From aa87fe80b3fbe9ed266a1e9ed47bb3dea430d297 Mon Sep 17 00:00:00 2001
From: Frederic Massart <fred@moodle.com>
Date: Fri, 16 Aug 2013 10:21:01 +0800
Subject: [PATCH] MDL-40877 core_text: Added UTF-8 safe strrchr method

---
 lib/classes/text.php    | 32 +++++++++++++++++++++++++++++++-
 lib/tests/text_test.php | 11 +++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/lib/classes/text.php b/lib/classes/text.php
index 1ca51f8608b..9ce3ea4e8c9 100644
--- a/lib/classes/text.php
+++ b/lib/classes/text.php
@@ -238,6 +238,36 @@ class core_text {
         return $result;
     }
 
+    /**
+     * Finds the last occurrence of a character in a string within another.
+     * UTF-8 ONLY safe mb_strrchr().
+     *
+     * @param string $haystack The string from which to get the last occurrence of needle.
+     * @param string $needle The string to find in haystack.
+     * @param boolean $part If true, returns the portion before needle, else return the portion after (including needle).
+     * @return string|false False when not found.
+     * @since 2.4.6, 2.5.2, 2.6
+     */
+    public static function strrchr($haystack, $needle, $part = false) {
+
+        if (function_exists('mb_strrchr')) {
+            return mb_strrchr($haystack, $needle, $part, 'UTF-8');
+        }
+
+        $pos = self::strrpos($haystack, $needle);
+        if ($pos === false) {
+            return false;
+        }
+
+        $length = null;
+        if ($part) {
+            $length = $pos;
+            $pos = 0;
+        }
+
+        return self::substr($haystack, $pos, $length, 'utf-8');
+    }
+
     /**
      * Multibyte safe strlen() function, uses mbstring or iconv for UTF-8, falls back to typo3.
      *
@@ -331,7 +361,7 @@ class core_text {
      * @return int the numeric position of the last occurrence of needle in haystack
      */
     public static function strrpos($haystack, $needle) {
-        if (function_exists('mb_strpos')) {
+        if (function_exists('mb_strrpos')) {
             return mb_strrpos($haystack, $needle, null, 'UTF-8');
         } else {
             return iconv_strrpos($haystack, $needle, 'UTF-8');
diff --git a/lib/tests/text_test.php b/lib/tests/text_test.php
index 1aa16f30c43..fb33750405b 100644
--- a/lib/tests/text_test.php
+++ b/lib/tests/text_test.php
@@ -360,5 +360,16 @@ class core_text_testcase extends advanced_testcase {
         $this->assertSame($textlib->specialtoascii('ábc'), 'abc');
         $this->assertSame($textlib->strtotitle('abc ABC'), 'Abc Abc');
     }
+
+    /**
+     * Test strrchr.
+     */
+    public function test_strrchr() {
+        $str = "Žluťoučký koníček";
+        $this->assertSame('koníček', core_text::strrchr($str, 'koní'));
+        $this->assertSame('Žluťoučký ', core_text::strrchr($str, 'koní', true));
+        $this->assertFalse(core_text::strrchr($str, 'A'));
+        $this->assertFalse(core_text::strrchr($str, 'ç', true));
+    }
 }