NOBUG: Added a new function handling with the grades precission

We should provide a common approach to float grade values so modules
will be consistent in grading algorithm. That is why I push it here.
Note that basically this complements grade_floats_different().
Used in Workshop 2.0.

diff --git a/lib/gradelib.php b/lib/gradelib.php
index 1d67131772e0c5178e87ed4fe7645068644fe9a4..75a7439d6dfc06dbe97d34677d16a266a7a02645 100644 (file)
--- a/lib/gradelib.php
+++ b/lib/gradelib.php
@@ -1285,7 +1285,7 @@ function grade_course_reset($courseid) {
 }
 
 /**
- * Convert number to 5 decimalfloat, empty tring or null db compatible format
+ * Convert number to 5 decimalfloat, empty string or null db compatible format
  * (we need this to decide if db value changed)
  *
  * @param mixed $number
@@ -1313,4 +1313,17 @@ function grade_floats_different($f1, $f2) {
     return (grade_floatval($f1) !== grade_floatval($f2));
 }
 
-?>
+/**
+ * Compare two float numbers safely. Uses 5 decimals php precision.
+ *
+ * Do not use rounding for 10,5 at the database level as the results may be
+ * different from php round() function.
+ *
+ * @since 2.0
+ * @param float $f1
+ * @param float $f2
+ * @return bool true if the values should be considered as the same grades
+ */
+function grade_floats_equal($f1, $f2) {
+    return (grade_floatval($f1) === grade_floatval($f2));
+}