t42parse.c

下载来的一个看图软件的源代码

/***************************************************************************/
/*                                                                         */
/*  t42parse.c                                                             */
/*                                                                         */
/*    Type 42 font parser (body).                                          */
/*                                                                         */
/*  Copyright 2002, 2003 by Roberto Alameda.                               */
/*                                                                         */
/*  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.                                        */
/*                                                                         */
/***************************************************************************/


#include "t42parse.h"
#include "t42error.h"
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_STREAM_H
#include FT_LIST_H
#include FT_INTERNAL_POSTSCRIPT_AUX_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_t42


  static void
  t42_parse_font_matrix( T42_Face    face,
                         T42_Loader  loader );
  static void
  t42_parse_encoding( T42_Face    face,
                      T42_Loader  loader );

  static void
  t42_parse_charstrings( T42_Face    face,
                         T42_Loader  loader );

  static void
  t42_parse_sfnts( T42_Face    face,
                   T42_Loader  loader );


  static const
  T1_FieldRec  t42_keywords[] = {

#undef  FT_STRUCTURE
#define FT_STRUCTURE  T1_FontInfo
#undef  T1CODE
#define T1CODE        T1_FIELD_LOCATION_FONT_INFO

    T1_FIELD_STRING( "version",            version )
    T1_FIELD_STRING( "Notice",             notice )
    T1_FIELD_STRING( "FullName",           full_name )
    T1_FIELD_STRING( "FamilyName",         family_name )
    T1_FIELD_STRING( "Weight",             weight )
    T1_FIELD_NUM   ( "ItalicAngle",        italic_angle )
    T1_FIELD_BOOL  ( "isFixedPitch",       is_fixed_pitch )
    T1_FIELD_NUM   ( "UnderlinePosition",  underline_position )
    T1_FIELD_NUM   ( "UnderlineThickness", underline_thickness )

#undef  FT_STRUCTURE
#define FT_STRUCTURE  T1_FontRec
#undef  T1CODE
#define T1CODE        T1_FIELD_LOCATION_FONT_DICT

    T1_FIELD_KEY  ( "FontName",    font_name )
    T1_FIELD_NUM  ( "PaintType",   paint_type )
    T1_FIELD_NUM  ( "FontType",    font_type )
    T1_FIELD_FIXED( "StrokeWidth", stroke_width )

#undef  FT_STRUCTURE
#define FT_STRUCTURE  FT_BBox
#undef  T1CODE
#define T1CODE        T1_FIELD_LOCATION_BBOX

    T1_FIELD_BBOX("FontBBox", xMin )

    T1_FIELD_CALLBACK( "FontMatrix",  t42_parse_font_matrix )
    T1_FIELD_CALLBACK( "Encoding",    t42_parse_encoding )
    T1_FIELD_CALLBACK( "CharStrings", t42_parse_charstrings )
    T1_FIELD_CALLBACK( "sfnts",       t42_parse_sfnts )

    { 0, T1_FIELD_LOCATION_CID_INFO, T1_FIELD_TYPE_NONE, 0, 0, 0, 0, 0 }
  };


#define T42_KEYWORD_COUNT                                          \
          ( sizeof ( t42_keywords ) / sizeof ( t42_keywords[0] ) )


#define T1_Add_Table( p, i, o, l )  (p)->funcs.add( (p), i, o, l )
#define T1_Done_Table( p )          \
          do                        \
          {                         \
            if ( (p)->funcs.done )  \
              (p)->funcs.done( p ); \
          } while ( 0 )
#define T1_Release_Table( p )          \
          do                           \
          {                            \
            if ( (p)->funcs.release )  \
              (p)->funcs.release( p ); \
          } while ( 0 )

#define T1_Skip_Spaces( p )  (p)->root.funcs.skip_spaces( &(p)->root )
#define T1_Skip_Alpha( p )   (p)->root.funcs.skip_alpha ( &(p)->root )

#define T1_ToInt( p )       (p)->root.funcs.to_int( &(p)->root )
#define T1_ToFixed( p, t )  (p)->root.funcs.to_fixed( &(p)->root, t )

#define T1_ToCoordArray( p, m, c )                           \
          (p)->root.funcs.to_coord_array( &(p)->root, m, c )
#define T1_ToFixedArray( p, m, f, t )                           \
          (p)->root.funcs.to_fixed_array( &(p)->root, m, f, t )
#define T1_ToToken( p, t )                          \
          (p)->root.funcs.to_token( &(p)->root, t )
#define T1_ToTokenArray( p, t, m, c )                           \
          (p)->root.funcs.to_token_array( &(p)->root, t, m, c )

#define T1_Load_Field( p, f, o, m, pf )                         \
          (p)->root.funcs.load_field( &(p)->root, f, o, m, pf )
#define T1_Load_Field_Table( p, f, o, m, pf )                         \
          (p)->root.funcs.load_field_table( &(p)->root, f, o, m, pf )


  /********************* Parsing Functions ******************/

  FT_LOCAL_DEF( FT_Error )
  t42_parser_init( T42_Parser     parser,
                   FT_Stream      stream,
                   FT_Memory      memory,
                   PSAux_Service  psaux )
  {
    FT_Error  error = T42_Err_Ok;
    FT_Long   size;


    psaux->ps_parser_funcs->init( &parser->root, 0, 0, memory );

    parser->stream    = stream;
    parser->base_len  = 0;
    parser->base_dict = 0;
    parser->in_memory = 0;

    /*******************************************************************/
    /*                                                                 */
    /* Here a short summary of what is going on:                       */
    /*                                                                 */
    /*   When creating a new Type 42 parser, we try to locate and load */
    /*   the base dictionary, loading 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_memory is set if we have a memory stream.          */
    /*                                                                 */

    if ( FT_STREAM_SEEK( 0L ) )
      goto Exit;

    size = stream->size;

    /* 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 */
      if ( FT_ALLOC( parser->base_dict, size )       ||
           FT_STREAM_READ( parser->base_dict, size ) )
        goto Exit;

      parser->base_len = size;
    }

    /* Now check font format; we must see `%!PS-TrueTypeFont' */
    if (size <= 17                                    ||
        ( ft_strncmp( (const char*)parser->base_dict,
                      "%!PS-TrueTypeFont", 17) )      )
      error = T42_Err_Unknown_File_Format;
    else
    {
      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 )
  t42_parser_done( T42_Parser  parser )
  {
    FT_Memory  memory = parser->root.memory;


    /* 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 );
  }


  static int
  t42_is_alpha( FT_Byte  c )
  {
    /* Note: we must accept "+" as a valid character, as it is used in */
    /*       embedded type1 fonts in PDF documents.                    */
    /*                                                                 */
    return ( ft_isalnum( c ) ||
             c == '.'        ||
             c == '_'        ||
             c == '-'        ||
             c == '+'        );
  }


  static int
  t42_is_space( FT_Byte  c )
  {
    return ( c == ' ' || c == '\t' || c == '\r' || c == '\n' );
  }


  static void
  t42_parse_font_matrix( T42_Face    face,
                         T42_Loader  loader )
  {
    T42_Parser  parser = &loader->parser;
    FT_Matrix*  matrix = &face->type1.font_matrix;
    FT_Vector*  offset = &face->type1.font_offset;
    FT_Face     root   = (FT_Face)&face->root;
    FT_Fixed    temp[6];
    FT_Fixed    temp_scale;


    (void)T1_ToFixedArray( parser, 6, temp, 3 );

    temp_scale = ABS( temp[3] );

    /* Set Units per EM based on FontMatrix values.  We set the value to */
    /* 1000 / temp_scale, because temp_scale was already multiplied by   */
    /* 1000 (in t1_tofixed, from psobjs.c).                              */

    root->units_per_EM = (FT_UShort)( FT_DivFix( 1000 * 0x10000L,
                                                 temp_scale ) >> 16 );

    /* we need to scale the values by 1.0/temp_scale */
    if ( temp_scale != 0x10000L ) {
      temp[0] = FT_DivFix( temp[0], temp_scale );
      temp[1] = FT_DivFix( temp[1], temp_scale );
      temp[2] = FT_DivFix( temp[2], temp_scale );
      temp[4] = FT_DivFix( temp[4], temp_scale );
      temp[5] = FT_DivFix( temp[5], temp_scale );
      temp[3] = 0x10000L;
    }

    matrix->xx = temp[0];
    matrix->yx = temp[1];
    matrix->xy = temp[2];
    matrix->yy = temp[3];

    /* note that the offsets must be expressed in integer font units */
    offset->x  = temp[4] >> 16;
    offset->y  = temp[5] >> 16;
  }


  static void
  t42_parse_encoding( T42_Face    face,
                      T42_Loader  loader )
  {
    T42_Parser     parser = &loader->parser;
    FT_Byte*       cur    = parser->root.cursor;
    FT_Byte*       limit  = parser->root.limit;

    PSAux_Service  psaux  = (PSAux_Service)face->psaux;


    /* skip whitespace */
    while ( t42_is_space( *cur ) )
    {
      cur++;
      if ( cur >= limit )
      {
        FT_ERROR(( "t42_parse_encoding: out of bounds!\n" ));
        parser->root.error = T42_Err_Invalid_File_Format;
        return;
      }
    }

    /* if we have a number, then the encoding is an array, */
    /* and we must load it now                             */
    if ( (FT_Byte)( *cur - '0' ) < 10 )
    {
      T1_Encoding  encode     = &face->type1.encoding;
      FT_Int       count, n;
      PS_Table     char_table = &loader->encoding_table;
      FT_Memory    memory     = parser->root.memory;
      FT_Error     error;


      /* read the number of entries in the encoding, should be 256 */
      count = (FT_Int)T1_ToInt( parser );
      if ( parser->root.error )
        return;

      /* we use a T1_Table to store our charnames */
      loader->num_chars = encode->num_chars = count;
      if ( FT_NEW_ARRAY( encode->char_index, count ) ||
           FT_NEW_ARRAY( encode->char_name,  count ) ||
           FT_SET_ERROR( psaux->ps_table_funcs->init(
                           char_table, count, memory ) ) )
      {
        parser->root.error = error;
        return;
      }

      /* We need to `zero' out encoding_table.elements */
      for ( n = 0; n < count; n++ )
      {
        char*  notdef = (char *)".notdef";


        T1_Add_Table( char_table, n, notdef, 8 );
      }

      /* Now, we will need to read a record of the form         */
      /* ... charcode /charname ... for each entry in our table */
      /*                                                        */
      /* We simply look for a number followed by an immediate   */
      /* name.  Note that this ignores correctly the sequence   */
      /* that is often seen in type1 fonts:                     */
      /*                                                        */
      /*   0 1 255 { 1 index exch /.notdef put } for dup        */
      /*                                                        */
      /* used to clean the encoding array before anything else. */
      /*                                                        */
      /* We stop when we encounter a `def'.                     */

      cur   = parser->root.cursor;
      limit = parser->root.limit;
      n     = 0;

      for ( ; cur < limit; )
      {
        FT_Byte  c;


        c = *cur;

        /* we stop when we encounter a `def' */
        if ( c == 'd' && cur + 3 < limit )
        {
          if ( cur[1] == 'e'       &&
               cur[2] == 'f'       &&
               t42_is_space( cur[-1] ) &&
               t42_is_space( cur[3] )  )
          {
            FT_TRACE6(( "encoding end\n" ));
            break;
          }
        }

        /* otherwise, we must find a number before anything else */
        if ( (FT_Byte)( c - '0' ) < 10 )
        {
          FT_Int  charcode;


          parser->root.cursor = cur;
          charcode = (FT_Int)T1_ToInt( parser );
          cur      = parser->root.cursor;

          /* skip whitespace */
          while ( cur < limit && t42_is_space( *cur ) )
            cur++;

          if ( cur < limit && *cur == '/' )
          {
            /* bingo, we have an immediate name -- it must be a */
            /* character name                                   */
            FT_Byte*  cur2 = cur + 1;
            FT_Int    len;


            while ( cur2 < limit && t42_is_alpha( *cur2 ) )
              cur2++;

            len = (FT_Int)( cur2 - cur - 1 );

            parser->root.error = T1_Add_Table( char_table, charcode,
                                               cur + 1, len + 1 );
            char_table->elements[charcode][len] = '\0';
            if ( parser->root.error )
              return;

            cur = cur2;
          }
        }
        else
          cur++;
      }

      face->type1.encoding_type  = T1_ENCODING_TYPE_ARRAY;
      parser->root.cursor        = cur;
    }
    /* Otherwise, we should have either `StandardEncoding', */
    /* `ExpertEncoding', or `ISOLatin1Encoding'             */
    else
    {
      if ( cur + 17 < limit                                            &&
           ft_strncmp( (const char*)cur, "StandardEncoding", 16 ) == 0 )
        face->type1.encoding_type = T1_ENCODING_TYPE_STANDARD;

      else if ( cur + 15 < limit                                          &&
                ft_strncmp( (const char*)cur, "ExpertEncoding", 14 ) == 0 )
        face->type1.encoding_type = T1_ENCODING_TYPE_EXPERT;

      else if ( cur + 18 < limit                                             &&
                ft_strncmp( (const char*)cur, "ISOLatin1Encoding", 17 ) == 0 )
        face->type1.encoding_type = T1_ENCODING_TYPE_ISOLATIN1;

      else {
        FT_ERROR(( "t42_parse_encoding: invalid token!\n" ));
        parser->root.error = T42_Err_Invalid_File_Format;
      }
    }
  }


  static FT_UInt
  t42_hexval( FT_Byte  v )
  {
    FT_UInt  d;

    d = (FT_UInt)( v - 'A' );
    if ( d < 6 )
    {
      d += 10;
      goto Exit;
    }

    d = (FT_UInt)( v - 'a' );
    if ( d < 6 )
    {
      d += 10;
      goto Exit;
    }

    d = (FT_UInt)( v - '0' );
    if ( d < 10 )
      goto Exit;