mathops Module

The following modules must be loaded before this module:

The following libraries or applications must be installed before running OpenSIPS with this module loaded:

The precision of the results returned by all the module functions. The higher the “decimal_digits” value, the more decimal digits the results will have.

Default value is “6”.

modparam("mathops", "decimal_digits", 10)

The function evaluates a given expression and writes the result in the output pseudo-variable. Evaluation uses tinyexpr (see https://github.com/codeplea/tinyexpr).

Currently allowed syntax for specifying an expression:

Meaning of the parameters is as follows:

This function can be used from any route.

...
# Compute some random math expression

$avp(1) = "3.141592";
$avp(2) = "2.71828";
$avp(3) = "123.45678";

if (math_eval("$avp(1) * ($avp(3) - ($avp(1) - $avp(2))) / $avp(3)", $avp(result))) {
	xlog("Result of expression: $avp(result)\n");
} else {
	xlog("Math eval failed!\n");
}

...

The function evaluates a given RPN expression and writes the result in the output variable.

The expression is specified in Reverse Polish Notation. Values are pushed onto a stack, while operations are executed on that stack. The following operations are supported:

Meaning of the parameters is as follows:

This function can be used from any route.

$avp(1) = "3";

if (math_rpn("1 $avp(1) swap swap dup drop / exp ln 1 swap /", $avp(result))) {
	xlog("Result of expression: $avp(result)\n");
} else {
	xlog("RPN eval failed!\n");
}

/* This example RPN script will push 1 then 3 onto the stack, then do a couple no-ops
(exchange the two values twice, duplicate one of them then drop the duplicate),
compute the division of 1 by 3, then do another no-op (exponentiation then logarithm), and
finally compute 1 divided by the result, giving 3 as the result. */

Truncation of a number towards zero. This means that trunc(3.7) = 3.0 and trunc(-2.9) = -2.0.

Meaning of the parameters is as follows:

This function can be used from any route.

...
# Truncate a random number

$avp(1) = "3.141492";

if (math_trunc($avp(1), $avp(result))) {
	xlog("Truncate result: $avp(result)\n");
} else {
	xlog("Truncate failed!\n");
}
...

Truncates a number, always towards -infinity. This means that floor(3.7) = 3.0 and floor(-2.9) = -3.0

Meaning of the parameters is as follows:

This function can be used from any route.

...
# Truncate a random number

$avp(1) = "3.141492";

if (math_floor($avp(1), $avp(result))) {
	xlog("Floor result: $avp(result)\n");
} else {
	xlog("Floor operation failed!\n");
}
...

Truncates a number, always towards +infinity. This means that ceil(3.2) = 4.0 and ceil(-2.9) = -2.0

Meaning of the parameters is as follows:

This function can be used from any route.

...
# Truncate a random number

$avp(1) = "3.141492";

if (math_ceil($avp(1), $avp(result))) {
	xlog("Ceil result: $avp(result)\n");
} else {
	xlog("Ceil operation failed!\n");
}
...

The round function returns the nearest integer, and tie-breaking is done away from zero. Examples: round(1.2) = 1.0, round(0.5) = 1.0, round(-0.5) = -1.0

By default, the function returns an integer. An additional parameter controls the number of decimal digits of the initial number which will be kept. The rounding will then be done using the remaining decimal digits, and the result will be a float value, represented as a string.

Meaning of the parameters is as follows:

This function can be used from any route.

...
# Rounding PI

$avp(1) = "3.141492";

if (math_round($avp(1), $avp(result))) {

	# result should be: 3
	xlog("Round result: $avp(result)\n");
} else {
	xlog("Round operation failed!\n");
}

...

if (math_round($avp(1), $avp(result), 4)) {

	# result should be: "3.1415"
	xlog("Round result: $avp(result)\n");
} else {
	xlog("Round operation failed!\n");
}
...

To give a simple explanation, rounding to N significant figures is done by first obtaining the number resulted from keeping N significant figures (0 padded if necessary), then adjusting it if the N+1'th digit is greater or equal to 5.

Some examples:

Meaning of the parameters is as follows:

This function can be used from any route.

...
# Rounding PI

$avp(1) = "3.141492";

if (math_round_sf($avp(1), $avp(result), 4)) {

	# result should be: "3.141"
	xlog("Round result: $avp(result)\n");
} else {
	xlog("Round operation failed!\n");
}

...