ttload.c

神龙卡开发原代码

/*******************************************************************
 *
 *  ttload.c                                                    1.0
 *
 *    TrueType Tables Loader.
 *
 *  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 "tttypes.h"
#include "ttdebug.h"
#include "ttcalc.h"
#include "ttfile.h"

#include "tttables.h"
#include "ttobjs.h"

#include "ttmemory.h"
#include "tttags.h"
#include "ttload.h"

/* required by the tracing mode */
#undef  TT_COMPONENT
#define TT_COMPONENT      trace_load

/* In all functions, the stream is taken from the 'face' object */
#define DEFINE_LOCALS           DEFINE_LOAD_LOCALS( face->stream )
#define DEFINE_LOCALS_WO_FRAME  DEFINE_LOAD_LOCALS_WO_FRAME( face->stream )


/*******************************************************************
 *
 *  Function    :  LookUp_TrueType_Table
 *
 *  Description :  Looks for a TrueType table by name.
 *
 *  Input  :  face       face table to look for
 *            tag        searched tag
 *
 *  Output :  Index of table if found, -1 otherwise.
 *
 ******************************************************************/

  EXPORT_FUNC
  Long  TT_LookUp_Table( PFace  face,
                         ULong  tag  )
  {
    UShort  i;


    PTRACE4(( "TT_LookUp_Table( %08lx, %c%c%c%c )\n",
                  (Long)face,
                  (Char)(tag >> 24),
                  (Char)(tag >> 16),
                  (Char)(tag >> 8),
                  (Char)(tag) ));

    for ( i = 0; i < face->numTables; i++ )
      if ( face->dirTables[i].Tag == tag )
        return i;

    PTRACE4(( "    Could not find table!\n" ));
    return -1;
  }


/*******************************************************************
 *
 *  Function    :  Load_TrueType_Collection
 *
 *  Description :  Loads the TTC table directory into face table.
 *
 *  Input  :  face    face record to look for
 *
 *  Output :  Error code.
 *
 ******************************************************************/

  static TT_Error  Load_TrueType_Collection( PFace  face )
  {
    DEFINE_LOCALS;

    ULong  n;


    PTRACE3(( "Load_TrueType_Collection( %08lx )\n", (long)face ));

    if ( FILE_Seek   ( 0L ) ||
         ACCESS_Frame( 12L ) )
      return error;

    face->ttcHeader.Tag      = GET_Tag4();
    face->ttcHeader.version  = GET_Long();
    face->ttcHeader.DirCount = GET_Long();

    FORGET_Frame();

    if ( face->ttcHeader.Tag != TTAG_ttcf )
    {
      face->ttcHeader.Tag      = 0;
      face->ttcHeader.version  = 0;
      face->ttcHeader.DirCount = 0;

      face->ttcHeader.TableDirectory = NULL;

      PTRACE3(("skipped.\n"));

      return TT_Err_File_Is_Not_Collection;
    }

    if ( ALLOC_ARRAY( face->ttcHeader.TableDirectory,
                      face->ttcHeader.DirCount,
                      ULong )                         ||
         ACCESS_Frame( face->ttcHeader.DirCount * 4L ) )
      return error;

    for ( n = 0; n < face->ttcHeader.DirCount; n++ )
      face->ttcHeader.TableDirectory[n] = GET_ULong();

    FORGET_Frame();

    PTRACE3(( "collections directory loaded.\n" ));
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Load_TrueType_Directory
 *
 *  Description :  Loads the table directory into face table.
 *
 *  Input  :  face       face record to look for
 *
 *            faceIndex  the index of the TrueType font, when
 *                       we're opening a collection.
 *
 *  Output :  SUCCESS on success.  FAILURE on error.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  Load_TrueType_Directory( PFace  face, ULong  faceIndex )
  {
    DEFINE_LOCALS;

    UShort     n, limit;
    TTableDir  tableDir;

    PTableDirEntry  entry;


    PTRACE2(("Load_TT_Directory( %08lx, %ld )\n", (long)face, faceIndex));

    error = Load_TrueType_Collection( face );

    if ( error )
    {
      if ( error != TT_Err_File_Is_Not_Collection )
        return error;

      /* the file isn't a collection, exit if we're asking */
      /* for a collected font                              */
      if ( faceIndex != 0 )
        return error;

      /* Now skip to the beginning of the file */
      if ( FILE_Seek( 0L ) )
        return error;
    }
    else
    {
      /* The file is a collection. Check the font index */
      if ( faceIndex >= face->ttcHeader.DirCount )
        return TT_Err_Invalid_Argument;

      /* select a TrueType font in the ttc file   */
      if ( FILE_Seek( face->ttcHeader.TableDirectory[faceIndex] ) )
        return error;
    }

    if ( ACCESS_Frame( 12L ) )
      return error;

    tableDir.version   = GET_Long();
    tableDir.numTables = GET_UShort();

    tableDir.searchRange   = GET_UShort();
    tableDir.entrySelector = GET_UShort();
    tableDir.rangeShift    = GET_UShort();

    FORGET_Frame();

    PTRACE2(( "-- Tables count   : %12u\n", tableDir.numTables ));
    PTRACE2(( "-- Format version : %08lx\n", tableDir.version ));

    /* Check that we have a 'sfnt' format there */

    if ( tableDir.version != 0x00010000  &&      /* MS fonts */
         tableDir.version != 0x74727565  &&      /* Mac fonts */
         tableDir.version != 0x00000000  )       /* some Korean fonts */
    {
      PERROR(( "!! invalid file format" ));
      return TT_Err_Invalid_File_Format;
    }

    face->numTables = tableDir.numTables;

    if ( ALLOC_ARRAY( face->dirTables,
                      face->numTables,
                      TTableDirEntry ) )
      return error;

    if ( ACCESS_Frame( face->numTables * 16L ) )
      return error;

    limit = face->numTables;
    entry = face->dirTables;

    for ( n = 0; n < limit; n++ )
    {                      /* loop through the tables and get all entries */
      entry->Tag      = GET_Tag4();
      entry->CheckSum = GET_ULong();
      entry->Offset   = GET_Long();
      entry->Length   = GET_Long();

      PTRACE2(( "  %c%c%c%c  -  %08lx  -  %08lx\n",
                (Char)(entry->Tag >> 24),
                (Char)(entry->Tag >> 16),
                (Char)(entry->Tag >> 8 ),
                (Char)(entry->Tag),
                entry->Offset,
                entry->Length ));
      entry++;
    }

    FORGET_Frame();

    PTRACE2(( "Directory loaded\n\n" ));
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Load_TrueType_MaxProfile
 *
 *  Description :  Loads the maxp table into face table.
 *
 *  Input  :  face     face table to look for
 *
 *  Output :  Error code.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  Load_TrueType_MaxProfile( PFace  face )
  {
    DEFINE_LOCALS;

    Long         i;
    PMaxProfile  maxProfile = &face->maxProfile;


    PTRACE2(( "Load_TT_MaxProfile( %08lx )\n", (long)face ));

    if ( ( i = TT_LookUp_Table( face, TTAG_maxp ) ) < 0 )
      return TT_Err_Max_Profile_Missing;

    if ( FILE_Seek( face->dirTables[i].Offset ) )   /* seek to maxprofile */
      return error;

    if ( ACCESS_Frame( 32L ) )  /* read into frame */
      return error;

    /* read frame data into face table */
    maxProfile->version               = GET_ULong();

    maxProfile->numGlyphs             = GET_UShort();

    maxProfile->maxPoints             = GET_UShort();
    maxProfile->maxContours           = GET_UShort();
    maxProfile->maxCompositePoints    = GET_UShort();
    maxProfile->maxCompositeContours  = GET_UShort();

    maxProfile->maxZones              = GET_UShort();
    maxProfile->maxTwilightPoints     = GET_UShort();

    maxProfile->maxStorage            = GET_UShort();
    maxProfile->maxFunctionDefs       = GET_UShort();
    maxProfile->maxInstructionDefs    = GET_UShort();
    maxProfile->maxStackElements      = GET_UShort();
    maxProfile->maxSizeOfInstructions = GET_UShort();
    maxProfile->maxComponentElements  = GET_UShort();
    maxProfile->maxComponentDepth     = GET_UShort();

    FORGET_Frame();

    /* XXX : an adjustement that is necessary to load certain */
    /*       broken fonts like "Keystrokes MT" :-(            */
    /*                                                        */
    /*   We allocate 64 function entries by default when      */
    /*   the maxFunctionDefs field is null.                   */

    if (maxProfile->maxFunctionDefs == 0)
      maxProfile->maxFunctionDefs = 64;

    face->numGlyphs     = maxProfile->numGlyphs;

    face->maxPoints     = MAX( maxProfile->maxCompositePoints,
                               maxProfile->maxPoints );
    face->maxContours   = MAX( maxProfile->maxCompositeContours,
                               maxProfile->maxContours );
    face->maxComponents = maxProfile->maxComponentElements +
                          maxProfile->maxComponentDepth;

    /* XXX: Some fonts have maxComponents set to 0; we will */
    /*      then use 16 of them by default.                 */
    if ( face->maxComponents == 0 )
      face->maxComponents = 16;
     
    /* We also increase maxPoints and maxContours in order to support */
    /* some broken fonts.                                             */
    face->maxPoints   += 8;
    face->maxContours += 4;

    PTRACE2(( "GASP loaded.\n" ));
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Load_TrueType_Gasp
 *
 *  Description :  Loads the TrueType Gasp table into the face
 *                 table.
 *
 *  Input  :  face     face table to look for
 *
 *  Output :  Error code.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  Load_TrueType_Gasp( PFace  face )
  {
    DEFINE_LOCALS;

    Long        i;
    UShort      j;
    TGasp*      gas;
    GaspRange*  gaspranges;


    PTRACE2(( "Load_TT_Gasp( %08lx )\n", (long)face ));

    if ( ( i = TT_LookUp_Table( face, TTAG_gasp ) ) < 0 )
      return TT_Err_Ok; /* gasp table is not required */

    if ( FILE_Seek( face->dirTables[i].Offset ) ||
         ACCESS_Frame( 4L ) )
      return error;

    gas = &face->gasp;

    gas->version   = GET_UShort();
    gas->numRanges = GET_UShort();

    FORGET_Frame();

    PTRACE3(( "number of ranges = %d\n", gas->numRanges ));

    if ( ALLOC_ARRAY( gaspranges, gas->numRanges, GaspRange ) ||
         ACCESS_Frame( gas->numRanges * 4L ) )
      goto Fail;

    face->gasp.gaspRanges = gaspranges;

    for ( j = 0; j < gas->numRanges; j++ )
    {
      gaspranges[j].maxPPEM  = GET_UShort();
      gaspranges[j].gaspFlag = GET_UShort();

      PTRACE3(( " [max:%d flag:%d]",
                gaspranges[j].maxPPEM,
                gaspranges[j].gaspFlag ));
    }
    PTRACE3(("\n"));

    FORGET_Frame();

    PTRACE2(( "GASP loaded\n" ));
    return TT_Err_Ok;

  Fail:
    FREE( gaspranges );
    gas->numRanges = 0;
    return error;
  }


/*******************************************************************
 *
 *  Function    :  Load_TrueType_Header
 *
 *  Description :  Loads the TrueType header table into the face
 *                 table.
 *
 *  Input  :  face     face table to look for
 *
 *  Output :  Error code.
 *
 ******************************************************************/

  LOCAL_FUNC
  TT_Error  Load_TrueType_Header( PFace  face )
  {
    DEFINE_LOCALS;

    Long        i;
    TT_Header*  header;


    PTRACE2(( "Load_TT_Header( %08lx )\n", (long)face ));

    if ( ( i = TT_LookUp_Table( face, TTAG_head ) ) < 0 )
    {
      PTRACE0(( "Font Header is missing !!\n" ));
      return TT_Err_Header_Table_Missing;
    }

    if ( FILE_Seek( face->dirTables[i].Offset ) ||
         ACCESS_Frame( 54L ) )
      return error;

    header = &face->fontHeader;

    header->Table_Version = GET_ULong();
    header->Font_Revision = GET_ULong();

    header->CheckSum_Adjust = GET_Long();
    header->Magic_Number    = GET_Long();

    header->Flags        = GET_UShort();
    header->Units_Per_EM = GET_UShort();

    header->Created [0] = GET_Long();
    header->Created [1] = GET_Long();
    header->Modified[0] = GET_Long();
    header->Modified[1] = GET_Long();

    header->xMin = GET_Short();
    header->yMin = GET_Short();
    header->xMax = GET_Short();
    header->yMax = GET_Short();

    header->Mac_Style       = GET_UShort();
    header->Lowest_Rec_PPEM = GET_UShort();

    header->Font_Direction      = GET_Short();
    header->Index_To_Loc_Format = GET_Short();
    header->Glyph_Data_Format   = GET_Short();

    FORGET_Frame();

    PTRACE2(( "    Units per EM : %8u\n", header->Units_Per_EM ));
    PTRACE2(( "    IndexToLoc   : %8d\n", header->Index_To_Loc_Format ));
    PTRACE2(( "Font Header Loaded.\n" ));
    return TT_Err_Ok;
  }


/*******************************************************************
 *
 *  Function    :  Load_TrueType_Metrics
 *
 *  Description :  Loads the horizontal or vertical metrics table
 *                 into face object.
 *
 *  Input  :  face
 *            vertical   set to true when loading the vmtx table,
 *                       or false for hmtx
 *
 *  Output :  Error code.
 *
 ******************************************************************/

  static
  TT_Error  Load_TrueType_Metrics( PFace  face,
                                   Bool   vertical )
  {
    DEFINE_LOCALS;

    Long              n, num_shorts, num_shorts_checked, num_longs;

    PLongMetrics*     longs;
    PShortMetrics*    shorts;

    PLongMetrics      long_metric;


    PTRACE2(( "Load_TT_%s_Metrics( %08lx )\n",
              vertical ? "Vertical" : "Horizontal",
              (long)face ));

    if ( vertical )
    {
      /* The table is optional, quit silently if it wasn't found       */
      /* XXX : Some fonts have a valid vertical header with a non-null */
      /*       "number_of_VMetrics" fields, but no corresponding       */
      /*       'vmtx' table to get the metrics from (e.g. mingliu)     */
      /*                                                               */
      /*       For safety, we set the field to 0 !                     */
      /*                                                               */
      n = TT_LookUp_Table( face, TTAG_vmtx );