如何在PHP中从unicode码点获取字符？

Question

例如，

如何获取U+010F对应的字符？

Answer 1

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

Answer 2

我刚刚为缺少多字节版本的

polyfill

和

ord

编写了一个

chr

，并牢记以下内容：

• 仅当函数

  mb_ord

  和

  mb_chr

  尚不存在时才定义它们。如果它们确实存在于您的框架或某些未来版本的 PHP 中，polyfill 将被忽略。

• 它使用广泛使用的

  mbstring

  扩展来进行转换。如果未加载

  mbstring

  扩展，它将使用

  iconv

  扩展。

---

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如何使用这些函数的演示代码

---

代码：

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"

Answer 3

如果这对任何人都有用，PHP 7.2 现在添加了

mb_ord

和

mb_chr

相当于

ord

和

chr

。例如，以下代码将在 PHP 7.2 中运行

$charPoint = "U+010F";
echo mb_chr(hexdec(substr($charPoint,2)); // prints ď

这有 2 个副作用（a）不需要实现自己的，（b）如果已经实现了自己的，则需要将其包装在

if (!function_exists('mb_chr'))

Answer 4

IntlChar 是一个随 PHP/7 一起发布的新的基于 ICU 的内置类，它恰好解决了这个问题：

IntlChar 提供对许多实用方法的访问，这些方法可用于访问有关 Unicode 字符的信息。

// PHP 7.0 and later
var_dump(
  "\u{010F}" === IntlChar::chr(0x010F),
  0x010F === IntlChar::ord("\u{010F}")
);

// PHP 7.2.0-dev
var_dump(
  "\u{010F}" === mb_chr(0x010F, "UTF-8"),
  0x010F === mb_ord("\u{010F}", "UTF-8")
);

Answer 5

如果您控制字符串的 UTF-8 编码（按照拉丁和其他欧洲标准的建议），您只需要

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

参见 php man 的示例 #1。您可以将第二个参数更改为 ENT_NOQUOTES 等，并且，注意，如果您的字符串是标记语言（！），请使用 ENT_XHTML 等。

Answer 6

<?php

function chr_utf8($n,$f='C*'){
return $n<(1<<7)?chr($n):($n<1<<11?pack($f,192|$n>>6,1<<7|191&$n):
($n<(1<<16)?pack($f,224|$n>>12,1<<7|63&$n>>6,1<<7|63&$n):
($n<(1<<20|1<<16)?pack($f,240|$n>>18,1<<7|63&$n>>12,1<<7|63&$n>>6,1<<7|63&$n):'')));
}

echo chr_utf8(hexdec('010F'));

// Output the UTF-8 character corresponding to U+010F