ttcmap.c

Qt/Embedded是一个多平台的C++图形用户界面应用程序框架

/***************************************************************************/
/*                                                                         */
/*  ttcmap.c                                                               */
/*                                                                         */
/*    TrueType character mapping table (cmap) support (body).              */
/*                                                                         */
/*  Copyright 1996-1999 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.                                        */
/*                                                                         */
/***************************************************************************/


#include <ftdebug.h>

#include <ttload.h>
#include <ttcmap.h>
#include <tterrors.h>

/* required by the tracing mode */
#undef  FT_COMPONENT
#define FT_COMPONENT      trace_ttcmap


  static TT_UInt  code_to_index0( TT_CMapTable*  charmap, TT_ULong  char_code );
  static TT_UInt  code_to_index2( TT_CMapTable*  charmap, TT_ULong  char_code );
  static TT_UInt  code_to_index4( TT_CMapTable*  charmap, TT_ULong  char_code );
  static TT_UInt  code_to_index6( TT_CMapTable*  charmap, TT_ULong  char_code );      

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    TT_CharMap_Load                                                    */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Loads a given TrueType character map into memory.                  */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face   :: A handle to the parent face object.                      */
  /*    stream :: A handle to the current stream object.                   */
  /*                                                                       */
  /* <InOut>                                                               */
  /*    table  :: A pointer to a cmap object.                              */
  /*                                                                       */
  /* <Return>                                                              */
  /*    Error code.  0 means success.                                      */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The function assumes that the stream is already in use (i.e.,      */
  /*    opened).  In case of error, all partially allocated tables are     */
  /*    released.                                                          */
  /*                                                                       */
  LOCAL_FUNC
  TT_Error  TT_CharMap_Load( TT_Face        face,
                             TT_CMapTable*  cmap,
                             FT_Stream      stream )
  {
    TT_Error   error;
    FT_Memory  memory;
    TT_UShort  num_SH, num_Seg, i;

    TT_UShort  u, l;

    TT_CMap0*  cmap0;
    TT_CMap2*  cmap2;
    TT_CMap4*  cmap4;
    TT_CMap6*  cmap6;

    TT_CMap2SubHeader* cmap2sub;
    TT_CMap4Segment*   segments;


    if ( cmap->loaded )
      return TT_Err_Ok;

    memory = stream->memory;

    if ( FILE_Seek( cmap->offset ) )
      return error;

    switch ( cmap->format )
    {
    case 0:
      cmap0 = &cmap->c.cmap0;

      if ( ALLOC( cmap0->glyphIdArray, 256L )            ||
           FILE_Read( (void*)cmap0->glyphIdArray, 256L ) )
         goto Fail;

      cmap->get_index = code_to_index0;
      break;

    case 2:
      num_SH = 0;
      cmap2  = &cmap->c.cmap2;

      /* allocate subheader keys */

      if ( ALLOC_ARRAY( cmap2->subHeaderKeys, 256, TT_UShort ) ||
           ACCESS_Frame( 512L )                                )
        goto Fail;

      for ( i = 0; i < 256; i++ )
      {
        u = GET_UShort() / 8;
        cmap2->subHeaderKeys[i] = u;

        if ( num_SH < u )
          num_SH = u;
      }

      FORGET_Frame();

      /* load subheaders */

      cmap2->numGlyphId = l =
        ( ( cmap->length - 2L*(256+3) - num_SH*8L ) & 0xffff ) / 2;

      if ( ALLOC_ARRAY( cmap2->subHeaders,
                        num_SH + 1,
                        TT_CMap2SubHeader )    ||
           ACCESS_Frame( ( num_SH + 1 ) * 8L ) )
        goto Fail;

      cmap2sub = cmap2->subHeaders;

      for ( i = 0; i <= num_SH; i++ )
      {
        cmap2sub->firstCode     = GET_UShort();
        cmap2sub->entryCount    = GET_UShort();
        cmap2sub->idDelta       = GET_Short();
        /* we apply the location offset immediately */
        cmap2sub->idRangeOffset = GET_UShort() - ( num_SH - i ) * 8 - 2;

        cmap2sub++;
      }

      FORGET_Frame();

      /* load glyph IDs */

      if ( ALLOC_ARRAY( cmap2->glyphIdArray, l, TT_UShort ) ||
           ACCESS_Frame( l * 2L )                           )
        goto Fail;

      for ( i = 0; i < l; i++ )
        cmap2->glyphIdArray[i] = GET_UShort();

      FORGET_Frame();
      
      cmap->get_index = code_to_index2;
      break;

    case 4:
      cmap4 = &cmap->c.cmap4;

      /* load header */

      if ( ACCESS_Frame( 8L ) )
        goto Fail;

      cmap4->segCountX2    = GET_UShort();
      cmap4->searchRange   = GET_UShort();
      cmap4->entrySelector = GET_UShort();
      cmap4->rangeShift    = GET_UShort();

      num_Seg = cmap4->segCountX2 / 2;

      FORGET_Frame();

      /* load segments */

      if ( ALLOC_ARRAY( cmap4->segments,
                        num_Seg,
                        TT_CMap4Segment )         ||
           ACCESS_Frame( (num_Seg * 4 + 1) * 2L ) )
        goto Fail;

      segments = cmap4->segments;

      for ( i = 0; i < num_Seg; i++ )
        segments[i].endCount      = GET_UShort();

      (void)GET_UShort();

      for ( i = 0; i < num_Seg; i++ )
        segments[i].startCount    = GET_UShort();

      for ( i = 0; i < num_Seg; i++ )
        segments[i].idDelta       = GET_Short();

      for ( i = 0; i < num_Seg; i++ )
        segments[i].idRangeOffset = GET_UShort();

      FORGET_Frame();

      cmap4->numGlyphId = l =
        ( ( cmap->length - ( 16L + 8L * num_Seg ) ) & 0xFFFF ) /2;

      /* load IDs */

      if ( ALLOC_ARRAY( cmap4->glyphIdArray, l, TT_UShort ) ||
           ACCESS_Frame( l*2L )                             )
        goto Fail;

      for ( i = 0; i < l; i++ )
        cmap4->glyphIdArray[i] = GET_UShort();

      FORGET_Frame();
      
      cmap->get_index = code_to_index4;
      break;

    case 6:
      cmap6 = &cmap->c.cmap6;

      if ( ACCESS_Frame( 4L ) )
        goto Fail;

      cmap6->firstCode  = GET_UShort();
      cmap6->entryCount = GET_UShort();

      FORGET_Frame();

      l = cmap6->entryCount;

      if ( ALLOC_ARRAY( cmap6->glyphIdArray,
                        cmap6->entryCount,
                        TT_Short )           ||
           ACCESS_Frame( l * 2L )            )
        goto Fail;

      for ( i = 0; i < l; i++ )
        cmap6->glyphIdArray[i] = GET_UShort();

      FORGET_Frame();
      cmap->get_index = code_to_index6;
      break;

    default:   /* corrupt character mapping table */
      return TT_Err_Invalid_CharMap_Format;

    }
    return TT_Err_Ok;

  Fail:
    TT_CharMap_Free( face, cmap );
    return error;
  }