Insert a Chinese charachter string to label resource result error.

For example. Insert a label, Content as [????]: ?????! ??????, ?????????????.

Error report as follow:
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Data too long for column 'name' at row 1

INSERT INTO mdl_label ( COURSE, NAME, CONTENT, TIMEMODIFIED ) VALUES ( 1, '[????]: ?????! ??????..', '[????]: ?????! ??????, ?????????????. ', 1159673300 )

Could not add a new instance of label
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This bug is in /moodle/mod/label/lib.php line 16:

$label->name = substr($label->name, 0, LABEL_MAX_NAME_LENGTH)."...";

Suggest correct source as follow:

mb_internal_encoding("UTF-8");
$label->name = mb_substr($label->name, 0, LABEL_MAX_NAME_LENGTH)."...";