comparison core/lib/Drupal/Component/Transliteration/PhpTransliteration.php @ 0:4c8ae668cc8c

Initial import (non-working)

+<?php
+
+namespace Drupal\Component\Transliteration;
+
+/**
+ * Implements transliteration without using the PECL extensions.
+ *
+ * Transliterations are done character-by-character, by looking up non-US-ASCII
+ * characters in a transliteration database.
+ *
+ * The database comes from two types of files, both of which are searched for in
+ * the PhpTransliteration::$dataDirectory directory. First, language-specific
+ * overrides are searched (see PhpTransliteration::readLanguageOverrides()). If
+ * there is no language-specific override for a character, the generic
+ * transliteration character tables are searched (see
+ * PhpTransliteration::readGenericData()). If looking up the character in the
+ * generic table results in a NULL value, or an illegal character is
+ * encountered, then a substitute character is returned.
+ *
+ * Some parts of this code were derived from the MediaWiki project's UtfNormal
+ * class, Copyright © 2004 Brion Vibber <[e-mail]>,
+ * http://www.mediawiki.org/
+ */
+class PhpTransliteration implements TransliterationInterface {
+
+  /**
+   * Directory where data for transliteration resides.
+   *
+   * The constructor sets this (by default) to subdirectory 'data' underneath
+   * the directory where the class's PHP file resides.
+   *
+   * @var string
+   */
+  protected $dataDirectory;
+
+  /**
+   * Associative array of language-specific character transliteration tables.
+   *
+   * The outermost array keys are language codes. For each language code key,
+   * the value is an array whose keys are Unicode character codes, and whose
+   * values are the transliterations of those characters to US-ASCII. This is
+   * set up as needed in PhpTransliteration::replace() by calling
+   * PhpTransliteration::readLanguageOverrides().
+   *
+   * @var array
+   */
+  protected $languageOverrides = [];
+
+  /**
+   * Non-language-specific transliteration tables.
+   *
+   * Array whose keys are the upper two bytes of the Unicode character, and
+   * whose values are an array of transliterations for each lower-two bytes
+   * character code. This is set up as needed in PhpTransliteration::replace()
+   * by calling PhpTransliteration::readGenericData().
+   *
+   * @var array
+   */
+  protected $genericMap = [];
+
+  /**
+   * Constructs a transliteration object.
+   *
+   * @param string $data_directory
+   *   (optional) The directory where data files reside. If omitted, defaults
+   *   to subdirectory 'data' underneath the directory where the class's PHP
+   *   file resides.
+   */
+  public function __construct($data_directory = NULL) {
+    $this->dataDirectory = (isset($data_directory)) ? $data_directory : __DIR__ . '/data';
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function removeDiacritics($string) {
+    $result = '';
+
+    foreach (preg_split('//u', $string, 0, PREG_SPLIT_NO_EMPTY) as $character) {
+      $code = self::ordUTF8($character);
+
+      // These two Unicode ranges include the accented US-ASCII letters, with a
+      // few characters that aren't accented letters mixed in. So define the
+      // ranges and the excluded characters.
+      $range1 = $code > 0x00bf && $code < 0x017f;
+      $exclusions_range1 = [0x00d0, 0x00d7, 0x00f0, 0x00f7, 0x0138, 0x014a, 0x014b];
+      $range2 = $code > 0x01cc && $code < 0x0250;
+      $exclusions_range2 = [0x01DD, 0x01f7, 0x021c, 0x021d, 0x0220, 0x0221, 0x0241, 0x0242, 0x0245];
+
+      $replacement = $character;
+      if (($range1 && !in_array($code, $exclusions_range1)) || ($range2 && !in_array($code, $exclusions_range2))) {
+        $to_add = $this->lookupReplacement($code, 'xyz');
+        if (strlen($to_add) === 1) {
+          $replacement = $to_add;
+        }
+      }
+
+      $result .= $replacement;
+    }
+
+    return $result;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transliterate($string, $langcode = 'en', $unknown_character = '?', $max_length = NULL) {
+    $result = '';
+    $length = 0;
+    // Split into Unicode characters and transliterate each one.
+    foreach (preg_split('//u', $string, 0, PREG_SPLIT_NO_EMPTY) as $character) {
+      $code = self::ordUTF8($character);
+      if ($code == -1) {
+        $to_add = $unknown_character;
+      }
+      else {
+        $to_add = $this->replace($code, $langcode, $unknown_character);
+      }
+
+      // Check if this exceeds the maximum allowed length.
+      if (isset($max_length)) {
+        $length += strlen($to_add);
+        if ($length > $max_length) {
+          // There is no more space.
+          return $result;
+        }
+      }
+
+      $result .= $to_add;
+    }
+
+    return $result;
+  }
+
+  /**
+   * Finds the character code for a UTF-8 character: like ord() but for UTF-8.
+   *
+   * @param string $character
+   *   A single UTF-8 character.
+   *
+   * @return int
+   *   The character code, or -1 if an illegal character is found.
+   */
+  protected static function ordUTF8($character) {
+    $first_byte = ord($character[0]);
+
+    if (($first_byte & 0x80) == 0) {
+      // Single-byte form: 0xxxxxxxx.
+      return $first_byte;
+    }
+    if (($first_byte & 0xe0) == 0xc0) {
+      // Two-byte form: 110xxxxx 10xxxxxx.
+      return (($first_byte & 0x1f) << 6) + (ord($character[1]) & 0x3f);
+    }
+    if (($first_byte & 0xf0) == 0xe0) {
+      // Three-byte form: 1110xxxx 10xxxxxx 10xxxxxx.
+      return (($first_byte & 0x0f) << 12) + ((ord($character[1]) & 0x3f) << 6) + (ord($character[2]) & 0x3f);
+    }
+    if (($first_byte & 0xf8) == 0xf0) {
+      // Four-byte form: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx.
+      return (($first_byte & 0x07) << 18) + ((ord($character[1]) & 0x3f) << 12) + ((ord($character[2]) & 0x3f) << 6) + (ord($character[3]) & 0x3f);
+    }
+
+    // Other forms are not legal.
+    return -1;
+  }
+
+  /**
+   * Replaces a single Unicode character using the transliteration database.
+   *
+   * @param int $code
+   *   The character code of a Unicode character.
+   * @param string $langcode
+   *   The language code of the language the character is in.
+   * @param string $unknown_character
+   *   The character to substitute for characters without transliterated
+   *   equivalents.
+   *
+   * @return string
+   *   US-ASCII replacement character. If it has a mapping, it is returned;
+   *   otherwise, $unknown_character is returned. The replacement can contain
+   *   multiple characters.
+   */
+  protected function replace($code, $langcode, $unknown_character) {
+    if ($code < 0x80) {
+      // Already lower ASCII.
+      return chr($code);
+    }
+
+    // See if there is a language-specific override for this character.
+    if (!isset($this->languageOverrides[$langcode])) {
+      $this->readLanguageOverrides($langcode);
+    }
+    if (isset($this->languageOverrides[$langcode][$code])) {
+      return $this->languageOverrides[$langcode][$code];
+    }
+
+    return $this->lookupReplacement($code, $unknown_character);
+  }
+
+  /**
+   * Look up the generic replacement for a UTF-8 character code.
+   *
+   * @param $code
+   *   The UTF-8 character code.
+   * @param string $unknown_character
+   *   (optional) The character to substitute for characters without entries in
+   *   the replacement tables.
+   *
+   * @return string
+   *   US-ASCII replacement characters. If it has a mapping, it is returned;
+   *   otherwise, $unknown_character is returned. The replacement can contain
+   *   multiple characters.
+   */
+  protected function lookupReplacement($code, $unknown_character = '?') {
+    // See if there is a generic mapping for this character.
+    $bank = $code >> 8;
+    if (!isset($this->genericMap[$bank])) {
+      $this->readGenericData($bank);
+    }
+    $code = $code & 0xff;
+    return isset($this->genericMap[$bank][$code]) ? $this->genericMap[$bank][$code] : $unknown_character;
+  }
+
+  /**
+   * Reads in language overrides for a language code.
+   *
+   * The data is read from files named "$langcode.php" in
+   * PhpTransliteration::$dataDirectory. These files should set up an array
+   * variable $overrides with an element whose key is $langcode and whose value
+   * is an array whose keys are character codes, and whose values are their
+   * transliterations in this language. The character codes can be for any valid
+   * Unicode character, independent of the number of bytes.
+   *
+   * @param $langcode
+   *   Code for the language to read.
+   */
+  protected function readLanguageOverrides($langcode) {
+    // Figure out the file name to use by sanitizing the language code,
+    // just in case.
+    $file = $this->dataDirectory . '/' . preg_replace('/[^a-zA-Z\-]/', '', $langcode) . '.php';
+
+    // Read in this file, which should set up a variable called $overrides,
+    // which will be local to this function.
+    if (is_file($file)) {
+      include $file;
+    }
+    if (!isset($overrides) || !is_array($overrides)) {
+      $overrides = [$langcode => []];
+    }
+    $this->languageOverrides[$langcode] = $overrides[$langcode];
+  }
+
+  /**
+   * Reads in generic transliteration data for a bank of characters.
+   *
+   * The data is read in from a file named "x$bank.php" (with $bank in
+   * hexadecimal notation) in PhpTransliteration::$dataDirectory. These files
+   * should set up a variable $bank containing an array whose numerical indices
+   * are the remaining two bytes of the character code, and whose values are the
+   * transliterations of these characters into US-ASCII. Note that the maximum
+   * Unicode character that can be encoded in this way is 4 bytes.
+   *
+   * @param $bank
+   *   First two bytes of the Unicode character, or 0 for the ASCII range.
+   */
+  protected function readGenericData($bank) {
+    // Figure out the file name.
+    $file = $this->dataDirectory . '/x' . sprintf('%02x', $bank) . '.php';
+
+    // Read in this file, which should set up a variable called $base, which
+    // will be local to this function.
+    if (is_file($file)) {
+      include $file;
+    }
+    if (!isset($base) || !is_array($base)) {
+      $base = [];
+    }
+
+    // Save this data.
+    $this->genericMap[$bank] = $base;
+  }
+
+}