/*
  * This file is part of libswresample
  *
  * libswresample 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.
  *
  * libswresample 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 libswresample; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 
 #if defined(TEMPLATE_DITHER_DBL)
 #    define RENAME(N) N ## _double
 #    define DELEM  double

 #    define CLIP(v) while(0)

 
 #elif defined(TEMPLATE_DITHER_FLT)
 #    define RENAME(N) N ## _float
 #    define DELEM  float

 #    define CLIP(v) while(0)

 
 #elif defined(TEMPLATE_DITHER_S32)
 #    define RENAME(N) N ## _int32
 #    define DELEM  int32_t
 #    define CLIP(v) v = FFMAX(FFMIN(v, INT32_MAX), INT32_MIN)
 
 #elif defined(TEMPLATE_DITHER_S16)
 #    define RENAME(N) N ## _int16
 #    define DELEM  int16_t
 #    define CLIP(v) v = FFMAX(FFMIN(v, INT16_MAX), INT16_MIN)
 
 #else
 ERROR
 #endif
 

 void RENAME(swri_noise_shaping)(SwrContext *s, AudioData *dsts, const AudioData *srcs, const AudioData *noises, int count){

     int pos = s->dither.ns_pos;
     int i, j, ch;

     int taps  = s->dither.ns_taps;
     float S   = s->dither.ns_scale;
     float S_1 = s->dither.ns_scale_1;

     av_assert2((taps&3) != 2);
     av_assert2((taps&3) != 3 || s->dither.ns_coeffs[taps] == 0);
 

     for (ch=0; ch<srcs->ch_count; ch++) {

         const float *noise = ((const float *)noises->ch[ch]) + s->dither.noise_pos;

         const DELEM *src = (const DELEM*)srcs->ch[ch];
         DELEM *dst = (DELEM*)dsts->ch[ch];

         float *ns_errors = s->dither.ns_errors[ch];

         const float *ns_coeffs = s->dither.ns_coeffs;

         pos  = s->dither.ns_pos;

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

             double d1, d = src[i]*S_1;

             for(j=0; j<taps-2; j+=4) {
                 d -= ns_coeffs[j    ] * ns_errors[pos + j    ]
                     +ns_coeffs[j + 1] * ns_errors[pos + j + 1]
                     +ns_coeffs[j + 2] * ns_errors[pos + j + 2]
                     +ns_coeffs[j + 3] * ns_errors[pos + j + 3];
             }
             if(j < taps)

                 d -= ns_coeffs[j] * ns_errors[pos + j];

             pos = pos ? pos - 1 : taps - 1;

             d1 = rint(d + noise[i]);

             ns_errors[pos + taps] = ns_errors[pos] = d1 - d;

             d1 *= S;

             CLIP(d1);

             dst[i] = d1;

         }
     }
 

     s->dither.ns_pos = pos;

 }
 
 #undef RENAME
 #undef DELEM
 #undef CLIP