xref: /inferno-os/libfreetype/ttcmap0.c (revision 37da2899f40661e3e9631e497da8dc59b971cbd0)

/***************************************************************************/
/*                                                                         */
/*  ttcmap0.c                                                              */
/*                                                                         */
/*    TrueType new character mapping table (cmap) support (body).          */
/*                                                                         */
/*  Copyright 2002 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 <ft2build.h>
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_STREAM_H
#include "ttload.h"
#include "ttcmap0.h"

#include "sferrors.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_ttcmap


#define TT_PEEK_SHORT   FT_PEEK_SHORT
#define TT_PEEK_USHORT  FT_PEEK_USHORT
#define TT_PEEK_LONG    FT_PEEK_LONG
#define TT_PEEK_ULONG   FT_PEEK_ULONG

#define TT_NEXT_SHORT   FT_NEXT_SHORT
#define TT_NEXT_USHORT  FT_NEXT_USHORT
#define TT_NEXT_LONG    FT_NEXT_LONG
#define TT_NEXT_ULONG   FT_NEXT_ULONG


  FT_CALLBACK_DEF( FT_Error )
  tt_cmap_init( TT_CMap   cmap,
                FT_Byte*  table )
  {
    cmap->data = table;
    return 0;
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                           FORMAT 0                            *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET         TYPE          DESCRIPTION                */
  /*                                                                       */
  /*   format      0              USHORT        must be 0                  */
  /*   length      2              USHORT        table length in bytes      */
  /*   language    4              USHORT        Mac language code          */
  /*   glyph_ids   6              BYTE[256]     array of glyph indices     */
  /*               262                                                     */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_0

  FT_CALLBACK_DEF( void )
  tt_cmap0_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*  p      = table + 2;
    FT_UInt   length = TT_NEXT_USHORT( p );


    if ( table + length > valid->limit || length < 262 )
      FT_INVALID_TOO_SHORT;

    /* check glyph indices whenever necessary */
    if ( valid->level >= FT_VALIDATE_TIGHT )
    {
      FT_UInt  n, idx;


      p = table + 6;
      for ( n = 0; n < 256; n++ )
      {
        idx = *p++;
        if ( idx >= TT_VALID_GLYPH_COUNT( valid ) )
          FT_INVALID_GLYPH_ID;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap0_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*  table = cmap->data;


    return char_code < 256 ? table[6 + char_code] : 0;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap0_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_Byte*   table    = cmap->data;
    FT_UInt32  charcode = *pchar_code;
    FT_UInt32  result   = 0;
    FT_UInt    gindex   = 0;


    table += 6;  /* go to glyph ids */
    while ( ++charcode < 256 )
    {
      gindex = table[charcode];
      if ( gindex != 0 )
      {
        result = charcode;
        break;
      }
    }

    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap0_class_rec =
  {
    {
      sizeof( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap0_char_index,
      (FT_CMap_CharNextFunc) tt_cmap0_char_next
    },
    0,
    (TT_CMap_ValidateFunc)   tt_cmap0_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_0 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 2                             *****/
  /*****                                                               *****/
  /***** This is used for certain CJK encodings that encode text in a  *****/
  /***** mixed 8/16 bits encoding along the following lines:           *****/
  /*****                                                               *****/
  /***** * Certain byte values correspond to an 8-bit character code   *****/
  /*****   (typically in the range 0..127 for ASCII compatibility).    *****/
  /*****                                                               *****/
  /***** * Certain byte values signal the first byte of a 2-byte       *****/
  /*****   character code (but these values are also valid as the      *****/
  /*****   second byte of a 2-byte character).                         *****/
  /*****                                                               *****/
  /***** The following charmap lookup and iteration functions all      *****/
  /***** assume that the value "charcode" correspond to following:     *****/
  /*****                                                               *****/
  /*****   - For one byte characters, "charcode" is simply the         *****/
  /*****     character code.                                           *****/
  /*****                                                               *****/
  /*****   - For two byte characters, "charcode" is the 2-byte         *****/
  /*****     character code in big endian format.  More exactly:       *****/
  /*****                                                               *****/
  /*****       (charcode >> 8)    is the first byte value              *****/
  /*****       (charcode & 0xFF)  is the second byte value             *****/
  /*****                                                               *****/
  /***** Note that not all values of "charcode" are valid according    *****/
  /***** to these rules, and the function moderately check the         *****/
  /***** arguments.                                                    *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET         TYPE            DESCRIPTION              */
  /*                                                                       */
  /*   format      0              USHORT          must be 2                */
  /*   length      2              USHORT          table length in bytes    */
  /*   language    4              USHORT          Mac language code        */
  /*   keys        6              USHORT[256]     sub-header keys          */
  /*   subs        518            SUBHEAD[NSUBS]  sub-headers array        */
  /*   glyph_ids   518+NSUB*8     USHORT[]        glyph id array           */
  /*                                                                       */
  /* The `keys' table is used to map charcode high-bytes to sub-headers.   */
  /* The value of `NSUBS' is the number of sub-headers defined in the      */
  /* table and is computed by finding the maximum of the `keys' table.     */
  /*                                                                       */
  /* Note that for any n, `keys[n]' is a byte offset within the `subs'     */
  /* table, i.e., it is the corresponding sub-header index multiplied      */
  /* by 8.                                                                 */
  /*                                                                       */
  /* Each sub-header has the following format:                             */
  /*                                                                       */
  /*   NAME        OFFSET      TYPE            DESCRIPTION                 */
  /*                                                                       */
  /*   first       0           USHORT          first valid low-byte        */
  /*   count       2           USHORT          number of valid low-bytes   */
  /*   delta       4           SHORT           see below                   */
  /*   offset      6           USHORT          see below                   */
  /*                                                                       */
  /* A sub-header defines, for each high-byte, the range of valid          */
  /* low-bytes within the charmap.  Note that the range defined by `first' */
  /* and `count' must be completely included in the interval [0..255]      */
  /* according to the specification.                                       */
  /*                                                                       */
  /* If a character code is contained within a given sub-header, then      */
  /* mapping it to a glyph index is done as follows:                       */
  /*                                                                       */
  /* * The value of `offset' is read.  This is a _byte_ distance from the  */
  /*   location of the `offset' field itself into a slice of the           */
  /*   `glyph_ids' table.  Let's call it `slice' (it's a USHORT[] too).    */
  /*                                                                       */
  /* * The value `slice[char.lo - first]' is read.  If it is 0, there is   */
  /*   no glyph for the charcode.  Otherwise, the value of `delta' is      */
  /*   added to it (modulo 65536) to form a new glyph index.               */
  /*                                                                       */
  /* It is up to the validation routine to check that all offsets fall     */
  /* within the glyph ids table (and not within the `subs' table itself or */
  /* outside of the CMap).                                                 */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_2

  FT_CALLBACK_DEF( void )
  tt_cmap2_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*  p      = table + 2;           /* skip format */
    FT_UInt   length = TT_PEEK_USHORT( p );
    FT_UInt   n, max_subs;
    FT_Byte*  keys;                         /* keys table */
    FT_Byte*  subs;                         /* sub-headers */
    FT_Byte*  glyph_ids;                    /* glyph id array */


    if ( table + length > valid->limit || length < 6 + 512 )
      FT_INVALID_TOO_SHORT;

    keys = table + 6;

    /* parse keys to compute sub-headers count */
    p        = keys;
    max_subs = 0;
    for ( n = 0; n < 256; n++ )
    {
      FT_UInt  idx = TT_NEXT_USHORT( p );


      /* value must be multiple of 8 */
      if ( valid->level >= FT_VALIDATE_PARANOID && ( idx & 7 ) != 0 )
        FT_INVALID_DATA;

      idx >>= 3;

      if ( idx > max_subs )
        max_subs = idx;
    }

    FT_ASSERT( p == table + 518 );

    subs      = p;
    glyph_ids = subs + (max_subs + 1) * 8;
    if ( glyph_ids > valid->limit )
      FT_INVALID_TOO_SHORT;

    /* parse sub-headers */
    for ( n = 0; n <= max_subs; n++ )
    {
      FT_UInt   first_code, code_count, offset;
      FT_Int    delta;
      FT_Byte*  ids;


      first_code = TT_NEXT_USHORT( p );
      code_count = TT_NEXT_USHORT( p );
      delta      = TT_NEXT_SHORT( p );
      offset     = TT_NEXT_USHORT( p );

      /* check range within 0..255 */
      if ( valid->level >= FT_VALIDATE_PARANOID )
      {
        if ( first_code >= 256 || first_code + code_count > 256 )
          FT_INVALID_DATA;
      }

      /* check offset */
      if ( offset != 0 )
      {
        ids = p - 2 + offset;
        if ( ids < glyph_ids || ids + code_count*2 > table + length )
          FT_INVALID_OFFSET;

        /* check glyph ids */
        if ( valid->level >= FT_VALIDATE_TIGHT )
        {
          FT_Byte*  limit = p + code_count * 2;
          FT_UInt   idx;


          for ( ; p < limit; )
          {
            idx = TT_NEXT_USHORT( p );
            if ( idx != 0 )
            {
              idx = ( idx + delta ) & 0xFFFFU;
              if ( idx >= TT_VALID_GLYPH_COUNT( valid ) )
                FT_INVALID_GLYPH_ID;
            }
          }
        }
      }
    }
  }


  /* return sub header corresponding to a given character code */
  /* NULL on invalid charcode                                  */
  static FT_Byte*
  tt_cmap2_get_subheader( FT_Byte*   table,
                          FT_UInt32  char_code )
  {
    FT_Byte*  result = NULL;


    if ( char_code < 0x10000UL )
    {
      FT_UInt   char_lo = (FT_UInt)( char_code & 0xFF );
      FT_UInt   char_hi = (FT_UInt)( char_code >> 8 );
      FT_Byte*  p       = table + 6;    /* keys table */
      FT_Byte*  subs    = table + 518;  /* subheaders table */
      FT_Byte*  sub;


      if ( char_hi == 0 )
      {
        /* an 8-bit character code -- we use subHeader 0 in this case */
        /* to test whether the character code is in the charmap       */
        /*                                                            */
        sub = subs;  /* jump to first sub-header */

        /* check that the sub-header for this byte is 0, which */
        /* indicates that it's really a valid one-byte value   */
        /* Otherwise, return 0                                 */
        /*                                                     */
        p += char_lo * 2;
        if ( TT_PEEK_USHORT( p ) != 0 )
          goto Exit;
      }
      else
      {
        /* a 16-bit character code */
        p  += char_hi * 2;                          /* jump to key entry  */
        sub = subs + ( TT_PEEK_USHORT( p ) & -8 );  /* jump to sub-header */

        /* check that the hi byte isn't a valid one-byte value */
        if ( sub == subs )
          goto Exit;
      }
      result = sub;
    }
  Exit:
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap2_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*  table   = cmap->data;
    FT_UInt   result  = 0;
    FT_Byte*  subheader;


    subheader = tt_cmap2_get_subheader( table, char_code );
    if ( subheader )
    {
      FT_Byte*  p   = subheader;
      FT_UInt   idx = (FT_UInt)(char_code & 0xFF);
      FT_UInt   start, count;
      FT_Int    delta;
      FT_UInt   offset;


      start  = TT_NEXT_USHORT( p );
      count  = TT_NEXT_USHORT( p );
      delta  = TT_NEXT_SHORT ( p );
      offset = TT_PEEK_USHORT( p );

      idx -= start;
      if ( idx < count && offset != 0 )
      {
        p  += offset + 2 * idx;
        idx = TT_PEEK_USHORT( p );

        if ( idx != 0 )
          result = (FT_UInt)( idx + delta ) & 0xFFFFU;
      }
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap2_char_next( TT_CMap     cmap,
                      FT_UInt32  *pcharcode )
  {
    FT_Byte*   table    = cmap->data;
    FT_UInt    gindex   = 0;
    FT_UInt32  result   = 0;
    FT_UInt32  charcode = *pcharcode + 1;
    FT_Byte*   subheader;


    while ( charcode < 0x10000UL )
    {
      subheader = tt_cmap2_get_subheader( table, charcode );
      if ( subheader )
      {
        FT_Byte*  p       = subheader;
        FT_UInt   start   = TT_NEXT_USHORT( p );
        FT_UInt   count   = TT_NEXT_USHORT( p );
        FT_Int    delta   = TT_NEXT_SHORT ( p );
        FT_UInt   offset  = TT_PEEK_USHORT( p );
        FT_UInt   char_lo = (FT_UInt)( charcode & 0xFF );
        FT_UInt   pos, idx;


        if ( offset == 0 )
          goto Next_SubHeader;

        if ( char_lo < start )
        {
          char_lo = start;
          pos     = 0;
        }
        else
          pos = (FT_UInt)( char_lo - start );

        p       += offset + pos * 2;
        charcode = ( charcode & -256 ) + char_lo;

        for ( ; pos < count; pos++, charcode++ )
        {
          idx = TT_NEXT_USHORT( p );

          if ( idx != 0 )
          {
            gindex = ( idx + delta ) & 0xFFFFU;
            if ( gindex != 0 )
            {
              result = charcode;
              goto Exit;
            }
          }
        }
      }

      /* jump to next sub-header, i.e. higher byte value */
    Next_SubHeader:
      charcode = ( charcode & -256 ) + 256;
    }

  Exit:
    *pcharcode = result;

    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap2_class_rec =
  {
    {
      sizeof( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap2_char_index,
      (FT_CMap_CharNextFunc) tt_cmap2_char_next
    },
    2,
    (TT_CMap_ValidateFunc)   tt_cmap2_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_2 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                           FORMAT 4                            *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME          OFFSET         TYPE              DESCRIPTION          */
  /*                                                                       */
  /*   format        0              USHORT            must be 4            */
  /*   length        2              USHORT            table length         */
  /*                                                  in bytes             */
  /*   language      4              USHORT            Mac language code    */
  /*                                                                       */
  /*   segCountX2    6              USHORT            2*NUM_SEGS           */
  /*   searchRange   8              USHORT            2*(1 << LOG_SEGS)    */
  /*   entrySelector 10             USHORT            LOG_SEGS             */
  /*   rangeShift    12             USHORT            segCountX2 -         */
  /*                                                    searchRange        */
  /*                                                                       */
  /*   endCount      14             USHORT[NUM_SEGS]  end charcode for     */
  /*                                                  each segment; last   */
  /*                                                  is 0xFFFF            */
  /*                                                                       */
  /*   pad           14+NUM_SEGS*2  USHORT            padding              */
  /*                                                                       */
  /*   startCount    16+NUM_SEGS*2  USHORT[NUM_SEGS]  first charcode for   */
  /*                                                  each segment         */
  /*                                                                       */
  /*   idDelta       16+NUM_SEGS*4  SHORT[NUM_SEGS]   delta for each       */
  /*                                                  segment              */
  /*   idOffset      16+NUM_SEGS*6  SHORT[NUM_SEGS]   range offset for     */
  /*                                                  each segment; can be */
  /*                                                  zero                 */
  /*                                                                       */
  /*   glyphIds      16+NUM_SEGS*8  USHORT[]          array of glyph id    */
  /*                                                  ranges               */
  /*                                                                       */
  /* Character codes are modelled by a series of ordered (increasing)      */
  /* intervals called segments.  Each segment has start and end codes,     */
  /* provided by the `startCount' and `endCount' arrays.  Segments must    */
  /* not be overlapping and the last segment should always contain the     */
  /* `0xFFFF' endCount.                                                    */
  /*                                                                       */
  /* The fields `searchRange', `entrySelector' and `rangeShift' are better */
  /* ignored (they are traces of over-engineering in the TrueType          */
  /* specification).                                                       */
  /*                                                                       */
  /* Each segment also has a signed `delta', as well as an optional offset */
  /* within the `glyphIds' table.                                          */
  /*                                                                       */
  /* If a segment's idOffset is 0, the glyph index corresponding to any    */
  /* charcode within the segment is obtained by adding the value of        */
  /* `idDelta' directly to the charcode, modulo 65536.                     */
  /*                                                                       */
  /* Otherwise, a glyph index is taken from the glyph ids sub-array for    */
  /* the segment, and the value of `idDelta' is added to it.               */
  /*                                                                       */
  /*                                                                       */
  /* Finally, note that certain fonts contain invalid charmaps that        */
  /* contain end=0xFFFF, start=0xFFFF, delta=0x0001, offset=0xFFFF at the  */
  /* of their charmaps (e.g. opens___.ttf which comes with OpenOffice.org) */
  /* we need special code to deal with them correctly...                   */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_4

  FT_CALLBACK_DEF( void )
  tt_cmap4_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*  p      = table + 2;               /* skip format */
    FT_UInt   length = TT_NEXT_USHORT( p );
    FT_Byte   *ends, *starts, *offsets, *deltas, *glyph_ids;
    FT_UInt   num_segs;


    /* in certain fonts, the `length' field is invalid and goes */
    /* out of bound.  We try to correct this here...            */
    if ( length < 16 )
      FT_INVALID_TOO_SHORT;

    if ( table + length > valid->limit )
    {
      if ( valid->level >= FT_VALIDATE_TIGHT )
        FT_INVALID_TOO_SHORT;

      length = (FT_UInt)( valid->limit - table );
    }

    p        = table + 6;
    num_segs = TT_NEXT_USHORT( p );   /* read segCountX2 */

    if ( valid->level >= FT_VALIDATE_PARANOID )
    {
      /* check that we have an even value here */
      if ( num_segs & 1 )
        FT_INVALID_DATA;
    }

    num_segs /= 2;

    /* check the search parameters - even though we never use them */
    /*                                                             */
    if ( valid->level >= FT_VALIDATE_PARANOID )
    {
      /* check the values of 'searchRange', 'entrySelector', 'rangeShift' */
      FT_UInt  search_range   = TT_NEXT_USHORT( p );
      FT_UInt  entry_selector = TT_NEXT_USHORT( p );
      FT_UInt  range_shift    = TT_NEXT_USHORT( p );


      if ( ( search_range | range_shift ) & 1 )  /* must be even values */
        FT_INVALID_DATA;

      search_range /= 2;
      range_shift  /= 2;

      /* `search range' is the greatest power of 2 that is <= num_segs */

      if ( search_range                > num_segs                 ||
           search_range * 2            < num_segs                 ||
           search_range + range_shift != num_segs                 ||
           search_range               != ( 1U << entry_selector ) )
        FT_INVALID_DATA;
    }

    ends      = table   + 14;
    starts    = table   + 16 + num_segs * 2;
    deltas    = starts  + num_segs * 2;
    offsets   = deltas  + num_segs * 2;
    glyph_ids = offsets + num_segs * 2;

    if ( glyph_ids > table + length )
      FT_INVALID_TOO_SHORT;

    /* check last segment, its end count must be FFFF */
    if ( valid->level >= FT_VALIDATE_PARANOID )
    {
      p = ends + ( num_segs - 1 ) * 2;
      if ( TT_PEEK_USHORT( p ) != 0xFFFFU )
        FT_INVALID_DATA;
    }

    /* check that segments are sorted in increasing order and do not */
    /* overlap; check also the offsets                               */
    {
      FT_UInt  start, end, last = 0, offset, n;
      FT_Int   delta;


      for ( n = 0; n < num_segs; n++ )
      {
        p = starts + n * 2;
        start = TT_PEEK_USHORT( p );
        p = ends + n * 2;
        end = TT_PEEK_USHORT( p );
        p = deltas + n * 2;
        delta = TT_PEEK_SHORT( p );
        p = offsets + n * 2;
        offset = TT_PEEK_USHORT( p );

        if ( start > end )
          FT_INVALID_DATA;

        /* this test should be performed at default validation level;  */
        /* unfortunately, some popular Asian fonts present overlapping */
        /* ranges in their charmaps                                    */
        /*                                                             */
        if ( valid->level >= FT_VALIDATE_TIGHT )
        {
          if ( n > 0 && start <= last )
            FT_INVALID_DATA;
        }

        if ( offset && offset != 0xFFFFU )
        {
          p += offset;  /* start of glyph id array */

          /* check that we point within the glyph ids table only */
          if ( p < glyph_ids                                ||
               p + ( end - start + 1 ) * 2 > table + length )
            FT_INVALID_DATA;

          /* check glyph indices within the segment range */
          if ( valid->level >= FT_VALIDATE_TIGHT )
          {
            FT_UInt  i, idx;


            for ( i = start; i < end; i++ )
            {
              idx = FT_NEXT_USHORT( p );
              if ( idx != 0 )
              {
                idx = (FT_UInt)( idx + delta ) & 0xFFFFU;

                if ( idx >= TT_VALID_GLYPH_COUNT( valid ) )
                  FT_INVALID_GLYPH_ID;
              }
            }
          }
        }
        else if ( offset == 0xFFFFU )
        {
          /* Some fonts (erroneously?) use a range offset of 0xFFFF */
          /* to mean missing glyph in cmap table                    */
          /*                                                        */
          if ( valid->level >= FT_VALIDATE_PARANOID                     ||
               n != num_segs - 1                                        ||
               !( start == 0xFFFFU && end == 0xFFFFU && delta == 0x1U ) )
            FT_INVALID_DATA;
        }

        last = end;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap4_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*  table  = cmap->data;
    FT_UInt   result = 0;


    if ( char_code < 0x10000UL )
    {
      FT_UInt   idx, num_segs2;
      FT_Int    delta;
      FT_UInt   code = (FT_UInt)char_code;
      FT_Byte*  p;


      p         = table + 6;
      num_segs2 = TT_PEEK_USHORT( p ) & -2;  /* be paranoid! */

#if 1
      /* Some fonts have more than 170 segments in their charmaps! */
      /* We changed this function to use a more efficient binary   */
      /* search for improving performance                          */
      {
        FT_UInt  min = 0;
        FT_UInt  max = num_segs2 >> 1;
        FT_UInt  mid, start, end, offset;


        while ( min < max )
        {
          mid   = ( min + max ) >> 1;
          p     = table + 14 + mid * 2;
          end   = TT_NEXT_USHORT( p );
          p    += num_segs2;
          start = TT_PEEK_USHORT( p);

          if ( code < start )
            max = mid;

          else if ( code > end )
            min = mid + 1;

          else
          {
            /* we found the segment */
            idx = code;

            p += num_segs2;
            delta = TT_PEEK_SHORT( p );

            p += num_segs2;
            offset = TT_PEEK_USHORT( p );

            if ( offset == 0xFFFFU )
              goto Exit;

            if ( offset != 0 )
            {
              p  += offset + 2 * ( idx - start );
              idx = TT_PEEK_USHORT( p );
            }

            if ( idx != 0 )
              result = (FT_UInt)( idx + delta ) & 0xFFFFU;

            goto Exit;
          }
        }
      }

#else /* 0 - old code */

      {
        FT_UInt   n;
        FT_Byte*  q;


        p = table + 14;               /* ends table   */
        q = table + 16 + num_segs2;   /* starts table */


        for ( n = 0; n < num_segs2; n += 2 )
        {
          FT_UInt  end   = TT_NEXT_USHORT( p );
          FT_UInt  start = TT_NEXT_USHORT( q );
          FT_UInt  offset;


          if ( code < start )
            break;

          if ( code <= end )
          {
            idx = code;

            p = q + num_segs2 - 2;
            delta = TT_PEEK_SHORT( p );
            p += num_segs2;
            offset = TT_PEEK_USHORT( p );

            if ( offset == 0xFFFFU )
              goto Exit;

            if ( offset != 0 )
            {
              p  += offset + 2 * ( idx - start );
              idx = TT_PEEK_USHORT( p );
            }

            if ( idx != 0 )
              result = (FT_UInt)( idx + delta ) & 0xFFFFU;
          }
        }
      }

#endif /* 0 */

    }

  Exit:
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap4_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_Byte*   table     = cmap->data;
    FT_UInt32  result    = 0;
    FT_UInt32  char_code = *pchar_code + 1;
    FT_UInt    gindex    = 0;
    FT_Byte*   p;
    FT_Byte*   q;
    FT_UInt    code, num_segs2;


    if ( char_code >= 0x10000UL )
      goto Exit;

    code      = (FT_UInt)char_code;
    p         = table + 6;
    num_segs2 = TT_PEEK_USHORT(p) & -2;  /* ensure even-ness */

    for (;;)
    {
      FT_UInt  offset, n;
      FT_Int   delta;


      p = table + 14;              /* ends table  */
      q = table + 16 + num_segs2;  /* starts table */

      for ( n = 0; n < num_segs2; n += 2 )
      {
        FT_UInt  end   = TT_NEXT_USHORT( p );
        FT_UInt  start = TT_NEXT_USHORT( q );


        if ( code < start )
          code = start;

        if ( code <= end )
        {
          p = q + num_segs2 - 2;
          delta = TT_PEEK_SHORT( p );
          p += num_segs2;
          offset = TT_PEEK_USHORT( p );

          if ( offset != 0 && offset != 0xFFFFU )
          {
            /* parse the glyph ids array for non-0 index */
            p += offset + ( code - start ) * 2;
            while ( code <= end )
            {
              gindex = TT_NEXT_USHORT( p );
              if ( gindex != 0 )
              {
                gindex = (FT_UInt)( gindex + delta ) & 0xFFFFU;
                if ( gindex != 0 )
                  break;
              }
              code++;
            }
          }
          else if ( offset == 0xFFFFU )
          {
            /* an offset of 0xFFFF means an empty glyph in certain fonts! */
            code = end;
            break;
          }
          else
            gindex = (FT_UInt)( code + delta ) & 0xFFFFU;

          if ( gindex == 0 )
            break;

          result = code;
          goto Exit;
        }
      }

      /* loop to next trial charcode */
      if ( code >= 0xFFFFU )
        break;

      code++;
    }
    return (FT_UInt)result;

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap4_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap4_char_index,
      (FT_CMap_CharNextFunc) tt_cmap4_char_next
    },
    4,
    (TT_CMap_ValidateFunc)   tt_cmap4_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_4 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 6                             *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET          TYPE             DESCRIPTION            */
  /*                                                                       */
  /*   format       0              USHORT           must be 4              */
  /*   length       2              USHORT           table length in bytes  */
  /*   language     4              USHORT           Mac language code      */
  /*                                                                       */
  /*   first        6              USHORT           first segment code     */
  /*   count        8              USHORT           segment size in chars  */
  /*   glyphIds     10             USHORT[count]    glyph ids              */
  /*                                                                       */
  /* A very simplified segment mapping.                                    */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_6

  FT_CALLBACK_DEF( void )
  tt_cmap6_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*  p;
    FT_UInt   length, start, count;


    if ( table + 10 > valid->limit )
      FT_INVALID_TOO_SHORT;

    p      = table + 2;
    length = TT_NEXT_USHORT( p );

    p      = table + 6;             /* skip language */
    start  = TT_NEXT_USHORT( p );
    count  = TT_NEXT_USHORT( p );

    if ( table + length > valid->limit || length < 10 + count * 2 )
      FT_INVALID_TOO_SHORT;

    /* check glyph indices */
    if ( valid->level >= FT_VALIDATE_TIGHT )
    {
      FT_UInt  gindex;


      for ( ; count > 0; count-- )
      {
        gindex = TT_NEXT_USHORT( p );
        if ( gindex >= TT_VALID_GLYPH_COUNT( valid ) )
          FT_INVALID_GLYPH_ID;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap6_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*  table  = cmap->data;
    FT_UInt   result = 0;
    FT_Byte*  p      = table + 6;
    FT_UInt   start  = TT_NEXT_USHORT( p );
    FT_UInt   count  = TT_NEXT_USHORT( p );
    FT_UInt   idx    = (FT_UInt)( char_code - start );


    if ( idx < count )
    {
      p += 2 * idx;
      result = TT_PEEK_USHORT( p );
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap6_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_Byte*   table     = cmap->data;
    FT_UInt32  result    = 0;
    FT_UInt32  char_code = *pchar_code + 1;
    FT_UInt    gindex    = 0;

    FT_Byte*   p         = table + 6;
    FT_UInt    start     = TT_NEXT_USHORT( p );
    FT_UInt    count     = TT_NEXT_USHORT( p );
    FT_UInt    idx;


    if ( char_code >= 0x10000UL )
      goto Exit;

    if ( char_code < start )
      char_code = start;

    idx = (FT_UInt)( char_code - start );
    p  += 2 * idx;

    for ( ; idx < count; idx++ )
    {
      gindex = TT_NEXT_USHORT( p );
      if ( gindex != 0 )
      {
        result = char_code;
        break;
      }
      char_code++;
    }

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap6_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap6_char_index,
      (FT_CMap_CharNextFunc) tt_cmap6_char_next
    },
    6,
    (TT_CMap_ValidateFunc)   tt_cmap6_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_6 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 8                             *****/
  /*****                                                               *****/
  /***** It's hard to completely understand what the OpenType spec     *****/
  /***** says about this format, but here is my conclusion.            *****/
  /*****                                                               *****/
  /***** The purpose of this format is to easily map UTF-16 text to    *****/
  /***** glyph indices.  Basically, the `char_code' must be in one of  *****/
  /***** the following formats:                                        *****/
  /*****                                                               *****/
  /*****   - A 16-bit value that isn't part of the Unicode Surrogates  *****/
  /*****     Area (i.e. U+D800-U+DFFF).                                *****/
  /*****                                                               *****/
  /*****   - A 32-bit value, made of two surrogate values, i.e.. if    *****/
  /*****     `char_code = (char_hi << 16) | char_lo', then both        *****/
  /*****     `char_hi' and `char_lo' must be in the Surrogates Area.   *****/
  /*****      Area.                                                    *****/
  /*****                                                               *****/
  /***** The 'is32' table embedded in the charmap indicates whether a  *****/
  /***** given 16-bit value is in the surrogates area or not.          *****/
  /*****                                                               *****/
  /***** So, for any given `char_code', we can assert the following:   *****/
  /*****                                                               *****/
  /*****   If `char_hi == 0' then we must have `is32[char_lo] == 0'.   *****/
  /*****                                                               *****/
  /*****   If `char_hi != 0' then we must have both                    *****/
  /*****   `is32[char_hi] != 0' and `is32[char_lo] != 0'.              *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET         TYPE        DESCRIPTION                  */
  /*                                                                       */
  /*   format      0              USHORT      must be 8                    */
  /*   reseved     2              USHORT      reserved                     */
  /*   length      4              ULONG       length in bytes              */
  /*   language    8              ULONG       Mac language code            */
  /*   is32        12             BYTE[8192]  32-bitness bitmap            */
  /*   count       8204           ULONG       number of groups             */
  /*                                                                       */
  /* This header is followed by 'count' groups of the following format:    */
  /*                                                                       */
  /*   start       0              ULONG       first charcode               */
  /*   end         4              ULONG       last charcode                */
  /*   startId     8              ULONG       start glyph id for the group */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_8

  FT_CALLBACK_DEF( void )
  tt_cmap8_validate( FT_Byte*      table,
                     FT_Validator  valid )
  {
    FT_Byte*   p = table + 4;
    FT_Byte*   is32;
    FT_UInt32  length;
    FT_UInt32  num_groups;


    if ( table + 16 + 8192 > valid->limit )
      FT_INVALID_TOO_SHORT;

    length = TT_NEXT_ULONG( p );
    if ( table + length > valid->limit || length < 8208 )
      FT_INVALID_TOO_SHORT;

    is32       = table + 12;
    p          = is32  + 8192;          /* skip `is32' array */
    num_groups = TT_NEXT_ULONG( p );

    if ( p + num_groups * 12 > valid->limit )
      FT_INVALID_TOO_SHORT;

    /* check groups, they must be in increasing order */
    {
      FT_UInt32  n, start, end, start_id, count, last = 0;


      for ( n = 0; n < num_groups; n++ )
      {
        FT_UInt   hi, lo;


        start    = TT_NEXT_ULONG( p );
        end      = TT_NEXT_ULONG( p );
        start_id = TT_NEXT_ULONG( p );

        if ( start > end )
          FT_INVALID_DATA;

        if ( n > 0 && start <= last )
          FT_INVALID_DATA;

        if ( valid->level >= FT_VALIDATE_TIGHT )
        {
          if ( start_id + end - start >= TT_VALID_GLYPH_COUNT( valid ) )
            FT_INVALID_GLYPH_ID;

          count = (FT_UInt32)( end - start + 1 );

          if ( start & ~0xFFFFU )
          {
            /* start_hi != 0; check that is32[i] is 1 for each i in */
            /* the `hi' and `lo' of the range [start..end]          */
            for ( ; count > 0; count--, start++ )
            {
              hi = (FT_UInt)( start >> 16 );
              lo = (FT_UInt)( start & 0xFFFFU );

              if ( (is32[hi >> 3] & ( 0x80 >> ( hi & 7 ) ) ) == 0 )
                FT_INVALID_DATA;

              if ( (is32[lo >> 3] & ( 0x80 >> ( lo & 7 ) ) ) == 0 )
                FT_INVALID_DATA;
            }
          }
          else
          {
            /* start_hi == 0; check that is32[i] is 0 for each i in */
            /* the range [start..end]                               */

            /* end_hi cannot be != 0! */
            if ( end & ~0xFFFFU )
              FT_INVALID_DATA;

            for ( ; count > 0; count--, start++ )
            {
              lo = (FT_UInt)( start & 0xFFFFU );

              if ( (is32[lo >> 3] & ( 0x80 >> ( lo & 7 ) ) ) != 0 )
                FT_INVALID_DATA;
            }
          }
        }

        last = end;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap8_char_index( TT_CMap    cmap,
                       FT_UInt32  char_code )
  {
    FT_Byte*   table      = cmap->data;
    FT_UInt    result     = 0;
    FT_Byte*   p          = table + 8204;
    FT_UInt32  num_groups = TT_NEXT_ULONG( p );
    FT_UInt32  start, end, start_id;


    for ( ; num_groups > 0; num_groups-- )
    {
      start    = TT_NEXT_ULONG( p );
      end      = TT_NEXT_ULONG( p );
      start_id = TT_NEXT_ULONG( p );

      if ( char_code < start )
        break;

      if ( char_code <= end )
      {
        result = (FT_UInt)( start_id + char_code - start );
        break;
      }
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap8_char_next( TT_CMap     cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_UInt32  result     = 0;
    FT_UInt32  char_code  = *pchar_code + 1;
    FT_UInt    gindex     = 0;
    FT_Byte*   table      = cmap->data;
    FT_Byte*   p          = table + 8204;
    FT_UInt32  num_groups = TT_NEXT_ULONG( p );
    FT_UInt32  start, end, start_id;


    p = table + 8208;

    for ( ; num_groups > 0; num_groups-- )
    {
      start    = TT_NEXT_ULONG( p );
      end      = TT_NEXT_ULONG( p );
      start_id = TT_NEXT_ULONG( p );

      if ( char_code < start )
        char_code = start;

      if ( char_code <= end )
      {
        gindex = (FT_UInt)( char_code - start + start_id );
        if ( gindex != 0 )
        {
          result = char_code;
          goto Exit;
        }
      }
    }

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap8_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap8_char_index,
      (FT_CMap_CharNextFunc) tt_cmap8_char_next
    },
    8,
    (TT_CMap_ValidateFunc)   tt_cmap8_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_8 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 10                            *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME      OFFSET  TYPE               DESCRIPTION                    */
  /*                                                                       */
  /*   format     0      USHORT             must be 10                     */
  /*   reserved   2      USHORT             reserved                       */
  /*   length     4      ULONG              length in bytes                */
  /*   language   8      ULONG              Mac language code              */
  /*                                                                       */
  /*   start     12      ULONG              first char in range            */
  /*   count     16      ULONG              number of chars in range       */
  /*   glyphIds  20      USHORT[count]      glyph indices covered          */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_10

  FT_CALLBACK_DEF( void )
  tt_cmap10_validate( FT_Byte*      table,
                      FT_Validator  valid )
  {
    FT_Byte*  p = table + 4;
    FT_ULong  length, start, count;


    if ( table + 20 > valid->limit )
      FT_INVALID_TOO_SHORT;

    length = TT_NEXT_ULONG( p );
    p      = table + 12;
    start  = TT_NEXT_ULONG( p );
    count  = TT_NEXT_ULONG( p );

    if ( table + length > valid->limit || length < 20 + count * 2 )
      FT_INVALID_TOO_SHORT;

    /* check glyph indices */
    if ( valid->level >= FT_VALIDATE_TIGHT )
    {
      FT_UInt  gindex;


      for ( ; count > 0; count-- )
      {
        gindex = TT_NEXT_USHORT( p );
        if ( gindex >= TT_VALID_GLYPH_COUNT( valid ) )
          FT_INVALID_GLYPH_ID;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap10_char_index( TT_CMap    cmap,
                        FT_UInt32  char_code )
  {
    FT_Byte*   table  = cmap->data;
    FT_UInt    result = 0;
    FT_Byte*   p      = table + 12;
    FT_UInt32  start  = TT_NEXT_ULONG( p );
    FT_UInt32  count  = TT_NEXT_ULONG( p );
    FT_UInt32  idx    = (FT_ULong)( char_code - start );


    if ( idx < count )
    {
      p     += 2 * idx;
      result = TT_PEEK_USHORT( p );
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap10_char_next( TT_CMap     cmap,
                       FT_UInt32  *pchar_code )
  {
    FT_Byte*   table     = cmap->data;
    FT_UInt32  result    = 0;
    FT_UInt32  char_code = *pchar_code + 1;
    FT_UInt    gindex    = 0;
    FT_Byte*   p         = table + 12;
    FT_UInt32  start     = TT_NEXT_ULONG( p );
    FT_UInt32  count     = TT_NEXT_ULONG( p );
    FT_UInt32  idx;


    if ( char_code < start )
      char_code = start;

    idx = (FT_UInt32)( char_code - start );
    p  += 2 * idx;

    for ( ; idx < count; idx++ )
    {
      gindex = TT_NEXT_USHORT( p );
      if ( gindex != 0 )
      {
        result = char_code;
        break;
      }
      char_code++;
    }

    *pchar_code = char_code;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap10_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap10_char_index,
      (FT_CMap_CharNextFunc) tt_cmap10_char_next
    },
    10,
    (TT_CMap_ValidateFunc)   tt_cmap10_validate
  };

#endif /* TT_CONFIG_CMAP_FORMAT_10 */


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                          FORMAT 12                            *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* TABLE OVERVIEW                                                        */
  /* --------------                                                        */
  /*                                                                       */
  /*   NAME        OFFSET     TYPE       DESCRIPTION                       */
  /*                                                                       */
  /*   format      0          USHORT     must be 12                        */
  /*   reserved    2          USHORT     reserved                          */
  /*   length      4          ULONG      length in bytes                   */
  /*   language    8          ULONG      Mac language code                 */
  /*   count       12         ULONG      number of groups                  */
  /*               16                                                      */
  /*                                                                       */
  /* This header is followed by `count' groups of the following format:    */
  /*                                                                       */
  /*   start       0          ULONG      first charcode                    */
  /*   end         4          ULONG      last charcode                     */
  /*   startId     8          ULONG      start glyph id for the group      */
  /*                                                                       */

#ifdef TT_CONFIG_CMAP_FORMAT_12

  FT_CALLBACK_DEF( void )
  tt_cmap12_validate( FT_Byte*      table,
                      FT_Validator  valid )
  {
    FT_Byte*   p;
    FT_ULong   length;
    FT_ULong   num_groups;


    if ( table + 16 > valid->limit )
      FT_INVALID_TOO_SHORT;

    p      = table + 4;
    length = TT_NEXT_ULONG( p );

    p          = table + 12;
    num_groups = TT_NEXT_ULONG( p );

    if ( table + length > valid->limit || length < 16 + 12 * num_groups )
      FT_INVALID_TOO_SHORT;

    /* check groups, they must be in increasing order */
    {
      FT_ULong  n, start, end, start_id, last = 0;


      for ( n = 0; n < num_groups; n++ )
      {
        start    = TT_NEXT_ULONG( p );
        end      = TT_NEXT_ULONG( p );
        start_id = TT_NEXT_ULONG( p );

        if ( start > end )
          FT_INVALID_DATA;

        if ( n > 0 && start <= last )
          FT_INVALID_DATA;

        if ( valid->level >= FT_VALIDATE_TIGHT )
        {
          if ( start_id + end - start >= TT_VALID_GLYPH_COUNT( valid ) )
            FT_INVALID_GLYPH_ID;
        }

        last = end;
      }
    }
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap12_char_index( TT_CMap    cmap,
                        FT_UInt32  char_code )
  {
    FT_UInt    result     = 0;
    FT_Byte*   table      = cmap->data;
    FT_Byte*   p          = table + 12;
    FT_UInt32  num_groups = TT_NEXT_ULONG( p );
    FT_UInt32  start, end, start_id;


    for ( ; num_groups > 0; num_groups-- )
    {
      start    = TT_NEXT_ULONG( p );
      end      = TT_NEXT_ULONG( p );
      start_id = TT_NEXT_ULONG( p );

      if ( char_code < start )
        break;

      if ( char_code <= end )
      {
        result = (FT_UInt)( start_id + char_code - start );
        break;
      }
    }
    return result;
  }


  FT_CALLBACK_DEF( FT_UInt )
  tt_cmap12_char_next( TT_CMap     cmap,
                       FT_UInt32  *pchar_code )
  {
    FT_Byte*   table      = cmap->data;
    FT_UInt32  result     = 0;
    FT_UInt32  char_code  = *pchar_code + 1;
    FT_UInt    gindex     = 0;
    FT_Byte*   p          = table + 12;
    FT_UInt32  num_groups = TT_NEXT_ULONG( p );
    FT_UInt32  start, end, start_id;


    p = table + 16;

    for ( ; num_groups > 0; num_groups-- )
    {
      start    = TT_NEXT_ULONG( p );
      end      = TT_NEXT_ULONG( p );
      start_id = TT_NEXT_ULONG( p );

      if ( char_code < start )
        char_code = start;

      if ( char_code <= end )
      {
        gindex = (FT_UInt)(char_code - start + start_id);
        if ( gindex != 0 )
        {
          result = char_code;
          goto Exit;
        }
      }
    }

  Exit:
    *pchar_code = result;
    return gindex;
  }


  FT_CALLBACK_TABLE_DEF
  const TT_CMap_ClassRec  tt_cmap12_class_rec =
  {
    {
      sizeof ( TT_CMapRec ),

      (FT_CMap_InitFunc)     tt_cmap_init,
      (FT_CMap_DoneFunc)     NULL,
      (FT_CMap_CharIndexFunc)tt_cmap12_char_index,
      (FT_CMap_CharNextFunc) tt_cmap12_char_next
    },
    12,
    (TT_CMap_ValidateFunc)   tt_cmap12_validate
  };


#endif /* TT_CONFIG_CMAP_FORMAT_12 */


  static const TT_CMap_Class  tt_cmap_classes[] =
  {
#ifdef TT_CONFIG_CMAP_FORMAT_0
    &tt_cmap0_class_rec,
#endif

#ifdef TT_CONFIG_CMAP_FORMAT_2
    &tt_cmap2_class_rec,
#endif

#ifdef TT_CONFIG_CMAP_FORMAT_4
    &tt_cmap4_class_rec,
#endif

#ifdef TT_CONFIG_CMAP_FORMAT_6
    &tt_cmap6_class_rec,
#endif

#ifdef TT_CONFIG_CMAP_FORMAT_8
    &tt_cmap8_class_rec,
#endif

#ifdef TT_CONFIG_CMAP_FORMAT_10
    &tt_cmap10_class_rec,
#endif

#ifdef TT_CONFIG_CMAP_FORMAT_12
    &tt_cmap12_class_rec,
#endif

    NULL,
  };


  /* parse the `cmap' table and build the corresponding TT_CMap objects */
  /* in the current face                                                */
  /*                                                                    */
  FT_LOCAL_DEF( FT_Error )
  tt_face_build_cmaps( TT_Face  face )
  {
    FT_Byte*           table = face->cmap_table;
    FT_Byte*           limit = table + face->cmap_size;
    FT_UInt volatile   num_cmaps;
    FT_Byte* volatile  p     = table;


    if ( p + 4 > limit )
      return FT_Err_Invalid_Table;

    /* only recognize format 0 */
    if ( TT_NEXT_USHORT( p ) != 0 )
    {
      p -= 2;
      FT_ERROR(( "tt_face_build_cmaps: unsupported `cmap' table format = %d\n",
                 TT_PEEK_USHORT( p ) ));
      return FT_Err_Invalid_Table;
    }

    num_cmaps = TT_NEXT_USHORT( p );

    for ( ; num_cmaps > 0 && p + 8 <= limit; num_cmaps-- )
    {
      FT_CharMapRec  charmap;
      FT_UInt32      offset;


      charmap.platform_id = TT_NEXT_USHORT( p );
      charmap.encoding_id = TT_NEXT_USHORT( p );
      charmap.face        = FT_FACE( face );
      charmap.encoding    = FT_ENCODING_NONE;  /* will be filled later */
      offset              = TT_NEXT_ULONG( p );

      if ( offset && table + offset + 2 < limit )
      {
        FT_Byte*                       cmap   = table + offset;
        FT_UInt                        format = TT_PEEK_USHORT( cmap );
        const TT_CMap_Class* volatile  pclazz = tt_cmap_classes;
        TT_CMap_Class                  clazz;


        for ( ; *pclazz; pclazz++ )
        {
          clazz = *pclazz;
          if ( clazz->format == format )
          {
            volatile TT_ValidatorRec  valid;


            ft_validator_init( FT_VALIDATOR( &valid ), cmap, limit,
                               FT_VALIDATE_DEFAULT );

            valid.num_glyphs = (FT_UInt)face->root.num_glyphs;

            if ( ft_setjmp( FT_VALIDATOR( &valid )->jump_buffer ) == 0 )
            {
              /* validate this cmap sub-table */
              clazz->validate( cmap, FT_VALIDATOR( &valid ) );
            }

            if ( valid.validator.error == 0 )
              (void)FT_CMap_New( (FT_CMap_Class)clazz, cmap, &charmap, NULL );
            else
            {
              FT_ERROR(( "tt_face_build_cmaps:" ));
              FT_ERROR(( " broken cmap sub-table ignored!\n" ));
            }
          }
        }
      }
    }

    return 0;
  }


/* END */