RetroArch/audio/resampler.h

/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 * 
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */


#ifndef __RARCH_RESAMPLER_H
#define __RARCH_RESAMPLER_H

#ifdef HAVE_CONFIG_H
#include "../config.h"
#endif

#include <stddef.h>
#include <stdint.h>
#include <math.h>
#include "../boolean.h"

#ifndef M_PI
/* M_PI is left out of ISO C99 :( */
#define M_PI 3.14159265358979323846264338327
#endif

struct resampler_data
{
   const float *data_in;
   float *data_out;

   size_t input_frames;
   size_t output_frames;

   double ratio;
};

typedef struct rarch_resampler
{
   /* Bandwidth factor. Will be < 1.0 for downsampling, > 1.0 for upsamling. 
    * Corresponds to expected resampling ratio. */
   void *(*init)(double bandwidth_mod);
   void (*process)(void *re, struct resampler_data *data);
   void (*free)(void *re);
   const char *ident;
} rarch_resampler_t;

extern const rarch_resampler_t sinc_resampler;
extern const rarch_resampler_t CC_resampler;

/* Reallocs resampler. Will free previous handle before 
 * allocating a new one. If ident is NULL, first resampler will be used. */
bool rarch_resampler_realloc(void **re, const rarch_resampler_t **backend,
      const char *ident, double bw_ratio);

/* Convenience macros.
 * freep makes sure to set handles to NULL to avoid double-free 
 * in rarch_resampler_realloc. */
#define rarch_resampler_freep(backend, handle) do { \
   if (*(backend) && *(handle)) \
      (*backend)->free(*handle); \
   *backend = NULL; \
   *handle = NULL; \
} while(0)

#define rarch_resampler_process(backend, handle, data) do { \
   (backend)->process(handle, data); \
} while(0)

#endif