/*
  * Floating point AAN IDCT
  * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 #include "faanidct.h"

 #include "libavutil/common.h"

 /* To allow switching to double. */

 typedef float FLOAT;

 
 #define B0 1.0000000000000000000000
 #define B1 1.3870398453221474618216 // cos(pi*1/16)sqrt(2)
 #define B2 1.3065629648763765278566 // cos(pi*2/16)sqrt(2)
 #define B3 1.1758756024193587169745 // cos(pi*3/16)sqrt(2)
 #define B4 1.0000000000000000000000 // cos(pi*4/16)sqrt(2)
 #define B5 0.7856949583871021812779 // cos(pi*5/16)sqrt(2)
 #define B6 0.5411961001461969843997 // cos(pi*6/16)sqrt(2)
 #define B7 0.2758993792829430123360 // cos(pi*7/16)sqrt(2)
 
 #define A4 0.70710678118654752438 // cos(pi*4/16)
 #define A2 0.92387953251128675613 // cos(pi*2/16)
 
 static const FLOAT prescale[64]={
 B0*B0/8, B0*B1/8, B0*B2/8, B0*B3/8, B0*B4/8, B0*B5/8, B0*B6/8, B0*B7/8,
 B1*B0/8, B1*B1/8, B1*B2/8, B1*B3/8, B1*B4/8, B1*B5/8, B1*B6/8, B1*B7/8,
 B2*B0/8, B2*B1/8, B2*B2/8, B2*B3/8, B2*B4/8, B2*B5/8, B2*B6/8, B2*B7/8,
 B3*B0/8, B3*B1/8, B3*B2/8, B3*B3/8, B3*B4/8, B3*B5/8, B3*B6/8, B3*B7/8,
 B4*B0/8, B4*B1/8, B4*B2/8, B4*B3/8, B4*B4/8, B4*B5/8, B4*B6/8, B4*B7/8,
 B5*B0/8, B5*B1/8, B5*B2/8, B5*B3/8, B5*B4/8, B5*B5/8, B5*B6/8, B5*B7/8,
 B6*B0/8, B6*B1/8, B6*B2/8, B6*B3/8, B6*B4/8, B6*B5/8, B6*B6/8, B6*B7/8,
 B7*B0/8, B7*B1/8, B7*B2/8, B7*B3/8, B7*B4/8, B7*B5/8, B7*B6/8, B7*B7/8,
 };
 

 static inline void p8idct(int16_t data[64], FLOAT temp[64], uint8_t *dest,
                           ptrdiff_t stride, int x, int y, int type)
 {

     int i;
     FLOAT s04, d04, s17, d17, s26, d26, s53, d53;
     FLOAT os07, os16, os25, os34;
     FLOAT od07, od16, od25, od34;
 
     for(i=0; i<y*8; i+=y){
         s17= temp[1*x + i] + temp[7*x + i];
         d17= temp[1*x + i] - temp[7*x + i];
         s53= temp[5*x + i] + temp[3*x + i];
         d53= temp[5*x + i] - temp[3*x + i];
 
         od07=  s17 + s53;
         od25= (s17 - s53)*(2*A4);
 
         od34=  d17*(2*(B6-A2)) - d53*(2*A2);
         od16=  d53*(2*(A2-B2)) + d17*(2*A2);
 
         od16 -= od07;
         od25 -= od16;
         od34 += od25;
 
         s26 = temp[2*x + i] + temp[6*x + i];
         d26 = temp[2*x + i] - temp[6*x + i];

         d26*= 2*A4;
         d26-= s26;

 
         s04= temp[0*x + i] + temp[4*x + i];
         d04= temp[0*x + i] - temp[4*x + i];
 
         os07= s04 + s26;
         os34= s04 - s26;

         os16= d04 + d26;
         os25= d04 - d26;

 
         if(type==0){
             temp[0*x + i]= os07 + od07;
             temp[7*x + i]= os07 - od07;
             temp[1*x + i]= os16 + od16;
             temp[6*x + i]= os16 - od16;
             temp[2*x + i]= os25 + od25;
             temp[5*x + i]= os25 - od25;
             temp[3*x + i]= os34 - od34;
             temp[4*x + i]= os34 + od34;
         }else if(type==1){
             data[0*x + i]= lrintf(os07 + od07);
             data[7*x + i]= lrintf(os07 - od07);
             data[1*x + i]= lrintf(os16 + od16);
             data[6*x + i]= lrintf(os16 - od16);
             data[2*x + i]= lrintf(os25 + od25);
             data[5*x + i]= lrintf(os25 - od25);
             data[3*x + i]= lrintf(os34 - od34);
             data[4*x + i]= lrintf(os34 + od34);
         }else if(type==2){
             dest[0*stride + i]= av_clip_uint8(((int)dest[0*stride + i]) + lrintf(os07 + od07));
             dest[7*stride + i]= av_clip_uint8(((int)dest[7*stride + i]) + lrintf(os07 - od07));
             dest[1*stride + i]= av_clip_uint8(((int)dest[1*stride + i]) + lrintf(os16 + od16));
             dest[6*stride + i]= av_clip_uint8(((int)dest[6*stride + i]) + lrintf(os16 - od16));
             dest[2*stride + i]= av_clip_uint8(((int)dest[2*stride + i]) + lrintf(os25 + od25));
             dest[5*stride + i]= av_clip_uint8(((int)dest[5*stride + i]) + lrintf(os25 - od25));
             dest[3*stride + i]= av_clip_uint8(((int)dest[3*stride + i]) + lrintf(os34 - od34));
             dest[4*stride + i]= av_clip_uint8(((int)dest[4*stride + i]) + lrintf(os34 + od34));
         }else{
             dest[0*stride + i]= av_clip_uint8(lrintf(os07 + od07));
             dest[7*stride + i]= av_clip_uint8(lrintf(os07 - od07));
             dest[1*stride + i]= av_clip_uint8(lrintf(os16 + od16));
             dest[6*stride + i]= av_clip_uint8(lrintf(os16 - od16));
             dest[2*stride + i]= av_clip_uint8(lrintf(os25 + od25));
             dest[5*stride + i]= av_clip_uint8(lrintf(os25 - od25));
             dest[3*stride + i]= av_clip_uint8(lrintf(os34 - od34));
             dest[4*stride + i]= av_clip_uint8(lrintf(os34 + od34));
         }
     }
 }
 

 void ff_faanidct(int16_t block[64]){

     FLOAT temp[64];
     int i;
 
     emms_c();
 
     for(i=0; i<64; i++)
         temp[i] = block[i] * prescale[i];
 
     p8idct(block, temp, NULL, 0, 1, 8, 0);
     p8idct(block, temp, NULL, 0, 8, 1, 1);
 }
 

 void ff_faanidct_add(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])
 {

     FLOAT temp[64];
     int i;
 
     emms_c();
 
     for(i=0; i<64; i++)
         temp[i] = block[i] * prescale[i];
 
     p8idct(block, temp, NULL,         0, 1, 8, 0);
     p8idct(NULL , temp, dest, line_size, 8, 1, 2);
 }
 

 void ff_faanidct_put(uint8_t *dest, ptrdiff_t line_size, int16_t block[64])
 {

     FLOAT temp[64];
     int i;
 
     emms_c();
 
     for(i=0; i<64; i++)
         temp[i] = block[i] * prescale[i];
 
     p8idct(block, temp, NULL,         0, 1, 8, 0);
     p8idct(NULL , temp, dest, line_size, 8, 1, 3);
 }