Edit
kc3-lang/freetype/src/type1/t1parse.c
Werner Lemberg
- src/type1/t1parse.c
-
/***************************************************************************/ /* */ /* t1parse.c */ /* */ /* Type 1 parser (body). */ /* */ /* Copyright 1996-2016 by */ /* David Turner, Robert Wilhelm, and Werner Lemberg. */ /* */ /* This file is part of the FreeType project, and may only be used, */ /* modified, and distributed under the terms of the FreeType project */ /* license, LICENSE.TXT. By continuing to use, modify, or distribute */ /* this file you indicate that you have read the license and */ /* understand and accept it fully. */ /* */ /***************************************************************************/ /*************************************************************************/ /* */ /* The Type 1 parser is in charge of the following: */ /* */ /* - provide an implementation of a growing sequence of objects called */ /* a `T1_Table' (used to build various tables needed by the loader). */ /* */ /* - opening .pfb and .pfa files to extract their top-level and private */ /* dictionaries. */ /* */ /* - read numbers, arrays & strings from any dictionary. */ /* */ /* See `t1load.c' to see how data is loaded from the font file. */ /* */ /*************************************************************************/ #include <ft2build.h> #include FT_INTERNAL_DEBUG_H #include FT_INTERNAL_STREAM_H #include FT_INTERNAL_POSTSCRIPT_AUX_H #include "t1parse.h" #include "t1errors.h" /*************************************************************************/ /* */ /* The macro FT_COMPONENT is used in trace mode. It is an implicit */ /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log */ /* messages during execution. */ /* */ #undef FT_COMPONENT #define FT_COMPONENT trace_t1parse /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** INPUT STREAM PARSER *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /*************************************************************************/ /* see Adobe Technical Note 5040.Download_Fonts.pdf */ static FT_Error read_pfb_tag( FT_Stream stream, FT_UShort *atag, FT_ULong *asize ) { FT_Error error; FT_UShort tag; FT_ULong size; *atag = 0; *asize = 0; if ( !FT_READ_USHORT( tag ) ) { if ( tag == 0x8001U || tag == 0x8002U ) { if ( !FT_READ_ULONG_LE( size ) ) *asize = size; } *atag = tag; } return error; } static FT_Error check_type1_format( FT_Stream stream, const char* header_string, size_t header_length ) { FT_Error error; FT_UShort tag; FT_ULong dummy; if ( FT_STREAM_SEEK( 0 ) ) goto Exit; error = read_pfb_tag( stream, &tag, &dummy ); if ( error ) goto Exit; /* We assume that the first segment in a PFB is always encoded as */ /* text. This might be wrong (and the specification doesn't insist */ /* on that), but we have never seen a counterexample. */ if ( tag != 0x8001U && FT_STREAM_SEEK( 0 ) ) goto Exit; if ( !FT_FRAME_ENTER( header_length ) ) { error = FT_Err_Ok; if ( ft_memcmp( stream->cursor, header_string, header_length ) != 0 ) error = FT_THROW( Unknown_File_Format ); FT_FRAME_EXIT(); } Exit: return error; } FT_LOCAL_DEF( FT_Error ) T1_New_Parser( T1_Parser parser, FT_Stream stream, FT_Memory memory, PSAux_Service psaux ) { FT_Error error; FT_UShort tag; FT_ULong size; psaux->ps_parser_funcs->init( &parser->root, NULL, NULL, memory ); parser->stream = stream; parser->base_len = 0; parser->base_dict = NULL; parser->private_len = 0; parser->private_dict = NULL; parser->in_pfb = 0; parser->in_memory = 0; parser->single_block = 0; /* check the header format */ error = check_type1_format( stream, "%!PS-AdobeFont", 14 ); if ( error ) { if ( FT_ERR_NEQ( error, Unknown_File_Format ) ) goto Exit; error = check_type1_format( stream, "%!FontType", 10 ); if ( error ) { FT_TRACE2(( " not a Type 1 font\n" )); goto Exit; } } /******************************************************************/ /* */ /* Here a short summary of what is going on: */ /* */ /* When creating a new Type 1 parser, we try to locate and load */ /* the base dictionary if this is possible (i.e., for PFB */ /* files). Otherwise, we load the whole font into memory. */ /* */ /* When `loading' the base dictionary, we only setup pointers */ /* in the case of a memory-based stream. Otherwise, we */ /* allocate and load the base dictionary in it. */ /* */ /* parser->in_pfb is set if we are in a binary (`.pfb') font. */ /* parser->in_memory is set if we have a memory stream. */ /* */ /* try to compute the size of the base dictionary; */ /* look for a Postscript binary file tag, i.e., 0x8001 */ if ( FT_STREAM_SEEK( 0L ) ) goto Exit; error = read_pfb_tag( stream, &tag, &size ); if ( error ) goto Exit; if ( tag != 0x8001U ) { /* assume that this is a PFA file for now; an error will */ /* be produced later when more things are checked */ if ( FT_STREAM_SEEK( 0L ) ) goto Exit; size = stream->size; } else parser->in_pfb = 1; /* now, try to load `size' bytes of the `base' dictionary we */ /* found previously */ /* if it is a memory-based resource, set up pointers */ if ( !stream->read ) { parser->base_dict = (FT_Byte*)stream->base + stream->pos; parser->base_len = size; parser->in_memory = 1; /* check that the `size' field is valid */ if ( FT_STREAM_SKIP( size ) ) goto Exit; } else { /* read segment in memory -- this is clumsy, but so does the format */ if ( FT_ALLOC( parser->base_dict, size ) || FT_STREAM_READ( parser->base_dict, size ) ) goto Exit; parser->base_len = size; } parser->root.base = parser->base_dict; parser->root.cursor = parser->base_dict; parser->root.limit = parser->root.cursor + parser->base_len; Exit: if ( error && !parser->in_memory ) FT_FREE( parser->base_dict ); return error; } FT_LOCAL_DEF( void ) T1_Finalize_Parser( T1_Parser parser ) { FT_Memory memory = parser->root.memory; /* always free the private dictionary */ FT_FREE( parser->private_dict ); /* free the base dictionary only when we have a disk stream */ if ( !parser->in_memory ) FT_FREE( parser->base_dict ); parser->root.funcs.done( &parser->root ); } FT_LOCAL_DEF( FT_Error ) T1_Get_Private_Dict( T1_Parser parser, PSAux_Service psaux ) { FT_Stream stream = parser->stream; FT_Memory memory = parser->root.memory; FT_Error error = FT_Err_Ok; FT_ULong size; if ( parser->in_pfb ) { /* in the case of the PFB format, the private dictionary can be */ /* made of several segments. We thus first read the number of */ /* segments to compute the total size of the private dictionary */ /* then re-read them into memory. */ FT_ULong start_pos = FT_STREAM_POS(); FT_UShort tag; parser->private_len = 0; for (;;) { error = read_pfb_tag( stream, &tag, &size ); if ( error ) goto Fail; if ( tag != 0x8002U ) break; parser->private_len += size; if ( FT_STREAM_SKIP( size ) ) goto Fail; } /* Check that we have a private dictionary there */ /* and allocate private dictionary buffer */ if ( parser->private_len == 0 ) { FT_ERROR(( "T1_Get_Private_Dict:" " invalid private dictionary section\n" )); error = FT_THROW( Invalid_File_Format ); goto Fail; } if ( FT_STREAM_SEEK( start_pos ) || FT_ALLOC( parser->private_dict, parser->private_len ) ) goto Fail; parser->private_len = 0; for (;;) { error = read_pfb_tag( stream, &tag, &size ); if ( error || tag != 0x8002U ) { error = FT_Err_Ok; break; } if ( FT_STREAM_READ( parser->private_dict + parser->private_len, size ) ) goto Fail; parser->private_len += size; } } else { /* We have already `loaded' the whole PFA font file into memory; */ /* if this is a memory resource, allocate a new block to hold */ /* the private dict. Otherwise, simply overwrite into the base */ /* dictionary block in the heap. */ /* first of all, look at the `eexec' keyword */ FT_Byte* cur = parser->base_dict; FT_Byte* limit = cur + parser->base_len; FT_Pointer pos_lf; FT_Bool test_cr; Again: for (;;) { if ( cur[0] == 'e' && cur + 9 < limit ) /* 9 = 5 letters for `eexec' + */ /* whitespace + 4 chars */ { if ( cur[1] == 'e' && cur[2] == 'x' && cur[3] == 'e' && cur[4] == 'c' ) break; } cur++; if ( cur >= limit ) { FT_ERROR(( "T1_Get_Private_Dict:" " could not find `eexec' keyword\n" )); error = FT_THROW( Invalid_File_Format ); goto Exit; } } /* check whether `eexec' was real -- it could be in a comment */ /* or string (as e.g. in u003043t.gsf from ghostscript) */ parser->root.cursor = parser->base_dict; /* set limit to `eexec' + whitespace + 4 characters */ parser->root.limit = cur + 10; cur = parser->root.cursor; limit = parser->root.limit; while ( cur < limit ) { if ( cur[0] == 'e' && cur + 5 < limit ) { if ( cur[1] == 'e' && cur[2] == 'x' && cur[3] == 'e' && cur[4] == 'c' ) goto Found; } T1_Skip_PS_Token( parser ); if ( parser->root.error ) break; T1_Skip_Spaces ( parser ); cur = parser->root.cursor; } /* we haven't found the correct `eexec'; go back and continue */ /* searching */ cur = limit; limit = parser->base_dict + parser->base_len; if ( cur >= limit ) { FT_ERROR(( "T1_Get_Private_Dict:" " premature end in private dictionary\n" )); error = FT_THROW( Invalid_File_Format ); goto Exit; } goto Again; /* now determine where to write the _encrypted_ binary private */ /* dictionary. We overwrite the base dictionary for disk-based */ /* resources and allocate a new block otherwise */ Found: parser->root.limit = parser->base_dict + parser->base_len; T1_Skip_PS_Token( parser ); cur = parser->root.cursor; limit = parser->root.limit; /* According to the Type 1 spec, the first cipher byte must not be */ /* an ASCII whitespace character code (blank, tab, carriage return */ /* or line feed). We have seen Type 1 fonts with two line feed */ /* characters... So skip now all whitespace character codes. */ /* */ /* On the other hand, Adobe's Type 1 parser handles fonts just */ /* fine that are violating this limitation, so we add a heuristic */ /* test to stop at \r only if it is not used for EOL. */ pos_lf = ft_memchr( cur, '\n', (size_t)( limit - cur ) ); test_cr = FT_BOOL( !pos_lf || pos_lf > ft_memchr( cur, '\r', (size_t)( limit - cur ) ) ); while ( cur < limit && ( *cur == ' ' || *cur == '\t' || (test_cr && *cur == '\r' ) || *cur == '\n' ) ) ++cur; if ( cur >= limit ) { FT_ERROR(( "T1_Get_Private_Dict:" " `eexec' not properly terminated\n" )); error = FT_THROW( Invalid_File_Format ); goto Exit; } size = parser->base_len - (FT_ULong)( cur - parser->base_dict ); if ( parser->in_memory ) { /* note that we allocate one more byte to put a terminating `0' */ if ( FT_ALLOC( parser->private_dict, size + 1 ) ) goto Fail; parser->private_len = size; } else { parser->single_block = 1; parser->private_dict = parser->base_dict; parser->private_len = size; parser->base_dict = NULL; parser->base_len = 0; } /* now determine whether the private dictionary is encoded in binary */ /* or hexadecimal ASCII format -- decode it accordingly */ /* we need to access the next 4 bytes (after the final whitespace */ /* following the `eexec' keyword); if they all are hexadecimal */ /* digits, then we have a case of ASCII storage */ if ( cur + 3 < limit && ft_isxdigit( cur[0] ) && ft_isxdigit( cur[1] ) && ft_isxdigit( cur[2] ) && ft_isxdigit( cur[3] ) ) { /* ASCII hexadecimal encoding */ FT_ULong len; parser->root.cursor = cur; (void)psaux->ps_parser_funcs->to_bytes( &parser->root, parser->private_dict, parser->private_len, &len, 0 ); parser->private_len = len; /* put a safeguard */ parser->private_dict[len] = '\0'; } else /* binary encoding -- copy the private dict */ FT_MEM_MOVE( parser->private_dict, cur, size ); } /* we now decrypt the encoded binary private dictionary */ psaux->t1_decrypt( parser->private_dict, parser->private_len, 55665U ); if ( parser->private_len < 4 ) { FT_ERROR(( "T1_Get_Private_Dict:" " invalid private dictionary section\n" )); error = FT_THROW( Invalid_File_Format ); goto Fail; } /* replace the four random bytes at the beginning with whitespace */ parser->private_dict[0] = ' '; parser->private_dict[1] = ' '; parser->private_dict[2] = ' '; parser->private_dict[3] = ' '; parser->root.base = parser->private_dict; parser->root.cursor = parser->private_dict; parser->root.limit = parser->root.cursor + parser->private_len; Fail: Exit: return error; } /* END */