--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/spandsp/silence_gen.h	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,100 @@
+/*
+ * 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.h,v 1.4 2006/10/24 13:45:28 steveu Exp $
+ */
+
+#if !defined(_SILENCE_GEN_H_)
+#define _SILENCE_GEN_H_
+
+typedef struct
+{
+    int remaining_samples;
+    int total_samples;
+} silence_gen_state_t;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*! Generate a block of silent audio samples.
+    \brief Generate a block of silent audio samples.
+    \param s The silence generator context.
+    \param amp The audio sample buffer.
+    \param max_len The number of samples to be generated.
+    \return The number of samples actually generated. This will be zero when
+            there is nothing to send.
+*/
+int silence_gen(silence_gen_state_t *s, int16_t *amp, int max_len);
+
+/*! Set a silence generator context to output continuous silence.
+    \brief Set a silence generator context to output continuous silence.
+    \param s The silence generator context.
+*/
+void silence_gen_always(silence_gen_state_t *s);
+
+/*! Set a silence generator context to output a specified period of silence.
+    \brief Set a silence generator context to output a specified period of silence.
+    \param s The silence generator context.
+    \param silent_samples The number of samples to be generated.
+*/
+void silence_gen_set(silence_gen_state_t *s, int silent_samples);
+
+/*! Alter the period of a silence generator context by a specified amount.
+    \brief Alter the period of a silence generator context by a specified amount.
+    \param s The silence generator context.
+    \param silent_samples The number of samples to change the setting by. A positive number
+                          increases the duration. A negative number reduces it. The duration
+                          is prevented from going negative.
+*/
+void silence_gen_alter(silence_gen_state_t *s, int silent_samples);
+
+/*! Find how long a silence generator context has to run.
+    \brief Find how long a silence generator context has to run.
+    \param s The silence generator context.
+    \return The number of samples remaining.
+*/
+int silence_gen_remainder(silence_gen_state_t *s);
+
+/*! Find the total silence generated to date by a silence generator context.
+    \brief Find the total silence generated to date.
+    \param s The silence generator context.
+    \return The number of samples generated.
+*/
+int silence_gen_generated(silence_gen_state_t *s);
+
+/*! Initialise a timed silence generator context.
+    \brief Initialise a timed silence generator context.
+    \param s The silence generator context.
+    \param the initial number of samples to set the silence to.
+    \return A pointer to the silence generator context.
+*/
+silence_gen_state_t *silence_gen_init(silence_gen_state_t *s, int silent_samples);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/