302 lines
7.3 KiB
C
302 lines
7.3 KiB
C
/*
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** Copyright (c) 2002-2016, Erik de Castro Lopo <erikd@mega-nerd.com>
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** All rights reserved.
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**
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** This code is released under 2-clause BSD license. Please see the
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** file at : https://github.com/libsndfile/libsamplerate/blob/master/COPYING
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <assert.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <math.h>
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#include "common.h"
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static SRC_ERROR linear_vari_process (SRC_STATE *state, SRC_DATA *data) ;
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static void linear_reset (SRC_STATE *state) ;
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static SRC_STATE *linear_copy (SRC_STATE *state) ;
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static void linear_close (SRC_STATE *state) ;
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/*========================================================================================
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*/
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#define LINEAR_MAGIC_MARKER MAKE_MAGIC ('l', 'i', 'n', 'e', 'a', 'r')
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#define SRC_DEBUG 0
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typedef struct
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{ int linear_magic_marker ;
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bool dirty ;
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long in_count, in_used ;
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long out_count, out_gen ;
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float *last_value ;
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} LINEAR_DATA ;
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static SRC_STATE_VT linear_state_vt =
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{
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linear_vari_process,
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linear_vari_process,
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linear_reset,
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linear_copy,
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linear_close
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} ;
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/*----------------------------------------------------------------------------------------
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*/
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static SRC_ERROR
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linear_vari_process (SRC_STATE *state, SRC_DATA *data)
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{ LINEAR_DATA *priv ;
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double src_ratio, input_index, rem ;
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int ch ;
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if (data->input_frames <= 0)
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return SRC_ERR_NO_ERROR ;
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if (state->private_data == NULL)
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return SRC_ERR_NO_PRIVATE ;
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priv = (LINEAR_DATA*) state->private_data ;
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if (!priv->dirty)
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{ /* If we have just been reset, set the last_value data. */
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for (ch = 0 ; ch < state->channels ; ch++)
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priv->last_value [ch] = data->data_in [ch] ;
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priv->dirty = true ;
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} ;
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priv->in_count = data->input_frames * state->channels ;
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priv->out_count = data->output_frames * state->channels ;
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priv->in_used = priv->out_gen = 0 ;
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src_ratio = state->last_ratio ;
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if (is_bad_src_ratio (src_ratio))
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return SRC_ERR_BAD_INTERNAL_STATE ;
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input_index = state->last_position ;
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/* Calculate samples before first sample in input array. */
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while (input_index < 1.0 && priv->out_gen < priv->out_count)
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{
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if (priv->in_used + state->channels * (1.0 + input_index) >= priv->in_count)
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break ;
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if (priv->out_count > 0 && fabs (state->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF)
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src_ratio = state->last_ratio + priv->out_gen * (data->src_ratio - state->last_ratio) / priv->out_count ;
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for (ch = 0 ; ch < state->channels ; ch++)
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{ data->data_out [priv->out_gen] = (float) (priv->last_value [ch] + input_index *
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((double) data->data_in [ch] - priv->last_value [ch])) ;
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priv->out_gen ++ ;
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} ;
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/* Figure out the next index. */
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input_index += 1.0 / src_ratio ;
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} ;
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rem = fmod_one (input_index) ;
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priv->in_used += state->channels * lrint (input_index - rem) ;
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input_index = rem ;
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/* Main processing loop. */
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while (priv->out_gen < priv->out_count && priv->in_used + state->channels * input_index < priv->in_count)
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{
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if (priv->out_count > 0 && fabs (state->last_ratio - data->src_ratio) > SRC_MIN_RATIO_DIFF)
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src_ratio = state->last_ratio + priv->out_gen * (data->src_ratio - state->last_ratio) / priv->out_count ;
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#if SRC_DEBUG
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if (priv->in_used < state->channels && input_index < 1.0)
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{ printf ("Whoops!!!! in_used : %ld channels : %d input_index : %f\n", priv->in_used, state->channels, input_index) ;
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exit (1) ;
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} ;
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#endif
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for (ch = 0 ; ch < state->channels ; ch++)
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{ data->data_out [priv->out_gen] = (float) (data->data_in [priv->in_used - state->channels + ch] + input_index *
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((double) data->data_in [priv->in_used + ch] - data->data_in [priv->in_used - state->channels + ch])) ;
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priv->out_gen ++ ;
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} ;
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/* Figure out the next index. */
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input_index += 1.0 / src_ratio ;
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rem = fmod_one (input_index) ;
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priv->in_used += state->channels * lrint (input_index - rem) ;
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input_index = rem ;
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} ;
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if (priv->in_used > priv->in_count)
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{ input_index += (priv->in_used - priv->in_count) / state->channels ;
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priv->in_used = priv->in_count ;
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} ;
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state->last_position = input_index ;
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if (priv->in_used > 0)
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for (ch = 0 ; ch < state->channels ; ch++)
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priv->last_value [ch] = data->data_in [priv->in_used - state->channels + ch] ;
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/* Save current ratio rather then target ratio. */
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state->last_ratio = src_ratio ;
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data->input_frames_used = priv->in_used / state->channels ;
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data->output_frames_gen = priv->out_gen / state->channels ;
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return SRC_ERR_NO_ERROR ;
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} /* linear_vari_process */
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/*------------------------------------------------------------------------------
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*/
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const char*
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linear_get_name (int src_enum)
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{
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if (src_enum == SRC_LINEAR)
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return "Linear Interpolator" ;
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return NULL ;
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} /* linear_get_name */
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const char*
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linear_get_description (int src_enum)
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{
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if (src_enum == SRC_LINEAR)
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return "Linear interpolator, very fast, poor quality." ;
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return NULL ;
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} /* linear_get_descrition */
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static LINEAR_DATA *
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linear_data_new (int channels)
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{
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assert (channels > 0) ;
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LINEAR_DATA *priv = (LINEAR_DATA *) calloc (1, sizeof (LINEAR_DATA)) ;
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if (priv)
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{
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priv->linear_magic_marker = LINEAR_MAGIC_MARKER ;
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priv->last_value = (float *) calloc (channels, sizeof (float)) ;
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if (!priv->last_value)
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{
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free (priv) ;
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priv = NULL ;
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}
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}
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return priv ;
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}
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SRC_STATE *
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linear_state_new (int channels, SRC_ERROR *error)
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{
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assert (channels > 0) ;
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assert (error != NULL) ;
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SRC_STATE *state = (SRC_STATE *) calloc (1, sizeof (SRC_STATE)) ;
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if (!state)
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{
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*error = SRC_ERR_MALLOC_FAILED ;
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return NULL ;
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}
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state->channels = channels ;
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state->mode = SRC_MODE_PROCESS ;
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state->private_data = linear_data_new (state->channels) ;
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if (!state->private_data)
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{
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free (state) ;
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*error = SRC_ERR_MALLOC_FAILED ;
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return NULL ;
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}
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state->vt = &linear_state_vt ;
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linear_reset (state) ;
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*error = SRC_ERR_NO_ERROR ;
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return state ;
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}
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/*===================================================================================
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*/
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static void
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linear_reset (SRC_STATE *state)
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{ LINEAR_DATA *priv = NULL ;
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priv = (LINEAR_DATA*) state->private_data ;
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if (priv == NULL)
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return ;
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priv->dirty = false ;
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memset (priv->last_value, 0, sizeof (priv->last_value [0]) * state->channels) ;
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return ;
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} /* linear_reset */
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SRC_STATE *
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linear_copy (SRC_STATE *state)
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{
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assert (state != NULL) ;
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if (state->private_data == NULL)
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return NULL ;
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SRC_STATE *to = (SRC_STATE *) calloc (1, sizeof (SRC_STATE)) ;
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if (!state)
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return NULL ;
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memcpy (to, state, sizeof (SRC_STATE)) ;
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LINEAR_DATA* from_priv = (LINEAR_DATA*) state->private_data ;
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LINEAR_DATA *to_priv = (LINEAR_DATA *) calloc (1, sizeof (LINEAR_DATA)) ;
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if (!to_priv)
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{
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free (to) ;
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return NULL ;
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}
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memcpy (to_priv, from_priv, sizeof (LINEAR_DATA)) ;
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to_priv->last_value = (float *) malloc (sizeof (float) * state->channels) ;
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if (!to_priv->last_value)
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{
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free (to) ;
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free (to_priv) ;
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return NULL ;
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}
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memcpy (to_priv->last_value, from_priv->last_value, sizeof (float) * state->channels) ;
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to->private_data = to_priv ;
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return to ;
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} /* linear_copy */
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static void
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linear_close (SRC_STATE *state)
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{
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if (state)
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{
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LINEAR_DATA *linear = (LINEAR_DATA *) state->private_data ;
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if (linear)
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{
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if (linear->last_value)
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{
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free (linear->last_value) ;
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linear->last_value = NULL ;
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}
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free (linear) ;
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linear = NULL ;
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}
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free (state) ;
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state = NULL ;
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}
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} /* linear_close */
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