--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/smarty/plugins/function.math.php	Sun Mar 23 14:59:33 2008 -0400
@@ -0,0 +1,84 @@
+<?php
+/**
+ * Smarty plugin
+ * @package Smarty
+ * @subpackage plugins
+ */
+
+
+/**
+ * Smarty {math} function plugin
+ *
+ * Type:     function<br>
+ * Name:     math<br>
+ * Purpose:  handle math computations in template<br>
+ * @link http://smarty.php.net/manual/en/language.function.math.php {math}
+ *          (Smarty online manual)
+ * @author   Monte Ohrt <monte at ohrt dot com>
+ * @param array
+ * @param Smarty
+ * @return string
+ */
+function smarty_function_math($params, &$smarty)
+{
+    // be sure equation parameter is present
+    if (empty($params['equation'])) {
+        $smarty->trigger_error("math: missing equation parameter");
+        return;
+    }
+
+    $equation = $params['equation'];
+
+    // make sure parenthesis are balanced
+    if (substr_count($equation,"(") != substr_count($equation,")")) {
+        $smarty->trigger_error("math: unbalanced parenthesis");
+        return;
+    }
+
+    // match all vars in equation, make sure all are passed
+    preg_match_all("!(?:0x[a-fA-F0-9]+)|([a-zA-Z][a-zA-Z0-9_]+)!",$equation, $match);
+    $allowed_funcs = array('int','abs','ceil','cos','exp','floor','log','log10',
+                           'max','min','pi','pow','rand','round','sin','sqrt','srand','tan');
+    
+    foreach($match[1] as $curr_var) {
+        if ($curr_var && !in_array($curr_var, array_keys($params)) && !in_array($curr_var, $allowed_funcs)) {
+            $smarty->trigger_error("math: function call $curr_var not allowed");
+            return;
+        }
+    }
+
+    foreach($params as $key => $val) {
+        if ($key != "equation" && $key != "format" && $key != "assign") {
+            // make sure value is not empty
+            if (strlen($val)==0) {
+                $smarty->trigger_error("math: parameter $key is empty");
+                return;
+            }
+            if (!is_numeric($val)) {
+                $smarty->trigger_error("math: parameter $key: is not numeric");
+                return;
+            }
+            $equation = preg_replace("/\b$key\b/", " \$params['$key'] ", $equation);
+        }
+    }
+
+    eval("\$smarty_math_result = ".$equation.";");
+
+    if (empty($params['format'])) {
+        if (empty($params['assign'])) {
+            return $smarty_math_result;
+        } else {
+            $smarty->assign($params['assign'],$smarty_math_result);
+        }
+    } else {
+        if (empty($params['assign'])){
+            printf($params['format'],$smarty_math_result);
+        } else {
+            $smarty->assign($params['assign'],sprintf($params['format'],$smarty_math_result));
+        }
+    }
+}
+
+/* vim: set expandtab: */
+
+?>