/*****************************************************************************
 *
 *  XVID MPEG-4 VIDEO CODEC
 *   Reduced-Resolution utilities
 *
 *  Copyright(C) 2002 Pascal Massimino <skal@planet-d.net>
 *
 *  This file is part of XviD, a free MPEG-4 video encoder/decoder
 *
 *  XviD is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 *  Under section 8 of the GNU General Public License, the copyright
 *  holders of XVID explicitly forbid distribution in the following
 *  countries:
 *
 *    - Japan
 *    - United States of America
 *
 *  Linking XviD statically or dynamically with other modules is making a
 *  combined work based on XviD.  Thus, the terms and conditions of the
 *  GNU General Public License cover the whole combination.
 *
 *  As a special exception, the copyright holders of XviD give you
 *  permission to link XviD with independent modules that communicate with
 *  XviD solely through the VFW1.1 and DShow interfaces, regardless of the
 *  license terms of these independent modules, and to copy and distribute
 *  the resulting combined work under terms of your choice, provided that
 *  every copy of the combined work is accompanied by a complete copy of
 *  the source code of XviD (the version of XviD used to produce the
 *  combined work), being distributed under the terms of the GNU General
 *  Public License plus this exception.  An independent module is a module
 *  which is not derived from or based on XviD.
 *
 *  Note that people who make modified versions of XviD are not obligated
 *  to grant this special exception for their modified versions; it is
 *  their choice whether to do so.  The GNU General Public License gives
 *  permission to release a modified version without this exception; this
 *  exception also makes it possible to release a modified version which
 *  carries forward this exception.
 *
 * $Id: reduced.cpp,v 1.1 2005/01/04 13:44:37 jeanlf Exp $
 *
 ****************************************************************************/

#include "portab.h"
#include "global.h"
#include "reduced.h"

/*----------------------------------------------------------------------------
 * Upsampling (1/3/3/1) filter
 *--------------------------------------------------------------------------*/

#define ADD(dst,src)  (dst) = CLIP((dst)+(src), 0, 255)

inline void Filter_31(byte *Dst1, byte *Dst2, const int *Src1, const int *Src2){

    /* Src[] is assumed to be >=0. So we can use ">>2" instead of "/2" */
  int a = (3*Src1[0]+  Src2[0]+2) >> 2;
  int b = (  Src1[0]+3*Src2[0]+2) >> 2;
  Dst1[0] = CLIP(a, 0, 255);
  Dst2[0] = CLIP(b, 0, 255);
}

//----------------------------

inline void Filter_9331(byte *Dst1, byte *Dst2, const int *Src1, const int *Src2){

    /* Src[] is assumed to be >=0. So we can use ">>4" instead of "/16" */
  int a = (9*Src1[0]+  3*Src1[1]+ 3*Src2[0] + 1*Src2[1] + 8) >> 4;
  int b = (3*Src1[0]+  9*Src1[1]+ 1*Src2[0] + 3*Src2[1] + 8) >> 4;
  int c = (3*Src1[0]+  1*Src1[1]+ 9*Src2[0] + 3*Src2[1] + 8) >> 4;
  int d = (1*Src1[0]+  3*Src1[1]+ 3*Src2[0] + 9*Src2[1] + 8) >> 4;
  Dst1[0] = CLIP(a, 0, 255);
  Dst1[1] = CLIP(b, 0, 255);
  Dst2[0] = CLIP(c, 0, 255);
  Dst2[1] = CLIP(d, 0, 255);
}

//----------------------------

void copy_upsampled_8x8_16to8(byte *Dst, const int *Src, int BpS){
   int x, y;
   
   Dst[0] = CLIP(Src[0], 0, 255);
   for(x=0; x<7; ++x)
      Filter_31(Dst+2*x+1, Dst+2*x+2, Src+x, Src+x+1);
   Dst[15] = CLIP(Src[7], 0, 255);
   Dst += BpS;
   for(y=0; y<7; ++y) {
      byte *const Dst2 = Dst + BpS;
      Filter_31(Dst, Dst2, Src, Src+8);
      for(x=0; x<7; ++x)
         Filter_9331(Dst+2*x+1, Dst2+2*x+1, Src+x, Src+x+8);
      Filter_31(Dst+15, Dst2+15, Src+7, Src+7+8);
      Src += 8;
      Dst += 2*BpS;
   }
   Dst[0] = CLIP(Src[0], 0, 255);
   for(x=0; x<7; ++x) Filter_31(Dst+2*x+1, Dst+2*x+2, Src+x, Src+x+1);
   Dst[15] = CLIP(Src[7], 0, 255);
}

//----------------------------

inline void Filter_Add_31(byte *Dst1, byte *Dst2, const int *Src1, const int *Src2){

    /* Here, we must use "/4", since Src[] is in [-256, 255] */
  int a = (3*Src1[0]+  Src2[0] + 2) / 4;
  int b = (  Src1[0]+3*Src2[0] + 2) / 4;
  ADD(Dst1[0], a);
  ADD(Dst2[0], b);
}

//----------------------------

inline void Filter_Add_9331(byte *Dst1, byte *Dst2, const int *Src1, const int *Src2){

  int a = (9*Src1[0]+  3*Src1[1]+ 3*Src2[0] + 1*Src2[1] + 8) / 16;
  int b = (3*Src1[0]+  9*Src1[1]+ 1*Src2[0] + 3*Src2[1] + 8) / 16;
  int c = (3*Src1[0]+  1*Src1[1]+ 9*Src2[0] + 3*Src2[1] + 8) / 16;
  int d = (1*Src1[0]+  3*Src1[1]+ 3*Src2[0] + 9*Src2[1] + 8) / 16;
  ADD(Dst1[0], a);
  ADD(Dst1[1], b);
  ADD(Dst2[0], c);
  ADD(Dst2[1], d);
}

//----------------------------

void add_upsampled_8x8_16to8(byte *Dst, const int *Src, const int BpS){
   
   int x, y;
   
   ADD(Dst[0], Src[0]);
   for(x=0; x<7; ++x)
      Filter_Add_31(Dst+2*x+1, Dst+2*x+2, Src+x, Src+x+1);
   ADD(Dst[15], Src[7]);
   Dst += BpS;
   for(y=0; y<7; ++y) {
      byte *const Dst2 = Dst + BpS;
      Filter_Add_31(Dst, Dst2, Src, Src+8);
      for(x=0; x<7; ++x)
         Filter_Add_9331(Dst+2*x+1, Dst2+2*x+1, Src+x, Src+x+8);
      Filter_Add_31(Dst+15, Dst2+15, Src+7, Src+7+8);
      Src += 8;
      Dst += 2*BpS;
   }
   ADD(Dst[0], Src[0]);
   for(x=0; x<7; ++x) Filter_Add_31(Dst+2*x+1, Dst+2*x+2, Src+x, Src+x+1);
   ADD(Dst[15], Src[7]);
}
#undef ADD

/*----------------------------------------------------------------------------
 * horizontal and vertical deblocking
 *--------------------------------------------------------------------------*/

void hfilter_31(byte *Src1, byte *Src2, int Nb_Blks){

  Nb_Blks *= 8;
  while(Nb_Blks-->0) {
    byte a = ( 3*Src1[0] + 1*Src2[0] + 2 ) >> 2;
    byte b = ( 1*Src1[0] + 3*Src2[0] + 2 ) >> 2;
    *Src1++ = a;
    *Src2++ = b;
  }
}

//----------------------------

void vfilter_31(byte *Src1, byte *Src2, const int BpS, int Nb_Blks){
  Nb_Blks *= 8;
  while(Nb_Blks-->0) {
    byte a = ( 3*Src1[0] + 1*Src2[0] + 2 ) >> 2;
    byte b = ( 1*Src1[0] + 3*Src2[0] + 2 ) >> 2;
    *Src1 = a;
    *Src2 = b;
    Src1 += BpS;
    Src2 += BpS;
  }
}

//----------------------------
