/*** 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 <unistd.h>#include <string.h>#include <math.h> #include "src_config.h" #if (HAVE_SNDFILE) #include <samplerate.h>#include <sndfile.h> #include "audio_out.h" #define ARRAY_LEN(x)	((int) (sizeof (x) / sizeof ((x) [0]))) #define	BUFFER_LEN			4096#define	VARISPEED_BLOCK_LEN	64 #define	MIN(a,b)		((a) < (b) ? (a) : (b)) #define	SRC_MAGIC		((int) ('S' << 16) + ('R' << 8) + ('C'))#define	SNDFILE_MAGIC	((int) ('s' << 24) + ('n' << 20) + ('d' << 16) + ('f' << 12) + ('i' << 8) + ('l' << 4) + 'e') #ifndef	M_PI#define	M_PI			3.14159265358979323846264338#endif  typedef struct{	int			magic ;	SNDFILE 	*sndfile ;	SF_INFO 	sfinfo ; 	float		buffer	[BUFFER_LEN] ;} SNDFILE_CB_DATA ; typedef struct{	int			magic ; 	SNDFILE_CB_DATA	sf ; 	int			freq_point ; 	SRC_STATE	*src_state ; } SRC_CB_DATA ; static int varispeed_get_data (SRC_CB_DATA *data, float *samples, int frames) ;static void varispeed_play (const char *filename, int converter) ; static long src_input_callback (void *cb_data, float **data) ; intmain (int argc, char *argv []){	const char	*cptr, *progname, *filename ;	int			k, converter ; 	converter = SRC_SINC_FASTEST ; 	progname = argv [0] ; 	if ((cptr = strrchr (progname, '/')) != NULL)		progname = cptr + 1 ; 	if ((cptr = strrchr (progname, '\\')) != NULL)		progname = cptr + 1 ; 	printf ("\n"		"  %s\n"		"\n"		"  This is a demo program which plays the given file at a slowly \n"		"  varying speed. Lots of fun with drum loops and full mixes.\n"		"\n"		"  It uses Secret Rabbit Code (aka libsamplerate) to perform the \n"		"  vari-speeding and libsndfile for file I/O.\n"		"\n", progname) ; 	if (argc == 2)		filename = argv [1] ;	else if (argc == 4 && strcmp (argv [1], "-c") == 0)	{	filename = argv [3] ;		converter = atoi (argv [2]) ;		}	else	{	printf ("  Usage :\n\n       %s [-c <number>] <input file>\n\n", progname) ;		puts (			"  The optional -c argument allows the converter type to be chosen from\n"			"  the following list :"			"\n"			) ; 		for (k = 0 ; (cptr = src_get_name (k)) != NULL ; k++)			printf ("       %d : %s\n", k, cptr) ; 		puts ("") ;		exit (1) ;		} ; 	varispeed_play (filename, converter) ; 	return 0 ;} /* main */ /*==============================================================================*/ static voidvarispeed_play (const char *filename, int converter){	SRC_CB_DATA		data ;	AUDIO_OUT		*audio_out ;	int				error ; 	memset (&data, 0, sizeof (data)) ; 	data.magic = SRC_MAGIC ;	data.sf.magic = SNDFILE_MAGIC ; 	if ((data.sf.sndfile = sf_open (filename, SFM_READ, &data.sf.sfinfo)) == NULL)	{	puts (sf_strerror (NULL)) ;		exit (1) ;		} ; 	/* Initialize the sample rate converter. */	if ((data.src_state = src_callback_new (src_input_callback, converter, data.sf.sfinfo.channels, &error, &data.sf)) == NULL)	{	printf ("\n\nError : src_new() failed : %s.\n\n", src_strerror (error)) ;		exit (1) ;		} ; 	printf ( 		"  Playing   : %s\n"		"  Converter : %s\n"		"\n"		"  Press <control-c> to exit.\n"		"\n",		filename, src_get_name (converter)) ; 	if ((audio_out = audio_open (data.sf.sfinfo.channels, data.sf.sfinfo.samplerate)) == NULL)	{	printf ("\n\nError : audio_open () failed.\n") ;		exit (1) ;		} ; 	/* Pass the data and the callbacl function to audio_play */	audio_play ((get_audio_callback_t) varispeed_get_data, audio_out, &data) ; 	/* Cleanup */	audio_close (audio_out) ;	sf_close (data.sf.sndfile) ;	src_delete (data.src_state) ; } /* varispeed_play */ static longsrc_input_callback (void *cb_data, float **audio){	SNDFILE_CB_DATA * data = (SNDFILE_CB_DATA *) cb_data ;	const int input_frames = ARRAY_LEN (data->buffer) / data->sfinfo.channels ;	int		read_frames ; 	if (data->magic != SNDFILE_MAGIC)	{	printf ("\n\n%s:%d Eeeek, something really bad happened!\n", __FILE__, __LINE__) ;		exit (1) ;		} ; 	for (read_frames = 0 ; read_frames < input_frames ; )	{	sf_count_t position ; 		read_frames += (int) sf_readf_float (data->sndfile, data->buffer + read_frames * data->sfinfo.channels, input_frames - read_frames) ; 		position = sf_seek (data->sndfile, 0, SEEK_CUR) ; 		if (position < 0 || position == data->sfinfo.frames)			sf_seek (data->sndfile, 0, SEEK_SET) ;		} ; 	*audio = & (data->buffer [0]) ; 	return input_frames ;} /* src_input_callback */  /*==============================================================================*/ static intvarispeed_get_data (SRC_CB_DATA *data, float *samples, int out_frames){	float	*output ;	int		rc, out_frame_count ; 	if (data->magic != SRC_MAGIC)	{	printf ("\n\n%s:%d Eeeek, something really bad happened!\n", __FILE__, __LINE__) ;		exit (1) ;		} ; 	for (out_frame_count = 0 ; out_frame_count < out_frames ; out_frame_count += VARISPEED_BLOCK_LEN)	{	double	src_ratio = 1.0 - 0.5 * sin (data->freq_point * 2 * M_PI / 20000) ; 		data->freq_point ++ ; 		output = samples + out_frame_count * data->sf.sfinfo.channels ; 		if ((rc = src_callback_read (data->src_state, src_ratio, VARISPEED_BLOCK_LEN, output)) < VARISPEED_BLOCK_LEN)		{	printf ("\nError : src_callback_read short output (%d instead of %d)\n\n", rc, VARISPEED_BLOCK_LEN) ;			exit (1) ;			} ;		} ; 	return out_frames ;} /* varispeed_get_data */ /*==============================================================================*/ #else /* (HAVE_SNFILE == 0) */ /* Alternative main function when libsndfile is not available. */ intmain (void){	puts (		"\n"		"****************************************************************\n"		" This example program was compiled without libsndfile \n"		" (http://www.zip.com.au/~erikd/libsndfile/).\n"		" It is therefore completely broken and non-functional.\n"		"****************************************************************\n"		"\n"		) ; 	return 0 ;} /* main */ #endif