如何在PHP中从Unicode代码点获取字符？

header('Content-Encoding: UTF-8');

function mb_html_entity_decode($string)
{
    if (extension_loaded('mbstring') === true)
    {
        mb_language('Neutral');
        mb_internal_encoding('UTF-8');
        mb_detect_order(array('UTF-8', 'ISO-8859-15', 'ISO-8859-1', 'ASCII'));

        return mb_convert_encoding($string, 'UTF-8', 'HTML-ENTITIES');
    }

    return html_entity_decode($string, ENT_COMPAT, 'UTF-8');
}

function mb_ord($string)
{
    if (extension_loaded('mbstring') === true)
    {
        mb_language('Neutral');
        mb_internal_encoding('UTF-8');
        mb_detect_order(array('UTF-8', 'ISO-8859-15', 'ISO-8859-1', 'ASCII'));

        $result = unpack('N', mb_convert_encoding($string, 'UCS-4BE', 'UTF-8'));

        if (is_array($result) === true)
        {
            return $result[1];
        }
    }

    return ord($string);
}

function mb_chr($string)
{
    return mb_html_entity_decode('&#' . intval($string) . ';');
}

var_dump(hexdec('010F'));

var_dump(mb_ord('ó')); // 243
var_dump(mb_chr(243)); // ó

我刚刚写了一个缺少多字节版本，并牢记以下几点：polyfillordchr

• 它定义函数，并且仅当它们尚不存在时。如果它们确实存在于您的框架或某些未来版本的PHP中，则polyfill将被忽略。mb_ordmb_chr

• 它使用广泛使用的扩展来执行转换。如果未加载扩展，它将改用该扩展。mbstringmbstringiconv

编辑：

我添加了 HTMLentities 编码/解码和编码/解码为 JSON 格式的函数，以及一些有关如何使用这些函数的演示代码

验证码 ：

if (!function_exists('codepoint_encode')) {
    function codepoint_encode($str) {
        return substr(json_encode($str), 1, -1);
    }
}

if (!function_exists('codepoint_decode')) {
    function codepoint_decode($str) {
        return json_decode(sprintf('"%s"', $str));
    }
}

if (!function_exists('mb_internal_encoding')) {
    function mb_internal_encoding($encoding = NULL) {
        return ($from_encoding === NULL) ? iconv_get_encoding() : iconv_set_encoding($encoding);
    }
}

if (!function_exists('mb_convert_encoding')) {
    function mb_convert_encoding($str, $to_encoding, $from_encoding = NULL) {
        return iconv(($from_encoding === NULL) ? mb_internal_encoding() : $from_encoding, $to_encoding, $str);
    }
}

if (!function_exists('mb_chr')) {
    function mb_chr($ord, $encoding = 'UTF-8') {
        if ($encoding === 'UCS-4BE') {
            return pack("N", $ord);
        } else {
            return mb_convert_encoding(mb_chr($ord, 'UCS-4BE'), $encoding, 'UCS-4BE');
        }
    }
}

if (!function_exists('mb_ord')) {
    function mb_ord($char, $encoding = 'UTF-8') {
        if ($encoding === 'UCS-4BE') {
            list(, $ord) = (strlen($char) === 4) ? @unpack('N', $char) : @unpack('n', $char);
            return $ord;
        } else {
            return mb_ord(mb_convert_encoding($char, 'UCS-4BE', $encoding), 'UCS-4BE');
        }
    }
}

if (!function_exists('mb_htmlentities')) {
    function mb_htmlentities($string, $hex = true, $encoding = 'UTF-8') {
        return preg_replace_callback('/[\x{80}-\x{10FFFF}]/u', function ($match) use ($hex) {
            return sprintf($hex ? '&#x%X;' : '&#%d;', mb_ord($match[0]));
        }, $string);
    }
}

if (!function_exists('mb_html_entity_decode')) {
    function mb_html_entity_decode($string, $flags = null, $encoding = 'UTF-8') {
        return html_entity_decode($string, ($flags === NULL) ? ENT_COMPAT | ENT_HTML401 : $flags, $encoding);
    }
}

如何使用 ：

echo "Get string from numeric DEC value\n";
var_dump(mb_chr(50319, 'UCS-4BE'));
var_dump(mb_chr(271));

echo "\nGet string from numeric HEX value\n";
var_dump(mb_chr(0xC48F, 'UCS-4BE'));
var_dump(mb_chr(0x010F));

echo "\nGet numeric value of character as DEC string\n";
var_dump(mb_ord('ď', 'UCS-4BE'));
var_dump(mb_ord('ď'));

echo "\nGet numeric value of character as HEX string\n";
var_dump(dechex(mb_ord('ď', 'UCS-4BE')));
var_dump(dechex(mb_ord('ď')));

echo "\nEncode / decode to DEC based HTML entities\n";
var_dump(mb_htmlentities('tchüß', false));
var_dump(mb_html_entity_decode('tchüß'));

echo "\nEncode / decode to HEX based HTML entities\n";
var_dump(mb_htmlentities('tchüß'));
var_dump(mb_html_entity_decode('tchüß'));

echo "\nUse JSON encoding / decoding\n";
var_dump(codepoint_encode("tchüß"));
var_dump(codepoint_decode('tch\u00fc\u00df'));

输出 ：

Get string from numeric DEC value
string(4) "ď"
string(2) "ď"

Get string from numeric HEX value
string(4) "ď"
string(2) "ď"

Get numeric value of character as DEC int
int(50319)
int(271)

Get numeric value of character as HEX string
string(4) "c48f"
string(3) "10f"

Encode / decode to DEC based HTML entities
string(15) "tchüß"
string(7) "tchüß"

Encode / decode to HEX based HTML entities
string(15) "tchüß"
string(7) "tchüß"

Use JSON encoding / decoding
string(15) "tch\u00fc\u00df"
string(7) "tchüß"