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