--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/spandsp/super_tone_tx.h	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,94 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * super_tone_tx.h - Flexible telephony supervisory tone generation.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2001 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: super_tone_tx.h,v 1.8 2006/10/24 13:45:28 steveu Exp $
+ */
+
+#if !defined(_SUPER_TONE_TX_H_)
+#define _SUPER_TONE_TX_H_
+
+/*! \page super_tone_tx_page Supervisory tone generation
+
+\section super_tone_tx_page_sec_1 What does it do?
+
+The supervisory tone generator may be configured to generate most of the world's
+telephone supervisory tones - things like ringback, busy, number unobtainable,
+and so on. It uses tree structure tone descriptions, which can deal with quite
+complex cadence patterns. 
+
+\section super_tone_tx_page_sec_2 How does it work?
+
+*/
+
+typedef struct super_tone_tx_step_s super_tone_tx_step_t;
+
+typedef struct
+{
+    int32_t phase_rate[2];
+    float gain[2];
+    uint32_t phase[2];
+    int current_position;
+    int level;
+    super_tone_tx_step_t *levels[4];
+    int cycles[4];
+} super_tone_tx_state_t;
+
+struct super_tone_tx_step_s
+{
+    int32_t phase_rate[2];
+    float gain[2];
+    int tone;
+    int length;
+    int cycles;
+    super_tone_tx_step_t *next;
+    super_tone_tx_step_t *nest;
+};
+
+super_tone_tx_step_t *super_tone_tx_make_step(super_tone_tx_step_t *s,
+                                              float f1,
+                                              float l1,
+                                              float f2,
+                                              float l2,
+                                              int length,
+                                              int cycles);
+
+void super_tone_tx_free(super_tone_tx_step_t *s);
+
+/*! Initialise a supervisory tone generator.
+    \brief Initialise a supervisory tone generator.
+    \param s The supervisory tone generator context.
+    \param tree The supervisory tone tree to be generated.
+    \return The supervisory tone generator context. */
+super_tone_tx_state_t *super_tone_tx_init(super_tone_tx_state_t *s, super_tone_tx_step_t *tree);
+
+/*! Generate a block of audio samples for a supervisory tone pattern.
+    \brief Generate a block of audio samples for a supervisory tone pattern.
+    \param tone The supervisory tone context.
+    \param amp The audio sample buffer.
+    \param max_samples The maximum number of samples to be generated.
+    \return The number of samples generated. */
+int super_tone_tx(super_tone_tx_state_t *s, int16_t amp[], int max_samples);
+
+#endif
+/*- End of file ------------------------------------------------------------*/