winfnt.c

a very goog book

/***************************************************************************/
/*                                                                         */
/*  winfnt.c                                                               */
/*                                                                         */
/*    FreeType font driver for Windows FNT/FON files                       */
/*                                                                         */
/*  Copyright 1996-2001, 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_STREAM_H
#include FT_INTERNAL_OBJECTS_H
#include FT_INTERNAL_FNT_TYPES_H

#include "winfnt.h"

#include "fnterrs.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_winfnt


  static
  const FT_Frame_Field  winmz_header_fields[] =
  {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  WinMZ_HeaderRec

    FT_FRAME_START( 64 ),
      FT_FRAME_USHORT_LE ( magic ),
      FT_FRAME_SKIP_BYTES( 29 * 2 ),
      FT_FRAME_ULONG_LE  ( lfanew ),
    FT_FRAME_END
  };

  static
  const FT_Frame_Field  winne_header_fields[] =
  {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  WinNE_HeaderRec

    FT_FRAME_START( 40 ),
      FT_FRAME_USHORT_LE ( magic ),
      FT_FRAME_SKIP_BYTES( 34 ),
      FT_FRAME_USHORT_LE ( resource_tab_offset ),
      FT_FRAME_USHORT_LE ( rname_tab_offset ),
    FT_FRAME_END
  };

  static
  const FT_Frame_Field  winfnt_header_fields[] =
  {
#undef  FT_STRUCTURE
#define FT_STRUCTURE  WinFNT_HeaderRec

    FT_FRAME_START( 134 ),
      FT_FRAME_USHORT_LE( version ),
      FT_FRAME_ULONG_LE ( file_size ),
      FT_FRAME_BYTES    ( copyright, 60 ),
      FT_FRAME_USHORT_LE( file_type ),
      FT_FRAME_USHORT_LE( nominal_point_size ),
      FT_FRAME_USHORT_LE( vertical_resolution ),
      FT_FRAME_USHORT_LE( horizontal_resolution ),
      FT_FRAME_USHORT_LE( ascent ),
      FT_FRAME_USHORT_LE( internal_leading ),
      FT_FRAME_USHORT_LE( external_leading ),
      FT_FRAME_BYTE     ( italic ),
      FT_FRAME_BYTE     ( underline ),
      FT_FRAME_BYTE     ( strike_out ),
      FT_FRAME_USHORT_LE( weight ),
      FT_FRAME_BYTE     ( charset ),
      FT_FRAME_USHORT_LE( pixel_width ),
      FT_FRAME_USHORT_LE( pixel_height ),
      FT_FRAME_BYTE     ( pitch_and_family ),
      FT_FRAME_USHORT_LE( avg_width ),
      FT_FRAME_USHORT_LE( max_width ),
      FT_FRAME_BYTE     ( first_char ),
      FT_FRAME_BYTE     ( last_char ),
      FT_FRAME_BYTE     ( default_char ),
      FT_FRAME_BYTE     ( break_char ),
      FT_FRAME_USHORT_LE( bytes_per_row ),
      FT_FRAME_ULONG_LE ( device_offset ),
      FT_FRAME_ULONG_LE ( face_name_offset ),
      FT_FRAME_ULONG_LE ( bits_pointer ),
      FT_FRAME_ULONG_LE ( bits_offset ),
      FT_FRAME_BYTE     ( reserved ),
      FT_FRAME_ULONG_LE ( flags ),
      FT_FRAME_USHORT_LE( A_space ),
      FT_FRAME_USHORT_LE( B_space ),
      FT_FRAME_USHORT_LE( C_space ),
      FT_FRAME_USHORT_LE( color_table_offset ),
      FT_FRAME_BYTES    ( reserved, 4 ),
    FT_FRAME_END
  };


  static void
  fnt_font_done( FNT_Font   font,
                 FT_Stream  stream )
  {
    if ( font->fnt_frame )
      FT_FRAME_RELEASE( font->fnt_frame );

    font->fnt_size  = 0;
    font->fnt_frame = 0;
  }


  static FT_Error
  fnt_font_load( FNT_Font   font,
                 FT_Stream  stream )
  {
    FT_Error       error;
    WinFNT_Header  header = &font->header;


    /* first of all, read the FNT header */
    if ( FT_STREAM_SEEK( font->offset )                   ||
         FT_STREAM_READ_FIELDS( winfnt_header_fields, header ) )
      goto Exit;

    /* check header */
    if ( header->version != 0x200 &&
         header->version != 0x300 )
    {
      FT_TRACE2(( "[not a valid FNT file]\n" ));
      error = FNT_Err_Unknown_File_Format;
      goto Exit;
    }

    if ( header->file_type & 1 )
    {
      FT_TRACE2(( "[can't handle vector FNT fonts]\n" ));
      error = FNT_Err_Unknown_File_Format;
      goto Exit;
    }

    /* small fixup -- some fonts have the `pixel_width' field set to 0 */
    if ( header->pixel_width == 0 )
      header->pixel_width = header->pixel_height;

    /* this is a FNT file/table, we now extract its frame */
    if ( FT_STREAM_SEEK( font->offset )                         ||
         FT_FRAME_EXTRACT( header->file_size, font->fnt_frame ) )
      goto Exit;

  Exit:
    return error;
  }


  static void
  fnt_face_done_fonts( FNT_Face  face )
  {
    FT_Memory  memory = FT_FACE( face )->memory;
    FT_Stream  stream = FT_FACE( face )->stream;
    FNT_Font   cur    = face->fonts;
    FNT_Font   limit  = cur + face->num_fonts;


    for ( ; cur < limit; cur++ )
      fnt_font_done( cur, stream );

    FT_FREE( face->fonts );
    face->num_fonts = 0;
  }


  static FT_Error
  fnt_face_get_dll_fonts( FNT_Face  face )
  {
    FT_Error         error;
    FT_Stream        stream = FT_FACE( face )->stream;
    FT_Memory        memory = FT_FACE( face )->memory;
    WinMZ_HeaderRec  mz_header;


    face->fonts     = 0;
    face->num_fonts = 0;

    /* does it begin with a MZ header? */
    if ( FT_STREAM_SEEK( 0 )                                 ||
         FT_STREAM_READ_FIELDS( winmz_header_fields, &mz_header ) )
      goto Exit;

    error = FNT_Err_Unknown_File_Format;
    if ( mz_header.magic == WINFNT_MZ_MAGIC )
    {
      /* yes, now look for a NE header in the file */
      WinNE_HeaderRec  ne_header;


      if ( FT_STREAM_SEEK( mz_header.lfanew )                  ||
           FT_STREAM_READ_FIELDS( winne_header_fields, &ne_header ) )
        goto Exit;

      error = FNT_Err_Unknown_File_Format;
      if ( ne_header.magic == WINFNT_NE_MAGIC )
      {
        /* good, now look in the resource table for each FNT resource */
        FT_ULong   res_offset = mz_header.lfanew +
                                ne_header.resource_tab_offset;

        FT_UShort  size_shift;
        FT_UShort  font_count  = 0;
        FT_ULong   font_offset = 0;


        if ( FT_STREAM_SEEK( res_offset ) ||
             FT_FRAME_ENTER( ne_header.rname_tab_offset -
                             ne_header.resource_tab_offset ) )
          goto Exit;

        size_shift = FT_GET_USHORT_LE();

        for (;;)
        {
          FT_UShort  type_id, count;


          type_id = FT_GET_USHORT_LE();
          if ( !type_id )
            break;

          count = FT_GET_USHORT_LE();

          if ( type_id == 0x8008 )
          {
            font_count  = count;
            font_offset = (FT_ULong)( FT_STREAM_POS() + 4 +
                                      ( stream->cursor - stream->limit ) );
            break;
          }

          stream->cursor += 4 + count * 12;
        }
        FT_FRAME_EXIT();

        if ( !font_count || !font_offset )
        {
          FT_TRACE2(( "this file doesn't contain any FNT resources!\n" ));
          error = FNT_Err_Unknown_File_Format;
          goto Exit;
        }

        if ( FT_STREAM_SEEK( font_offset )           ||
             FT_NEW_ARRAY( face->fonts, font_count ) )
          goto Exit;

        face->num_fonts = font_count;

        if ( FT_FRAME_ENTER( (FT_Long)font_count * 12 ) )
          goto Exit;

        /* now read the offset and position of each FNT font */
        {
          FNT_Font  cur   = face->fonts;
          FNT_Font  limit = cur + font_count;


          for ( ; cur < limit; cur++ )
          {
            cur->offset     = (FT_ULong)FT_GET_USHORT_LE() << size_shift;
            cur->fnt_size   = (FT_ULong)FT_GET_USHORT_LE() << size_shift;
            cur->size_shift = size_shift;
            stream->cursor += 8;
          }
        }
        FT_FRAME_EXIT();

        /* finally, try to load each font there */
        {
          FNT_Font  cur   = face->fonts;
          FNT_Font  limit = cur + font_count;


          for ( ; cur < limit; cur++ )
          {
            error = fnt_font_load( cur, stream );
            if ( error )
              goto Fail;
          }
        }
      }
    }

  Fail:
    if ( error )
      fnt_face_done_fonts( face );

  Exit:
    return error;
  }


#ifdef FT_CONFIG_OPTION_USE_CMAPS


  typedef struct  FNT_CMapRec_
  {
    FT_CMapRec  cmap;
    FT_UInt32   first;
    FT_UInt32   count;

  } FNT_CMapRec, *FNT_CMap;


  static FT_Error
  fnt_cmap_init( FNT_CMap  cmap )
  {
    FNT_Face  face = (FNT_Face)FT_CMAP_FACE( cmap );
    FNT_Font  font = face->fonts;


    cmap->first = (FT_UInt32)  font->header.first_char;
    cmap->count = (FT_UInt32)( font->header.last_char - cmap->first + 1 );

    return 0;
  }


  static FT_UInt
  fnt_cmap_char_index( FNT_CMap   cmap,
                       FT_UInt32  char_code )
  {
    FT_UInt  gindex = 0;


    char_code -= cmap->first;
    if ( char_code < cmap->count )
      gindex = char_code + 1;

    return gindex;
  }


  static FT_UInt
  fnt_cmap_char_next( FNT_CMap    cmap,
                      FT_UInt32  *pchar_code )
  {
    FT_UInt    gindex = 0;
    FT_UInt32  result = 0;
    FT_UInt32  char_code = *pchar_code + 1;


    if ( char_code <= cmap->first )
    {
      result = cmap->first;
      gindex = 1;
    }
    else
    {
      char_code -= cmap->first;
      if ( char_code < cmap->count )
      {
        result = cmap->first + char_code;
        gindex = char_code + 1;
      }
    }

    *pchar_code = result;
    return gindex;
  }


  static FT_CMap_ClassRec  fnt_cmap_class_rec =
  {
    sizeof ( FNT_CMapRec ),

    (FT_CMap_InitFunc)     fnt_cmap_init,
    (FT_CMap_DoneFunc)     NULL,
    (FT_CMap_CharIndexFunc)fnt_cmap_char_index,