Implemented plugin architecture.

libs/plugins/function.math.php

@@ -0,0 +1,73 @@
+<?php
+
+/*
+ * Smarty plugin
+ * -------------------------------------------------------------
+ * Type:     function
+ * Name:     math
+ * Purpose:  handle math computations in template
+ * -------------------------------------------------------------
+ */
+function smarty_function_math($args, &$smarty_obj)
+{
+    // be sure equation parameter is present
+    if (empty($args["equation"])) {
+        $smarty_obj->_trigger_error_msg("math: missing equation parameter");
+        return;
+    }
+
+    $equation = $args["equation"];
+
+    // make sure parenthesis are balanced
+    if (substr_count($equation,"(") != substr_count($equation,")")) {
+        $smarty_obj->_trigger_error_msg("math: unbalanced parenthesis");
+        return;
+    }
+
+    // match all vars in equation, make sure all are passed
+    preg_match_all("![a-zA-Z][a-zA-Z0-9]*!",$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[0] as $curr_var) {
+        if (!in_array($curr_var,array_keys($args)) && !in_array($curr_var, $allowed_funcs)) {
+            $smarty_obj->_trigger_error_msg("math: parameter $curr_var not passed as argument");
+            return;
+        }
+    }
+
+    foreach($args as $key => $val) {
+        if ($key != "equation" && $key != "format" && $key != "assign") {
+            // make sure value is not empty
+            if (strlen($val)==0) {
+                $smarty_obj->_trigger_error_msg("math: parameter $key is empty");
+                return;
+            }
+            if (!is_numeric($val)) {
+                $smarty_obj->_trigger_error_msg("math: parameter $key: is not numeric");
+                return;
+            }
+            $equation = preg_replace("/\b$key\b/",$val, $equation);
+        }
+    }
+
+    eval("\$smarty_math_result = ".$equation.";");
+
+    if (empty($args["format"])) {
+        if (empty($args["assign"])) {
+            echo $smarty_math_result;
+        } else {
+            $smarty_obj->assign($args["assign"],$smarty_math_result);
+        }
+    } else {
+        if (empty($args["assign"])){
+            printf($args["format"],$smarty_math_result);
+        } else {
+            $smarty_obj->assign($assign,sprintf($args["format"],$smarty_math_result));
+        }
+    }
+}
+
+/* vim: set expandtab: */
+
+?>