/*
  * 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 "fft.h"

 #include "synth_filter.h"
 

 static void synth_filter_float(FFTContext *imdct,

                            float *synth_buf_ptr, int *synth_buf_offset,
                            float synth_buf2[32], const float window[512],

                            float out[32], const float in[32], float scale)

 {
     float *synth_buf= synth_buf_ptr + *synth_buf_offset;
     int i, j;
 

     imdct->imdct_half(imdct, synth_buf, in);

 
     for (i = 0; i < 16; i++){

         float a= synth_buf2[i     ];
         float b= synth_buf2[i + 16];

         float c= 0;
         float d= 0;
         for (j = 0; j < 512 - *synth_buf_offset; j += 64){

             a += window[i + j     ]*(-synth_buf[15 - i + j      ]);
             b += window[i + j + 16]*( synth_buf[     i + j      ]);
             c += window[i + j + 32]*( synth_buf[16 + i + j      ]);
             d += window[i + j + 48]*( synth_buf[31 - i + j      ]);

         }
         for (     ; j < 512; j += 64){

             a += window[i + j     ]*(-synth_buf[15 - i + j - 512]);
             b += window[i + j + 16]*( synth_buf[     i + j - 512]);
             c += window[i + j + 32]*( synth_buf[16 + i + j - 512]);
             d += window[i + j + 48]*( synth_buf[31 - i + j - 512]);

         }

         out[i     ] = a*scale;
         out[i + 16] = b*scale;

         synth_buf2[i     ] = c;
         synth_buf2[i + 16] = d;

     }

     *synth_buf_offset= (*synth_buf_offset - 32)&511;

 }

 
 av_cold void ff_synth_filter_init(SynthFilterContext *c)
 {
     c->synth_filter_float = synth_filter_float;
 
     if (ARCH_ARM) ff_synth_filter_init_arm(c);
 }