cops/transliteration.php

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<?php
/**
* @file
* Transliteration processing functions.
*/
/**
* Transliterates UTF-8 encoded text to US-ASCII.
*
* Based on Mediawiki's UtfNormal::quickIsNFCVerify().
* Based on Drupal 7 transliteration module.
*
* @param $string
* UTF-8 encoded text input.
* @param $unknown
* Replacement string for characters that do not have a suitable ASCII
* equivalent.
* @param $source_langcode
* Optional ISO 639 language code that denotes the language of the input and
* is used to apply language-specific variations. If the source language is
* not known at the time of transliteration, it is recommended to set this
* argument to the site default language to produce consistent results.
* Otherwise the current display language will be used.
* @return
* Transliterated text.
*/
function _transliteration_process($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;
}
static $tail_bytes;
if (!isset($tail_bytes)) {
// Each UTF-8 head byte is followed by a certain number of 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;
}
}
// Chop the text into pure-ASCII and non-ASCII areas; large ASCII parts can
// be handled much more quickly. Don't chop up Unicode areas for punctuation,
// though, that wastes energy.
preg_match_all('/[\x00-\x7f]+|[\x80-\xff][\x00-\x40\x5b-\x5f\x7b-\xff]*/', $string, $matches);
$result = '';
foreach ($matches[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);
}
$result .= _transliteration_replace($ord, $unknown, $source_langcode);
$head = '';
}
elseif ($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;
}
/**
* Replaces a Unicode character using the transliteration database.
*
* @param $ord
* An ordinal Unicode character code.
* @param $unknown
* Replacement string for characters that do not have a suitable ASCII
* equivalent.
* @param $langcode
* Optional ISO 639 language code that denotes the language of the input and
* is used to apply language-specific variations. Defaults to the current
* display language.
* @return
* ASCII replacement character.
*/
function _transliteration_replace($ord, $unknown = '?', $langcode = NULL) {
static $map = array();
//GL: set language later
/*
if (!isset($langcode)) {
global $language;
$langcode = $language->language;
}
*/
$bank = $ord >> 8;
if (!isset($map[$bank][$langcode])) {
$file = './resources/transliteration-data/' . sprintf('x%02x', $bank) . '.php';
if (file_exists($file)) {
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;
}