/src/freetype/src/type1/t1parse.c
C | 494 lines | 288 code | 94 blank | 112 comment | 71 complexity | 183ad04ee764ebeeb4da559d08b1e18d MD5 | raw file
1/***************************************************************************/ 2/* */ 3/* t1parse.c */ 4/* */ 5/* Type 1 parser (body). */ 6/* */ 7/* Copyright 1996-2005, 2008, 2009, 2012 by */ 8/* David Turner, Robert Wilhelm, and Werner Lemberg. */ 9/* */ 10/* This file is part of the FreeType project, and may only be used, */ 11/* modified, and distributed under the terms of the FreeType project */ 12/* license, LICENSE.TXT. By continuing to use, modify, or distribute */ 13/* this file you indicate that you have read the license and */ 14/* understand and accept it fully. */ 15/* */ 16/***************************************************************************/ 17 18 19 /*************************************************************************/ 20 /* */ 21 /* The Type 1 parser is in charge of the following: */ 22 /* */ 23 /* - provide an implementation of a growing sequence of objects called */ 24 /* a `T1_Table' (used to build various tables needed by the loader). */ 25 /* */ 26 /* - opening .pfb and .pfa files to extract their top-level and private */ 27 /* dictionaries. */ 28 /* */ 29 /* - read numbers, arrays & strings from any dictionary. */ 30 /* */ 31 /* See `t1load.c' to see how data is loaded from the font file. */ 32 /* */ 33 /*************************************************************************/ 34 35 36#include <ft2build.h> 37#include FT_INTERNAL_DEBUG_H 38#include FT_INTERNAL_STREAM_H 39#include FT_INTERNAL_POSTSCRIPT_AUX_H 40 41#include "t1parse.h" 42 43#include "t1errors.h" 44 45 46 /*************************************************************************/ 47 /* */ 48 /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ 49 /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ 50 /* messages during execution. */ 51 /* */ 52#undef FT_COMPONENT 53#define FT_COMPONENT trace_t1parse 54 55 56 /*************************************************************************/ 57 /*************************************************************************/ 58 /*************************************************************************/ 59 /***** *****/ 60 /***** INPUT STREAM PARSER *****/ 61 /***** *****/ 62 /*************************************************************************/ 63 /*************************************************************************/ 64 /*************************************************************************/ 65 66 67 /* see Adobe Technical Note 5040.Download_Fonts.pdf */ 68 69 static FT_Error 70 read_pfb_tag( FT_Stream stream, 71 FT_UShort *atag, 72 FT_ULong *asize ) 73 { 74 FT_Error error; 75 FT_UShort tag; 76 FT_ULong size; 77 78 79 *atag = 0; 80 *asize = 0; 81 82 if ( !FT_READ_USHORT( tag ) ) 83 { 84 if ( tag == 0x8001U || tag == 0x8002U ) 85 { 86 if ( !FT_READ_ULONG_LE( size ) ) 87 *asize = size; 88 } 89 90 *atag = tag; 91 } 92 93 return error; 94 } 95 96 97 static FT_Error 98 check_type1_format( FT_Stream stream, 99 const char* header_string, 100 size_t header_length ) 101 { 102 FT_Error error; 103 FT_UShort tag; 104 FT_ULong dummy; 105 106 107 if ( FT_STREAM_SEEK( 0 ) ) 108 goto Exit; 109 110 error = read_pfb_tag( stream, &tag, &dummy ); 111 if ( error ) 112 goto Exit; 113 114 /* We assume that the first segment in a PFB is always encoded as */ 115 /* text. This might be wrong (and the specification doesn't insist */ 116 /* on that), but we have never seen a counterexample. */ 117 if ( tag != 0x8001U && FT_STREAM_SEEK( 0 ) ) 118 goto Exit; 119 120 if ( !FT_FRAME_ENTER( header_length ) ) 121 { 122 error = T1_Err_Ok; 123 124 if ( ft_memcmp( stream->cursor, header_string, header_length ) != 0 ) 125 error = T1_Err_Unknown_File_Format; 126 127 FT_FRAME_EXIT(); 128 } 129 130 Exit: 131 return error; 132 } 133 134 135 FT_LOCAL_DEF( FT_Error ) 136 T1_New_Parser( T1_Parser parser, 137 FT_Stream stream, 138 FT_Memory memory, 139 PSAux_Service psaux ) 140 { 141 FT_Error error; 142 FT_UShort tag; 143 FT_ULong size; 144 145 146 psaux->ps_parser_funcs->init( &parser->root, 0, 0, memory ); 147 148 parser->stream = stream; 149 parser->base_len = 0; 150 parser->base_dict = 0; 151 parser->private_len = 0; 152 parser->private_dict = 0; 153 parser->in_pfb = 0; 154 parser->in_memory = 0; 155 parser->single_block = 0; 156 157 /* check the header format */ 158 error = check_type1_format( stream, "%!PS-AdobeFont", 14 ); 159 if ( error ) 160 { 161 if ( error != T1_Err_Unknown_File_Format ) 162 goto Exit; 163 164 error = check_type1_format( stream, "%!FontType", 10 ); 165 if ( error ) 166 { 167 FT_TRACE2(( " not a Type 1 font\n" )); 168 goto Exit; 169 } 170 } 171 172 /******************************************************************/ 173 /* */ 174 /* Here a short summary of what is going on: */ 175 /* */ 176 /* When creating a new Type 1 parser, we try to locate and load */ 177 /* the base dictionary if this is possible (i.e., for PFB */ 178 /* files). Otherwise, we load the whole font into memory. */ 179 /* */ 180 /* When `loading' the base dictionary, we only setup pointers */ 181 /* in the case of a memory-based stream. Otherwise, we */ 182 /* allocate and load the base dictionary in it. */ 183 /* */ 184 /* parser->in_pfb is set if we are in a binary (`.pfb') font. */ 185 /* parser->in_memory is set if we have a memory stream. */ 186 /* */ 187 188 /* try to compute the size of the base dictionary; */ 189 /* look for a Postscript binary file tag, i.e., 0x8001 */ 190 if ( FT_STREAM_SEEK( 0L ) ) 191 goto Exit; 192 193 error = read_pfb_tag( stream, &tag, &size ); 194 if ( error ) 195 goto Exit; 196 197 if ( tag != 0x8001U ) 198 { 199 /* assume that this is a PFA file for now; an error will */ 200 /* be produced later when more things are checked */ 201 if ( FT_STREAM_SEEK( 0L ) ) 202 goto Exit; 203 size = stream->size; 204 } 205 else 206 parser->in_pfb = 1; 207 208 /* now, try to load `size' bytes of the `base' dictionary we */ 209 /* found previously */ 210 211 /* if it is a memory-based resource, set up pointers */ 212 if ( !stream->read ) 213 { 214 parser->base_dict = (FT_Byte*)stream->base + stream->pos; 215 parser->base_len = size; 216 parser->in_memory = 1; 217 218 /* check that the `size' field is valid */ 219 if ( FT_STREAM_SKIP( size ) ) 220 goto Exit; 221 } 222 else 223 { 224 /* read segment in memory -- this is clumsy, but so does the format */ 225 if ( FT_ALLOC( parser->base_dict, size ) || 226 FT_STREAM_READ( parser->base_dict, size ) ) 227 goto Exit; 228 parser->base_len = size; 229 } 230 231 parser->root.base = parser->base_dict; 232 parser->root.cursor = parser->base_dict; 233 parser->root.limit = parser->root.cursor + parser->base_len; 234 235 Exit: 236 if ( error && !parser->in_memory ) 237 FT_FREE( parser->base_dict ); 238 239 return error; 240 } 241 242 243 FT_LOCAL_DEF( void ) 244 T1_Finalize_Parser( T1_Parser parser ) 245 { 246 FT_Memory memory = parser->root.memory; 247 248 249 /* always free the private dictionary */ 250 FT_FREE( parser->private_dict ); 251 252 /* free the base dictionary only when we have a disk stream */ 253 if ( !parser->in_memory ) 254 FT_FREE( parser->base_dict ); 255 256 parser->root.funcs.done( &parser->root ); 257 } 258 259 260 FT_LOCAL_DEF( FT_Error ) 261 T1_Get_Private_Dict( T1_Parser parser, 262 PSAux_Service psaux ) 263 { 264 FT_Stream stream = parser->stream; 265 FT_Memory memory = parser->root.memory; 266 FT_Error error = T1_Err_Ok; 267 FT_ULong size; 268 269 270 if ( parser->in_pfb ) 271 { 272 /* in the case of the PFB format, the private dictionary can be */ 273 /* made of several segments. We thus first read the number of */ 274 /* segments to compute the total size of the private dictionary */ 275 /* then re-read them into memory. */ 276 FT_Long start_pos = FT_STREAM_POS(); 277 FT_UShort tag; 278 279 280 parser->private_len = 0; 281 for (;;) 282 { 283 error = read_pfb_tag( stream, &tag, &size ); 284 if ( error ) 285 goto Fail; 286 287 if ( tag != 0x8002U ) 288 break; 289 290 parser->private_len += size; 291 292 if ( FT_STREAM_SKIP( size ) ) 293 goto Fail; 294 } 295 296 /* Check that we have a private dictionary there */ 297 /* and allocate private dictionary buffer */ 298 if ( parser->private_len == 0 ) 299 { 300 FT_ERROR(( "T1_Get_Private_Dict:" 301 " invalid private dictionary section\n" )); 302 error = T1_Err_Invalid_File_Format; 303 goto Fail; 304 } 305 306 if ( FT_STREAM_SEEK( start_pos ) || 307 FT_ALLOC( parser->private_dict, parser->private_len ) ) 308 goto Fail; 309 310 parser->private_len = 0; 311 for (;;) 312 { 313 error = read_pfb_tag( stream, &tag, &size ); 314 if ( error || tag != 0x8002U ) 315 { 316 error = T1_Err_Ok; 317 break; 318 } 319 320 if ( FT_STREAM_READ( parser->private_dict + parser->private_len, 321 size ) ) 322 goto Fail; 323 324 parser->private_len += size; 325 } 326 } 327 else 328 { 329 /* We have already `loaded' the whole PFA font file into memory; */ 330 /* if this is a memory resource, allocate a new block to hold */ 331 /* the private dict. Otherwise, simply overwrite into the base */ 332 /* dictionary block in the heap. */ 333 334 /* first of all, look at the `eexec' keyword */ 335 FT_Byte* cur = parser->base_dict; 336 FT_Byte* limit = cur + parser->base_len; 337 FT_Byte c; 338 339 340 Again: 341 for (;;) 342 { 343 c = cur[0]; 344 if ( c == 'e' && cur + 9 < limit ) /* 9 = 5 letters for `eexec' + */ 345 /* newline + 4 chars */ 346 { 347 if ( cur[1] == 'e' && 348 cur[2] == 'x' && 349 cur[3] == 'e' && 350 cur[4] == 'c' ) 351 break; 352 } 353 cur++; 354 if ( cur >= limit ) 355 { 356 FT_ERROR(( "T1_Get_Private_Dict:" 357 " could not find `eexec' keyword\n" )); 358 error = T1_Err_Invalid_File_Format; 359 goto Exit; 360 } 361 } 362 363 /* check whether `eexec' was real -- it could be in a comment */ 364 /* or string (as e.g. in u003043t.gsf from ghostscript) */ 365 366 parser->root.cursor = parser->base_dict; 367 parser->root.limit = cur + 9; 368 369 cur = parser->root.cursor; 370 limit = parser->root.limit; 371 372 while ( cur < limit ) 373 { 374 if ( *cur == 'e' && ft_strncmp( (char*)cur, "eexec", 5 ) == 0 ) 375 goto Found; 376 377 T1_Skip_PS_Token( parser ); 378 if ( parser->root.error ) 379 break; 380 T1_Skip_Spaces ( parser ); 381 cur = parser->root.cursor; 382 } 383 384 /* we haven't found the correct `eexec'; go back and continue */ 385 /* searching */ 386 387 cur = limit; 388 limit = parser->base_dict + parser->base_len; 389 goto Again; 390 391 /* now determine where to write the _encrypted_ binary private */ 392 /* dictionary. We overwrite the base dictionary for disk-based */ 393 /* resources and allocate a new block otherwise */ 394 395 Found: 396 parser->root.limit = parser->base_dict + parser->base_len; 397 398 T1_Skip_PS_Token( parser ); 399 cur = parser->root.cursor; 400 401 /* according to the Type1 spec, the first cipher byte must not be */ 402 /* an ASCII whitespace character code (blank, tab, carriage return */ 403 /* or line feed). We have seen Type 1 fonts with two line feed */ 404 /* characters... So skip now all whitespace character codes. */ 405 while ( cur < limit && 406 ( *cur == ' ' || 407 *cur == '\t' || 408 *cur == '\r' || 409 *cur == '\n' ) ) 410 ++cur; 411 if ( cur >= limit ) 412 { 413 FT_ERROR(( "T1_Get_Private_Dict:" 414 " `eexec' not properly terminated\n" )); 415 error = T1_Err_Invalid_File_Format; 416 goto Exit; 417 } 418 419 size = parser->base_len - ( cur - parser->base_dict ); 420 421 if ( parser->in_memory ) 422 { 423 /* note that we allocate one more byte to put a terminating `0' */ 424 if ( FT_ALLOC( parser->private_dict, size + 1 ) ) 425 goto Fail; 426 parser->private_len = size; 427 } 428 else 429 { 430 parser->single_block = 1; 431 parser->private_dict = parser->base_dict; 432 parser->private_len = size; 433 parser->base_dict = 0; 434 parser->base_len = 0; 435 } 436 437 /* now determine whether the private dictionary is encoded in binary */ 438 /* or hexadecimal ASCII format -- decode it accordingly */ 439 440 /* we need to access the next 4 bytes (after the final \r following */ 441 /* the `eexec' keyword); if they all are hexadecimal digits, then */ 442 /* we have a case of ASCII storage */ 443 444 if ( ft_isxdigit( cur[0] ) && ft_isxdigit( cur[1] ) && 445 ft_isxdigit( cur[2] ) && ft_isxdigit( cur[3] ) ) 446 { 447 /* ASCII hexadecimal encoding */ 448 FT_Long len; 449 450 451 parser->root.cursor = cur; 452 (void)psaux->ps_parser_funcs->to_bytes( &parser->root, 453 parser->private_dict, 454 parser->private_len, 455 &len, 456 0 ); 457 parser->private_len = len; 458 459 /* put a safeguard */ 460 parser->private_dict[len] = '\0'; 461 } 462 else 463 /* binary encoding -- copy the private dict */ 464 FT_MEM_MOVE( parser->private_dict, cur, size ); 465 } 466 467 /* we now decrypt the encoded binary private dictionary */ 468 psaux->t1_decrypt( parser->private_dict, parser->private_len, 55665U ); 469 470 if ( parser->private_len < 4 ) 471 { 472 FT_ERROR(( "T1_Get_Private_Dict:" 473 " invalid private dictionary section\n" )); 474 error = T1_Err_Invalid_File_Format; 475 goto Fail; 476 } 477 478 /* replace the four random bytes at the beginning with whitespace */ 479 parser->private_dict[0] = ' '; 480 parser->private_dict[1] = ' '; 481 parser->private_dict[2] = ' '; 482 parser->private_dict[3] = ' '; 483 484 parser->root.base = parser->private_dict; 485 parser->root.cursor = parser->private_dict; 486 parser->root.limit = parser->root.cursor + parser->private_len; 487 488 Fail: 489 Exit: 490 return error; 491 } 492 493 494/* END */