Add 'contrib/libsamplerate/' from commit '69a539a327ef8d78260056c5394363569b5751ef'

Initial import. Needed by upcoming patches which port virtual_oss to
base.

Sponsored by:	The FreeBSD Foundation

git-subtree-dir: contrib/libsamplerate
git-subtree-mainline: e9dd9f95f8
git-subtree-split: 69a539a327

contrib/libsamplerate/COPYING

@@ -0,0 +1,25 @@
+Copyright (c) 2012-2016, Erik de Castro Lopo <erikd@mega-nerd.com>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+1. Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

contrib/libsamplerate/common.h

@@ -0,0 +1,185 @@
+/*
+** Copyright (c) 2002-2021, 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
+*/
+
+#ifndef COMMON_H_INCLUDED
+#define COMMON_H_INCLUDED
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include <math.h>
+
+#ifdef HAVE_VISIBILITY
+  #define LIBSAMPLERATE_DLL_PRIVATE __attribute__ ((visibility ("hidden")))
+#elif defined (__APPLE__)
+  #define LIBSAMPLERATE_DLL_PRIVATE __private_extern__
+#else
+  #define LIBSAMPLERATE_DLL_PRIVATE
+#endif
+
+#define	SRC_MAX_RATIO			256
+#define	SRC_MAX_RATIO_STR		"256"
+
+#define	SRC_MIN_RATIO_DIFF		(1e-20)
+
+#ifndef MAX
+#define	MAX(a,b)	(((a) > (b)) ? (a) : (b))
+#endif
+
+#ifndef MIN
+#define	MIN(a,b)	(((a) < (b)) ? (a) : (b))
+#endif
+
+#define	ARRAY_LEN(x)			((int) (sizeof (x) / sizeof ((x) [0])))
+#define OFFSETOF(type,member)	((int) (&((type*) 0)->member))
+
+#define	MAKE_MAGIC(a,b,c,d,e,f)	((a) + ((b) << 4) + ((c) << 8) + ((d) << 12) + ((e) << 16) + ((f) << 20))
+
+/*
+** Inspiration : http://sourcefrog.net/weblog/software/languages/C/unused.html
+*/
+#ifdef UNUSED
+#elif defined (__GNUC__)
+#	define UNUSED(x) UNUSED_ ## x __attribute__ ((unused))
+#elif defined (__LCLINT__)
+#	define UNUSED(x) /*@unused@*/ x
+#else
+#	define UNUSED(x) x
+#endif
+
+#ifdef __GNUC__
+#	define WARN_UNUSED	__attribute__ ((warn_unused_result))
+#else
+#	define WARN_UNUSED
+#endif
+
+#include "samplerate.h"
+
+enum
+{	SRC_FALSE	= 0,
+	SRC_TRUE	= 1,
+} ;
+
+enum SRC_MODE
+{
+	SRC_MODE_PROCESS	= 0,
+	SRC_MODE_CALLBACK	= 1
+} ;
+
+typedef enum SRC_ERROR
+{
+	SRC_ERR_NO_ERROR = 0,
+
+	SRC_ERR_MALLOC_FAILED,
+	SRC_ERR_BAD_STATE,
+	SRC_ERR_BAD_DATA,
+	SRC_ERR_BAD_DATA_PTR,
+	SRC_ERR_NO_PRIVATE,
+	SRC_ERR_BAD_SRC_RATIO,
+	SRC_ERR_BAD_PROC_PTR,
+	SRC_ERR_SHIFT_BITS,
+	SRC_ERR_FILTER_LEN,
+	SRC_ERR_BAD_CONVERTER,
+	SRC_ERR_BAD_CHANNEL_COUNT,
+	SRC_ERR_SINC_BAD_BUFFER_LEN,
+	SRC_ERR_SIZE_INCOMPATIBILITY,
+	SRC_ERR_BAD_PRIV_PTR,
+	SRC_ERR_BAD_SINC_STATE,
+	SRC_ERR_DATA_OVERLAP,
+	SRC_ERR_BAD_CALLBACK,
+	SRC_ERR_BAD_MODE,
+	SRC_ERR_NULL_CALLBACK,
+	SRC_ERR_NO_VARIABLE_RATIO,
+	SRC_ERR_SINC_PREPARE_DATA_BAD_LEN,
+	SRC_ERR_BAD_INTERNAL_STATE,
+
+	/* This must be the last error number. */
+	SRC_ERR_MAX_ERROR
+} SRC_ERROR ;
+
+typedef struct SRC_STATE_VT_tag
+{
+	/* Varispeed process function. */
+	SRC_ERROR		(*vari_process) (SRC_STATE *state, SRC_DATA *data) ;
+
+	/* Constant speed process function. */
+	SRC_ERROR		(*const_process) (SRC_STATE *state, SRC_DATA *data) ;
+
+	/* State reset. */
+	void			(*reset) (SRC_STATE *state) ;
+
+	/* State clone. */
+	SRC_STATE		*(*copy) (SRC_STATE *state) ;
+
+	/* State close. */
+	void			(*close) (SRC_STATE *state) ;
+} SRC_STATE_VT ;
+
+struct SRC_STATE_tag
+{
+	SRC_STATE_VT *vt ;
+
+	double	last_ratio, last_position ;
+
+	SRC_ERROR	error ;
+	int		channels ;
+
+	/* SRC_MODE_PROCESS or SRC_MODE_CALLBACK */
+	enum SRC_MODE	mode ;
+
+	/* Data specific to SRC_MODE_CALLBACK. */
+	src_callback_t	callback_func ;
+	void			*user_callback_data ;
+	long			saved_frames ;
+	const float		*saved_data ;
+
+	/* Pointer to data to converter specific data. */
+	void	*private_data ;
+} ;
+
+/* In src_sinc.c */
+const char* sinc_get_name (int src_enum) ;
+const char* sinc_get_description (int src_enum) ;
+
+SRC_STATE *sinc_state_new (int converter_type, int channels, SRC_ERROR *error) ;
+
+/* In src_linear.c */
+const char* linear_get_name (int src_enum) ;
+const char* linear_get_description (int src_enum) ;
+
+SRC_STATE *linear_state_new (int channels, SRC_ERROR *error) ;
+
+/* In src_zoh.c */
+const char* zoh_get_name (int src_enum) ;
+const char* zoh_get_description (int src_enum) ;
+
+SRC_STATE *zoh_state_new (int channels, SRC_ERROR *error) ;
+
+/*----------------------------------------------------------
+**	Common static inline functions.
+*/
+
+static inline double
+fmod_one (double x)
+{	double res ;
+
+	res = x - lrint (x) ;
+	if (res < 0.0)
+		return res + 1.0 ;
+
+	return res ;
+} /* fmod_one */
+
+static inline int
+is_bad_src_ratio (double ratio)
+{	return (ratio < (1.0 / SRC_MAX_RATIO) || ratio > (1.0 * SRC_MAX_RATIO)) ;
+} /* is_bad_src_ratio */
+
+
+#endif	/* COMMON_H_INCLUDED */
+

contrib/libsamplerate/samplerate.c

@@ -0,0 +1,532 @@
+/*
+** 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
+*/
+
+#ifdef HAVE_CONFIG_H
+#include	"config.h"
+#endif
+
+#include	<stdio.h>
+#include	<stdlib.h>
+#include	<string.h>
+#include	<math.h>
+
+#include	"samplerate.h"
+#include	"common.h"
+
+static SRC_STATE *psrc_set_converter (int converter_type, int channels, int *error) ;
+
+
+SRC_STATE *
+src_new (int converter_type, int channels, int *error)
+{
+	return psrc_set_converter (converter_type, channels, error) ;
+} /* src_new */
+
+#if 0
+SRC_STATE*
+src_clone (SRC_STATE* orig, int *error)
+{
+	if (!orig)
+	{
+		if (error)
+			*error = SRC_ERR_BAD_STATE ;
+		return NULL ;
+	}
+	if (error)
+		*error = SRC_ERR_NO_ERROR ;
+
+	SRC_STATE *state = orig->vt->copy (orig) ;
+	if (!state)
+		if (error)
+			*error = SRC_ERR_MALLOC_FAILED ;
+
+	return state ;
+}
+
+SRC_STATE*
+src_callback_new (src_callback_t func, int converter_type, int channels, int *error, void* cb_data)
+{	SRC_STATE	*state ;
+
+	if (func == NULL)
+	{	if (error)
+			*error = SRC_ERR_BAD_CALLBACK ;
+		return NULL ;
+		} ;
+
+	if (error != NULL)
+		*error = 0 ;
+
+	if ((state = src_new (converter_type, channels, error)) == NULL)
+		return NULL ;
+
+	src_reset (state) ;
+
+	state->mode = SRC_MODE_CALLBACK ;
+	state->callback_func = func ;
+	state->user_callback_data = cb_data ;
+
+	return state ;
+} /* src_callback_new */
+#endif
+
+SRC_STATE *
+src_delete (SRC_STATE *state)
+{
+	if (state)
+		state->vt->close (state) ;
+
+	return NULL ;
+} /* src_state */
+
+int
+src_process (SRC_STATE *state, SRC_DATA *data)
+{
+	int error ;
+
+	if (state == NULL)
+		return SRC_ERR_BAD_STATE ;
+
+	if (state->mode != SRC_MODE_PROCESS)
+		return SRC_ERR_BAD_MODE ;
+
+	/* Check for valid SRC_DATA first. */
+	if (data == NULL)
+		return SRC_ERR_BAD_DATA ;
+
+	/* And that data_in and data_out are valid. */
+	if ((data->data_in == NULL && data->input_frames > 0)
+			|| (data->data_out == NULL && data->output_frames > 0))
+		return SRC_ERR_BAD_DATA_PTR ;
+
+	/* Check src_ratio is in range. */
+	if (is_bad_src_ratio (data->src_ratio))
+		return SRC_ERR_BAD_SRC_RATIO ;
+
+	if (data->input_frames < 0)
+		data->input_frames = 0 ;
+	if (data->output_frames < 0)
+		data->output_frames = 0 ;
+
+	if (data->data_in < data->data_out)
+	{	if (data->data_in + data->input_frames * state->channels > data->data_out)
+		{	/*-printf ("\n\ndata_in: %p    data_out: %p\n",
+				(void*) (data->data_in + data->input_frames * psrc->channels), (void*) data->data_out) ;-*/
+			return SRC_ERR_DATA_OVERLAP ;
+			} ;
+		}
+	else if (data->data_out + data->output_frames * state->channels > data->data_in)
+	{	/*-printf ("\n\ndata_in : %p   ouput frames: %ld    data_out: %p\n", (void*) data->data_in, data->output_frames, (void*) data->data_out) ;
+
+		printf ("data_out: %p (%p)    data_in: %p\n", (void*) data->data_out,
+			(void*) (data->data_out + data->input_frames * psrc->channels), (void*) data->data_in) ;-*/
+		return SRC_ERR_DATA_OVERLAP ;
+		} ;
+
+	/* Set the input and output counts to zero. */
+	data->input_frames_used = 0 ;
+	data->output_frames_gen = 0 ;
+
+	/* Special case for when last_ratio has not been set. */
+	if (state->last_ratio < (1.0 / SRC_MAX_RATIO))
+		state->last_ratio = data->src_ratio ;
+
+	/* Now process. */
+	if (fabs (state->last_ratio - data->src_ratio) < 1e-15)
+		error = state->vt->const_process (state, data) ;
+	else
+		error = state->vt->vari_process (state, data) ;
+
+	return error ;
+} /* src_process */
+
+#if 0
+long
+src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data)
+{
+	SRC_DATA	src_data ;
+
+	long	output_frames_gen ;
+	int		error = 0 ;
+
+	if (state == NULL)
+		return 0 ;
+
+	if (frames <= 0)
+		return 0 ;
+
+	if (state->mode != SRC_MODE_CALLBACK)
+	{	state->error = SRC_ERR_BAD_MODE ;
+		return 0 ;
+		} ;
+
+	if (state->callback_func == NULL)
+	{	state->error = SRC_ERR_NULL_CALLBACK ;
+		return 0 ;
+		} ;
+
+	memset (&src_data, 0, sizeof (src_data)) ;
+
+	/* Check src_ratio is in range. */
+	if (is_bad_src_ratio (src_ratio))
+	{	state->error = SRC_ERR_BAD_SRC_RATIO ;
+		return 0 ;
+		} ;
+
+	/* Switch modes temporarily. */
+	src_data.src_ratio = src_ratio ;
+	src_data.data_out = data ;
+	src_data.output_frames = frames ;
+
+	src_data.data_in = state->saved_data ;
+	src_data.input_frames = state->saved_frames ;
+
+	output_frames_gen = 0 ;
+	while (output_frames_gen < frames)
+	{	/*	Use a dummy array for the case where the callback function
+		**	returns without setting the ptr.
+		*/
+		float dummy [1] ;
+
+		if (src_data.input_frames == 0)
+		{	float *ptr = dummy ;
+
+			src_data.input_frames = state->callback_func (state->user_callback_data, &ptr) ;
+			src_data.data_in = ptr ;
+
+			if (src_data.input_frames == 0)
+				src_data.end_of_input = 1 ;
+			} ;
+
+		/*
+		** Now call process function. However, we need to set the mode
+		** to SRC_MODE_PROCESS first and when we return set it back to
+		** SRC_MODE_CALLBACK.
+		*/
+		state->mode = SRC_MODE_PROCESS ;
+		error = src_process (state, &src_data) ;
+		state->mode = SRC_MODE_CALLBACK ;
+
+		if (error != 0)
+			break ;
+
+		src_data.data_in += src_data.input_frames_used * state->channels ;
+		src_data.input_frames -= src_data.input_frames_used ;
+
+		src_data.data_out += src_data.output_frames_gen * state->channels ;
+		src_data.output_frames -= src_data.output_frames_gen ;
+
+		output_frames_gen += src_data.output_frames_gen ;
+
+		if (src_data.end_of_input == SRC_TRUE && src_data.output_frames_gen == 0)
+			break ;
+		} ;
+
+	state->saved_data = src_data.data_in ;
+	state->saved_frames = src_data.input_frames ;
+
+	if (error != 0)
+	{	state->error = (SRC_ERROR) error ;
+		return 0 ;
+		} ;
+
+	return output_frames_gen ;
+} /* src_callback_read */
+
+/*==========================================================================
+*/
+
+int
+src_set_ratio (SRC_STATE *state, double new_ratio)
+{
+	if (state == NULL)
+		return SRC_ERR_BAD_STATE ;
+
+	if (is_bad_src_ratio (new_ratio))
+		return SRC_ERR_BAD_SRC_RATIO ;
+
+	state->last_ratio = new_ratio ;
+
+	return SRC_ERR_NO_ERROR ;
+} /* src_set_ratio */
+
+int
+src_get_channels (SRC_STATE *state)
+{
+	if (state == NULL)
+		return -SRC_ERR_BAD_STATE ;
+
+	return state->channels ;
+} /* src_get_channels */
+
+int
+src_reset (SRC_STATE *state)
+{
+	if (state == NULL)
+		return SRC_ERR_BAD_STATE ;
+
+	state->vt->reset (state) ;
+
+	state->last_position = 0.0 ;
+	state->last_ratio = 0.0 ;
+
+	state->saved_data = NULL ;
+	state->saved_frames = 0 ;
+
+	state->error = SRC_ERR_NO_ERROR ;
+
+	return SRC_ERR_NO_ERROR ;
+} /* src_reset */
+
+/*==============================================================================
+**	Control functions.
+*/
+
+const char *
+src_get_name (int converter_type)
+{	const char *desc ;
+
+	if ((desc = sinc_get_name (converter_type)) != NULL)
+		return desc ;
+
+	if ((desc = zoh_get_name (converter_type)) != NULL)
+		return desc ;
+
+	if ((desc = linear_get_name (converter_type)) != NULL)
+		return desc ;
+
+	return NULL ;
+} /* src_get_name */
+
+const char *
+src_get_description (int converter_type)
+{	const char *desc ;
+
+	if ((desc = sinc_get_description (converter_type)) != NULL)
+		return desc ;
+
+	if ((desc = zoh_get_description (converter_type)) != NULL)
+		return desc ;
+
+	if ((desc = linear_get_description (converter_type)) != NULL)
+		return desc ;
+
+	return NULL ;
+} /* src_get_description */
+
+const char *
+src_get_version (void)
+{	return PACKAGE "-" VERSION " (c) 2002-2008 Erik de Castro Lopo" ;
+} /* src_get_version */
+
+int
+src_is_valid_ratio (double ratio)
+{
+	if (is_bad_src_ratio (ratio))
+		return SRC_FALSE ;
+
+	return SRC_TRUE ;
+} /* src_is_valid_ratio */
+
+/*==============================================================================
+**	Error reporting functions.
+*/
+
+int
+src_error (SRC_STATE *state)
+{	if (state)
+		return state->error ;
+	return SRC_ERR_NO_ERROR ;
+} /* src_error */
+
+const char*
+src_strerror (int error)
+{
+	switch (error)
+	{	case SRC_ERR_NO_ERROR :
+				return "No error." ;
+		case SRC_ERR_MALLOC_FAILED :
+				return "Malloc failed." ;
+		case SRC_ERR_BAD_STATE :
+				return "SRC_STATE pointer is NULL." ;
+		case SRC_ERR_BAD_DATA :
+				return "SRC_DATA pointer is NULL." ;
+		case SRC_ERR_BAD_DATA_PTR :
+				return "SRC_DATA->data_out or SRC_DATA->data_in is NULL." ;
+		case SRC_ERR_NO_PRIVATE :
+				return "Internal error. No private data." ;
+
+		case SRC_ERR_BAD_SRC_RATIO :
+				return "SRC ratio outside [1/" SRC_MAX_RATIO_STR ", " SRC_MAX_RATIO_STR "] range." ;
+
+		case SRC_ERR_BAD_SINC_STATE :
+				return "src_process() called without reset after end_of_input." ;
+		case SRC_ERR_BAD_PROC_PTR :
+				return "Internal error. No process pointer." ;
+		case SRC_ERR_SHIFT_BITS :
+				return "Internal error. SHIFT_BITS too large." ;
+		case SRC_ERR_FILTER_LEN :
+				return "Internal error. Filter length too large." ;
+		case SRC_ERR_BAD_CONVERTER :
+				return "Bad converter number." ;
+		case SRC_ERR_BAD_CHANNEL_COUNT :
+				return "Channel count must be >= 1." ;
+		case SRC_ERR_SINC_BAD_BUFFER_LEN :
+				return "Internal error. Bad buffer length. Please report this." ;
+		case SRC_ERR_SIZE_INCOMPATIBILITY :
+				return "Internal error. Input data / internal buffer size difference. Please report this." ;
+		case SRC_ERR_BAD_PRIV_PTR :
+				return "Internal error. Private pointer is NULL. Please report this." ;
+		case SRC_ERR_DATA_OVERLAP :
+				return "Input and output data arrays overlap." ;
+		case SRC_ERR_BAD_CALLBACK :
+				return "Supplied callback function pointer is NULL." ;
+		case SRC_ERR_BAD_MODE :
+				return "Calling mode differs from initialisation mode (ie process v callback)." ;
+		case SRC_ERR_NULL_CALLBACK :
+				return "Callback function pointer is NULL in src_callback_read ()." ;
+		case SRC_ERR_NO_VARIABLE_RATIO :
+				return "This converter only allows constant conversion ratios." ;
+		case SRC_ERR_SINC_PREPARE_DATA_BAD_LEN :
+				return "Internal error : Bad length in prepare_data ()." ;
+		case SRC_ERR_BAD_INTERNAL_STATE :
+				return "Error : Someone is trampling on my internal state." ;
+
+		case SRC_ERR_MAX_ERROR :
+				return "Placeholder. No error defined for this error number." ;
+
+		default : 						break ;
+		}
+
+	return NULL ;
+} /* src_strerror */
+
+/*==============================================================================
+**	Simple interface for performing a single conversion from input buffer to
+**	output buffer at a fixed conversion ratio.
+*/
+
+int
+src_simple (SRC_DATA *src_data, int converter, int channels)
+{	SRC_STATE	*src_state ;
+	int 		error ;
+
+	if ((src_state = src_new (converter, channels, &error)) == NULL)
+		return error ;
+
+	src_data->end_of_input = 1 ; /* Only one buffer worth of input. */
+
+	error = src_process (src_state, src_data) ;
+
+	src_delete (src_state) ;
+
+	return error ;
+} /* src_simple */
+
+void
+src_short_to_float_array (const short *in, float *out, int len)
+{
+	for (int i = 0 ; i < len ; i++)
+	{	out [i] = (float) (in [i] / (1.0 * 0x8000)) ;
+		} ;
+
+	return ;
+} /* src_short_to_float_array */
+
+void
+src_float_to_short_array (const float *in, short *out, int len)
+{
+	for (int i = 0 ; i < len ; i++)
+	{	float scaled_value ;
+		scaled_value = in [i] * 32768.f ;
+		if (scaled_value >= 32767.f)
+			out [i] = 32767 ;
+		else if (scaled_value <= -32768.f)
+			out [i] = -32768 ;
+		else
+			out [i] = (short) (lrintf (scaled_value)) ;
+	}
+} /* src_float_to_short_array */
+
+void
+src_int_to_float_array (const int *in, float *out, int len)
+{
+	for (int i = 0 ; i < len ; i++)
+	{	out [i] = (float) (in [i] / (8.0 * 0x10000000)) ;
+		} ;
+
+	return ;
+} /* src_int_to_float_array */
+
+void
+src_float_to_int_array (const float *in, int *out, int len)
+{	double scaled_value ;
+
+	for (int i = 0 ; i < len ; i++)
+	{	scaled_value = in [i] * (8.0 * 0x10000000) ;
+#if CPU_CLIPS_POSITIVE == 0
+		if (scaled_value >= (1.0 * 0x7FFFFFFF))
+		{	out [i] = 0x7fffffff ;
+			continue ;
+			} ;
+#endif
+#if CPU_CLIPS_NEGATIVE == 0
+		if (scaled_value <= (-8.0 * 0x10000000))
+		{	out [i] = -1 - 0x7fffffff ;
+			continue ;
+			} ;
+#endif
+		out [i] = (int) lrint (scaled_value) ;
+		} ;
+
+} /* src_float_to_int_array */
+#endif
+
+/*==============================================================================
+**	Private functions.
+*/
+
+static SRC_STATE *
+psrc_set_converter (int converter_type, int channels, int *error)
+{
+	SRC_ERROR temp_error;
+	SRC_STATE *state ;
+	switch (converter_type)
+	{
+#ifdef ENABLE_SINC_BEST_CONVERTER
+	case SRC_SINC_BEST_QUALITY :
+		state = sinc_state_new (converter_type, channels, &temp_error) ;
+		break ;
+#endif
+#ifdef ENABLE_SINC_MEDIUM_CONVERTER
+	case SRC_SINC_MEDIUM_QUALITY :
+		state = sinc_state_new (converter_type, channels, &temp_error) ;
+		break ;
+#endif
+#ifdef ENABLE_SINC_FAST_CONVERTER
+	case SRC_SINC_FASTEST :
+		state = sinc_state_new (converter_type, channels, &temp_error) ;
+		break ;
+#endif
+	case SRC_ZERO_ORDER_HOLD :
+		state = zoh_state_new (channels, &temp_error) ;
+		break ;
+	case SRC_LINEAR :
+		state = linear_state_new (channels, &temp_error) ;
+		break ;
+	default :
+		temp_error = SRC_ERR_BAD_CONVERTER ;
+		state = NULL ;
+		break ;
+	}
+
+	if (error)
+		*error = (int) temp_error ;
+
+	return state ;
+} /* psrc_set_converter */
+

contrib/libsamplerate/samplerate.h

@@ -0,0 +1,189 @@
+/*
+** 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
+*/
+
+/*
+** API documentation is available here:
+**     http://libsndfile.github.io/libsamplerate/api.html
+*/
+
+#ifndef SAMPLERATE_H
+#define SAMPLERATE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif	/* __cplusplus */
+
+
+/* Opaque data type SRC_STATE. */
+typedef struct SRC_STATE_tag SRC_STATE ;
+
+/* SRC_DATA is used to pass data to src_simple() and src_process(). */
+typedef struct
+{	const float	*data_in ;
+	float	*data_out ;
+
+	long	input_frames, output_frames ;
+	long	input_frames_used, output_frames_gen ;
+
+	int		end_of_input ;
+
+	double	src_ratio ;
+} SRC_DATA ;
+
+/*
+** User supplied callback function type for use with src_callback_new()
+** and src_callback_read(). First parameter is the same pointer that was
+** passed into src_callback_new(). Second parameter is pointer to a
+** pointer. The user supplied callback function must modify *data to
+** point to the start of the user supplied float array. The user supplied
+** function must return the number of frames that **data points to.
+*/
+
+typedef long (*src_callback_t) (void *cb_data, float **data) ;
+
+/*
+**	Standard initialisation function : return an anonymous pointer to the
+**	internal state of the converter. Choose a converter from the enums below.
+**	Error returned in *error.
+*/
+
+SRC_STATE* src_new (int converter_type, int channels, int *error) ;
+
+/*
+** Clone a handle : return an anonymous pointer to a new converter
+** containing the same internal state as orig. Error returned in *error.
+*/
+SRC_STATE* src_clone (SRC_STATE* orig, int *error) ;
+
+/*
+**	Initilisation for callback based API : return an anonymous pointer to the
+**	internal state of the converter. Choose a converter from the enums below.
+**	The cb_data pointer can point to any data or be set to NULL. Whatever the
+**	value, when processing, user supplied function "func" gets called with
+**	cb_data as first parameter.
+*/
+
+SRC_STATE* src_callback_new (src_callback_t func, int converter_type, int channels,
+				int *error, void* cb_data) ;
+
+/*
+**	Cleanup all internal allocations.
+**	Always returns NULL.
+*/
+
+SRC_STATE* src_delete (SRC_STATE *state) ;
+
+/*
+**	Standard processing function.
+**	Returns non zero on error.
+*/
+
+int src_process (SRC_STATE *state, SRC_DATA *data) ;
+
+/*
+**	Callback based processing function. Read up to frames worth of data from
+**	the converter int *data and return frames read or -1 on error.
+*/
+long src_callback_read (SRC_STATE *state, double src_ratio, long frames, float *data) ;
+
+/*
+**	Simple interface for performing a single conversion from input buffer to
+**	output buffer at a fixed conversion ratio.
+**	Simple interface does not require initialisation as it can only operate on
+**	a single buffer worth of audio.
+*/
+
+int src_simple (SRC_DATA *data, int converter_type, int channels) ;
+
+/*
+** This library contains a number of different sample rate converters,
+** numbered 0 through N.
+**
+** Return a string giving either a name or a more full description of each
+** sample rate converter or NULL if no sample rate converter exists for
+** the given value. The converters are sequentially numbered from 0 to N.
+*/
+
+const char *src_get_name (int converter_type) ;
+const char *src_get_description (int converter_type) ;
+const char *src_get_version (void) ;
+
+/*
+**	Set a new SRC ratio. This allows step responses
+**	in the conversion ratio.
+**	Returns non zero on error.
+*/
+
+int src_set_ratio (SRC_STATE *state, double new_ratio) ;
+
+/*
+**	Get the current channel count.
+**	Returns negative on error, positive channel count otherwise
+*/
+
+int src_get_channels (SRC_STATE *state) ;
+
+/*
+**	Reset the internal SRC state.
+**	Does not modify the quality settings.
+**	Does not free any memory allocations.
+**	Returns non zero on error.
+*/
+
+int src_reset (SRC_STATE *state) ;
+
+/*
+** Return TRUE if ratio is a valid conversion ratio, FALSE
+** otherwise.
+*/
+
+int src_is_valid_ratio (double ratio) ;
+
+/*
+**	Return an error number.
+*/
+
+int src_error (SRC_STATE *state) ;
+
+/*
+**	Convert the error number into a string.
+*/
+const char* src_strerror (int error) ;
+
+/*
+** The following enums can be used to set the interpolator type
+** using the function src_set_converter().
+*/
+
+enum
+{
+	SRC_SINC_BEST_QUALITY		= 0,
+	SRC_SINC_MEDIUM_QUALITY		= 1,
+	SRC_SINC_FASTEST			= 2,
+	SRC_ZERO_ORDER_HOLD			= 3,
+	SRC_LINEAR					= 4,
+} ;
+
+/*
+** Extra helper functions for converting from short to float and
+** back again.
+*/
+
+void src_short_to_float_array (const short *in, float *out, int len) ;
+void src_float_to_short_array (const float *in, short *out, int len) ;
+
+void src_int_to_float_array (const int *in, float *out, int len) ;
+void src_float_to_int_array (const float *in, int *out, int len) ;
+
+
+#ifdef __cplusplus
+}		/* extern "C" */
+#endif	/* __cplusplus */
+
+#endif	/* SAMPLERATE_H */
+

contrib/libsamplerate/src_linear.c

@@ -0,0 +1,303 @@
+/*
+** Copyright (c) 2002-2021, 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
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "common.h"
+
+static SRC_ERROR linear_vari_process (SRC_STATE *state, SRC_DATA *data) ;
+static void linear_reset (SRC_STATE *state) ;
+static SRC_STATE *linear_copy (SRC_STATE *state) ;
+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 SRC_STATE_VT linear_state_vt =
+{
+	linear_vari_process,
+	linear_vari_process,
+	linear_reset,
+	linear_copy,
+	linear_close
+} ;
+
+/*----------------------------------------------------------------------------------------
+*/
+
+static SRC_ERROR
+linear_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 *
+										((double) 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
+		if (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) ;
+			} ;
+#endif
+
+		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 *
+						((double) 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 */
+
+/*------------------------------------------------------------------------------
+*/
+
+#if 0
+LIBSAMPLERATE_DLL_PRIVATE const char*
+linear_get_name (int src_enum)
+{
+	if (src_enum == SRC_LINEAR)
+		return "Linear Interpolator" ;
+
+	return NULL ;
+} /* linear_get_name */
+
+LIBSAMPLERATE_DLL_PRIVATE 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 */
+#endif
+
+static LINEAR_DATA *
+linear_data_new (int channels)
+{
+	assert (channels > 0) ;
+
+	LINEAR_DATA *priv = (LINEAR_DATA *) calloc (1, sizeof (LINEAR_DATA)) ;
+	if (priv)
+	{
+		priv->linear_magic_marker = LINEAR_MAGIC_MARKER ;
+		priv->last_value = (float *) calloc (channels, sizeof (float)) ;
+		if (!priv->last_value)
+		{
+			free (priv) ;
+			priv = NULL ;
+		}
+	}
+
+	return priv ;
+}
+
+LIBSAMPLERATE_DLL_PRIVATE SRC_STATE *
+linear_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 = linear_data_new (state->channels) ;
+	if (!state->private_data)
+	{
+		free (state) ;
+		*error = SRC_ERR_MALLOC_FAILED ;
+		return NULL ;
+	}
+
+	state->vt = &linear_state_vt ;
+
+	linear_reset (state) ;
+
+	*error = SRC_ERR_NO_ERROR ;
+
+	return state ;
+}
+
+/*===================================================================================
+*/
+
+static void
+linear_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 */
+
+SRC_STATE *
+linear_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 (!to)
+		return NULL ;
+	memcpy (to, state, sizeof (SRC_STATE)) ;
+
+	LINEAR_DATA* from_priv = (LINEAR_DATA*) state->private_data ;
+	LINEAR_DATA *to_priv = (LINEAR_DATA *) calloc (1, sizeof (LINEAR_DATA)) ;
+	if (!to_priv)
+	{
+		free (to) ;
+		return NULL ;
+	}
+
+	memcpy (to_priv, from_priv, sizeof (LINEAR_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 ;
+} /* linear_copy */
+
+static void
+linear_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 ;
+		}
+		free (state) ;
+		state = NULL ;
+	}
+} /* linear_close */

contrib/libsamplerate/src_zoh.c

@@ -0,0 +1,292 @@
+/*
+** Copyright (c) 2002-2021, 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
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.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_ERROR
+zoh_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 */
+
+/*------------------------------------------------------------------------------
+*/
+
+#if 0
+LIBSAMPLERATE_DLL_PRIVATE const char*
+zoh_get_name (int src_enum)
+{
+	if (src_enum == SRC_ZERO_ORDER_HOLD)
+		return "ZOH Interpolator" ;
+
+	return NULL ;
+} /* zoh_get_name */
+
+LIBSAMPLERATE_DLL_PRIVATE 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 */
+#endif
+
+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 ;
+}
+
+LIBSAMPLERATE_DLL_PRIVATE 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 void
+zoh_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 (!to)
+		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 void
+zoh_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) ;
+			zoh = NULL ;
+		}
+		free (state) ;
+		state = NULL ;
+	}
+} /* zoh_close */