Fixed issue #07277: log(xx) seems to return an incorrect value

Dev: add optionnal setting to log for base.
LimeSurvey · Feb 7, 2013 · e662664 · e662664
1 parent c8c2284
commit e662664
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Showing 2 changed files with 46 additions and 3 deletions.
diff --git a/application/helpers/expressions/em_core_helper.php b/application/helpers/expressions/em_core_helper.php
@@ -187,7 +187,7 @@ function __construct()
 'is_string' => array('is_string', 'LEMis_string', $this->gT('Find whether the type of a variable is string'), 'bool is_string(var)', 'http://www.php.net/manual/en/function.is-string.php', 1),
 'join' => array('exprmgr_join', 'LEMjoin', $this->gT('Join strings, return joined string.This function is an alias of implode("",argN)'), 'string join(arg1,arg2,...,argN)', '', -1),
 'list' => array('exprmgr_list', 'LEMlist', $this->gT('Return comma-separated list of values'), 'string list(arg1, arg2, ... argN)', '', -2),
-'log' => array('log', 'Math.log', $this->gT('Natural logarithm'), 'number log(number)', 'http://www.php.net/manual/en/function.log.php', 1),
+'log' => array('exprmgr_log', 'LEMlog', $this->gT('Natural logarithm'), 'number log(number,base=e)', 'http://www.php.net/manual/en/function.log.php', -2),
 'ltrim' => array('ltrim', 'ltrim', $this->gT('Strip whitespace (or other characters) from the beginning of a string'), 'string ltrim(string [, charlist])', 'http://www.php.net/manual/en/function.ltrim.php', 1,2),
 'max' => array('max', 'Math.max', $this->gT('Find highest value'), 'number max(arg1, arg2, ... argN)', 'http://www.php.net/manual/en/function.max.php', -2),
 'min' => array('min', 'Math.min', $this->gT('Find lowest value'), 'number min(arg1, arg2, ... argN)', 'http://www.php.net/manual/en/function.min.php', -2),
@@ -2000,7 +2000,7 @@ private function RDP_RunFunction($funcNameToken,$params)
                     if (!$this->RDP_onlyparse) {
                         switch($funcName) {
                             case 'sprintf':
-                                // PHP doesn't let you pass array of parameters to sprintf, so must use call_user_func_array
+                                // PHP doesn't let you pass array of parameters to function, so must use call_user_func_array
                                 $result = call_user_func_array('sprintf',$params);
                                 break;
                             default:
@@ -2026,7 +2026,6 @@ private function RDP_RunFunction($funcNameToken,$params)
                                 case 'cos':
                                 case 'exp':
                                 case 'is_nan':
-                                case 'log':
                                 case 'sin':
                                 case 'sqrt':
                                 case 'tan':
@@ -3385,6 +3384,25 @@ function exprmgr_list($args)
     return $result;
 }
 
+/**
+ * return log($arg[0],$arg[1]=e)
+ * @param <type> $args
+ * @return float
+ */
+function exprmgr_log($args)
+{
+    if (count($args) < 1)
+    {
+        return NAN;
+    }
+    $number=$args[0];
+    if(!is_numeric($number)){return NAN;}
+    $base=(isset($args[1]))?$args[1]:exp(1);
+    if(!is_numeric($base)){return NAN;}
+    if(floatval($base)<=0){return NAN;}
+    return log($number,$base);
+}
+
 /**
  * Join together $args[N]
  * @param <type> $args

diff --git a/scripts/expressions/em_javascript.js b/scripts/expressions/em_javascript.js
@@ -12,6 +12,7 @@
  * Core JavaScript functions needed by ExpressionManager
  * @author Thomas M. White (TMSWhite)
  * @author Denis Chenu (Shnoulle)
+ *
  * Portion from php.js is copyright 2012 Kevin van Zonneveld.
  * php.js is dual licensed under the MIT licenses.
  */
@@ -223,6 +224,30 @@ function LEMlist()
     return result;
 }
 
+/**
+ *  Returns Natural logarithm of a number
+ */
+
+function LEMlog()
+{
+    // takes variable number of arguments
+    if (arguments.length < 1) {
+        return NaN;
+    }
+    var base=Math.exp(1);
+    if(arguments.length>1){
+        base = arguments[1];
+        if (isNaN(base)) { return NaN;}
+        if (base<=0 ) { return NaN;}
+        base=Math.abs(parseFloat(arguments[1]));
+    }
+    if(base==Math.exp(1)){// Not needed
+        return Math.log(arguments[0]);
+    }else{
+        return Math.log(arguments[0])/Math.log(base);
+    }
+}
+
  /**
  * Returns concatenates list
  */