ftxgsub.c

qt-x11-opensource-src-4.1.4.tar.gz源码

/*******************************************************************
 *
 *  ftxgsub.c
 *
 *    TrueType Open GSUB table support.
 *
 *  Copyright 1996-2000 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.
 *
 ******************************************************************/

/* XXX There is *a lot* of duplicated code (cf. formats 5 and 6), but
       I don't care currently.  I believe that it would be possible to
       save about 50% of TTO code by carefully designing the structures,
       sharing as much as possible with extensive use of macros.  This
       is something for a volunteer :-)                                  */

#define EXPORT_FUNC

#include "ftxopen.h"
#include "ftxopenf.h"

#include "ftglue.h"

#include FT_TRUETYPE_TAGS_H

#define GSUB_ID  Build_Extension_ID( 'G', 'S', 'U', 'B' )


  static FT_Error  GSub_Do_Glyph_Lookup( TTO_GSUBHeader*   gsub,
                                         FT_UShort         lookup_index,
                                         OTL_Buffer        buffer,
                                         FT_UShort         context_length,
                                         int               nesting_level );



  /**********************
   * Auxiliary functions
   **********************/


  EXPORT_FUNC
  FT_Error  TT_Load_GSUB_Table( FT_Face          face,
                                TTO_GSUBHeader** retptr,
                                TTO_GDEFHeader*  gdef )
  {
    FT_Stream        stream = face->stream;
    FT_Memory        memory = face->memory;
    FT_Error         error;
    FT_ULong         cur_offset, new_offset, base_offset;

    FT_UShort        i, num_lookups;
    TTO_GSUBHeader*  gsub;
    TTO_Lookup*      lo;

    if ( !retptr )
      return TT_Err_Invalid_Argument;

    if (( error = ftglue_face_goto_table( face, TTAG_GSUB, stream ) ))
      return error;

    base_offset = FILE_Pos();

    if ( ALLOC ( gsub, sizeof( *gsub ) ) )
      return error;

    gsub->memory = memory;

    /* skip version */

    if ( FILE_Seek( base_offset + 4L ) ||
         ACCESS_Frame( 2L ) )
      goto Fail4;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
         ( error = Load_ScriptList( &gsub->ScriptList,
                                    stream ) ) != TT_Err_Ok )
      goto Fail4;
    (void)FILE_Seek( cur_offset );

    if ( ACCESS_Frame( 2L ) )
      goto Fail3;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
         ( error = Load_FeatureList( &gsub->FeatureList,
                                     stream ) ) != TT_Err_Ok )
      goto Fail3;
    (void)FILE_Seek( cur_offset );

    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    new_offset = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
         ( error = Load_LookupList( &gsub->LookupList,
                                    stream, GSUB ) ) != TT_Err_Ok )
      goto Fail2;

    gsub->gdef = gdef;      /* can be NULL */

    /* We now check the LookupFlags for values larger than 0xFF to find
       out whether we need to load the `MarkAttachClassDef' field of the
       GDEF table -- this hack is necessary for OpenType 1.2 tables since
       the version field of the GDEF table hasn't been incremented.

       For constructed GDEF tables, we only load it if
       `MarkAttachClassDef_offset' is not zero (nevertheless, a build of
       a constructed mark attach table is not supported currently).       */

    if ( gdef &&
         gdef->MarkAttachClassDef_offset && !gdef->MarkAttachClassDef.loaded )
    {
      lo          = gsub->LookupList.Lookup;
      num_lookups = gsub->LookupList.LookupCount;

      for ( i = 0; i < num_lookups; i++ )
      {

        if ( lo[i].LookupFlag & IGNORE_SPECIAL_MARKS )
        {
          if ( FILE_Seek( gdef->MarkAttachClassDef_offset ) ||
               ( error = Load_ClassDefinition( &gdef->MarkAttachClassDef,
                                               256, stream ) ) != TT_Err_Ok )
            goto Fail1;

          break;
        }
      }
    }

    *retptr = gsub;

    return TT_Err_Ok;

  Fail1:
    Free_LookupList( &gsub->LookupList, GSUB, memory );

  Fail2:
    Free_FeatureList( &gsub->FeatureList, memory );

  Fail3:
    Free_ScriptList( &gsub->ScriptList, memory );

  Fail4:
    FREE ( gsub );


    return error;
  }

  EXPORT_FUNC
  FT_Error   TT_Done_GSUB_Table( TTO_GSUBHeader* gsub )
  {
    FT_Memory memory = gsub->memory;
    
    Free_LookupList( &gsub->LookupList, GSUB, memory );
    Free_FeatureList( &gsub->FeatureList, memory );
    Free_ScriptList( &gsub->ScriptList, memory );

    FREE( gsub );

    return TT_Err_Ok;
  }

  /*****************************
   * SubTable related functions
   *****************************/


  /* LookupType 1 */

  /* SingleSubstFormat1 */
  /* SingleSubstFormat2 */

  FT_Error  Load_SingleSubst( TTO_SingleSubst*  ss,
                              FT_Stream         stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort n, count;
    FT_ULong cur_offset, new_offset, base_offset;

    FT_UShort*  s;


    base_offset = FILE_Pos();

    if ( ACCESS_Frame( 4L ) )
      return error;

    ss->SubstFormat = GET_UShort();
    new_offset      = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
         ( error = Load_Coverage( &ss->Coverage, stream ) ) != TT_Err_Ok )
      return error;
    (void)FILE_Seek( cur_offset );

    switch ( ss->SubstFormat )
    {
    case 1:
      if ( ACCESS_Frame( 2L ) )
        goto Fail2;

      ss->ssf.ssf1.DeltaGlyphID = GET_UShort();

      FORGET_Frame();

      break;

    case 2:
      if ( ACCESS_Frame( 2L ) )
        goto Fail2;

      count = ss->ssf.ssf2.GlyphCount = GET_UShort();

      FORGET_Frame();

      ss->ssf.ssf2.Substitute = NULL;

      if ( ALLOC_ARRAY( ss->ssf.ssf2.Substitute, count, FT_UShort ) )
        goto Fail2;

      s = ss->ssf.ssf2.Substitute;

      if ( ACCESS_Frame( count * 2L ) )
        goto Fail1;

      for ( n = 0; n < count; n++ )
        s[n] = GET_UShort();

      FORGET_Frame();

      break;

    default:
      return TTO_Err_Invalid_GSUB_SubTable_Format;
    }

    return TT_Err_Ok;

  Fail1:
    FREE( s );

  Fail2:
    Free_Coverage( &ss->Coverage, memory );
    return error;
  }


  void  Free_SingleSubst( TTO_SingleSubst*  ss,
			  FT_Memory         memory )
  {
    switch ( ss->SubstFormat )
    {
    case 1:
      break;

    case 2:
      FREE( ss->ssf.ssf2.Substitute );
      break;
    }

    Free_Coverage( &ss->Coverage, memory );
  }


  static FT_Error  Lookup_SingleSubst( TTO_SingleSubst*  ss,
				       OTL_Buffer        buffer,
                                       FT_UShort         flags,
                                       FT_UShort         context_length,
                                       TTO_GDEFHeader*   gdef )
  {
    FT_UShort index, value, property;
    FT_Error  error;


    if ( context_length != 0xFFFF && context_length < 1 )
      return TTO_Err_Not_Covered;

    if ( CHECK_Property( gdef, IN_CURITEM(), flags, &property ) )
      return error;

    error = Coverage_Index( &ss->Coverage, IN_CURGLYPH(), &index );
    if ( error )
      return error;

    switch ( ss->SubstFormat )
    {
    case 1:
	    value = ( IN_CURGLYPH() + ss->ssf.ssf1.DeltaGlyphID ) & 0xFFFF;
      if ( ADD_Glyph( buffer, value, 0xFFFF, 0xFFFF ) )
        return error;
      break;

    case 2:
      if ( index >= ss->ssf.ssf2.GlyphCount )
        return TTO_Err_Invalid_GSUB_SubTable;
      value = ss->ssf.ssf2.Substitute[index];
      if ( ADD_Glyph( buffer, value, 0xFFFF, 0xFFFF ) )
        return error;
      break;

    default:
      return TTO_Err_Invalid_GSUB_SubTable;
    }

    if ( gdef && gdef->NewGlyphClasses )
    {
      /* we inherit the old glyph class to the substituted glyph */

      error = Add_Glyph_Property( gdef, value, property );
      if ( error && error != TTO_Err_Not_Covered )
        return error;
    }

    return TT_Err_Ok;
  }


  /* LookupType 2 */

  /* Sequence */

  static FT_Error  Load_Sequence( TTO_Sequence*  s,
                                  FT_Stream      stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort n, count;
    FT_UShort*  sub;


    if ( ACCESS_Frame( 2L ) )
      return error;

    count = s->GlyphCount = GET_UShort();

    FORGET_Frame();

    s->Substitute = NULL;

    if ( count )
    {
      if ( ALLOC_ARRAY( s->Substitute, count, FT_UShort ) )
        return error;

      sub = s->Substitute;

      if ( ACCESS_Frame( count * 2L ) )
      {
        FREE( sub );
        return error;
      }

      for ( n = 0; n < count; n++ )
        sub[n] = GET_UShort();

      FORGET_Frame();
    }

    return TT_Err_Ok;
  }


  static void  Free_Sequence( TTO_Sequence*  s,
			      FT_Memory      memory )
  {
    FREE( s->Substitute );
  }


  /* MultipleSubstFormat1 */

  FT_Error  Load_MultipleSubst( TTO_MultipleSubst*  ms,
                                FT_Stream           stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort      n = 0, m, count;
    FT_ULong       cur_offset, new_offset, base_offset;

    TTO_Sequence*  s;


    base_offset = FILE_Pos();

    if ( ACCESS_Frame( 4L ) )
      return error;

    ms->SubstFormat = GET_UShort();             /* should be 1 */
    new_offset      = GET_UShort() + base_offset;

    FORGET_Frame();

    cur_offset = FILE_Pos();
    if ( FILE_Seek( new_offset ) ||
         ( error = Load_Coverage( &ms->Coverage, stream ) ) != TT_Err_Ok )
      return error;
    (void)FILE_Seek( cur_offset );

    if ( ACCESS_Frame( 2L ) )
      goto Fail2;

    count = ms->SequenceCount = GET_UShort();

    FORGET_Frame();

    ms->Sequence = NULL;

    if ( ALLOC_ARRAY( ms->Sequence, count, TTO_Sequence ) )
      goto Fail2;

    s = ms->Sequence;

    for ( n = 0; n < count; n++ )
    {
      if ( ACCESS_Frame( 2L ) )
        goto Fail1;

      new_offset = GET_UShort() + base_offset;

      FORGET_Frame();

      cur_offset = FILE_Pos();
      if ( FILE_Seek( new_offset ) ||
           ( error = Load_Sequence( &s[n], stream ) ) != TT_Err_Ok )
        goto Fail1;
      (void)FILE_Seek( cur_offset );
    }

    return TT_Err_Ok;

  Fail1:
    for ( m = 0; m < n; m++ )
      Free_Sequence( &s[m], memory );

    FREE( s );

  Fail2:
    Free_Coverage( &ms->Coverage, memory );
    return error;
  }


  void  Free_MultipleSubst( TTO_MultipleSubst*  ms,
			    FT_Memory           memory )
  {
    FT_UShort      n, count;

    TTO_Sequence*  s;


    if ( ms->Sequence )
    {
      count = ms->SequenceCount;
      s     = ms->Sequence;

      for ( n = 0; n < count; n++ )
        Free_Sequence( &s[n], memory );

      FREE( s );
    }

    Free_Coverage( &ms->Coverage, memory );
  }


  static FT_Error  Lookup_MultipleSubst( TTO_MultipleSubst*  ms,
					 OTL_Buffer          buffer,
                                         FT_UShort           flags,
                                         FT_UShort           context_length,
                                         TTO_GDEFHeader*     gdef )
  {
    FT_Error  error;
    FT_UShort index, property, n, count;
    FT_UShort*s;


    if ( context_length != 0xFFFF && context_length < 1 )
      return TTO_Err_Not_Covered;

    if ( CHECK_Property( gdef, IN_CURITEM(), flags, &property ) )
      return error;

    error = Coverage_Index( &ms->Coverage, IN_CURGLYPH(), &index );
    if ( error )
      return error;

    if ( index >= ms->SequenceCount )
      return TTO_Err_Invalid_GSUB_SubTable;

    count = ms->Sequence[index].GlyphCount;
    s     = ms->Sequence[index].Substitute;

    if ( ADD_String( buffer, 1, count, s, 0xFFFF, 0xFFFF ) )
      return error;

    if ( gdef && gdef->NewGlyphClasses )
    {
      /* this is a guess only ... */

      if ( property == TTO_LIGATURE )
        property = TTO_BASE_GLYPH;

      for ( n = 0; n < count; n++ )
      {
        error = Add_Glyph_Property( gdef, s[n], property );
        if ( error && error != TTO_Err_Not_Covered )
          return error;
      }
    }

    return TT_Err_Ok;
  }


  /* LookupType 3 */

  /* AlternateSet */

  static FT_Error  Load_AlternateSet( TTO_AlternateSet*  as,
                                      FT_Stream          stream )
  {
    FT_Error error;
    FT_Memory memory = stream->memory;

    FT_UShort n, count;
    FT_UShort*  a;


    if ( ACCESS_Frame( 2L ) )
      return error;

    count = as->GlyphCount = GET_UShort();

    FORGET_Frame();

    as->Alternate = NULL;

    if ( ALLOC_ARRAY( as->Alternate, count, FT_UShort ) )
      return error;

    a = as->Alternate;

    if ( ACCESS_Frame( count * 2L ) )
    {
      FREE( a );
      return error;
    }