--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/tone_generate.c	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,193 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * tone_generate.c - General telephony tone generation, and specific
+ *                   generation of Bell MF, MFC/R2, and network supervisory tones.
+ *
+ * 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: tone_generate.c,v 1.31 2006/11/28 16:59:56 steveu Exp $
+ */
+
+/*! \file */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <inttypes.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <fcntl.h>
+#if defined(HAVE_TGMATH_H)
+#include <tgmath.h>
+#endif
+#if defined(HAVE_MATH_H)
+#include <math.h>
+#endif
+
+#include "spandsp/telephony.h"
+#include "spandsp/dc_restore.h"
+#include "spandsp/dds.h"
+#include "spandsp/tone_generate.h"
+
+#if !defined(M_PI)
+/* C99 systems may not define M_PI */
+#define M_PI 3.14159265358979323846264338327
+#endif
+
+#define ms_to_samples(t)            (((t)*SAMPLE_RATE)/1000)
+
+void make_tone_gen_descriptor(tone_gen_descriptor_t *s,
+                              int f1,
+                              int l1,
+                              int f2,
+                              int l2,
+                              int d1,
+                              int d2,
+                              int d3,
+                              int d4,
+                              int repeat)
+{
+    memset(s, 0, sizeof(*s));
+    if (f1 >= 1)
+    {
+        s->phase_rate[0] = dds_phase_ratef((float) f1);
+        s->gain[0] = dds_scaling_dbm0f((float) l1);
+    }
+    s->modulate = (f2 < 0);
+    if (f2)
+    {
+        s->phase_rate[1] = dds_phase_ratef((float) abs(f2));
+        s->gain[1] = (s->modulate)  ?  (float) l2/100.0f  :  dds_scaling_dbm0f((float) l2);
+    }
+
+    s->duration[0] = d1*8;
+    s->duration[1] = d2*8;
+    s->duration[2] = d3*8;
+    s->duration[3] = d4*8;
+
+    s->repeat = repeat;
+}
+/*- End of function --------------------------------------------------------*/
+
+void make_tone_descriptor(tone_gen_descriptor_t *desc, cadenced_tone_t *tone)
+{
+    make_tone_gen_descriptor(desc,
+                             tone->f1,
+                             tone->level1,
+                             tone->f2,
+                             tone->level2,
+                             tone->on_time1,
+                             tone->off_time1,
+                             tone->on_time2,
+                             tone->off_time2,
+                             tone->repeat);
+}
+/*- End of function --------------------------------------------------------*/
+
+void tone_gen_init(tone_gen_state_t *s, tone_gen_descriptor_t *t)
+{
+    int i;
+
+    s->phase_rate[0] = t->phase_rate[0];
+    s->gain[0] = t->gain[0];
+    s->phase_rate[1] = t->phase_rate[1];
+    s->gain[1] = t->gain[1];
+    s->modulate = t->modulate;
+
+    for (i = 0;  i < 4;  i++)
+        s->duration[i] = t->duration[i];
+    s->repeat = t->repeat;
+
+    s->phase[0] = 0;
+    s->phase[1] = 0;
+
+    s->current_section = 0;
+    s->current_position = 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+int tone_gen(tone_gen_state_t *s, int16_t amp[], int max_samples)
+{
+    int samples;
+    int limit;
+    float xamp;
+    float yamp;
+
+    if (s->current_section < 0)
+        return  0;
+
+    for (samples = 0;  samples < max_samples;  )
+    {
+        limit = samples + s->duration[s->current_section] - s->current_position;
+        if (limit > max_samples)
+            limit = max_samples;
+        
+        s->current_position += (limit - samples);
+        if (s->current_section & 1)
+        {
+            /* A silent section */
+            for (  ;  samples < limit;  samples++)
+                amp[samples] = 0;
+        }
+        else
+        {
+            for (  ;  samples < limit;  samples++)
+            {
+                xamp = 0.0;
+                if (s->phase_rate[0])
+                    xamp = dds_modf(&(s->phase[0]), s->phase_rate[0], s->gain[0], 0);
+                if (s->phase_rate[1])
+                {
+                    yamp = dds_modf(&(s->phase[1]), s->phase_rate[1], s->gain[1], 0);
+                    if (s->modulate)
+                        xamp *= (1.0f + yamp);
+                    else
+                        xamp += yamp;
+                }
+                /* Saturation of the answer is the right thing at this point.
+                   However, we are normally generating well controlled tones,
+                   that cannot clip. So, the overhead of doing saturation is
+                   a waste of valuable time. */
+                amp[samples] = (int16_t) lrintf(xamp);
+            }
+        }
+        if (s->current_position >= s->duration[s->current_section])
+        {
+            s->current_position = 0;
+            if (++s->current_section > 3  ||  s->duration[s->current_section] == 0)
+            {
+                if (!s->repeat)
+                {
+                    /* Force a quick exit */
+                    s->current_section = -1;
+                    break;
+                }
+                s->current_section = 0;
+            }
+        }
+    }
+    return samples;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/