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

src/switch_channel.c

@@ -344,7 +344,7 @@ SWITCH_DECLARE(void) switch_channel_presence(switch_channel_t *channel, char *rp
 
 SWITCH_DECLARE(char *) switch_channel_get_variable(switch_channel_t *channel, char *varname)
 {
-	char *v;
+	char *v = NULL;
 	assert(channel != NULL);
 
 	if (!(v=switch_core_hash_find(channel->variables, varname))) {
@@ -352,6 +352,7 @@ SWITCH_DECLARE(char *) switch_channel_get_variable(switch_channel_t *channel, ch
 			if (!strcmp(varname, "base_dir")) {
 				return SWITCH_GLOBAL_dirs.base_dir;
 			}
+			v = switch_core_get_variable(varname);
 		}
 	}
 	
@@ -1113,7 +1114,7 @@ SWITCH_DECLARE(char *) switch_channel_expand_variables(switch_channel_t *channel
 {
 	char *p, *c;
 	char *data, *indup;
-	size_t sp = 0, len = 0, olen = 0, vtype = 0, br = 0, vnamepos, vvalpos, cpos, ppos, block = 128;
+	size_t sp = 0, len = 0, olen = 0, vtype = 0, br = 0, cpos, block = 128;
 	char *sub_val = NULL, *func_val = NULL;
 
 	if (!strchr(in, '$') && !strchr(in, '&')) {
@@ -1195,36 +1196,35 @@ SWITCH_DECLARE(char *) switch_channel_expand_variables(switch_channel_t *channel
 						return in;
 					}
 				}
-				nlen = strlen(sub_val);
+				nlen = sub_val ? strlen(sub_val) : 0;
+
 				if (len + nlen >= olen) {
-					olen += block;
+					olen = (olen + len + nlen + block);
 					cpos = c - data;
-					ppos = p - data;
-					vnamepos = vname - data;
-					vvalpos = vval - data;
 					data = realloc(data, olen);
-
 					c = data + cpos;
-					p = data + ppos;
-					vname = data + vnamepos;
-					vname = data + vvalpos;
+					memset(c, 0, olen - cpos);
 				}
-
-				len += nlen;
-				strcat(c, sub_val);
-				c += nlen;
-
-				if (func_val) {
-					free(func_val);
-					func_val = NULL;
+				if (nlen) {
+					len += nlen;
+					strcat(c, sub_val);
+					c += nlen;
 				}
+				
+				switch_safe_free(func_val);
 			}
 			if (sp) {
 				*c++ = ' ';
 				sp = 0;
+				len++;
 			}
-			*c++ = *p;
-			len++;
+
+			if (*p == '$' || *p == '&') {
+				p--;
+			} else {
+				*c++ = *p;
+				len++;
+			} 
 		}
 	}
 	free(indup);