testPngNativetZtxt requires zlib extension

[lhc/web/wiklou.git] / includes / StringUtils.php

diff --git a/includes/StringUtils.php b/includes/StringUtils.php
index fba31ea..54a85dc 100644 (file)
--- a/includes/StringUtils.php
+++ b/includes/StringUtils.php
@@ -24,6 +24,51 @@
  * A collection of static methods to play with strings.
  */
 class StringUtils {
+
+       /**
+        * Test whether a string is valid UTF-8.
+        *
+        * The function check for invalid byte sequences, overlong encoding but
+        * not for different normalisations.
+        *
+        * This relies internally on the mbstring function mb_check_encoding()
+        * hardcoded to check against UTF-8. Whenever the function is not available
+        * we fallback to a pure PHP implementation. Setting $disableMbstring to
+        * true will skip the use of mb_check_encoding, this is mostly intended for
+        * unit testing our internal implementation.
+        *
+        * @since 1.21
+        *
+        * @param string $value String to check
+        * @param boolean $disableMbstring Whether to use the pure PHP
+        * implementation instead of trying mb_check_encoding. Intended for unit
+        * testing. Default: false
+        *
+        * @return boolean Whether the given $value is a valid UTF-8 encoded string
+        */
+       static function isUtf8( $value, $disableMbstring = false ) {
+
+               if ( preg_match( '/[\x80-\xff]/', $value ) === 0 ) {
+                       # no high bit set, this is pure ASCII which is defacto
+                       # valid UTF-8
+                       return true;
+               }
+
+               if ( !$disableMbstring && function_exists( 'mb_check_encoding' ) ) {
+                       return mb_check_encoding( $value, 'UTF-8' );
+               } else {
+                       $hasUtf8 = preg_match( '/^(?>
+                                 [\x00-\x7f]
+                               | [\xc0-\xdf][\x80-\xbf]
+                               | [\xe0-\xef][\x80-\xbf]{2}
+                               | [\xf0-\xf7][\x80-\xbf]{3}
+                               | [\xf8-\xfb][\x80-\xbf]{4}
+                               | \xfc[\x84-\xbf][\x80-\xbf]{4}
+                       )+$/x', $value );
+                       return ($hasUtf8 > 0 );
+               }
+       }
+
        /**
         * Perform an operation equivalent to
         *