Genesis-Plus-GX/libretro-common/audio/resampler/drivers/nearest_resampler.c

/* Copyright  (C) 2010-2017 The RetroArch team
 *
 * ---------------------------------------------------------------------------------------
 * The following license statement only applies to this file (nearest_resampler.c).
 * ---------------------------------------------------------------------------------------
 *
 * Permission is hereby granted, free of charge,
 * to any person obtaining a copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
 * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include <stdint.h>
#include <stdlib.h>
#include <math.h>
 
#include <audio/audio_resampler.h>

typedef struct rarch_nearest_resampler
{
   float fraction;
} rarch_nearest_resampler_t;
 
static void resampler_nearest_process(
      void *re_, struct resampler_data *data)
{
   rarch_nearest_resampler_t *re = (rarch_nearest_resampler_t*)re_;
   audio_frame_float_t  *inp     = (audio_frame_float_t*)data->data_in;
   audio_frame_float_t  *inp_max = (audio_frame_float_t*)inp + data->input_frames;
   audio_frame_float_t  *outp    = (audio_frame_float_t*)data->data_out;
   float                   ratio = 1.0 / data->ratio;
 
   while(inp != inp_max)
   {
      while(re->fraction > 1)
      {
         *outp++ = *inp;
         re->fraction -= ratio;
      }
      re->fraction++;
      inp++;      
   }
   
   data->output_frames = (outp - (audio_frame_float_t*)data->data_out);
}
 
static void resampler_nearest_free(void *re_)
{
   rarch_nearest_resampler_t *re = (rarch_nearest_resampler_t*)re_;
   if (re)
      free(re);
}
 
static void *resampler_nearest_init(const struct resampler_config *config,
      double bandwidth_mod, resampler_simd_mask_t mask)
{
   rarch_nearest_resampler_t *re = (rarch_nearest_resampler_t*)
      calloc(1, sizeof(rarch_nearest_resampler_t));

   (void)config;
   (void)mask;

   if (!re)
      return NULL;
   
   re->fraction = 0;
   
   return re;
}
 
retro_resampler_t nearest_resampler = {
   resampler_nearest_init,
   resampler_nearest_process,
   resampler_nearest_free,
   RESAMPLER_API_VERSION,
   "nearest",
   "nearest"
};