asterisk/doc/README.math

Mathematical dialplan function

Yeah, I thought it was a little insane too.. 

adds:

Sum, Multiply, Divide, Subtract, Modulus, GT, LT, GTE, LTE, EQ functions to Asterisk

All functions follow the same basic pattern for parameters:

parameter 1 = the math expression
parameter 2 = the type of result

Perform calculation on number 1 to number 2. Valid ops are:
    +,-,/,*,%,<,>,>=,<=,==
and behave as their C equivalents.

<type_of_result> - wanted type of result:
	f, float - float(default)
	i, int - integer,
	h, hex - hex,
	c, char - char

Each math expression is performed as

 Action param1 on param2

eg: 

 Action = Divide
 Param1 = 10
 Param2 = 2

Results in 

 Divide 10 by 2


Example dialplan:

exten => 11099,1,Set(RV=${MATH(1+20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(10*2)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(10*2)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(10-2)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(2%10)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(10/0)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(10-200)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(1-20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(1<20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(1>=20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(101>20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(1==20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(20<=20)})
exten => 11099,n,NOOP(${RV})
exten => 11099,n,Set(RV=${MATH(123%16,int)})
exten => 11099,n,NOOP(${RV})