comparison src/libsndfile-1.0.27/tests/generate.c @ 40:1df64224f5ac

Current libsndfile source

+/*
+** Copyright (C) 2007-2012 Erik de Castro Lopo <[e-mail]>
+**
+** This program is free software; you can redistribute it and/or modify
+** it under the terms of the GNU General Public License as published by
+** the Free Software Foundation; either version 2 of the License, or
+** (at your option) any later version.
+**
+** This program is distributed in the hope that it will be useful,
+** but WITHOUT ANY WARRANTY; without even the implied warranty of
+** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+** GNU General Public License for more details.
+**
+** You should have received a copy of the GNU General Public License
+** along with this program; if not, write to the Free Software
+** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include <sndfile.h>
+
+#include "utils.h"
+#include "generate.h"
+
+#define	SF_MAX(x, y)		((x) > (y) ? (x) : (y))
+
+static float crappy_snare (float *output, int len, int offset, float gain, float maxabs) ;
+
+void
+generate_file (const char * filename, int format, int len)
+{	float * output ;
+	float maxabs = 0.0 ;
+
+	output = calloc (len, sizeof (float)) ;
+
+	maxabs = crappy_snare (output, len, 0, 0.95, maxabs) ;
+	maxabs = crappy_snare (output, len, len / 4, 0.85, maxabs) ;
+	maxabs = crappy_snare (output, len, 2 * len / 4, 0.85, maxabs) ;
+	crappy_snare (output, len, 3 * len / 4, 0.85, maxabs) ;
+
+	write_mono_file (filename, format, 44100, output, len) ;
+
+	free (output) ;
+} /* generate_file */
+
+static inline float
+rand_float (void)
+{	return rand () / (0.5 * RAND_MAX) - 1.0 ;
+} /* rand_float */
+
+static float
+crappy_snare (float *output, int len, int offset, float gain, float maxabs)
+{	int k ;
+	float env = 0.0 ;
+
+	for (k = offset ; k < len && env < gain ; k++)
+	{	env += 0.03 ;
+		output [k] += env * rand_float () ;
+		maxabs = SF_MAX (maxabs, fabs (output [k])) ;
+		} ;
+
+	for ( ; k < len && env > 1e-8 ; k++)
+	{	env *= 0.995 ;
+		output [k] += env * rand_float () ;
+		maxabs = SF_MAX (maxabs, fabs (output [k])) ;
+		} ;
+
+	return maxabs ;
+} /* crappy_snare */