gplcart / transliterator

helpers/Transliterator.php

<?php

/**
 * @package Transliterator
 * @author Iurii Makukh
 * @copyright Copyright (c) 2017, Iurii Makukh
 * @license https://www.gnu.org/licenses/gpl-3.0.en.html GPL-3.0+
 */

namespace gplcart\modules\transliterator\helpers;

/**
 * Helper class for Transliterator module
 * Based on code from https://www.drupal.org/project/transliteration
 */
class Transliterator
{

    /**
     * Transliterates a string
     * @param string $string
     * @param string $unknown
     * @param null|string $source_langcode
     * @return string
     */
    public function transliterate($string, $unknown = '?', $source_langcode = null)
    {
        // ASCII is always valid NFC! If we're only ever given plain ASCII, we can
        // avoid the overhead of initializing the decomposition tables by skipping
        // out early.
        if (!preg_match('/[\x80-\xff]/', $string)) {
            return $string;
        }

        $tail_bytes = $this->getTailBytes();
        $areas = $this->getAreas($string);
        $result = '';
        foreach ($areas[0] as $str) {

            if ($str[0] < "\x80") {
                // ASCII chunk: guaranteed to be valid UTF-8 and in normal form C, so
                // skip over it.
                $result .= $str;
                continue;
            }

            // We'll have to examine the chunk byte by byte to ensure that it consists
            // of valid UTF-8 sequences, and to see if any of them might not be normalized.
            // Since PHP is not the fastest language on earth, some of this code is a
            // little ugly with inner loop optimizations.
            $head = '';
            $chunk = strlen($str);

            // Counting down is faster. I'm *so* sorry.
            $len = $chunk + 1;
            for ($i = -1; --$len;) {
                $c = $str[++$i];
                if ($remaining = $tail_bytes[$c]) {
                    // UTF-8 head byte!
                    $sequence = $head = $c;
                    do {
                        // Look for the defined number of tail bytes...
                        if (--$len && ($c = $str[++$i]) >= "\x80" && $c < "\xc0") {
                            // Legal tail bytes are nice.
                            $sequence .= $c;
                        } else {
                            if ($len == 0) {
                                // Premature end of string! Drop a replacement character into
                                // output to represent the invalid UTF-8 sequence.
                                $result .= $unknown;
                                break 2;
                            } else {
                                // Illegal tail byte; abandon the sequence.
                                $result .= $unknown;
                                // Back up and reprocess this byte; it may itself be a legal
                                // ASCII or UTF-8 sequence head.
                                --$i;
                                ++$len;
                                continue 2;
                            }
                        }
                    } while (--$remaining);
                    $n = ord($head);
                    if ($n <= 0xdf) {
                        $ord = ($n - 192) * 64 + (ord($sequence[1]) - 128);
                    } elseif ($n <= 0xef) {
                        $ord = ($n - 224) * 4096 + (ord($sequence[1]) - 128) * 64 + (ord($sequence[2]) - 128);
                    } elseif ($n <= 0xf7) {
                        $ord = ($n - 240) * 262144 + (ord($sequence[1]) - 128) * 4096 + (ord($sequence[2]) - 128) * 64 + (ord($sequence[3]) - 128);
                    } elseif ($n <= 0xfb) {
                        $ord = ($n - 248) * 16777216 + (ord($sequence[1]) - 128) * 262144 + (ord($sequence[2]) - 128) * 4096 + (ord($sequence[3]) - 128) * 64 + (ord($sequence[4]) - 128);
                    } elseif ($n <= 0xfd) {
                        $ord = ($n - 252) * 1073741824 + (ord($sequence[1]) - 128) * 16777216 + (ord($sequence[2]) - 128) * 262144 + (ord($sequence[3]) - 128) * 4096 + (ord($sequence[4]) - 128) * 64 + (ord($sequence[5]) - 128);
                    }
                    $result .= $this->replace($ord, $unknown, $source_langcode);

The variable $ord does not seem to be defined for all execution paths leading up to this point.

                    $head = '';
                } elseif ($c < "\x80") {
                    // ASCII byte.
                    $result .= $c;
                    $head = '';
                } elseif ($c < "\xc0") {
                    // Illegal tail bytes.
                    if ($head == '') {
                        $result .= $unknown;
                    }
                } else {
                    // Miscellaneous freaks.
                    $result .= $unknown;
                    $head = '';
                }
            }
        }

        return $result;
    }

    /**
     * Chops the text into pure-ASCII and non-ASCII areas
     * @param string $string
     * @return array
     */
    protected function getAreas($string)
    {
        $matches = array();
        preg_match_all('/[\x00-\x7f]+|[\x80-\xff][\x00-\x40\x5b-\x5f\x7b-\xff]*/', $string, $matches);
        return $matches;
    }

    /**
     * Each UTF-8 head byte is followed by a certain number of tail bytes.
     * This method returns an array of tail bytes
     * @staticvar null|array $tail_bytes
     * @return array
     */
    protected function getTailBytes()
    {
        static $tail_bytes;

        if (isset($tail_bytes)) {
            return $tail_bytes;
        }

        $tail_bytes = array();

        for ($n = 0; $n < 256; $n++) {
            if ($n < 0xc0) {
                $remaining = 0;
            } elseif ($n < 0xe0) {
                $remaining = 1;
            } elseif ($n < 0xf0) {
                $remaining = 2;
            } elseif ($n < 0xf8) {
                $remaining = 3;
            } elseif ($n < 0xfc) {
                $remaining = 4;
            } elseif ($n < 0xfe) {
                $remaining = 5;
            } else {
                $remaining = 0;
            }

            $tail_bytes[chr($n)] = $remaining;
        }

        return $tail_bytes;
    }

    /**
     * Replaces a Unicode character using the transliteration database.
     * @param string $ord An ordinal Unicode character code.
     * @param string $unknown Replacement string for characters that do not have a suitable ASCII equivalent.
     * @param string $langcode Optional ISO 639 language code
     * @return string ASCII replacement character.
     */
    protected function replace($ord, $unknown = '?', $langcode)
    {
        static $map = array();

        $bank = $ord >> 8;
        if (!isset($map[$bank][$langcode])) {

            $file = __DIR__ . '/../data/' . sprintf('x%02x', $bank) . '.php';

            if (file_exists($file)) {

                $variant = $base = array();

                include $file;

                if ($langcode != 'en' && isset($variant[$langcode])) {
                    // Merge in language specific mappings.
                    $map[$bank][$langcode] = $variant[$langcode] + $base;
                } else {
                    $map[$bank][$langcode] = $base;
                }
            } else {
                $map[$bank][$langcode] = array();
            }
        }

        $ord = $ord & 255;
        return isset($map[$bank][$langcode][$ord]) ? $map[$bank][$langcode][$ord] : $unknown;
    }

}