/*
  * audio resampling
  * Copyright (c) 2004-2012 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
  */
 
 /**
  * @file
  * audio resampling
  * @author Michael Niedermayer <michaelni@gmx.at>
  */
 

 #if defined(TEMPLATE_RESAMPLE_DBL)

 #    define RENAME(N) N ## _double

 #    define FILTER_SHIFT 0
 #    define DELEM  double
 #    define FELEM  double
 #    define FELEM2 double

 #    define FOFFSET 0

 #    define OUT(d, v) d = v
 

 #elif    defined(TEMPLATE_RESAMPLE_FLT)

 #    define RENAME(N) N ## _float

 #    define FILTER_SHIFT 0
 #    define DELEM  float
 #    define FELEM  float
 #    define FELEM2 float

 #    define FOFFSET 0

 #    define OUT(d, v) d = v
 
 #elif defined(TEMPLATE_RESAMPLE_S32)

 #    define RENAME(N) N ## _int32
 #    define FILTER_SHIFT 30
 #    define DELEM  int32_t
 #    define FELEM  int32_t
 #    define FELEM2 int64_t
 #    define FELEM_MAX INT32_MAX
 #    define FELEM_MIN INT32_MIN

 #    define FOFFSET (1<<(FILTER_SHIFT-1))
 #    define OUT(d, v) (d) = av_clipl_int32((v)>>FILTER_SHIFT)

 #elif    defined(TEMPLATE_RESAMPLE_S16)

 #    define RENAME(N) N ## _int16

 #    define FILTER_SHIFT 15
 #    define DELEM  int16_t
 #    define FELEM  int16_t
 #    define FELEM2 int32_t
 #    define FELEML int64_t
 #    define FELEM_MAX INT16_MAX
 #    define FELEM_MIN INT16_MIN

 #    define FOFFSET (1<<(FILTER_SHIFT-1))
 #    define OUT(d, v) (d) = av_clip_int16((v)>>FILTER_SHIFT)

 
 #endif
 

 static void RENAME(resample_one)(void *dest, const void *source,

                                  int dst_size, int64_t index2, int64_t incr)
 {

     DELEM *dst = dest;
     const DELEM *src = source;

     int dst_index;

 
     for (dst_index = 0; dst_index < dst_size; dst_index++) {
         dst[dst_index] = src[index2 >> 32];
         index2 += incr;
     }
 }
 

 static int RENAME(resample_common)(ResampleContext *c,

                                    void *dest, const void *source,

                                    int n, int update_ctx)

 {

     DELEM *dst = dest;
     const DELEM *src = source;

     int dst_index;
     int index= c->index;
     int frac= c->frac;

     int sample_index = 0;
 
     while (index >= c->phase_count) {
         sample_index++;
         index -= c->phase_count;
     }

     for (dst_index = 0; dst_index < n; dst_index++) {
         FELEM *filter = ((FELEM *) c->filter_bank) + c->filter_alloc * index;

         FELEM2 val = FOFFSET;
         FELEM2 val2= 0;

         int i;

         for (i = 0; i + 1 < c->filter_length; i+=2) {
             val  += src[sample_index + i    ] * (FELEM2)filter[i    ];
             val2 += src[sample_index + i + 1] * (FELEM2)filter[i + 1];

         }

         if (i < c->filter_length)
             val  += src[sample_index + i    ] * (FELEM2)filter[i    ];
 #ifdef FELEML
         OUT(dst[dst_index], val + (FELEML)val2);
 #else
         OUT(dst[dst_index], val + val2);
 #endif

         frac  += c->dst_incr_mod;
         index += c->dst_incr_div;

         if (frac >= c->src_incr) {
             frac -= c->src_incr;
             index++;
         }

 
         while (index >= c->phase_count) {
             sample_index++;
             index -= c->phase_count;
         }

     }
 
     if(update_ctx){
         c->frac= frac;
         c->index= index;
     }

 
     return sample_index;
 }
 

 static int RENAME(resample_linear)(ResampleContext *c,

                                    void *dest, const void *source,

                                    int n, int update_ctx)

 {

     DELEM *dst = dest;
     const DELEM *src = source;

     int dst_index;
     int index= c->index;
     int frac= c->frac;

     int sample_index = 0;

 #if FILTER_SHIFT == 0
     double inv_src_incr = 1.0 / c->src_incr;
 #endif

     while (index >= c->phase_count) {
         sample_index++;
         index -= c->phase_count;
     }
 

     for (dst_index = 0; dst_index < n; dst_index++) {
         FELEM *filter = ((FELEM *) c->filter_bank) + c->filter_alloc * index;

         FELEM2 val = FOFFSET, v2 = FOFFSET;

         int i;
         for (i = 0; i < c->filter_length; i++) {
             val += src[sample_index + i] * (FELEM2)filter[i];
             v2  += src[sample_index + i] * (FELEM2)filter[i + c->filter_alloc];
         }

 #ifdef FELEML

         val += (v2 - val) * (FELEML) frac / c->src_incr;

 #else

 #    if FILTER_SHIFT == 0
         val += (v2 - val) * inv_src_incr * frac;
 #    else

         val += (v2 - val) / c->src_incr * frac;

 #    endif

 #endif

         OUT(dst[dst_index], val);
 

         frac += c->dst_incr_mod;
         index += c->dst_incr_div;

         if (frac >= c->src_incr) {
             frac -= c->src_incr;
             index++;
         }

 
         while (index >= c->phase_count) {
             sample_index++;
             index -= c->phase_count;
         }

     }
 
     if(update_ctx){
         c->frac= frac;
         c->index= index;
     }

     return sample_index;

 }

 
 #undef RENAME
 #undef FILTER_SHIFT
 #undef DELEM
 #undef FELEM
 #undef FELEM2
 #undef FELEML
 #undef FELEM_MAX
 #undef FELEM_MIN
 #undef OUT

 #undef FOFFSET