--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/silence_gen.c	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,112 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * silence_gen.c - A silence generator, for inserting timed silences.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2006 Steve Underwood
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2, as
+ * published by the Free Software Foundation.
+ *
+ * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: silence_gen.c,v 1.6 2006/11/19 14:07:25 steveu Exp $
+ */
+
+/*! \file */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+#include <assert.h>
+#include <limits.h>
+
+#include "spandsp/telephony.h"
+#include "spandsp/logging.h"
+#include "spandsp/silence_gen.h"
+
+int silence_gen(silence_gen_state_t *s, int16_t *amp, int max_len)
+{
+    if (s->remaining_samples != INT_MAX)
+    {
+        if (max_len > s->remaining_samples)
+            max_len = s->remaining_samples;
+        s->remaining_samples -= max_len;
+    }
+    if (INT_MAX - s->total_samples >= max_len)
+        s->total_samples += max_len;
+    memset(amp, 0, max_len*sizeof(int16_t));
+    return max_len;
+}
+/*- End of function --------------------------------------------------------*/
+
+void silence_gen_always(silence_gen_state_t *s)
+{
+    s->remaining_samples = INT_MAX;
+}
+/*- End of function --------------------------------------------------------*/
+
+void silence_gen_set(silence_gen_state_t *s, int silent_samples)
+{
+    s->remaining_samples = silent_samples;
+    s->total_samples = 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+void silence_gen_alter(silence_gen_state_t *s, int silent_samples)
+{
+    /* Block negative silences */
+    if (silent_samples < 0)
+    {
+        if (-silent_samples > s->remaining_samples)
+            silent_samples = -s->remaining_samples;
+    }
+    s->remaining_samples += silent_samples;
+    s->total_samples += silent_samples;
+}
+/*- End of function --------------------------------------------------------*/
+
+int silence_gen_remainder(silence_gen_state_t *s)
+{
+    return s->remaining_samples;
+}
+/*- End of function --------------------------------------------------------*/
+
+int silence_gen_generated(silence_gen_state_t *s)
+{
+    return s->total_samples;
+}
+/*- End of function --------------------------------------------------------*/
+
+silence_gen_state_t *silence_gen_init(silence_gen_state_t *s, int silent_samples)
+{
+    memset(s, 0, sizeof(*s));
+    s->remaining_samples = silent_samples;
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/