Ringback (sponsored by Front Logic)

This addition lets you set artifical ringback on a channel
that is waiting for an originated call to be answered.

the syntax is 

<action application="set" data="ringback=[data]"/>

where data is either the full path to an audio file
or a teletone generation script..


syntax of teletone scripts

LEGEND:

0-9,a-d,*,# (standard dtmf tones)

variables: c,r,d,v,>,<,+,w,l,L,%

c (channels)        - Sets the number of channels.
r (rate)            - Sets the sample rate.
d (duration)        - Sets the default tone duration.
v (volume)          - Sets the default volume.
> (decrease vol)    - factor to decrease volume by per frame (0 for even decrease across duration).
< (increase vol)    - factor to increase volume by per frame (0 for even increase across duration).
+ (step)            - factor to step by used by < and >.
w (wait)            - default silence after each tone.
l (loops)           - number of times to repeat each tone in the script.
L (LOOPS)           - number of times to repeat the the whole script.
% (manual tone)     - a generic tone specified by a duration, a wait and a list of frequencies.

standard tones can have custom duration per use with the () modifier
7(1000, 500) to generate DTMF 7 for 1 second then pause .5 seconds

EXAMPLES

UK Ring Tone [400+450 hz on for 400ms off for 200ms then 400+450 hz on for 400ms off for 2200ms]
%(400,200,400,450);%(400,2200,400,450)

US Ring Tone [440+480 hz on for 2000ms off for 4000ms]
%(2000,4000,440,480)

ATT BONG [volume level 4000, even decay, step by 2, # key for 60ms with no wait, volume level 2000, 350+440hz {us dialtone} for 940ms
v=4000;>=0;+=2;#(60,0);v=2000;%(940,0,350,440)

SIT Tone 913.8 hz for 274 ms with no wait, 1370.6 hz for 274 ms with no wait, 1776.7 hz for 380ms with no wait
%(274,0,913.8);%(274,0,1370.6);%(380,0,1776.7)

ATTN TONE (phone's off the hook!) 1400+2060+2450+2600 hz for 100ms with 100ms wait
%(100,100,1400,2060,2450,2600)



git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@3408 d0543943-73ff-0310-b7d9-9358b9ac24b2

libs/libteletone/src/libteletone_generate.c

@@ -84,11 +84,14 @@ int teletone_init_session(teletone_generation_session_t *ts, int buflen, tone_ha
 	ts->user_data = user_data;
 	ts->volume = 1500;
 	ts->decay_step = 0;
-	if ((ts->buffer = calloc(buflen, sizeof(teletone_audio_t))) == 0) {
-		return -1;
+	if (buflen) {
+		if ((ts->buffer = calloc(buflen, sizeof(teletone_audio_t))) == 0) {
+			return -1;
+		}
+		ts->datalen = buflen;
+	} else {
+		ts->dynamic = 1024;
 	}
-	ts->datalen = buflen;
-
 	/* Add Standard DTMF Tones */
 	teletone_set_tone(ts, '1', 697.0, 1209.0, 0.0);
 	teletone_set_tone(ts, '2', 697.0, 1336.0, 0.0);
@@ -120,8 +123,21 @@ int teletone_destroy_session(teletone_generation_session_t *ts)
 	return 0;
 }
 
-/** Generate a specified number of samples containing the three specified
- *  frequencies (in hertz) and dump to the file descriptor audio_fd. */
+static int ensure_buffer(teletone_generation_session_t *ts, int need)
+{
+	need += ts->samples;
+	need *= sizeof(teletone_audio_t);
+	need *= ts->channels;
+
+	if (need > ts->datalen) {
+		ts->datalen = need + ts->dynamic;
+		if (!(ts->buffer = realloc(ts->buffer, ts->datalen))) {
+			return -1;
+		}
+	}
+
+	return 0;
+}
 
 int teletone_mux_tones(teletone_generation_session_t *ts, teletone_tone_map_t *map)
 {
@@ -159,6 +175,11 @@ int teletone_mux_tones(teletone_generation_session_t *ts, teletone_tone_map_t *m
 			duration *= ts->channels;
 		}
 
+		if (ts->dynamic) {
+			if (ensure_buffer(ts, duration)) {
+				return -1;
+			}
+		}
 		for (ts->samples = 0; ts->samples < ts->datalen && ts->samples < duration; ts->samples++) {
 			if (ts->decay_step && !(ts->samples % ts->decay_step) && ts->volume > 0 && ts->samples > decay) {
 				ts->volume += ts->decay_direction;
@@ -179,6 +200,11 @@ int teletone_mux_tones(teletone_generation_session_t *ts, teletone_tone_map_t *m
 			
 		}
 	}
+	if (ts->dynamic) {
+		if (ensure_buffer(ts, wait)) {
+			return -1;
+		}
+	}
 	for (c = 0; c < ts->channels; c++) {
 		for (i = 0; i < wait && ts->samples < ts->datalen; i++) {
 			ts->buffer[ts->samples++] = 0;
@@ -211,19 +237,37 @@ int teletone_mux_tones(teletone_generation_session_t *ts, teletone_tone_map_t *m
 	return ts->samples;
 }
 
+/* don't ask */
+static char *my_strdup (const char *s)
+{
+	size_t len = strlen (s) + 1;
+	void *new = malloc (len);
+	
+	if (new == NULL) {
+		return NULL;
+	}
+
+	return (char *) memcpy (new, s, len);
+}
 
 int teletone_run(teletone_generation_session_t *ts, char *cmd)
 {
-	char *data, *cur, *end;
+	char *data = NULL, *cur = NULL, *end = NULL;
 	int var = 0, LOOPING = 0;
+	
+	if (!cmd) {
+		return -1;
+	}
 
 	do {
-		data = strdup(cmd);
+		if (!(data = my_strdup(cmd))) {
+			return -1;
+		}
+
 		cur = data;
-		
+
 		while (*cur) {
 			var = 0;
-
 			if (*cur == ' ' || *cur == '\r' || *cur == '\n') {
 				cur++;
 				continue;