(PHP 5 >= 5.5.0, PHP 7, PHP 8, PECL >= 3.0.0a1)
UConverter::transcode — Convert a string from one character encoding to another
$str,$toEncoding,$fromEncoding,$options = null
Converts str from fromEncoding to toEncoding.
strThe string to be converted.
toEncodingThe desired encoding of the result.
fromEncoding
The current encoding used to interpret str.
optionsAn optional array, which may contain the following keys:
'to_subst' - the substitution character to use
in place of any character of str which cannot
be encoded in toEncoding. If specified, it must
represent a single character in the target encoding.
Returns the converted string or false on failure.
Example #1 Converting from UTF-8 to UTF-16 and back
<?php
$utf8_string = "\x5A\x6F\xC3\xAB"; // 'Zoë' in UTF-8
$utf16_string = UConverter::transcode($utf8_string, 'UTF-16BE', 'UTF-8');
echo bin2hex($utf16_string), "\n";
$new_utf8_string = UConverter::transcode($utf16_string, 'UTF-8', 'UTF-16BE');
echo bin2hex($new_utf8_string), "\n";
?>
The above example will output:
005a006f00eb 5a6fc3ab
Example #2 Invalid characters in input
If the input string contains a sequence of bytes which is not valid in
the encoding specified by fromEncoding, they are
replaced by Unicode code point U+FFFD (Replacement Character) before
converting to toEncoding.
<?php
$invalid_utf8_string = "\xC3"; // incomplete multi-byte UTF-8 sequence
$utf16_string = UConverter::transcode($invalid_utf8_string, 'UTF-16BE', 'UTF-8');
echo bin2hex($utf16_string), "\n";
?>
The above example will output:
fffd
Example #3 Characters which cannot be encoded
If the input string contains characters which cannot be represented
in toEncoding, they are replaced with a single
character. The default character to use depends on the encoding, and
can be controlled using the 'to_subst' option.
<?php
$utf8_string = "\xE2\x82\xAC"; // € (Euro Sign) does not exist in ISO 8859-1
// Default replacement in ISO 8859-1 is "\x1A" (Substitute)
$iso8859_1_string = UConverter::transcode($utf8_string, 'ISO-8859-1', 'UTF-8');
echo bin2hex($iso8859_1_string), "\n";
// Specify a replacement of '?' ("\x3F") instead
$iso8859_1_string = UConverter::transcode(
$utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
);
echo bin2hex($iso8859_1_string), "\n";
// Since ISO 8859-1 cannot map U+FFFD, invalid input is also replaced by to_subst
$invalid_utf8_string = "\xC3"; // incomplete multi-byte UTF-8 sequence
$iso8859_1_string = UConverter::transcode(
$invalid_utf8_string, 'ISO-8859-1', 'UTF-8', ['to_subst' => '?']
);
echo bin2hex($iso8859_1_string), "\n";
?>
The above example will output:
1a 3f 3f