/*** 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 <assert.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <math.h> #include "src_config.h"#include "common.h" static SRC_ERROR zoh_vari_process (SRC_STATE *state, SRC_DATA *data) ;static void zoh_reset (SRC_STATE *state) ;static SRC_STATE *zoh_copy (SRC_STATE *state) ;static void zoh_close (SRC_STATE *state) ; /*========================================================================================*/ #define	ZOH_MAGIC_MARKER	MAKE_MAGIC ('s', 'r', 'c', 'z', 'o', 'h') typedef struct{	int		zoh_magic_marker ;	bool	dirty ;	long	in_count, in_used ;	long	out_count, out_gen ;	float	*last_value ;} ZOH_DATA ; static SRC_STATE_VT zoh_state_vt ={	zoh_vari_process,	zoh_vari_process,	zoh_reset,	zoh_copy,	zoh_close} ; /*----------------------------------------------------------------------------------------*/ static SRC_ERRORzoh_vari_process (SRC_STATE *state, SRC_DATA *data){	ZOH_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 = (ZOH_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 * 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] = 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 ; 		for (ch = 0 ; ch < state->channels ; ch++)		{	data->data_out [priv->out_gen] = 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 ;} /* zoh_vari_process */ /*------------------------------------------------------------------------------*/ const char*zoh_get_name (int src_enum){	if (src_enum == SRC_ZERO_ORDER_HOLD)		return "ZOH Interpolator" ; 	return NULL ;} /* zoh_get_name */ const char*zoh_get_description (int src_enum){	if (src_enum == SRC_ZERO_ORDER_HOLD)		return "Zero order hold interpolator, very fast, poor quality." ; 	return NULL ;} /* zoh_get_descrition */ static ZOH_DATA *zoh_data_new (int channels){	assert (channels > 0) ; 	ZOH_DATA *priv = (ZOH_DATA *) calloc (1, sizeof (ZOH_DATA)) ;	if (priv)	{		priv->zoh_magic_marker = ZOH_MAGIC_MARKER ;		priv->last_value = (float *) calloc (channels, sizeof (float)) ;		if (!priv->last_value)		{			free (priv) ;			priv = NULL ;		}	} 	return priv ;} SRC_STATE *zoh_state_new (int channels, SRC_ERROR *error){	assert (channels > 0) ;	assert (error != NULL) ; 	SRC_STATE *state = (SRC_STATE *) calloc (1, sizeof (SRC_STATE)) ;	if (!state)	{		*error = SRC_ERR_MALLOC_FAILED ;		return NULL ;	} 	state->channels = channels ;	state->mode = SRC_MODE_PROCESS ; 	state->private_data = zoh_data_new (state->channels) ;	if (!state->private_data)	{		free (state) ;		*error = SRC_ERR_MALLOC_FAILED ;		return NULL ;	} 	state->vt = &zoh_state_vt ; 	zoh_reset (state) ; 	*error = SRC_ERR_NO_ERROR ; 	return state ;} /*===================================================================================*/ static voidzoh_reset (SRC_STATE *state){	ZOH_DATA *priv ; 	priv = (ZOH_DATA*) state->private_data ;	if (priv == NULL)		return ; 	priv->dirty = false ;	memset (priv->last_value, 0, sizeof (float) * state->channels) ; 	return ;} /* zoh_reset */ static SRC_STATE *zoh_copy (SRC_STATE *state){	assert (state != NULL) ; 	if (state->private_data == NULL)		return NULL ; 	SRC_STATE *to = (SRC_STATE *) calloc (1, sizeof (SRC_STATE)) ;	if (!state)		return NULL ;	memcpy (to, state, sizeof (SRC_STATE)) ; 	ZOH_DATA* from_priv = (ZOH_DATA*) state->private_data ;	ZOH_DATA *to_priv = (ZOH_DATA *) calloc (1, sizeof (ZOH_DATA)) ;	if (!to_priv)	{		free (to) ;		return NULL ;	} 	memcpy (to_priv, from_priv, sizeof (ZOH_DATA)) ;	to_priv->last_value = (float *) malloc (sizeof (float) * state->channels) ;	if (!to_priv->last_value)	{		free (to) ;		free (to_priv) ;		return NULL ;	}	memcpy (to_priv->last_value, from_priv->last_value, sizeof (float) * state->channels) ; 	to->private_data = to_priv ; 	return to ;} /* zoh_copy */ static voidzoh_close (SRC_STATE *state){	if (state)	{		ZOH_DATA *zoh = (ZOH_DATA *) state->private_data ;		if (zoh)		{			if (zoh->last_value)			{				free (zoh->last_value) ;				zoh->last_value = NULL ;			}			free (zoh) ;		}		free (state) ;	}} /* zoh_close */