/***************************************************************************/

/*                                                                         */

/*  ttsbit0.c                                                              */

/*                                                                         */

/*    TrueType and OpenType embedded bitmap support (body).                */

/*    This is a heap-optimized version.                                    */

/*                                                                         */

/*  Copyright 2005, 2006, 2007, 2008, 2009 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.                                        */

/*                                                                         */

/***************************************************************************/

/* This file is included by ttsbit.c */

#include <ft2build.h>

#include FT_INTERNAL_DEBUG_H

#include FT_INTERNAL_STREAM_H

#include FT_TRUETYPE_TAGS_H

#include "ttsbit.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_ttsbit

  FT_LOCAL_DEF( FT_Error )

  tt_face_load_eblc( TT_Face    face,

                     FT_Stream  stream )

  {

    FT_Error  error = SFNT_Err_Ok;

    FT_Fixed  version;

    FT_ULong  num_strikes, table_size;

    FT_Byte*  p;

    FT_Byte*  p_limit;

    FT_UInt   count;

    face->sbit_num_strikes = 0;

    /* this table is optional */

    error = face->goto_table( face, TTAG_EBLC, stream, &table_size );

    if ( error )

      error = face->goto_table( face, TTAG_bloc, stream, &table_size );

    if ( error )

      goto Exit;

    if ( table_size < 8 )

    {

      FT_ERROR(( "tt_face_load_sbit_strikes: table too short\n" ));

      error = SFNT_Err_Invalid_File_Format;

      goto Exit;

    }

    if ( FT_FRAME_EXTRACT( table_size, face->sbit_table ) )

      goto Exit;

    face->sbit_table_size = table_size;

    p       = face->sbit_table;

    p_limit = p + table_size;

    version     = FT_NEXT_ULONG( p );

    num_strikes = FT_NEXT_ULONG( p );

    if ( version != 0x00020000UL || num_strikes >= 0x10000UL )

    {

      FT_ERROR(( "tt_face_load_sbit_strikes: invalid table version\n" ));

      error = SFNT_Err_Invalid_File_Format;

      goto Fail;

    }

    /*

     *  Count the number of strikes available in the table.  We are a bit

     *  paranoid there and don't trust the data.

     */

    count = (FT_UInt)num_strikes;

    if ( 8 + 48UL * count > table_size )

      count = (FT_UInt)( ( p_limit - p ) / 48 );

    face->sbit_num_strikes = count;

    FT_TRACE3(( "sbit_num_strikes: %u\n", count ));

  Exit:

    return error;

  Fail:

    FT_FRAME_RELEASE( face->sbit_table );

    face->sbit_table_size = 0;

    goto Exit;

  }

  FT_LOCAL_DEF( void )

  tt_face_free_eblc( TT_Face  face )

  {

    FT_Stream  stream = face->root.stream;

    FT_FRAME_RELEASE( face->sbit_table );

    face->sbit_table_size  = 0;

    face->sbit_num_strikes = 0;

  }

  FT_LOCAL_DEF( FT_Error )

  tt_face_set_sbit_strike( TT_Face          face,

                           FT_Size_Request  req,

                           FT_ULong*        astrike_index )

  {

    return FT_Match_Size( (FT_Face)face, req, 0, astrike_index );

  }

  FT_LOCAL_DEF( FT_Error )

  tt_face_load_strike_metrics( TT_Face           face,

                               FT_ULong          strike_index,

                               FT_Size_Metrics*  metrics )

  {

    FT_Byte*  strike;

    if ( strike_index >= (FT_ULong)face->sbit_num_strikes )

      return SFNT_Err_Invalid_Argument;

    strike = face->sbit_table + 8 + strike_index * 48;

    metrics->x_ppem = (FT_UShort)strike[44];

    metrics->y_ppem = (FT_UShort)strike[45];

    metrics->ascender  = (FT_Char)strike[16] << 6;  /* hori.ascender  */

    metrics->descender = (FT_Char)strike[17] << 6;  /* hori.descender */

    metrics->height    = metrics->ascender - metrics->descender;

    /* XXX: Is this correct? */

    metrics->max_advance = ( (FT_Char)strike[22] + /* min_origin_SB  */

                                      strike[18] + /* max_width      */

                             (FT_Char)strike[23]   /* min_advance_SB */

                                                 ) << 6;

    return SFNT_Err_Ok;

  }

  typedef struct  TT_SBitDecoderRec_

  {

    TT_Face          face;

    FT_Stream        stream;

    FT_Bitmap*       bitmap;

    TT_SBit_Metrics  metrics;

    FT_Bool          metrics_loaded;

    FT_Bool          bitmap_allocated;

    FT_Byte          bit_depth;

    FT_ULong         ebdt_start;

    FT_ULong         ebdt_size;

    FT_ULong         strike_index_array;

    FT_ULong         strike_index_count;

    FT_Byte*         eblc_base;

    FT_Byte*         eblc_limit;

  } TT_SBitDecoderRec, *TT_SBitDecoder;

  static FT_Error

  tt_sbit_decoder_init( TT_SBitDecoder       decoder,

                        TT_Face              face,

                        FT_ULong             strike_index,

                        TT_SBit_MetricsRec*  metrics )

  {

    FT_Error   error;

    FT_Stream  stream = face->root.stream;

    FT_ULong   ebdt_size;

    error = face->goto_table( face, TTAG_EBDT, stream, &ebdt_size );

    if ( error )

      error = face->goto_table( face, TTAG_bdat, stream, &ebdt_size );

    if ( error )

      goto Exit;

    decoder->face    = face;

    decoder->stream  = stream;

    decoder->bitmap  = &face->root.glyph->bitmap;

    decoder->metrics = metrics;

    decoder->metrics_loaded   = 0;

    decoder->bitmap_allocated = 0;

    decoder->ebdt_start = FT_STREAM_POS();

    decoder->ebdt_size  = ebdt_size;

    decoder->eblc_base  = face->sbit_table;

    decoder->eblc_limit = face->sbit_table + face->sbit_table_size;

    /* now find the strike corresponding to the index */

    {

      FT_Byte*  p;

      if ( 8 + 48 * strike_index + 3 * 4 + 34 + 1 > face->sbit_table_size )

      {

        error = SFNT_Err_Invalid_File_Format;

        goto Exit;

      }

      p = decoder->eblc_base + 8 + 48 * strike_index;

      decoder->strike_index_array = FT_NEXT_ULONG( p );

      p                          += 4;

      decoder->strike_index_count = FT_NEXT_ULONG( p );

      p                          += 34;

      decoder->bit_depth          = *p;

      if ( decoder->strike_index_array > face->sbit_table_size             ||

           decoder->strike_index_array + 8 * decoder->strike_index_count >

             face->sbit_table_size                                         )

        error = SFNT_Err_Invalid_File_Format;

    }

  Exit:

    return error;

  }

  static void

  tt_sbit_decoder_done( TT_SBitDecoder  decoder )

  {

    FT_UNUSED( decoder );

  }

  static FT_Error

  tt_sbit_decoder_alloc_bitmap( TT_SBitDecoder  decoder )

  {

    FT_Error    error = SFNT_Err_Ok;

    FT_UInt     width, height;

    FT_Bitmap*  map = decoder->bitmap;

    FT_Long     size;

    if ( !decoder->metrics_loaded )

    {

      error = SFNT_Err_Invalid_Argument;

      goto Exit;

    }

    width  = decoder->metrics->width;

    height = decoder->metrics->height;

    map->width = (int)width;

    map->rows  = (int)height;

    switch ( decoder->bit_depth )

    {

    case 1:

      map->pixel_mode = FT_PIXEL_MODE_MONO;

      map->pitch      = ( map->width + 7 ) >> 3;

      break;

    case 2:

      map->pixel_mode = FT_PIXEL_MODE_GRAY2;

      map->pitch      = ( map->width + 3 ) >> 2;

      break;

    case 4:

      map->pixel_mode = FT_PIXEL_MODE_GRAY4;

      map->pitch      = ( map->width + 1 ) >> 1;

      break;

    case 8:

      map->pixel_mode = FT_PIXEL_MODE_GRAY;

      map->pitch      = map->width;

      break;

    default:

      error = SFNT_Err_Invalid_File_Format;

      goto Exit;

    }

    size = map->rows * map->pitch;

    /* check that there is no empty image */

    if ( size == 0 )

      goto Exit;     /* exit successfully! */

    error = ft_glyphslot_alloc_bitmap( decoder->face->root.glyph, size );

    if ( error )

      goto Exit;

    decoder->bitmap_allocated = 1;

  Exit:

    return error;

  }

  static FT_Error

  tt_sbit_decoder_load_metrics( TT_SBitDecoder  decoder,

                                FT_Byte*       *pp,

                                FT_Byte*        limit,

                                FT_Bool         big )

  {

    FT_Byte*         p       = *pp;

    TT_SBit_Metrics  metrics = decoder->metrics;

    if ( p + 5 > limit )

      goto Fail;

    metrics->height       = p[0];

    metrics->width        = p[1];

    metrics->horiBearingX = (FT_Char)p[2];

    metrics->horiBearingY = (FT_Char)p[3];

    metrics->horiAdvance  = p[4];

    p += 5;

    if ( big )

    {

      if ( p + 3 > limit )

        goto Fail;

      metrics->vertBearingX = (FT_Char)p[0];

      metrics->vertBearingY = (FT_Char)p[1];

      metrics->vertAdvance  = p[2];

      p += 3;

    }

    decoder->metrics_loaded = 1;

    *pp = p;

    return SFNT_Err_Ok;

  Fail:

    return SFNT_Err_Invalid_Argument;

  }

  /* forward declaration */

  static FT_Error

  tt_sbit_decoder_load_image( TT_SBitDecoder  decoder,

                              FT_UInt         glyph_index,

                              FT_Int          x_pos,

                              FT_Int          y_pos );

  typedef FT_Error  (*TT_SBitDecoder_LoadFunc)( TT_SBitDecoder  decoder,

                                                FT_Byte*        p,

                                                FT_Byte*        plimit,

                                                FT_Int          x_pos,

                                                FT_Int          y_pos );

  static FT_Error

  tt_sbit_decoder_load_byte_aligned( TT_SBitDecoder  decoder,

                                     FT_Byte*        p,

                                     FT_Byte*        limit,

                                     FT_Int          x_pos,

                                     FT_Int          y_pos )

  {

    FT_Error    error = SFNT_Err_Ok;

    FT_Byte*    line;

    FT_Int      bit_height, bit_width, pitch, width, height, h;

    FT_Bitmap*  bitmap;

    if ( !decoder->bitmap_allocated )

    {

      error = tt_sbit_decoder_alloc_bitmap( decoder );

      if ( error )

        goto Exit;

    }

    /* check that we can write the glyph into the bitmap */

    bitmap     = decoder->bitmap;

    bit_width  = bitmap->width;

    bit_height = bitmap->rows;

    pitch      = bitmap->pitch;

    line       = bitmap->buffer;

    width  = decoder->metrics->width;

    height = decoder->metrics->height;

    if ( x_pos < 0 || x_pos + width > bit_width   ||

         y_pos < 0 || y_pos + height > bit_height )

    {

      error = SFNT_Err_Invalid_File_Format;

      goto Exit;

    }

    if ( p + ( ( width + 7 ) >> 3 ) * height > limit )

    {

      error = SFNT_Err_Invalid_File_Format;

      goto Exit;

    }

    /* now do the blit */

    line  += y_pos * pitch + ( x_pos >> 3 );

    x_pos &= 7;

    if ( x_pos == 0 )  /* the easy one */

    {

      for ( h = height; h > 0; h--, line += pitch )

      {

        FT_Byte*  write = line;

        FT_Int    w;

        for ( w = width; w >= 8; w -= 8 )

        {

          write[0] = (FT_Byte)( write[0] | *p++ );

          write   += 1;

        }

        if ( w > 0 )

          write[0] = (FT_Byte)( write[0] | ( *p++ & ( 0xFF00U >> w ) ) );

      }

    }

    else  /* x_pos > 0 */

    {

      for ( h = height; h > 0; h--, line += pitch )

      {

        FT_Byte*  write = line;

        FT_Int    w;

        FT_UInt   wval = 0;

        for ( w = width; w >= 8; w -= 8 )

        {

          wval      = (FT_UInt)( wval | *p++ );

          write[0]  = (FT_Byte)( write[0] | ( wval >> x_pos ) );

          write    += 1;

          wval    <<= 8;

        }

        if ( w > 0 )

          wval = (FT_UInt)( wval | ( *p++ & ( 0xFF00U >> w ) ) );

        /* all bits read and there are `x_pos + w' bits to be written */

        write[0] = (FT_Byte)( write[0] | ( wval >> x_pos ) );

        if ( x_pos + w > 8 )

        {

          write++;

          wval   <<= 8;

          write[0] = (FT_Byte)( write[0] | ( wval >> x_pos ) );

        }

      }

    }

  Exit:

    return error;

  }

  /*

   * Load a bit-aligned bitmap (with pointer `p') into a line-aligned bitmap

   * (with pointer `write').  In the example below, the width is 3 pixel,

   * and `x_pos' is 1 pixel.

   *

   *       p                               p+1

   *     |                               |                               |

   *     | 7   6   5   4   3   2   1   0 | 7   6   5   4   3   2   1   0 |...

   *     |                               |                               |

   *       +-------+   +-------+   +-------+ ...

   *           .           .           .

   *           .           .           .

   *           v           .           .

   *       +-------+       .           .

   * |                               | .

   * | 7   6   5   4   3   2   1   0 | .

   * |                               | .

   *   write               .           .

   *                       .           .

   *                       v           .

   *                   +-------+       .

   *             |                               |

   *             | 7   6   5   4   3   2   1   0 |

   *             |                               |

   *               write+1             .

   *                                   .

   *                                   v

   *                               +-------+

   *                         |                               |

   *                         | 7   6   5   4   3   2   1   0 |

   *                         |                               |

   *                           write+2

   *

   */

  static FT_Error

  tt_sbit_decoder_load_bit_aligned( TT_SBitDecoder  decoder,

                                    FT_Byte*        p,

                                    FT_Byte*        limit,

                                    FT_Int          x_pos,

                                    FT_Int          y_pos )

  {

    FT_Error    error = SFNT_Err_Ok;

    FT_Byte*    line;

    FT_Int      bit_height, bit_width, pitch, width, height, h, nbits;

    FT_Bitmap*  bitmap;

    FT_UShort   rval;

    if ( !decoder->bitmap_allocated )

    {

      error = tt_sbit_decoder_alloc_bitmap( decoder );

      if ( error )

        goto Exit;

    }

    /* check that we can write the glyph into the bitmap */

    bitmap     = decoder->bitmap;