[PHP] Use mb_detect_encoding when available (#3952)
I've faced an issue where I want to serialize UTF-8 emojis and FlatBufferBuilder::is_utf8 would return false on them.
I was not able to add the corresponding hexadecimal code because I don't understand how the whole thing works but what i've done is using the `mb_detect_encoding` function which handles correctly all supposed UTF-8 characters.
diff --git a/php/FlatbufferBuilder.php b/php/FlatbufferBuilder.php
index 6f0ee48..5c18bf4 100644
--- a/php/FlatbufferBuilder.php
+++ b/php/FlatbufferBuilder.php
@@ -593,6 +593,10 @@
protected function is_utf8($bytes)
{
+ if (function_exists('mb_detect_encoding')) {
+ return (bool) mb_detect_encoding($bytes, 'UTF-8', true);
+ }
+
$len = strlen($bytes);
if ($len < 1) {
/* NOTE: always return 1 when passed string is null */
