1 /***************************************************************************/ |
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2 /* */ |
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3 /* ftlzw.c */ |
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4 /* */ |
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5 /* FreeType support for .Z compressed files. */ |
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6 /* */ |
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7 /* This optional component relies on NetBSD's zopen(). It should mainly */ |
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8 /* be used to parse compressed PCF fonts, as found with many X11 server */ |
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9 /* distributions. */ |
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10 /* */ |
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11 /* Copyright 2004, 2005, 2006, 2009, 2010 by */ |
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12 /* Albert Chin-A-Young. */ |
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13 /* */ |
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14 /* Based on code in src/gzip/ftgzip.c, Copyright 2004 by */ |
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15 /* David Turner, Robert Wilhelm, and Werner Lemberg. */ |
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16 /* */ |
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17 /* This file is part of the FreeType project, and may only be used, */ |
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18 /* modified, and distributed under the terms of the FreeType project */ |
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19 /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ |
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20 /* this file you indicate that you have read the license and */ |
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21 /* understand and accept it fully. */ |
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22 /* */ |
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23 /***************************************************************************/ |
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24 |
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25 #include <ft2build.h> |
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26 #include FT_INTERNAL_MEMORY_H |
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27 #include FT_INTERNAL_STREAM_H |
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28 #include FT_INTERNAL_DEBUG_H |
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29 #include FT_LZW_H |
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30 #include FT_CONFIG_STANDARD_LIBRARY_H |
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31 |
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32 |
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33 #include FT_MODULE_ERRORS_H |
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34 |
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35 #undef __FTERRORS_H__ |
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36 |
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37 #define FT_ERR_PREFIX LZW_Err_ |
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38 #define FT_ERR_BASE FT_Mod_Err_LZW |
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39 |
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40 #include FT_ERRORS_H |
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41 |
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42 |
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43 #ifdef FT_CONFIG_OPTION_USE_LZW |
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44 |
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45 #ifdef FT_CONFIG_OPTION_PIC |
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46 #error "lzw code does not support PIC yet" |
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47 #endif |
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48 |
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49 #include "ftzopen.h" |
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50 |
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51 |
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52 /***************************************************************************/ |
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53 /***************************************************************************/ |
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54 /***** *****/ |
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55 /***** M E M O R Y M A N A G E M E N T *****/ |
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56 /***** *****/ |
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57 /***************************************************************************/ |
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58 /***************************************************************************/ |
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59 |
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60 /***************************************************************************/ |
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61 /***************************************************************************/ |
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62 /***** *****/ |
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63 /***** F I L E D E S C R I P T O R *****/ |
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64 /***** *****/ |
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65 /***************************************************************************/ |
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66 /***************************************************************************/ |
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67 |
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68 #define FT_LZW_BUFFER_SIZE 4096 |
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69 |
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70 typedef struct FT_LZWFileRec_ |
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71 { |
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72 FT_Stream source; /* parent/source stream */ |
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73 FT_Stream stream; /* embedding stream */ |
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74 FT_Memory memory; /* memory allocator */ |
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75 FT_LzwStateRec lzw; /* lzw decompressor state */ |
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76 |
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77 FT_Byte buffer[FT_LZW_BUFFER_SIZE]; /* output buffer */ |
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78 FT_ULong pos; /* position in output */ |
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79 FT_Byte* cursor; |
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80 FT_Byte* limit; |
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81 |
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82 } FT_LZWFileRec, *FT_LZWFile; |
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83 |
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84 |
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85 /* check and skip .Z header */ |
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86 static FT_Error |
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87 ft_lzw_check_header( FT_Stream stream ) |
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88 { |
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89 FT_Error error; |
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90 FT_Byte head[2]; |
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91 |
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92 |
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93 if ( FT_STREAM_SEEK( 0 ) || |
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94 FT_STREAM_READ( head, 2 ) ) |
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95 goto Exit; |
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96 |
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97 /* head[0] && head[1] are the magic numbers */ |
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98 if ( head[0] != 0x1f || |
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99 head[1] != 0x9d ) |
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100 error = LZW_Err_Invalid_File_Format; |
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101 |
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102 Exit: |
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103 return error; |
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104 } |
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105 |
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106 |
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107 static FT_Error |
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108 ft_lzw_file_init( FT_LZWFile zip, |
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109 FT_Stream stream, |
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110 FT_Stream source ) |
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111 { |
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112 FT_LzwState lzw = &zip->lzw; |
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113 FT_Error error = LZW_Err_Ok; |
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114 |
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115 |
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116 zip->stream = stream; |
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117 zip->source = source; |
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118 zip->memory = stream->memory; |
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119 |
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120 zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE; |
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121 zip->cursor = zip->limit; |
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122 zip->pos = 0; |
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123 |
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124 /* check and skip .Z header */ |
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125 error = ft_lzw_check_header( source ); |
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126 if ( error ) |
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127 goto Exit; |
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128 |
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129 /* initialize internal lzw variable */ |
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130 ft_lzwstate_init( lzw, source ); |
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131 |
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132 Exit: |
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133 return error; |
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134 } |
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135 |
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136 |
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137 static void |
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138 ft_lzw_file_done( FT_LZWFile zip ) |
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139 { |
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140 /* clear the rest */ |
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141 ft_lzwstate_done( &zip->lzw ); |
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142 |
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143 zip->memory = NULL; |
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144 zip->source = NULL; |
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145 zip->stream = NULL; |
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146 } |
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147 |
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148 |
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149 static FT_Error |
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150 ft_lzw_file_reset( FT_LZWFile zip ) |
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151 { |
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152 FT_Stream stream = zip->source; |
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153 FT_Error error; |
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154 |
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155 |
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156 if ( !FT_STREAM_SEEK( 0 ) ) |
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157 { |
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158 ft_lzwstate_reset( &zip->lzw ); |
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159 |
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160 zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE; |
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161 zip->cursor = zip->limit; |
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162 zip->pos = 0; |
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163 } |
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164 |
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165 return error; |
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166 } |
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167 |
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168 |
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169 static FT_Error |
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170 ft_lzw_file_fill_output( FT_LZWFile zip ) |
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171 { |
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172 FT_LzwState lzw = &zip->lzw; |
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173 FT_ULong count; |
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174 FT_Error error = LZW_Err_Ok; |
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175 |
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176 |
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177 zip->cursor = zip->buffer; |
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178 |
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179 count = ft_lzwstate_io( lzw, zip->buffer, FT_LZW_BUFFER_SIZE ); |
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180 |
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181 zip->limit = zip->cursor + count; |
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182 |
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183 if ( count == 0 ) |
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184 error = LZW_Err_Invalid_Stream_Operation; |
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185 |
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186 return error; |
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187 } |
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188 |
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189 |
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190 /* fill output buffer; `count' must be <= FT_LZW_BUFFER_SIZE */ |
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191 static FT_Error |
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192 ft_lzw_file_skip_output( FT_LZWFile zip, |
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193 FT_ULong count ) |
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194 { |
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195 FT_Error error = LZW_Err_Ok; |
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196 |
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197 |
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198 /* first, we skip what we can from the output buffer */ |
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199 { |
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200 FT_ULong delta = (FT_ULong)( zip->limit - zip->cursor ); |
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201 |
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202 |
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203 if ( delta >= count ) |
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204 delta = count; |
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205 |
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206 zip->cursor += delta; |
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207 zip->pos += delta; |
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208 |
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209 count -= delta; |
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210 } |
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211 |
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212 /* next, we skip as many bytes remaining as possible */ |
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213 while ( count > 0 ) |
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214 { |
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215 FT_ULong delta = FT_LZW_BUFFER_SIZE; |
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216 FT_ULong numread; |
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217 |
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218 |
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219 if ( delta > count ) |
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220 delta = count; |
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221 |
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222 numread = ft_lzwstate_io( &zip->lzw, NULL, delta ); |
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223 if ( numread < delta ) |
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224 { |
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225 /* not enough bytes */ |
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226 error = LZW_Err_Invalid_Stream_Operation; |
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227 break; |
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228 } |
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229 |
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230 zip->pos += delta; |
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231 count -= delta; |
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232 } |
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233 |
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234 return error; |
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235 } |
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236 |
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237 |
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238 static FT_ULong |
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239 ft_lzw_file_io( FT_LZWFile zip, |
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240 FT_ULong pos, |
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241 FT_Byte* buffer, |
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242 FT_ULong count ) |
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243 { |
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244 FT_ULong result = 0; |
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245 FT_Error error; |
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246 |
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247 |
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248 /* seeking backwards. */ |
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249 if ( pos < zip->pos ) |
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250 { |
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251 /* If the new position is within the output buffer, simply */ |
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252 /* decrement pointers, otherwise we reset the stream completely! */ |
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253 if ( ( zip->pos - pos ) <= (FT_ULong)( zip->cursor - zip->buffer ) ) |
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254 { |
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255 zip->cursor -= zip->pos - pos; |
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256 zip->pos = pos; |
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257 } |
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258 else |
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259 { |
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260 error = ft_lzw_file_reset( zip ); |
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261 if ( error ) |
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262 goto Exit; |
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263 } |
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264 } |
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265 |
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266 /* skip unwanted bytes */ |
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267 if ( pos > zip->pos ) |
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268 { |
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269 error = ft_lzw_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) ); |
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270 if ( error ) |
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271 goto Exit; |
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272 } |
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273 |
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274 if ( count == 0 ) |
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275 goto Exit; |
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276 |
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277 /* now read the data */ |
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278 for (;;) |
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279 { |
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280 FT_ULong delta; |
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281 |
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282 |
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283 delta = (FT_ULong)( zip->limit - zip->cursor ); |
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284 if ( delta >= count ) |
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285 delta = count; |
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286 |
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287 FT_MEM_COPY( buffer + result, zip->cursor, delta ); |
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288 result += delta; |
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289 zip->cursor += delta; |
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290 zip->pos += delta; |
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291 |
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292 count -= delta; |
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293 if ( count == 0 ) |
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294 break; |
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295 |
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296 error = ft_lzw_file_fill_output( zip ); |
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297 if ( error ) |
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298 break; |
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299 } |
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300 |
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301 Exit: |
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302 return result; |
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303 } |
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304 |
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305 |
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306 /***************************************************************************/ |
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307 /***************************************************************************/ |
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308 /***** *****/ |
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309 /***** L Z W E M B E D D I N G S T R E A M *****/ |
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310 /***** *****/ |
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311 /***************************************************************************/ |
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312 /***************************************************************************/ |
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313 |
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314 static void |
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315 ft_lzw_stream_close( FT_Stream stream ) |
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316 { |
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317 FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer; |
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318 FT_Memory memory = stream->memory; |
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319 |
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320 |
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321 if ( zip ) |
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322 { |
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323 /* finalize lzw file descriptor */ |
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324 ft_lzw_file_done( zip ); |
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325 |
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326 FT_FREE( zip ); |
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327 |
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328 stream->descriptor.pointer = NULL; |
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329 } |
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330 } |
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331 |
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332 |
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333 static FT_ULong |
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334 ft_lzw_stream_io( FT_Stream stream, |
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335 FT_ULong pos, |
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336 FT_Byte* buffer, |
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337 FT_ULong count ) |
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338 { |
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339 FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer; |
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340 |
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341 |
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342 return ft_lzw_file_io( zip, pos, buffer, count ); |
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343 } |
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344 |
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345 |
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346 FT_EXPORT_DEF( FT_Error ) |
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347 FT_Stream_OpenLZW( FT_Stream stream, |
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348 FT_Stream source ) |
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349 { |
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350 FT_Error error; |
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351 FT_Memory memory = source->memory; |
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352 FT_LZWFile zip; |
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353 |
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354 |
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355 /* |
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356 * Check the header right now; this prevents allocation of a huge |
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357 * LZWFile object (400 KByte of heap memory) if not necessary. |
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358 * |
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359 * Did I mention that you should never use .Z compressed font |
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360 * files? |
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361 */ |
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362 error = ft_lzw_check_header( source ); |
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363 if ( error ) |
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364 goto Exit; |
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365 |
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366 FT_ZERO( stream ); |
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367 stream->memory = memory; |
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368 |
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369 if ( !FT_NEW( zip ) ) |
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370 { |
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371 error = ft_lzw_file_init( zip, stream, source ); |
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372 if ( error ) |
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373 { |
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374 FT_FREE( zip ); |
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375 goto Exit; |
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376 } |
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377 |
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378 stream->descriptor.pointer = zip; |
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379 } |
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380 |
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381 stream->size = 0x7FFFFFFFL; /* don't know the real size! */ |
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382 stream->pos = 0; |
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383 stream->base = 0; |
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384 stream->read = ft_lzw_stream_io; |
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385 stream->close = ft_lzw_stream_close; |
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386 |
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387 Exit: |
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388 return error; |
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389 } |
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390 |
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391 |
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392 #include "ftzopen.c" |
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393 |
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394 |
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395 #else /* !FT_CONFIG_OPTION_USE_LZW */ |
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396 |
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397 |
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398 FT_EXPORT_DEF( FT_Error ) |
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399 FT_Stream_OpenLZW( FT_Stream stream, |
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400 FT_Stream source ) |
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401 { |
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402 FT_UNUSED( stream ); |
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403 FT_UNUSED( source ); |
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404 |
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405 return LZW_Err_Unimplemented_Feature; |
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406 } |
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407 |
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408 |
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409 #endif /* !FT_CONFIG_OPTION_USE_LZW */ |
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410 |
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411 |
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412 /* END */ |
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