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/*
* Copyright (C) 2002-2004 Erik de Castro Lopo <[email protected]>
*
* This program 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 Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "float_cast.h"
#include "samplerate2.h"
#include "common.h"
#define ZOH_MAGIC_MARKER MAKE_MAGIC ('s', 'r', 'c', 'z', 'o', 'h')
typedef struct
{
long zoh_magic_marker;
long channels;
long reset;
long in_count, in_used;
long out_count, out_gen;
sr2_float_t last_value [1];
} SR2_(ZOH_DATA);
static void
SR2_(zoh_reset) (SR2_(SRC_PRIVATE) *psrc)
{
SR2_(ZOH_DATA) *priv;
priv = (SR2_(ZOH_DATA)*) psrc->private_data;
if(priv == NULL) return;
priv->channels = psrc->channels;
priv->reset = 1;
memset (priv->last_value, 0, sizeof (priv->last_value [0]) * priv->channels);
return;
}
static long SR2_(zoh_vari_process) (SR2_(SRC_PRIVATE) *psrc, SR2_(SRC_DATA) *data)
{
SR2_(ZOH_DATA) *priv;
double src_ratio, input_index, rem;
long ch;
if(psrc->private_data == NULL) return SRC_ERR_NO_PRIVATE;
priv = (SR2_(ZOH_DATA)*)psrc->private_data;
if(priv->reset)
{
/* If we have just been reset, set the last_value data. */
for(ch = 0;ch < priv->channels;ch ++)
priv->last_value [ch] = data->data_in [ch];
priv->reset = 0;
}
priv->in_count = data->input_frames * priv->channels;
priv->out_count = data->output_frames * priv->channels;
priv->in_used = priv->out_gen = 0;
src_ratio = psrc->last_ratio;
input_index = psrc->last_position;
/* Calculate samples before first sample in input array. */
while(input_index < 1.0 && priv->out_gen < priv->out_count)
{
if(priv->in_used + priv->channels * input_index >= priv->in_count)
break;
if(priv->out_count > 0 && fabs (psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF)
src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count;
for(ch = 0;ch < priv->channels;ch ++)
{
data->data_out [priv->out_gen] = priv->last_value [ch];
priv->out_gen ++;
}
/* Figure out the next index. */
input_index += 1.0 / src_ratio;
}
rem = SR2_(fmod_one)(input_index);
priv->in_used += priv->channels * lrint (input_index - rem);
input_index = rem;
/* Main processing loop. */
while(priv->out_gen < priv->out_count && priv->in_used + priv->channels * input_index <= priv->in_count)
{
if(priv->out_count > 0&& fabs(psrc->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF)
src_ratio = psrc->last_ratio + priv->out_gen * (data->src_ratio - psrc->last_ratio) / priv->out_count;
for(ch = 0;ch < priv->channels;ch ++)
{
data->data_out[priv->out_gen] = data->data_in[priv->in_used - priv->channels + ch];
priv->out_gen ++;
}
/* Figure out the next index. */
input_index += 1.0 / src_ratio;
rem = SR2_(fmod_one)(input_index);
priv->in_used += priv->channels * lrint (input_index - rem);
input_index = rem;
}
if(priv->in_used > priv->in_count)
{
input_index += (priv->in_used - priv->in_count) / priv->channels;
priv->in_used = priv->in_count;
}
psrc->last_position = input_index;
if(priv->in_used > 0)
for (ch = 0; ch < priv->channels; ch++)
priv->last_value [ch] = data->data_in [priv->in_used - priv->channels + ch];
/* Save current ratio rather then target ratio. */
psrc->last_ratio = src_ratio;
data->input_frames_used = priv->in_used / priv->channels;
data->output_frames_gen = priv->out_gen / priv->channels;
return SRC_ERR_NO_ERROR;
}
long SR2_(zoh_set_converter) (SR2_(SRC_PRIVATE) *psrc, long src_enum)
{
SR2_(ZOH_DATA) *priv = NULL;
if(src_enum != SRC_ZERO_ORDER_HOLD) return SRC_ERR_BAD_CONVERTER;
if(psrc->private_data != NULL)
{
free(psrc->private_data);
psrc->private_data = NULL;
}
if(psrc->private_data == NULL)
{
priv = calloc (1, sizeof (*priv) + psrc->channels * sizeof (sr2_float_t));
if(priv == NULL) return SRC_ERR_MALLOC_FAILED;
psrc->private_data = priv;
}
priv->zoh_magic_marker = ZOH_MAGIC_MARKER;
priv->channels = psrc->channels;
psrc->const_process = SR2_(zoh_vari_process);
psrc->vari_process = SR2_(zoh_vari_process);
psrc->reset = SR2_(zoh_reset);
SR2_(zoh_reset) (psrc);
return SRC_ERR_NO_ERROR;
} /* zoh_set_converter */
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