text: /*
  ** Copyright (c) 2005-2016, 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 "src_config.h"
  
  #include <stdio.h>
  #include <stdlib.h>
  #include <unistd.h>
  #include <string.h>
  #include <math.h>
  
  #if (HAVE_SNDFILE)
  
  #include <samplerate.h>
  #include <sndfile.h>
  
  #define ARRAY_LEN(x)	((int) (sizeof (x) / sizeof ((x) [0])))
  
  #define DEFAULT_CONVERTER 	SRC_SINC_MEDIUM_QUALITY
  
  #define	BUFFER_LEN			1024
  #define	INPUT_STEP_SIZE		8
  
  typedef struct
  {	sf_count_t	index ;
  	double		ratio ;
  } TIMEWARP_FACTOR ;
  
  static void usage_exit (const char *progname) ;
  static sf_count_t timewarp_convert (SNDFILE *infile, SNDFILE *outfile, int converter, int channels) ;
  
  int
  main (int argc, char *argv [])
  {	SNDFILE	*infile, *outfile ;
  	SF_INFO sfinfo ;
  	sf_count_t	count ;
  
  	if (argc != 3)
  		usage_exit (argv [0]) ;
  
  	putchar ('\n') ;
  	printf ("Input File    : %s\n", argv [argc - 2]) ;
  	if ((infile = sf_open (argv [argc - 2], SFM_READ, &sfinfo)) == NULL)
  	{	printf ("Error : Not able to open input file '%s'\n", argv [argc - 2]) ;
  		exit (1) ;
  		} ;
  
  	if (INPUT_STEP_SIZE * sfinfo.channels > BUFFER_LEN)
  	{	printf ("\n\nError : INPUT_STEP_SIZE * sfinfo.channels > BUFFER_LEN\n\n") ;
  		exit (1) ;
  		} ;
  
  
  	/* Delete the output file length to zero if already exists. */
  	remove (argv [argc - 1]) ;
  
  	if ((outfile = sf_open (argv [argc - 1], SFM_WRITE, &sfinfo)) == NULL)
  	{	printf ("Error : Not able to open output file '%s'\n", argv [argc - 1]) ;
  		sf_close (infile) ;
  		exit (1) ;
  		} ;
  
  	sf_command (outfile, SFC_SET_CLIPPING, NULL, SF_TRUE) ;
  
  	printf ("Output file   : %s\n", argv [argc - 1]) ;
  	printf ("Converter     : %s\n", src_get_name (DEFAULT_CONVERTER)) ;
  
  	count = timewarp_convert (infile, outfile, DEFAULT_CONVERTER, sfinfo.channels) ;
  
  	printf ("Output Frames : %ld\n\n", (long) count) ;
  
  	sf_close (infile) ;
  	sf_close (outfile) ;
  
  	return 0 ;
  } /* main */
  
  /*==============================================================================
  */
  
  static TIMEWARP_FACTOR warp [] =
  {	{	0		, 1.00000001 },
  	{	20000	, 1.01000000 },
  	{	20200	, 1.00000001 },
  	{	40000	, 1.20000000 },
  	{	40300	, 1.00000001 },
  	{	60000	, 1.10000000 },
  	{	60400	, 1.00000001 },
  	{	80000	, 1.50000000 },
  	{	81000	, 1.00000001 },
  } ;
  
  static sf_count_t
  timewarp_convert (SNDFILE *infile, SNDFILE *outfile, int converter, int channels)
  {	static float input [BUFFER_LEN] ;
  	static float output [BUFFER_LEN] ;
  
  	SRC_STATE	*src_state ;
  	SRC_DATA	src_data ;
  	int			error, warp_index = 0 ;
  	sf_count_t	input_count = 0, output_count = 0 ;
  
  	sf_seek (infile, 0, SEEK_SET) ;
  	sf_seek (outfile, 0, SEEK_SET) ;
  
  	/* Initialize the sample rate converter. */
  	if ((src_state = src_new (converter, channels, &error)) == NULL)
  	{	printf ("\n\nError : src_new() failed : %s.\n\n", src_strerror (error)) ;
  		exit (1) ;
  		} ;
  
  	src_data.end_of_input = 0 ; /* Set this later. */
  
  	/* Start with zero to force load in while loop. */
  	src_data.input_frames = 0 ;
  	src_data.data_in = input ;
  
  	if (warp [0].index > 0)
  		src_data.src_ratio = 1.0 ;
  	else
  	{	src_data.src_ratio = warp [0].ratio ;
  		warp_index ++ ;
  		} ;
  
  	src_data.data_out = output ;
  	src_data.output_frames = BUFFER_LEN /channels ;
  
  	while (1)
  	{
  		if (warp_index < ARRAY_LEN (warp) - 1 && input_count >= warp [warp_index].index)
  		{	src_data.src_ratio = warp [warp_index].ratio ;
  			warp_index ++ ;
  			} ;
  
  		/* If the input buffer is empty, refill it. */
  		if (src_data.input_frames == 0)
  		{	src_data.input_frames = (long) sf_readf_float (infile, input, INPUT_STEP_SIZE) ;
  			input_count += src_data.input_frames ;
  			src_data.data_in = input ;
  
  			/* The last read will not be a full buffer, so snd_of_input. */
  			if (src_data.input_frames < INPUT_STEP_SIZE)
  				src_data.end_of_input = SF_TRUE ;
  			} ;
  
  		/* Process current block. */
  		if ((error = src_process (src_state, &src_data)))
  		{	printf ("\nError : %s\n", src_strerror (error)) ;
  			exit (1) ;
  			} ;
  
  		/* Terminate if done. */
  		if (src_data.end_of_input && src_data.output_frames_gen == 0)
  			break ;
  
  		/* Write output. */
  		sf_writef_float (outfile, output, src_data.output_frames_gen) ;
  		output_count += src_data.output_frames_gen ;
  
  		src_data.data_in += src_data.input_frames_used * channels ;
  		src_data.input_frames -= src_data.input_frames_used ;
  		} ;
  
  	src_delete (src_state) ;
  
  	return output_count ;
  } /* timewarp_convert */
  
  /*------------------------------------------------------------------------------
  */
  
  static void
  usage_exit (const char *progname)
  {	const char	*cptr ;
  
  	if ((cptr = strrchr (progname, '/')) != NULL)
  		progname = cptr + 1 ;
  
  	if ((cptr = strrchr (progname, '\\')) != NULL)
  		progname = cptr + 1 ;
  
  	printf ("\n"
  		"  A program demonstrating the time warping capabilities of libsamplerate."
  		"  It uses libsndfile for file I/O and Secret Rabbit Code (aka libsamplerate)"
  		"  for performing the warping.\n"
  		"  It works on any file format supported by libsndfile with any \n"
  		"  number of channels (limited only by host memory).\n"
  		"\n"
  		"  The warping is dependant on a table hard code into the source code.\n"
  		"\n"
  		"  libsamplerate version : %s\n"
  		"\n"
  		"  Usage : \n"
  		"       %s <input file> <output file>\n"
  		"\n", src_get_version (), progname) ;
  
  	puts ("") ;
  
  	exit (1) ;
  } /* usage_exit */
  
  /*==============================================================================
  */
  
  #else /* (HAVE_SNFILE == 0) */
  
  /* Alternative main function when libsndfile is not available. */
  
  int
  main (void)
  {	puts (
  		"\n"
  		"****************************************************************\n"
  		"  This example program was compiled without libsndfile \n"
  		"  (https://github.com/libsndfile/libsndfile/).\n"
  		"  It is therefore completely broken and non-functional.\n"
  		"****************************************************************\n"
  		"\n"
  		) ;
  
  	return 0 ;
  } /* main */
  
  #endif
  
  