/src/freetype/src/lzw/ftlzw.c
C | 413 lines | 240 code | 106 blank | 67 comment | 28 complexity | b90f0caadc3ce08077e98176fc217daa MD5 | raw file
1/***************************************************************************/ 2/* */ 3/* ftlzw.c */ 4/* */ 5/* FreeType support for .Z compressed files. */ 6/* */ 7/* This optional component relies on NetBSD's zopen(). It should mainly */ 8/* be used to parse compressed PCF fonts, as found with many X11 server */ 9/* distributions. */ 10/* */ 11/* Copyright 2004-2006, 2009, 2010, 2012 by */ 12/* Albert Chin-A-Young. */ 13/* */ 14/* Based on code in src/gzip/ftgzip.c, Copyright 2004 by */ 15/* David Turner, Robert Wilhelm, and Werner Lemberg. */ 16/* */ 17/* This file is part of the FreeType project, and may only be used, */ 18/* modified, and distributed under the terms of the FreeType project */ 19/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 20/* this file you indicate that you have read the license and */ 21/* understand and accept it fully. */ 22/* */ 23/***************************************************************************/ 24 25#include <ft2build.h> 26#include FT_INTERNAL_MEMORY_H 27#include FT_INTERNAL_STREAM_H 28#include FT_INTERNAL_DEBUG_H 29#include FT_LZW_H 30#include FT_CONFIG_STANDARD_LIBRARY_H 31 32 33#include FT_MODULE_ERRORS_H 34 35#undef __FTERRORS_H__ 36 37#undef FT_ERR_PREFIX 38#define FT_ERR_PREFIX LZW_Err_ 39#define FT_ERR_BASE FT_Mod_Err_LZW 40 41#include FT_ERRORS_H 42 43 44#ifdef FT_CONFIG_OPTION_USE_LZW 45 46#ifdef FT_CONFIG_OPTION_PIC 47#error "lzw code does not support PIC yet" 48#endif 49 50#include "ftzopen.h" 51 52 53/***************************************************************************/ 54/***************************************************************************/ 55/***** *****/ 56/***** M E M O R Y M A N A G E M E N T *****/ 57/***** *****/ 58/***************************************************************************/ 59/***************************************************************************/ 60 61/***************************************************************************/ 62/***************************************************************************/ 63/***** *****/ 64/***** F I L E D E S C R I P T O R *****/ 65/***** *****/ 66/***************************************************************************/ 67/***************************************************************************/ 68 69#define FT_LZW_BUFFER_SIZE 4096 70 71 typedef struct FT_LZWFileRec_ 72 { 73 FT_Stream source; /* parent/source stream */ 74 FT_Stream stream; /* embedding stream */ 75 FT_Memory memory; /* memory allocator */ 76 FT_LzwStateRec lzw; /* lzw decompressor state */ 77 78 FT_Byte buffer[FT_LZW_BUFFER_SIZE]; /* output buffer */ 79 FT_ULong pos; /* position in output */ 80 FT_Byte* cursor; 81 FT_Byte* limit; 82 83 } FT_LZWFileRec, *FT_LZWFile; 84 85 86 /* check and skip .Z header */ 87 static FT_Error 88 ft_lzw_check_header( FT_Stream stream ) 89 { 90 FT_Error error; 91 FT_Byte head[2]; 92 93 94 if ( FT_STREAM_SEEK( 0 ) || 95 FT_STREAM_READ( head, 2 ) ) 96 goto Exit; 97 98 /* head[0] && head[1] are the magic numbers */ 99 if ( head[0] != 0x1f || 100 head[1] != 0x9d ) 101 error = LZW_Err_Invalid_File_Format; 102 103 Exit: 104 return error; 105 } 106 107 108 static FT_Error 109 ft_lzw_file_init( FT_LZWFile zip, 110 FT_Stream stream, 111 FT_Stream source ) 112 { 113 FT_LzwState lzw = &zip->lzw; 114 FT_Error error = LZW_Err_Ok; 115 116 117 zip->stream = stream; 118 zip->source = source; 119 zip->memory = stream->memory; 120 121 zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE; 122 zip->cursor = zip->limit; 123 zip->pos = 0; 124 125 /* check and skip .Z header */ 126 error = ft_lzw_check_header( source ); 127 if ( error ) 128 goto Exit; 129 130 /* initialize internal lzw variable */ 131 ft_lzwstate_init( lzw, source ); 132 133 Exit: 134 return error; 135 } 136 137 138 static void 139 ft_lzw_file_done( FT_LZWFile zip ) 140 { 141 /* clear the rest */ 142 ft_lzwstate_done( &zip->lzw ); 143 144 zip->memory = NULL; 145 zip->source = NULL; 146 zip->stream = NULL; 147 } 148 149 150 static FT_Error 151 ft_lzw_file_reset( FT_LZWFile zip ) 152 { 153 FT_Stream stream = zip->source; 154 FT_Error error; 155 156 157 if ( !FT_STREAM_SEEK( 0 ) ) 158 { 159 ft_lzwstate_reset( &zip->lzw ); 160 161 zip->limit = zip->buffer + FT_LZW_BUFFER_SIZE; 162 zip->cursor = zip->limit; 163 zip->pos = 0; 164 } 165 166 return error; 167 } 168 169 170 static FT_Error 171 ft_lzw_file_fill_output( FT_LZWFile zip ) 172 { 173 FT_LzwState lzw = &zip->lzw; 174 FT_ULong count; 175 FT_Error error = LZW_Err_Ok; 176 177 178 zip->cursor = zip->buffer; 179 180 count = ft_lzwstate_io( lzw, zip->buffer, FT_LZW_BUFFER_SIZE ); 181 182 zip->limit = zip->cursor + count; 183 184 if ( count == 0 ) 185 error = LZW_Err_Invalid_Stream_Operation; 186 187 return error; 188 } 189 190 191 /* fill output buffer; `count' must be <= FT_LZW_BUFFER_SIZE */ 192 static FT_Error 193 ft_lzw_file_skip_output( FT_LZWFile zip, 194 FT_ULong count ) 195 { 196 FT_Error error = LZW_Err_Ok; 197 198 199 /* first, we skip what we can from the output buffer */ 200 { 201 FT_ULong delta = (FT_ULong)( zip->limit - zip->cursor ); 202 203 204 if ( delta >= count ) 205 delta = count; 206 207 zip->cursor += delta; 208 zip->pos += delta; 209 210 count -= delta; 211 } 212 213 /* next, we skip as many bytes remaining as possible */ 214 while ( count > 0 ) 215 { 216 FT_ULong delta = FT_LZW_BUFFER_SIZE; 217 FT_ULong numread; 218 219 220 if ( delta > count ) 221 delta = count; 222 223 numread = ft_lzwstate_io( &zip->lzw, NULL, delta ); 224 if ( numread < delta ) 225 { 226 /* not enough bytes */ 227 error = LZW_Err_Invalid_Stream_Operation; 228 break; 229 } 230 231 zip->pos += delta; 232 count -= delta; 233 } 234 235 return error; 236 } 237 238 239 static FT_ULong 240 ft_lzw_file_io( FT_LZWFile zip, 241 FT_ULong pos, 242 FT_Byte* buffer, 243 FT_ULong count ) 244 { 245 FT_ULong result = 0; 246 FT_Error error; 247 248 249 /* seeking backwards. */ 250 if ( pos < zip->pos ) 251 { 252 /* If the new position is within the output buffer, simply */ 253 /* decrement pointers, otherwise we reset the stream completely! */ 254 if ( ( zip->pos - pos ) <= (FT_ULong)( zip->cursor - zip->buffer ) ) 255 { 256 zip->cursor -= zip->pos - pos; 257 zip->pos = pos; 258 } 259 else 260 { 261 error = ft_lzw_file_reset( zip ); 262 if ( error ) 263 goto Exit; 264 } 265 } 266 267 /* skip unwanted bytes */ 268 if ( pos > zip->pos ) 269 { 270 error = ft_lzw_file_skip_output( zip, (FT_ULong)( pos - zip->pos ) ); 271 if ( error ) 272 goto Exit; 273 } 274 275 if ( count == 0 ) 276 goto Exit; 277 278 /* now read the data */ 279 for (;;) 280 { 281 FT_ULong delta; 282 283 284 delta = (FT_ULong)( zip->limit - zip->cursor ); 285 if ( delta >= count ) 286 delta = count; 287 288 FT_MEM_COPY( buffer + result, zip->cursor, delta ); 289 result += delta; 290 zip->cursor += delta; 291 zip->pos += delta; 292 293 count -= delta; 294 if ( count == 0 ) 295 break; 296 297 error = ft_lzw_file_fill_output( zip ); 298 if ( error ) 299 break; 300 } 301 302 Exit: 303 return result; 304 } 305 306 307/***************************************************************************/ 308/***************************************************************************/ 309/***** *****/ 310/***** L Z W E M B E D D I N G S T R E A M *****/ 311/***** *****/ 312/***************************************************************************/ 313/***************************************************************************/ 314 315 static void 316 ft_lzw_stream_close( FT_Stream stream ) 317 { 318 FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer; 319 FT_Memory memory = stream->memory; 320 321 322 if ( zip ) 323 { 324 /* finalize lzw file descriptor */ 325 ft_lzw_file_done( zip ); 326 327 FT_FREE( zip ); 328 329 stream->descriptor.pointer = NULL; 330 } 331 } 332 333 334 static FT_ULong 335 ft_lzw_stream_io( FT_Stream stream, 336 FT_ULong pos, 337 FT_Byte* buffer, 338 FT_ULong count ) 339 { 340 FT_LZWFile zip = (FT_LZWFile)stream->descriptor.pointer; 341 342 343 return ft_lzw_file_io( zip, pos, buffer, count ); 344 } 345 346 347 FT_EXPORT_DEF( FT_Error ) 348 FT_Stream_OpenLZW( FT_Stream stream, 349 FT_Stream source ) 350 { 351 FT_Error error; 352 FT_Memory memory = source->memory; 353 FT_LZWFile zip = NULL; 354 355 356 /* 357 * Check the header right now; this prevents allocation of a huge 358 * LZWFile object (400 KByte of heap memory) if not necessary. 359 * 360 * Did I mention that you should never use .Z compressed font 361 * files? 362 */ 363 error = ft_lzw_check_header( source ); 364 if ( error ) 365 goto Exit; 366 367 FT_ZERO( stream ); 368 stream->memory = memory; 369 370 if ( !FT_NEW( zip ) ) 371 { 372 error = ft_lzw_file_init( zip, stream, source ); 373 if ( error ) 374 { 375 FT_FREE( zip ); 376 goto Exit; 377 } 378 379 stream->descriptor.pointer = zip; 380 } 381 382 stream->size = 0x7FFFFFFFL; /* don't know the real size! */ 383 stream->pos = 0; 384 stream->base = 0; 385 stream->read = ft_lzw_stream_io; 386 stream->close = ft_lzw_stream_close; 387 388 Exit: 389 return error; 390 } 391 392 393#include "ftzopen.c" 394 395 396#else /* !FT_CONFIG_OPTION_USE_LZW */ 397 398 399 FT_EXPORT_DEF( FT_Error ) 400 FT_Stream_OpenLZW( FT_Stream stream, 401 FT_Stream source ) 402 { 403 FT_UNUSED( stream ); 404 FT_UNUSED( source ); 405 406 return LZW_Err_Unimplemented_Feature; 407 } 408 409 410#endif /* !FT_CONFIG_OPTION_USE_LZW */ 411 412 413/* END */