS_READABLE(Private)) {
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309 /* This file was NOT open for reading: */
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310 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
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311 }
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312
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313 #if defined(__MSDOS__) || defined(__GNUC__)
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314 if (--Private->PixelCount > 0xffff0000UL)
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315 #else
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316 if (--Private->PixelCount > 0xffff0000)
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317 #endif /* __MSDOS__ */
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318 {
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319 GifInternError(GifFile, D_GIF_ERR_DATA_TOO_BIG);
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320 }
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321
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322 DGifDecompressLine(GifFile, &Pixel, 1);
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323 if (Private->PixelCount == 0) {
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324 /* We probably would not be called any more, so lets clean */
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325 /* everything before we return: need to flush out all rest of */
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326 /* image until empty block (size 0) detected. We use GetCodeNext.*/
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327 do
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328 DGifGetCodeNext(GifFile, &Dummy);
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329 while (Dummy != NULL);
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330 }
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331 }
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332
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333 /******************************************************************************
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334 * Get an extension block (see GIF manual) from gif file. This routine only *
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335 * returns the first data block, and DGifGetExtensionNext shouldbe called *
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336 * after this one until NULL extension is returned. *
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337 * The Extension should NOT be freed by the user (not dynamically allocated).*
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338 * Note it is assumed the Extension desc. header ('!') has been read. *
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339 ******************************************************************************/
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340 void DGifGetExtension(GifFileType *GifFile, int *ExtCode,
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341 GifByteType **Extension)
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342 {
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343 GifByteType Buf;
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344 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
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345
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346 if (!IS_READABLE(Private)) {
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347 /* This file was NOT open for reading: */
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348 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
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349 }
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350
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351 GifRead(&Buf, 1, GifFile);
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352 *ExtCode = Buf;
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353
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354 DGifGetExtensionNext(GifFile, Extension);
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355 }
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356
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357 /******************************************************************************
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358 * Get a following extension block (see GIF manual) from gif file. This *
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359 * routine sould be called until NULL Extension is returned. *
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360 * The Extension should NOT be freed by the user (not dynamically allocated).*
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361 ******************************************************************************/
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362 void DGifGetExtensionNext(GifFileType *GifFile, GifByteType **Extension)
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363 {
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364 GifByteType Buf;
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365 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
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366
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367 GifRead(&Buf, 1, GifFile);
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368 if (Buf > 0) {
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369 *Extension = Private->Buf; /* Use private unused buffer. */
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370 (*Extension)[0] = Buf; /* Pascal strings notation (pos. 0 is len.). */
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371 GifRead(&((*Extension)[1]), Buf, GifFile);
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372 }
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373 else
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374 *Extension = NULL;
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375 }
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376
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377 /******************************************************************************
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378 * This routine should be called second to last, to close the GIF file. *
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379 ******************************************************************************/
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380 int DGifCloseFile(GifFileType *GifFile)
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381 {
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382 GifFilePrivateType *Private = (GifFilePrivateType *)GifFile->Private;
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383
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384 if (GifFile == NULL) return -1;
|
|
|
385
|
|
|
386 if (!IS_READABLE(Private))
|
|
|
387 {
|
|
|
388 /* This file was NOT open for reading: */
|
|
|
389 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
|
|
|
390 }
|
|
|
391
|
|
|
392 if (GifClose (GifFile))
|
|
|
393 {
|
|
|
394 GifInternError(GifFile, D_GIF_ERR_CLOSE_FAILED);
|
|
|
395 }
|
|
|
396 return 0;
|
|
|
397 }
|
|
|
398
|
|
|
399 /******************************************************************************
|
|
|
400 * Get 2 bytes (word) from the given file: *
|
|
|
401 ******************************************************************************/
|
|
|
402 static void DGifGetWord(GifFileType *GifFile, int *Word)
|
|
|
403 {
|
|
|
404 unsigned char c[2];
|
|
|
405
|
|
|
406 GifRead(c, 2, GifFile);
|
|
|
407
|
|
|
408 *Word = (((unsigned int) c[1]) << 8) + c[0];
|
|
|
409 }
|
|
|
410
|
|
|
411 /******************************************************************************
|
|
|
412 * Get the image code in compressed form. his routine can be called if the *
|
|
|
413 * information needed to be piped out as is. Obviously this is much faster *
|
|
|
414 * than decoding and encoding again. This routine should be followed by calls *
|
|
|
415 * to DGifGetCodeNext, until NULL block is returned. *
|
|
|
416 * The block should NOT be freed by the user (not dynamically allocated). *
|
|
|
417 ******************************************************************************/
|
|
|
418 void DGifGetCode(GifFileType *GifFile, int *CodeSize, GifByteType **CodeBlock)
|
|
|
419 {
|
|
|
420 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
421
|
|
|
422 if (!IS_READABLE(Private)) {
|
|
|
423 /* This file was NOT open for reading: */
|
|
|
424 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
|
|
|
425 }
|
|
|
426
|
|
|
427 *CodeSize = Private->BitsPerPixel;
|
|
|
428
|
|
|
429 DGifGetCodeNext(GifFile, CodeBlock);
|
|
|
430 }
|
|
|
431
|
|
|
432 /******************************************************************************
|
|
|
433 * Continue to get the image code in compressed form. This routine should be *
|
|
|
434 * called until NULL block is returned. *
|
|
|
435 * The block should NOT be freed by the user (not dynamically allocated). *
|
|
|
436 ******************************************************************************/
|
|
|
437 void DGifGetCodeNext(GifFileType *GifFile, GifByteType **CodeBlock)
|
|
|
438 {
|
|
|
439 GifByteType Buf;
|
|
|
440 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
441
|
|
|
442 GifRead(&Buf, 1, GifFile);
|
|
|
443
|
|
|
444 if (Buf > 0) {
|
|
|
445 *CodeBlock = Private->Buf; /* Use private unused buffer. */
|
|
|
446 (*CodeBlock)[0] = Buf; /* Pascal strings notation (pos. 0 is len.). */
|
|
|
447 GifRead(&((*CodeBlock)[1]), Buf, GifFile);
|
|
|
448 }
|
|
|
449 else {
|
|
|
450 *CodeBlock = NULL;
|
|
|
451 Private->Buf[0] = 0; /* Make sure the buffer is empty! */
|
|
|
452 Private->PixelCount = 0; /* And local info. indicate image read. */
|
|
|
453 }
|
|
|
454
|
|
|
455 }
|
|
|
456
|
|
|
457 /******************************************************************************
|
|
|
458 * Setup the LZ decompression for this image: *
|
|
|
459 ******************************************************************************/
|
|
|
460 static void DGifSetupDecompress(GifFileType *GifFile)
|
|
|
461 {
|
|
|
462 int i, BitsPerPixel;
|
|
|
463 GifByteType CodeSize;
|
|
|
464 unsigned int *Prefix;
|
|
|
465 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
466
|
|
|
467 GifRead(&CodeSize, 1, GifFile); /* Read Code size from file. */
|
|
|
468 BitsPerPixel = CodeSize;
|
|
|
469
|
|
|
470 Private->Buf[0] = 0; /* Input Buffer empty. */
|
|
|
471 Private->BitsPerPixel = BitsPerPixel;
|
|
|
472 Private->ClearCode = (1 << BitsPerPixel);
|
|
|
473 Private->EOFCode = Private->ClearCode + 1;
|
|
|
474 Private->RunningCode = Private->EOFCode + 1;
|
|
|
475 Private->RunningBits = BitsPerPixel + 1; /* Number of bits per code. */
|
|
|
476 Private->MaxCode1 = 1 << Private->RunningBits; /* Max. code + 1. */
|
|
|
477 Private->StackPtr = 0; /* No pixels on the pixel stack. */
|
|
|
478 Private->LastCode = NO_SUCH_CODE;
|
|
|
479 Private->CrntShiftState = 0; /* No information in CrntShiftDWord. */
|
|
|
480 Private->CrntShiftDWord = 0;
|
|
|
481
|
|
|
482 Prefix = Private->Prefix;
|
|
|
483 for (i = 0; i <= LZ_MAX_CODE; i++) Prefix[i] = NO_SUCH_CODE;
|
|
|
484 }
|
|
|
485
|
|
|
486 /******************************************************************************
|
|
|
487 * The LZ decompression routine: *
|
|
|
488 * This version decompress the given gif file into Line of length LineLen. *
|
|
|
489 * This routine can be called few times (one per scan line, for example), in *
|
|
|
490 * order the complete the whole image. *
|
|
|
491 ******************************************************************************/
|
|
|
492 static void DGifDecompressLine(GifFileType *GifFile, GifPixelType *Line,
|
|
|
493 int LineLen)
|
|
|
494 {
|
|
|
495 int i = 0, j, CrntCode, EOFCode, ClearCode, CrntPrefix, LastCode, StackPtr;
|
|
|
496 GifByteType *Stack, *Suffix;
|
|
|
497 unsigned int *Prefix;
|
|
|
498 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
499
|
|
|
500 StackPtr = Private->StackPtr;
|
|
|
501 Prefix = Private->Prefix;
|
|
|
502 Suffix = Private->Suffix;
|
|
|
503 Stack = Private->Stack;
|
|
|
504 EOFCode = Private->EOFCode;
|
|
|
505 ClearCode = Private->ClearCode;
|
|
|
506 LastCode = Private->LastCode;
|
|
|
507
|
|
|
508 CrntPrefix = 0;
|
|
|
509 if (StackPtr != 0) {
|
|
|
510 /* Let pop the stack off before continueing to read the gif file: */
|
|
|
511 while (StackPtr != 0 && i < LineLen) Line[i++] = Stack[--StackPtr];
|
|
|
512 }
|
|
|
513
|
|
|
514 while (i < LineLen) { /* Decode LineLen items. */
|
|
|
515 DGifDecompressInput(GifFile, &CrntCode);
|
|
|
516
|
|
|
517 if (CrntCode == EOFCode) {
|
|
|
518 /* Note however that usually we will not be here as we will stop */
|
|
|
519 /* decoding as soon as we got all the pixel, or EOF code will */
|
|
|
520 /* not be read at all, and DGifGetLine/Pixel clean everything. */
|
|
|
521 if (i != LineLen - 1 || Private->PixelCount != 0) {
|
|
|
522 GifInternError(GifFile, D_GIF_ERR_EOF_TOO_SOON);
|
|
|
523 }
|
|
|
524 i++;
|
|
|
525 }
|
|
|
526 else if (CrntCode == ClearCode) {
|
|
|
527 /* We need to start over again: */
|
|
|
528 for (j = 0; j <= LZ_MAX_CODE; j++) Prefix[j] = NO_SUCH_CODE;
|
|
|
529 Private->RunningCode = Private->EOFCode + 1;
|
|
|
530 Private->RunningBits = Private->BitsPerPixel + 1;
|
|
|
531 Private->MaxCode1 = 1 << Private->RunningBits;
|
|
|
532 LastCode = Private->LastCode = NO_SUCH_CODE;
|
|
|
533 }
|
|
|
534 else {
|
|
|
535 /* Its regular code - if in pixel range simply add it to output */
|
|
|
536 /* stream, otherwise trace to codes linked list until the prefix */
|
|
|
537 /* is in pixel range: */
|
|
|
538 if (CrntCode < ClearCode) {
|
|
|
539 /* This is simple - its pixel scalar, so add it to output: */
|
|
|
540 Line[i++] = CrntCode;
|
|
|
541 }
|
|
|
542 else {
|
|
|
543 /* Its a code to needed to be traced: trace the linked list */
|
|
|
544 /* until the prefix is a pixel, while pushing the suffix */
|
|
|
545 /* pixels on our stack. If we done, pop the stack in reverse */
|
|
|
546 /* (thats what stack is good for!) order to output. */
|
|
|
547 if (Prefix[CrntCode] == NO_SUCH_CODE) {
|
|
|
548 /* Only allowed if CrntCode is exactly the running code: */
|
|
|
549 /* In that case CrntCode = XXXCode, CrntCode or the */
|
|
|
550 /* prefix code is last code and the suffix char is */
|
|
|
551 /* exactly the prefix of last code! */
|
|
|
552 if (CrntCode == Private->RunningCode - 2) {
|
|
|
553 CrntPrefix = LastCode;
|
|
|
554 Suffix[Private->RunningCode - 2] =
|
|
|
555 Stack[StackPtr++] = DGifGetPrefixChar(Prefix,
|
|
|
556 LastCode, ClearCode);
|
|
|
557 }
|
|
|
558 else {
|
|
|
559 GifInternError(GifFile, D_GIF_ERR_IMAGE_DEFECT);
|
|
|
560 }
|
|
|
561 }
|
|
|
562 else
|
|
|
563 CrntPrefix = CrntCode;
|
|
|
564
|
|
|
565 /* Now (if image is O.K.) we should not get an NO_SUCH_CODE */
|
|
|
566 /* During the trace. As we might loop forever, in case of */
|
|
|
567 /* defective image, we count the number of loops we trace */
|
|
|
568 /* and stop if we got LZ_MAX_CODE. obviously we can not */
|
|
|
569 /* loop more than that. */
|
|
|
570 j = 0;
|
|
|
571 while (j++ <= LZ_MAX_CODE &&
|
|
|
572 CrntPrefix > ClearCode &&
|
|
|
573 CrntPrefix <= LZ_MAX_CODE) {
|
|
|
574 Stack[StackPtr++] = Suffix[CrntPrefix];
|
|
|
575 CrntPrefix = Prefix[CrntPrefix];
|
|
|
576 }
|
|
|
577 if (j >= LZ_MAX_CODE || CrntPrefix > LZ_MAX_CODE) {
|
|
|
578 GifInternError(GifFile, D_GIF_ERR_IMAGE_DEFECT);
|
|
|
579 }
|
|
|
580 /* Push the last character on stack: */
|
|
|
581 Stack[StackPtr++] = CrntPrefix;
|
|
|
582
|
|
|
583 /* Now lets pop all the stack into output: */
|
|
|
584 while (StackPtr != 0 && i < LineLen)
|
|
|
585 Line[i++] = Stack[--StackPtr];
|
|
|
586 }
|
|
|
587 if (LastCode != NO_SUCH_CODE) {
|
|
|
588 Prefix[Private->RunningCode - 2] = LastCode;
|
|
|
589
|
|
|
590 if (CrntCode == Private->RunningCode - 2) {
|
|
|
591 /* Only allowed if CrntCode is exactly the running code: */
|
|
|
592 /* In that case CrntCode = XXXCode, CrntCode or the */
|
|
|
593 /* prefix code is last code and the suffix char is */
|
|
|
594 /* exactly the prefix of last code! */
|
|
|
595 Suffix[Private->RunningCode - 2] =
|
|
|
596 DGifGetPrefixChar(Prefix, LastCode, ClearCode);
|
|
|
597 }
|
|
|
598 else {
|
|
|
599 Suffix[Private->RunningCode - 2] =
|
|
|
600 DGifGetPrefixChar(Prefix, CrntCode, ClearCode);
|
|
|
601 }
|
|
|
602 }
|
|
|
603 LastCode = CrntCode;
|
|
|
604 }
|
|
|
605 }
|
|
|
606
|
|
|
607 Private->LastCode = LastCode;
|
|
|
608 Private->StackPtr = StackPtr;
|
|
|
609 }
|
|
|
610
|
|
|
611 /******************************************************************************
|
|
|
612 * Routine to trace the Prefixes linked list until we get a prefix which is *
|
|
|
613 * not code, but a pixel value (less than ClearCode). Returns that pixel value.*
|
|
|
614 * If image is defective, we might loop here forever, so we limit the loops to *
|
|
|
615 * the maximum possible if image O.k. - LZ_MAX_CODE times. *
|
|
|
616 ******************************************************************************/
|
|
|
617 static int DGifGetPrefixChar(unsigned int *Prefix, int Code, int ClearCode)
|
|
|
618 {
|
|
|
619 int i = 0;
|
|
|
620
|
|
|
621 while (Code > ClearCode && i++ <= LZ_MAX_CODE) Code = Prefix[Code];
|
|
|
622 return Code;
|
|
|
623 }
|
|
|
624
|
|
|
625 /******************************************************************************
|
|
|
626 * Interface for accessing the LZ codes directly. Set Code to the real code *
|
|
|
627 * (12bits), or to -1 if EOF code is returned. *
|
|
|
628 ******************************************************************************/
|
|
|
629 void DGifGetLZCodes(GifFileType *GifFile, int *Code)
|
|
|
630 {
|
|
|
631 GifByteType *CodeBlock;
|
|
|
632 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
633
|
|
|
634 if (!IS_READABLE(Private)) {
|
|
|
635 /* This file was NOT open for reading: */
|
|
|
636 GifInternError(GifFile, D_GIF_ERR_NOT_READABLE);
|
|
|
637 }
|
|
|
638
|
|
|
639 DGifDecompressInput(GifFile, Code);
|
|
|
640
|
|
|
641 if (*Code == Private->EOFCode) {
|
|
|
642 /* Skip rest of codes (hopefully only NULL terminating block): */
|
|
|
643 do
|
|
|
644 DGifGetCodeNext(GifFile, &CodeBlock);
|
|
|
645 while (CodeBlock != NULL);
|
|
|
646
|
|
|
647 *Code = -1;
|
|
|
648 }
|
|
|
649 else if (*Code == Private->ClearCode) {
|
|
|
650 /* We need to start over again: */
|
|
|
651 Private->RunningCode = Private->EOFCode + 1;
|
|
|
652 Private->RunningBits = Private->BitsPerPixel + 1;
|
|
|
653 Private->MaxCode1 = 1 << Private->RunningBits;
|
|
|
654 }
|
|
|
655 }
|
|
|
656
|
|
|
657 /******************************************************************************
|
|
|
658 * The LZ decompression input routine: *
|
|
|
659 * This routine is responsable for the decompression of the bit stream from *
|
|
|
660 * 8 bits (bytes) packets, into the real codes. *
|
|
|
661 * Returns GIF_OK if read succesfully. *
|
|
|
662 ******************************************************************************/
|
|
|
663 static void DGifDecompressInput(GifFileType *GifFile, int *Code)
|
|
|
664 {
|
|
|
665 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
666 GifByteType NextByte;
|
|
|
667 static unsigned int CodeMasks[] = {
|
|
|
668 0x0000, 0x0001, 0x0003, 0x0007,
|
|
|
669 0x000f, 0x001f, 0x003f, 0x007f,
|
|
|
670 0x00ff, 0x01ff, 0x03ff, 0x07ff,
|
|
|
671 0x0fff
|
|
|
672 };
|
|
|
673
|
|
|
674 while (Private->CrntShiftState < Private->RunningBits) {
|
|
|
675 /* Needs to get more bytes from input stream for next code: */
|
|
|
676 DGifBufferedInput(GifFile, &NextByte);
|
|
|
677 Private->CrntShiftDWord |=
|
|
|
678 ((unsigned long) NextByte) << Private->CrntShiftState;
|
|
|
679 Private->CrntShiftState += 8;
|
|
|
680 }
|
|
|
681 *Code = Private->CrntShiftDWord & CodeMasks[Private->RunningBits];
|
|
|
682
|
|
|
683 Private->CrntShiftDWord >>= Private->RunningBits;
|
|
|
684 Private->CrntShiftState -= Private->RunningBits;
|
|
|
685
|
|
|
686 /* If code cannt fit into RunningBits bits, must raise its size. Note */
|
|
|
687 /* however that codes above 4095 are used for special signaling. */
|
|
|
688 if (++Private->RunningCode > Private->MaxCode1 &&
|
|
|
689 Private->RunningBits < LZ_BITS) {
|
|
|
690 Private->MaxCode1 <<= 1;
|
|
|
691 Private->RunningBits++;
|
|
|
692 }
|
|
|
693 }
|
|
|
694
|
|
|
695 /******************************************************************************
|
|
|
696 * This routines read one gif data block at a time and buffers it internally *
|
|
|
697 * so that the decompression routine could access it. *
|
|
|
698 * The routine returns the next byte from its internal buffer (or read next *
|
|
|
699 * block in if buffer empty) *
|
|
|
700 ******************************************************************************/
|
|
|
701 static void DGifBufferedInput(GifFileType *GifFile, GifByteType *NextByte)
|
|
|
702 {
|
|
|
703 GifFilePrivateType *Private = (GifFilePrivateType *) GifFile->Private;
|
|
|
704 GifByteType *Buf = Private->Buf;
|
|
|
705
|
|
|
706 if (Buf[0] == 0) {
|
|
|
707 /* Needs to read the next buffer - this one is empty: */
|
|
|
708 GifRead(Buf, 1, GifFile);
|
|
|
709 GifRead((Buf + 1), Buf[0], GifFile);
|
|
|
710 *NextByte = Buf[1];
|
|
|
711 Buf[1] = 2; /* We use now the second place as last char read! */
|
|
|
712 Buf[0]--;
|
|
|
713 }
|
|
|
714 else {
|
|
|
715 *NextByte = Buf[Buf[1]++];
|
|
|
716 Buf[0]--;
|
|
|
717 }
|
|
|
718 }
|
|
|
719
|
|
|
720 /******************************************************************************
|
|
|
721 * This routine reads an entire GIF into core, hanging all its state info off *
|
|
|
722 * the GifFileType pointer. Call DGifOpenFileName() or DGifOpenFileHandle() *
|
|
|
723 * first to initialize I/O. Its inverse is EGifSpew(). *
|
|
|
724 ******************************************************************************/
|
|
|
725 void DGifSlurp(GifFileType *GifFile)
|
|
|
726 {
|
|
|
727 int ImageSize;
|
|
|
728 GifRecordType RecordType;
|
|
|
729 SavedImage *sp;
|
|
|
730 GifByteType *ExtData;
|
|
|
731
|
|
|
732 /* Some versions of malloc dislike 0-length requests */
|
|
|
733 GifFile->SavedImages = (SavedImage *)malloc(sizeof(SavedImage));
|
|
|
734 memset(GifFile->SavedImages, 0, sizeof(SavedImage));
|
|
|
735 sp = &GifFile->SavedImages[0];
|
|
|
736
|
|
|
737 do {
|
|
|
738 DGifGetRecordType(GifFile, &RecordType);
|
|
|
739
|
|
|
740 switch (RecordType) {
|
|
|
741 case IMAGE_DESC_RECORD_TYPE:
|
|
|
742 DGifGetImageDesc(GifFile);
|
|
|
743
|
|
|
744 sp = &GifFile->SavedImages[GifFile->ImageCount-1];
|
|
|
745 ImageSize = sp->ImageDesc.Width * sp->ImageDesc.Height;
|
|
|
746
|
|
|
747 sp->RasterBits
|
|
|
748 = (GifPixelType*) malloc(ImageSize * sizeof(GifPixelType));
|
|
|
749
|
|
|
750 DGifGetLine(GifFile, sp->RasterBits, ImageSize);
|
|
|
751 break;
|
|
|
752
|
|
|
753 case EXTENSION_RECORD_TYPE:
|
|
|
754 DGifGetExtension(GifFile,&sp->Function,&ExtData);
|
|
|
755
|
|
|
756 do {
|
|
|
757 if (AddExtensionBlock(sp, ExtData[0], ExtData+1) == GIF_ERROR)
|
|
|
758 GifInternError(GifFile, D_GIF_ERR_NOT_ENOUGH_MEM);
|
|
|
759 DGifGetExtensionNext(GifFile, &ExtData);
|
|
|
760 } while (ExtData != NULL);
|
|
|
761 break;
|
|
|
762
|
|
|
763 case TERMINATE_RECORD_TYPE:
|
|
|
764 break;
|
|
|
765
|
|
|
766 default: /* Should be trapped by DGifGetRecordType */
|
|
|
767 break;
|
|
|
768 }
|
|
|
769 } while (RecordType != TERMINATE_RECORD_TYPE);
|
|
|
770 }
|
|
|
771
|
|
|
772 /******************************************************************************
|
|
|
773 * Extension record functions *
|
|
|
774 ******************************************************************************/
|
|
|
775
|
|
|
776 void MakeExtension(SavedImage *New, int Function)
|
|
|
777 {
|
|
|
778 New->Function = Function;
|
|
|
779 /*
|
|
|
780 * Someday we might have to deal with multiple extensions.
|
|
|
781 */
|
|
|
782 }
|
|
|
783
|
|
|
784 int AddExtensionBlock(SavedImage *New, int Len, GifByteType *data)
|
|
|
785 {
|
|
|
786 int size;
|
|
|
787 ExtensionBlock *ep;
|
|
|
788
|
|
|
789 if (New->ExtensionBlocks == NULL)
|
|
|
790 New->ExtensionBlocks = (ExtensionBlock *)malloc(sizeof(ExtensionBlock));
|
|
|
791 else
|
|
|
792 New->ExtensionBlocks =
|
|
|
793 (ExtensionBlock *)realloc(New->ExtensionBlocks,
|
|
|
794 sizeof(ExtensionBlock) * (New->ExtensionBlockCount + 1));
|
|
|
795
|
|
|
796 if (New->ExtensionBlocks == NULL)
|
|
|
797 return(GIF_ERROR);
|
|
|
798
|
|
|
799 ep = &New->ExtensionBlocks[New->ExtensionBlockCount++];
|
|
|
800 ep->ByteCount = Len;
|
|
|
801 size = Len * sizeof(GifByteType);
|
|
|
802 ep->Bytes = (GifByteType *)malloc(size);
|
|
|
803 memcpy(ep->Bytes, data, size);
|
|
|
804 return(GIF_OK);
|
|
|
805 }
|
|
|
806
|
|
|
807 void FreeExtension(SavedImage *Image)
|
|
|
808 {
|
|
|
809 ExtensionBlock *ep;
|
|
|
810
|
|
|
811 for (ep = Image->ExtensionBlocks;
|
|
|
812 ep < Image->ExtensionBlocks + Image->ExtensionBlockCount;
|
|
|
813 ep++)
|
|
|
814 (void) free((char *)ep->Bytes);
|
|
|
815 free((char *)Image->ExtensionBlocks);
|
|
|
816 Image->ExtensionBlocks = NULL;
|
|
|
817 }
|
|
|
818
|
|
|
819 /******************************************************************************
|
|
|
820 * Image block allocation functions *
|
|
|
821 ******************************************************************************/
|
|
|
822 /*
|
|
|
823 * Append an image block to the SavedImages array
|
|
|
824 */
|
|
321
|
825 SavedImage *
|
|
|
826 MakeSavedImage(GifFileType *GifFile, SavedImage *CopyFrom)
|
|
308
|
827 {
|
|
|
828 SavedImage *sp;
|
|
|
829
|
|
|
830 if (GifFile->SavedImages == NULL)
|
|
|
831 GifFile->SavedImages = (SavedImage *)malloc(sizeof(SavedImage));
|
|
|
832 else
|
|
|
833 GifFile->SavedImages = (SavedImage *)realloc(GifFile->SavedImages,
|
|
|
834 sizeof(SavedImage) * (GifFile->ImageCount+1));
|
|
|
835
|
|
|
836 if (GifFile->SavedImages == NULL)
|
|
|
837 return((SavedImage *)NULL);
|
|
|
838 else
|
|
|
839 {
|
|
|
840 sp = &GifFile->SavedImages[GifFile->ImageCount++];
|
|
|
841 memset((char *)sp, '\0', sizeof(SavedImage));
|
|
|
842
|
|
|
843 if (CopyFrom)
|
|
|
844 {
|
|
|
845 memcpy((char *)sp, CopyFrom, sizeof(SavedImage));
|
|
|
846
|
|
|
847 /*
|
|
|
848 * Make our own allocated copies of the heap fields in the
|
|
|
849 * copied record. This guards against potential aliasing
|
|
|
850 * problems.
|
|
|
851 */
|
|
|
852
|
|
|
853 /* first, the local color map */
|
|
|
854 if (sp->ImageDesc.ColorMap)
|
|
|
855 sp->ImageDesc.ColorMap =
|
|
|
856 MakeMapObject(CopyFrom->ImageDesc.ColorMap->ColorCount,
|
|
|
857 CopyFrom->ImageDesc.ColorMap->Colors);
|
|
|
858
|
|
|
859 /* next, the raster */
|
|
321
|
860 sp->RasterBits = (GifPixelType*)malloc(sizeof(GifPixelType)
|
|
308
|
861 * CopyFrom->ImageDesc.Height
|
|
|
862 * CopyFrom->ImageDesc.Width);
|
|
|
863 memcpy(sp->RasterBits,
|
|
|
864 CopyFrom->RasterBits,
|
|
|
865 sizeof(GifPixelType)
|
|
|
866 * CopyFrom->ImageDesc.Height
|
|
|
867 * CopyFrom->ImageDesc.Width);
|
|
|
868
|
|
|
869 /* finally, the extension blocks */
|
|
|
870 if (sp->ExtensionBlocks)
|
|
|
871 {
|
|
|
872 sp->ExtensionBlocks
|
|
|
873 = (ExtensionBlock*)malloc(sizeof(ExtensionBlock)
|
|
|
874 * CopyFrom->ExtensionBlockCount);
|
|
|
875 memcpy(sp->ExtensionBlocks,
|
|
|
876 CopyFrom->ExtensionBlocks,
|
|
|
877 sizeof(ExtensionBlock)
|
|
|
878 * CopyFrom->ExtensionBlockCount);
|
|
|
879
|
|
|
880 /*
|
|
|
881 * For the moment, the actual blocks can take their
|
|
|
882 * chances with free(). We'll fix this later.
|
|
|
883 */
|
|
|
884 }
|
|
|
885 }
|
|
|
886
|
|
|
887 return(sp);
|
|
|
888 }
|
|
|
889 }
|
|
|
890
|
|
|
891 void FreeSavedImages(GifFileType *GifFile)
|
|
|
892 {
|
|
|
893 SavedImage *sp;
|
|
|
894
|
|
|
895 for (sp = GifFile->SavedImages;
|
|
|
896 sp < GifFile->SavedImages + GifFile->ImageCount;
|
|
|
897 sp++)
|
|
|
898 {
|
|
|
899 if (sp->ImageDesc.ColorMap)
|
|
|
900 FreeMapObject(sp->ImageDesc.ColorMap);
|
|
|
901
|
|
|
902 if (sp->RasterBits)
|
|
|
903 free((char *)sp->RasterBits);
|
|
|
904
|
|
|
905 if (sp->ExtensionBlocks)
|
|
|
906 FreeExtension(sp);
|
|
|
907 }
|
|
|
908 free((char *) GifFile->SavedImages);
|
|
|
909 }
|
|
|
910
|
|
|
911 /******************************************************************************
|
|
|
912 * Miscellaneous utility functions *
|
|
|
913 ******************************************************************************/
|
|
|
914
|
|
|
915 int BitSize(int n)
|
|
|
916 /* return smallest bitfield size n will fit in */
|
|
|
917 {
|
|
|
918 register int i;
|
|
|
919
|
|
|
920 for (i = 1; i <= 8; i++)
|
|
|
921 if ((1 << i) >= n)
|
|
|
922 break;
|
|
|
923 return(i);
|
|
|
924 }
|
|
|
925
|
|
|
926 /******************************************************************************
|
|
|
927 * Color map object functions *
|
|
|
928 ******************************************************************************/
|
|
|
929
|
|
|
930 ColorMapObject *MakeMapObject(int ColorCount, GifColorType *ColorMap)
|
|
|
931 /*
|
|
|
932 * Allocate a color map of given size; initialize with contents of
|
|
|
933 * ColorMap if that pointer is non-NULL.
|
|
|
934 */
|
|
|
935 {
|
|
|
936 ColorMapObject *Object;
|
|
|
937
|
|
|
938 if (ColorCount != (1 << BitSize(ColorCount)))
|
|
|
939 return((ColorMapObject *)NULL);
|
|
|
940
|
|
|
941 Object = (ColorMapObject *)malloc(sizeof(ColorMapObject));
|
|
|
942 if (Object == (ColorMapObject *)NULL)
|
|
|
943 return((ColorMapObject *)NULL);
|
|
|
944
|
|
|
945 Object->Colors = (GifColorType *)calloc(ColorCount, sizeof(GifColorType));
|
|
|
946 if (Object->Colors == (GifColorType *)NULL)
|
|
|
947 return((ColorMapObject *)NULL);
|
|
|
948
|
|
|
949 Object->ColorCount = ColorCount;
|
|
|
950 Object->BitsPerPixel = BitSize(ColorCount);
|
|
|
951
|
|
|
952 if (ColorMap)
|
|
|
953 memcpy((char *)Object->Colors,
|
|
|
954 (char *)ColorMap, ColorCount * sizeof(GifColorType));
|
|
|
955
|
|
|
956 return(Object);
|
|
|
957 }
|
|
|
958
|
|
|
959 void FreeMapObject(ColorMapObject *Object)
|
|
|
960 /*
|
|
|
961 * Free a color map object
|
|
|
962 */
|
|
|
963 {
|
|
|
964 free(Object->Colors);
|
|
|
965 free(Object);
|
|
|
966 }
|
