pfrsbit.c

winNT技术操作系统,国外开放的原代码和LIUX一样

/***************************************************************************/
/*                                                                         */
/*  pfrsbit.c                                                              */
/*                                                                         */
/*    FreeType PFR bitmap loader (body).                                   */
/*                                                                         */
/*  Copyright 2002, 2003, 2006 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 "pfrsbit.h"
#include "pfrload.h"
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_STREAM_H

#include "pfrerror.h"

#undef  FT_COMPONENT
#define FT_COMPONENT  trace_pfr


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                      PFR BIT WRITER                           *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  typedef struct  PFR_BitWriter_
  {
    FT_Byte*  line;      /* current line start                    */
    FT_Int    pitch;     /* line size in bytes                    */
    FT_Int    width;     /* width in pixels/bits                  */
    FT_Int    rows;      /* number of remaining rows to scan      */
    FT_Int    total;     /* total number of bits to draw          */

  } PFR_BitWriterRec, *PFR_BitWriter;


  static void
  pfr_bitwriter_init( PFR_BitWriter  writer,
                      FT_Bitmap*     target,
                      FT_Bool        decreasing )
  {
    writer->line   = target->buffer;
    writer->pitch  = target->pitch;
    writer->width  = target->width;
    writer->rows   = target->rows;
    writer->total  = writer->width * writer->rows;

    if ( !decreasing )
    {
      writer->line += writer->pitch * ( target->rows-1 );
      writer->pitch = -writer->pitch;
    }
  }


  static void
  pfr_bitwriter_decode_bytes( PFR_BitWriter  writer,
                              FT_Byte*       p,
                              FT_Byte*       limit )
  {
    FT_Int    n, reload;
    FT_Int    left = writer->width;
    FT_Byte*  cur  = writer->line;
    FT_UInt   mask = 0x80;
    FT_UInt   val  = 0;
    FT_UInt   c    = 0;


    n = (FT_Int)( limit - p ) * 8;
    if ( n > writer->total )
      n = writer->total;

    reload = n & 7;

    for ( ; n > 0; n-- )
    {
      if ( ( n & 7 ) == reload )
        val = *p++;

      if ( val & 0x80 )
        c |= mask;

      val  <<= 1;
      mask >>= 1;

      if ( --left <= 0 )
      {
        cur[0] = (FT_Byte)c;
        left   = writer->width;
        mask   = 0x80;

        writer->line += writer->pitch;
        cur           = writer->line;
        c             = 0;
      }
      else if ( mask == 0 )
      {
        cur[0] = (FT_Byte)c;
        mask   = 0x80;
        c      = 0;
        cur ++;
      }
    }

    if ( mask != 0x80 )
      cur[0] = (FT_Byte)c;
  }


  static void
  pfr_bitwriter_decode_rle1( PFR_BitWriter  writer,
                             FT_Byte*       p,
                             FT_Byte*       limit )
  {
    FT_Int    n, phase, count, counts[2], reload;
    FT_Int    left = writer->width;
    FT_Byte*  cur  = writer->line;
    FT_UInt   mask = 0x80;
    FT_UInt   c    = 0;


    n = writer->total;

    phase     = 1;
    counts[0] = 0;
    counts[1] = 0;
    count     = 0;
    reload    = 1;

    for ( ; n > 0; n-- )
    {
      if ( reload )
      {
        do
        {
          if ( phase )
          {
            FT_Int  v;


            if ( p >= limit )
              break;

            v         = *p++;
            counts[0] = v >> 4;
            counts[1] = v & 15;
            phase     = 0;
            count     = counts[0];
          }
          else
          {
            phase = 1;
            count = counts[1];
          }

        } while ( count == 0 );
      }

      if ( phase )
        c |= mask;

      mask >>= 1;

      if ( --left <= 0 )
      {
        cur[0] = (FT_Byte) c;
        left   = writer->width;
        mask   = 0x80;

        writer->line += writer->pitch;
        cur           = writer->line;
        c             = 0;
      }
      else if ( mask == 0 )
      {
        cur[0] = (FT_Byte)c;
        mask   = 0x80;
        c      = 0;
        cur ++;
      }

      reload = ( --count <= 0 );
    }

    if ( mask != 0x80 )
      cur[0] = (FT_Byte) c;
  }


  static void
  pfr_bitwriter_decode_rle2( PFR_BitWriter  writer,
                             FT_Byte*       p,
                             FT_Byte*       limit )
  {
    FT_Int    n, phase, count, reload;
    FT_Int    left = writer->width;
    FT_Byte*  cur  = writer->line;
    FT_UInt   mask = 0x80;
    FT_UInt   c    = 0;


    n = writer->total;

    phase  = 1;
    count  = 0;
    reload = 1;

    for ( ; n > 0; n-- )
    {
      if ( reload )
      {
        do
        {
          if ( p >= limit )
            break;

          count = *p++;
          phase = phase ^ 1;

        } while ( count == 0 );
      }

      if ( phase )
        c |= mask;

      mask >>= 1;

      if ( --left <= 0 )
      {
        cur[0] = (FT_Byte) c;
        c      = 0;
        mask   = 0x80;
        left   = writer->width;

        writer->line += writer->pitch;
        cur           = writer->line;
      }
      else if ( mask == 0 )
      {
        cur[0] = (FT_Byte)c;
        c      = 0;
        mask   = 0x80;
        cur ++;
      }

      reload = ( --count <= 0 );
    }

    if ( mask != 0x80 )
      cur[0] = (FT_Byte) c;
  }


  /*************************************************************************/
  /*************************************************************************/
  /*****                                                               *****/
  /*****                  BITMAP DATA DECODING                         *****/
  /*****                                                               *****/
  /*************************************************************************/
  /*************************************************************************/

  static void
  pfr_lookup_bitmap_data( FT_Byte*   base,
                          FT_Byte*   limit,
                          FT_UInt    count,
                          FT_UInt    flags,
                          FT_UInt    char_code,
                          FT_ULong*  found_offset,
                          FT_ULong*  found_size )
  {
    FT_UInt   left, right, char_len;
    FT_Bool   two = FT_BOOL( flags & 1 );
    FT_Byte*  buff;


    char_len = 4;
    if ( two )       char_len += 1;
    if ( flags & 2 ) char_len += 1;
    if ( flags & 4 ) char_len += 1;

    left  = 0;
    right = count;

    while ( left < right )
    {
      FT_UInt  middle, code;


      middle = ( left + right ) >> 1;
      buff   = base + middle * char_len;

      /* check that we are not outside of the table -- */
      /* this is possible with broken fonts...         */
      if ( buff + char_len > limit )
        goto Fail;

      if ( two )
        code = PFR_NEXT_USHORT( buff );
      else
        code = PFR_NEXT_BYTE( buff );

      if ( code == char_code )
        goto Found_It;

      if ( code < char_code )
        left = middle;
      else
        right = middle;
    }

  Fail:
    /* Not found */
    *found_size   = 0;
    *found_offset = 0;
    return;

  Found_It:
    if ( flags & 2 )
      *found_size = PFR_NEXT_USHORT( buff );
    else
      *found_size = PFR_NEXT_BYTE( buff );

    if ( flags & 4 )
      *found_offset = PFR_NEXT_ULONG( buff );
    else
      *found_offset = PFR_NEXT_USHORT( buff );
  }