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+/****************************************************************************
+ *
+ * t1parse.c
+ *
+ * Type 1 parser (body).
+ *
+ * Copyright (C) 1996-2023 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 <freetype/internal/ftdebug.h>
+#include <freetype/internal/ftstream.h>
+#include <freetype/internal/psaux.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 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_QALLOC( 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_QALLOC( 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 look for the `eexec' keyword. Ensure `eexec' is real -- */
+ /* it could be in a comment or string (as e.g. in u003043t.gsf */
+ /* from ghostscript). */
+ FT_Byte* cur = parser->base_dict;
+ FT_Byte* limit = cur + parser->base_len;
+ FT_Pointer pos_lf;
+ FT_Bool test_cr;
+
+
+ parser->root.cursor = parser->base_dict;
+ parser->root.limit = parser->base_dict + parser->base_len;
+
+ cur = parser->root.cursor;
+ limit = parser->root.limit;
+
+ while ( cur < limit )
+ {
+ /* 9 = 5 letters for `eexec' + whitespace + 4 chars */
+ if ( cur[0] == 'e' && cur + 9 < 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;
+ }
+
+ FT_ERROR(( "T1_Get_Private_Dict: could not find `eexec' keyword\n" ));
+ error = FT_THROW( Invalid_File_Format );
+ goto Exit;
+
+ /* 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_QALLOC( 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 */
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