UTF-8 的多字节安全 wordwrap() 函数

Question

PHP 的 wordwrap() 函数对于多字节字符串无法正常工作比如 UTF-8。

评论中有一些mb安全函数的例子，但是根据一些不同的测试数据，它们似乎都存在一些问题。

该函数应采用与 wordwrap() 完全相同的参数。

具体来说，请确保它的作用是：

• 则不要剪切单词中部，否则
• 如果 $cut = true 则剪切单词中部，如果 $break = ' ' 不在单词中插入额外的空格>
• 也适用于 $break = "\n"
• 适用于 ASCII 和所有有效的 UTF-8

Answer 1

我还没有找到任何适合我的工作代码。这是我写的。对我来说它正在工作，但认为它可能不是最快的。

function mb_wordwrap($str, $width = 75, $break = "\n", $cut = false) {
    $lines = explode($break, $str);
    foreach ($lines as &$line) {
        $line = rtrim($line);
        if (mb_strlen($line) <= $width)
            continue;
        $words = explode(' ', $line);
        $line = '';
        $actual = '';
        foreach ($words as $word) {
            if (mb_strlen($actual.$word) <= $width)
                $actual .= $word.' ';
            else {
                if ($actual != '')
                    $line .= rtrim($actual).$break;
                $actual = $word;
                if ($cut) {
                    while (mb_strlen($actual) > $width) {
                        $line .= mb_substr($actual, 0, $width).$break;
                        $actual = mb_substr($actual, $width);
                    }
                }
                $actual .= ' ';
            }
        }
        $line .= trim($actual);
    }
    return implode($break, $lines);
}

Answer 2

因为没有答案可以处理每个用例，所以这里有一个可以处理的东西。该代码基于 Drupal 的 AbstractStringWrapper::wordWrap。

<?php

/**
 * Wraps any string to a given number of characters.
 *
 * This implementation is multi-byte aware and relies on {@link
 * http://www.php.net/manual/en/book.mbstring.php PHP's multibyte
 * string extension}.
 *
 * @see wordwrap()
 * @link https://api.drupal.org/api/drupal/core%21vendor%21zendframework%21zend-stdlib%21Zend%21Stdlib%21StringWrapper%21AbstractStringWrapper.php/function/AbstractStringWrapper%3A%3AwordWrap/8
 * @param string $string
 *   The input string.
 * @param int $width [optional]
 *   The number of characters at which <var>$string</var> will be
 *   wrapped. Defaults to <code>75</code>.
 * @param string $break [optional]
 *   The line is broken using the optional break parameter. Defaults
 *   to <code>"\n"</code>.
 * @param boolean $cut [optional]
 *   If the <var>$cut</var> is set to <code>TRUE</code>, the string is
 *   always wrapped at or before the specified <var>$width</var>. So if
 *   you have a word that is larger than the given <var>$width</var>, it
 *   is broken apart. Defaults to <code>FALSE</code>.
 * @return string
 *   Returns the given <var>$string</var> wrapped at the specified
 *   <var>$width</var>.
 */
function mb_wordwrap($string, $width = 75, $break = "\n", $cut = false) {
  $string = (string) $string;
  if ($string === '') {
    return '';
  }

  $break = (string) $break;
  if ($break === '') {
    trigger_error('Break string cannot be empty', E_USER_ERROR);
  }

  $width = (int) $width;
  if ($width === 0 && $cut) {
    trigger_error('Cannot force cut when width is zero', E_USER_ERROR);
  }

  if (strlen($string) === mb_strlen($string)) {
    return wordwrap($string, $width, $break, $cut);
  }

  $stringWidth = mb_strlen($string);
  $breakWidth = mb_strlen($break);

  $result = '';
  $lastStart = $lastSpace = 0;

  for ($current = 0; $current < $stringWidth; $current++) {
    $char = mb_substr($string, $current, 1);

    $possibleBreak = $char;
    if ($breakWidth !== 1) {
      $possibleBreak = mb_substr($string, $current, $breakWidth);
    }

    if ($possibleBreak === $break) {
      $result .= mb_substr($string, $lastStart, $current - $lastStart + $breakWidth);
      $current += $breakWidth - 1;
      $lastStart = $lastSpace = $current + 1;
      continue;
    }

    if ($char === ' ') {
      if ($current - $lastStart >= $width) {
        $result .= mb_substr($string, $lastStart, $current - $lastStart) . $break;
        $lastStart = $current + 1;
      }

      $lastSpace = $current;
      continue;
    }

    if ($current - $lastStart >= $width && $cut && $lastStart >= $lastSpace) {
      $result .= mb_substr($string, $lastStart, $current - $lastStart) . $break;
      $lastStart = $lastSpace = $current;
      continue;
    }

    if ($current - $lastStart >= $width && $lastStart < $lastSpace) {
      $result .= mb_substr($string, $lastStart, $lastSpace - $lastStart) . $break;
      $lastStart = $lastSpace = $lastSpace + 1;
      continue;
    }
  }

  if ($lastStart !== $current) {
    $result .= mb_substr($string, $lastStart, $current - $lastStart);
  }

  return $result;
}

?>

Answer 3

/**
 * wordwrap for utf8 encoded strings
 *
 * @param string $str
 * @param integer $len
 * @param string $what
 * @return string
 * @author Milian Wolff <[email protected]>
 */

function utf8_wordwrap($str, $width, $break, $cut = false) {
    if (!$cut) {
        $regexp = '#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){'.$width.',}\b#U';
    } else {
        $regexp = '#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){'.$width.'}#';
    }
    if (function_exists('mb_strlen')) {
        $str_len = mb_strlen($str,'UTF-8');
    } else {
        $str_len = preg_match_all('/[\x00-\x7F\xC0-\xFD]/', $str, $var_empty);
    }
    $while_what = ceil($str_len / $width);
    $i = 1;
    $return = '';
    while ($i < $while_what) {
        preg_match($regexp, $str,$matches);
        $string = $matches[0];
        $return .= $string.$break;
        $str = substr($str, strlen($string));
        $i++;
    }
    return $return.$str;
}

总时间：0.0020880699 是个好时光:)

Answer 4

只是想分享我在网上找到的一些替代方案。

<?php
if ( !function_exists('mb_str_split') ) {
    function mb_str_split($string, $split_length = 1)
    {
        mb_internal_encoding('UTF-8'); 
        mb_regex_encoding('UTF-8');  

        $split_length = ($split_length <= 0) ? 1 : $split_length;

        $mb_strlen = mb_strlen($string, 'utf-8');

        $array = array();

        for($i = 0; $i < $mb_strlen; $i += $split_length) {
            $array[] = mb_substr($string, $i, $split_length);
        }

        return $array;
    }
}

使用 mb_str_split，您可以使用 join 将单词与
组合起来。

<?php
    $text = '<utf-8 content>';

    echo join('<br>', mb_str_split($text, 20));

最后创建你自己的助手，也许是 mb_textwrap

<?php

if( !function_exists('mb_textwrap') ) {
    function mb_textwrap($text, $length = 20, $concat = '<br>') 
    {
        return join($concat, mb_str_split($text, $length));
    }
}

$text = '<utf-8 content>';
// so simply call
echo mb_textwrap($text);

参见截图演示：

Answer 5

自定义字边界

Unicode 文本比 8 位编码具有更多的潜在字边界，包括 17 个空格分隔符 和 全角逗号< /a>.该解决方案允许您为您的应用程序自定义单词边界列表。

更好的性能

您曾经对 PHP 内置函数的 mb_* 系列进行过基准测试吗？它们根本无法很好地扩展。通过使用自定义 nextCharUtf8()，我们可以完成相同的工作，但速度要快几个数量级，尤其是在处理大型字符串时。

<?php

function wordWrapUtf8(
  string $phrase,
  int $width = 75,
  string $break = "\n",
  bool $cut = false,
  array $seps = [' ', "\n", "\t", '，']
): string
{
  $chunks = [];
  $chunk = '';
  $len = 0;
  $pointer = 0;
  while (!is_null($char = nextCharUtf8($phrase, $pointer))) {
    $chunk .= $char;
    $len++;
    if (in_array($char, $seps, true) || ($cut && $len === $width)) {
      $chunks[] = [$len, $chunk];
      $len = 0;
      $chunk = '';
    }
  }
  if ($chunk) {
    $chunks[] = [$len, $chunk];
  }
  $line = '';
  $lines = [];
  $lineLen = 0;
  foreach ($chunks as [$len, $chunk]) {
    if ($lineLen + $len > $width) {
      if ($line) {
        $lines[] = $line;
        $lineLen = 0;
        $line = '';
      }
    }
    $line .= $chunk;
    $lineLen += $len;
  }
  if ($line) {
    $lines[] = $line;
  }
  return implode($break, $lines);
}

function nextCharUtf8(&$string, &$pointer)
{
  // EOF
  if (!isset($string[$pointer])) {
    return null;
  }

  // Get the byte value at the pointer
  $char = ord($string[$pointer]);

  // ASCII
  if ($char < 128) {
    return $string[$pointer++];
  }

  // UTF-8
  if ($char < 224) {
    $bytes = 2;
  } elseif ($char < 240) {
    $bytes = 3;
  } elseif ($char < 248) {
    $bytes = 4;
  } elseif ($char == 252) {
    $bytes = 5;
  } else {
    $bytes = 6;
  }

  // Get full multibyte char
  $str = substr($string, $pointer, $bytes);

  // Increment pointer according to length of char
  $pointer += $bytes;

  // Return mb char
  return $str;
}

Answer 6

function mb_wordwrap($str, $width = 74, $break = "\r\n", $cut = false)
        {
            return preg_replace(
                '~(?P<str>.{' . $width . ',}?' . ($cut ? '(?(?!.+\s+)\s*|\s+)' : '\s+') . ')(?=\S+)~mus',
                '$1' . $break,
                $str
            );
        }

Answer 7

这是我自己尝试的一个函数，它通过了我自己的一些测试，但我不能保证它是 100% 完美的，所以如果您发现问题，请发布一个更好的函数。

/**
 * Multi-byte safe version of wordwrap()
 * Seems to me like wordwrap() is only broken on UTF-8 strings when $cut = true
 * @return string
 */
function wrap($str, $len = 75, $break = " ", $cut = true) { 
    $len = (int) $len;

    if (empty($str))
        return ""; 

    $pattern = "";

    if ($cut)
        $pattern = '/([^'.preg_quote($break).']{'.$len.'})/u'; 
    else
        return wordwrap($str, $len, $break);

    return preg_replace($pattern, "\${1}".$break, $str); 
}

Answer 8

这是我从互联网上找到的其他人的灵感中编写的多字节自动换行函数。

function mb_wordwrap($long_str, $width = 75, $break = "\n", $cut = false) {
    $long_str = html_entity_decode($long_str, ENT_COMPAT, 'UTF-8');
    $width -= mb_strlen($break);
    if ($cut) {
        $short_str = mb_substr($long_str, 0, $width);
        $short_str = trim($short_str);
    }
    else {
        $short_str = preg_replace('/^(.{1,'.$width.'})(?:\s.*|$)/', '$1', $long_str);
        if (mb_strlen($short_str) > $width) {
            $short_str = mb_substr($short_str, 0, $width);
        }
    }
    if (mb_strlen($long_str) != mb_strlen($short_str)) {
        $short_str .= $break;
    }
    return $short_str;
}

不要忘记将 PHP 配置为使用 UTF-8：

ini_set('default_charset', 'UTF-8');
mb_internal_encoding('UTF-8');
mb_regex_encoding('UTF-8');

我希望这会有所帮助。
纪尧姆

Answer 9

就我而言，输入是日语段落，需要在大约 70 个字符处换行，而上面给出的解决方案并未将其换行。

我最终编写了一个适合我的解决方案。我还没有测试该代码片段的性能。

function trimtonumchars($value, $numchars) {
    $value = trim($value);
    if (strlen($value) < $numchars) {
        return str_pad($value, $numchars);
    } else {
        return substr($value, 0, $numchars);
    }
}

function utf8_wordwrap($long_str, $width, $break, $cut) {
    function internalsafetrimtonumchars($value, $numchars) {
        while (true) {
            $data = trimtonumchars($value, $numchars);
            json_encode($data);
            if(json_last_error() == 0) {
                return array($data, $numchars);
            }
            $numchars--;
        }
    }

    $tokens = array();
    while(strlen($long_str) > 0) {
        $result = internalsafetrimtonumchars($long_str, $width);
        $token = $result[0];
        $length = $result[1];
        $long_str = substr(trim($long_str), $length);
    
        array_push($tokens, $token);   
    }
    return join($break, $tokens);
}

Answer 10

这个好像效果不错...

function mb_wordwrap($str, $width = 75, $break = "\n", $cut = false, $charset = null) {
    if ($charset === null) $charset = mb_internal_encoding();

    $pieces = explode($break, $str);
    $result = array();
    foreach ($pieces as $piece) {
      $current = $piece;
      while ($cut && mb_strlen($current) > $width) {
        $result[] = mb_substr($current, 0, $width, $charset);
        $current = mb_substr($current, $width, 2048, $charset);
      }
      $result[] = $current;
    }
    return implode($break, $result);
}