/* Resampling library

 * Copyright (C) <2001> David A. Schleef <ds@schleef.org>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or any later version.

 *

 * This library 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

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#ifdef HAVE_CONFIG_H

#ifndef __SYMBIAN32__

#include <config.h>

#else

#include "config.h"

#endif

#endif

#include <string.h>

#include <math.h>

#include <stdio.h>

#include <stdlib.h>

#include <limits.h>

#ifndef __SYMBIAN32__

#include <liboil/liboil.h>

#endif

#include "resample.h"

#include "buffer.h"

#include "debug.h"

static double

resample_sinc_window (double x, double halfwidth, double scale)

{

  double y;

  if (x == 0)

    return 1.0;

  if (x < -halfwidth || x > halfwidth)

    return 0.0;

  y = sin (x * M_PI * scale) / (x * M_PI * scale) * scale;

  x /= halfwidth;

  y *= (1 - x * x) * (1 - x * x);

  return y;

}

#ifdef __SYMBIAN32__

EXPORT_C

#endif

void

resample_scale_chunk (ResampleState * r)

{

  if (r->need_reinit) {

    RESAMPLE_DEBUG ("sample size %d", r->sample_size);

    if (r->buffer)

      free (r->buffer);

    r->buffer_len = r->sample_size * 1000;

    r->buffer = malloc (r->buffer_len);

    memset (r->buffer, 0, r->buffer_len);

    r->i_inc = r->o_rate / r->i_rate;

    r->o_inc = r->i_rate / r->o_rate;

    RESAMPLE_DEBUG ("i_inc %g o_inc %g", r->i_inc, r->o_inc);

    r->i_start = -r->i_inc * r->filter_length;

    r->need_reinit = 0;

#if 0

    if (r->i_inc < 1.0) {

      r->sinc_scale = r->i_inc;

      if (r->sinc_scale == 0.5) {

        /* strange things happen at integer multiples */

        r->sinc_scale = 1.0;

      }

    } else {

      r->sinc_scale = 1.0;

    }

#else

    r->sinc_scale = 1.0;

#endif

  }

  while (r->o_size > 0) {

    double midpoint;

    int i;

    int j;

    RESAMPLE_DEBUG ("i_start %g", r->i_start);

    midpoint = r->i_start + (r->filter_length - 1) * 0.5 * r->i_inc;

    if (midpoint > 0.5 * r->i_inc) {

      RESAMPLE_ERROR ("inconsistent state");

    }

    while (midpoint < -0.5 * r->i_inc) {

      AudioresampleBuffer *buffer;

      buffer = audioresample_buffer_queue_pull (r->queue, r->sample_size);

      if (buffer == NULL) {

        RESAMPLE_ERROR ("buffer_queue_pull returned NULL");

        return;

      }

      r->i_start += r->i_inc;

      RESAMPLE_DEBUG ("pulling (i_start = %g)", r->i_start);

      midpoint += r->i_inc;

      memmove (r->buffer, r->buffer + r->sample_size,

          r->buffer_len - r->sample_size);

      memcpy (r->buffer + r->buffer_len - r->sample_size, buffer->data,

          r->sample_size);

      audioresample_buffer_unref (buffer);

    }

    switch (r->format) {

      case RESAMPLE_FORMAT_S16:

        for (i = 0; i < r->n_channels; i++) {

          double acc = 0;

          double offset;

          double x;

          for (j = 0; j < r->filter_length; j++) {

            offset = (r->i_start + j * r->i_inc) * r->o_inc;

            x = *(int16_t *) (r->buffer + i * sizeof (int16_t) +

                j * r->sample_size);

            acc +=

                resample_sinc_window (offset, r->filter_length * 0.5,

                r->sinc_scale) * x;

          }

          if (acc < -32768.0)

            acc = -32768.0;

          if (acc > 32767.0)

            acc = 32767.0;

          *(int16_t *) (r->o_buf + i * sizeof (int16_t)) = rint (acc);

        }

        break;

      case RESAMPLE_FORMAT_S32:

        for (i = 0; i < r->n_channels; i++) {

          double acc = 0;

          double offset;

          double x;

          for (j = 0; j < r->filter_length; j++) {

            offset = (r->i_start + j * r->i_inc) * r->o_inc;

            x = *(int32_t *) (r->buffer + i * sizeof (int32_t) +

                j * r->sample_size);

            acc +=

                resample_sinc_window (offset, r->filter_length * 0.5,

                r->sinc_scale) * x;

          }

          if (acc < -2147483648.0)

            acc = -2147483648.0;

          if (acc > 2147483647.0)

            acc = 2147483647.0;

          *(int32_t *) (r->o_buf + i * sizeof (int32_t)) = rint (acc);

        }

        break;

      case RESAMPLE_FORMAT_F32:

        for (i = 0; i < r->n_channels; i++) {

          double acc = 0;

          double offset;

          double x;

          for (j = 0; j < r->filter_length; j++) {

            offset = (r->i_start + j * r->i_inc) * r->o_inc;

            x = *(float *) (r->buffer + i * sizeof (float) +

                j * r->sample_size);

            acc +=

                resample_sinc_window (offset, r->filter_length * 0.5,

                r->sinc_scale) * x;

          }

          *(float *) (r->o_buf + i * sizeof (float)) = acc;

        }

        break;

      case RESAMPLE_FORMAT_F64:

        for (i = 0; i < r->n_channels; i++) {

          double acc = 0;

          double offset;

          double x;

          for (j = 0; j < r->filter_length; j++) {

            offset = (r->i_start + j * r->i_inc) * r->o_inc;

            x = *(double *) (r->buffer + i * sizeof (double) +

                j * r->sample_size);

            acc +=

                resample_sinc_window (offset, r->filter_length * 0.5,

                r->sinc_scale) * x;

          }

          *(double *) (r->o_buf + i * sizeof (double)) = acc;

        }

        break;

    }

    r->i_start -= 1.0;

    r->o_buf += r->sample_size;

    r->o_size -= r->sample_size;

  }

}