public static function Unicode::substr in Zircon Profile 8

Same name and namespace in other branches

1. 8.0 core/lib/Drupal/Component/Utility/Unicode.php \Drupal\Component\Utility\Unicode::substr()

Cuts off a piece of a string based on character indices and counts.

Follows the same behavior as PHP's own substr() function. Note that for cutting off a string at a known character/substring location, the usage of PHP's normal strpos/substr is safe and much faster.

Parameters

string $text: The input string.

int $start: The position at which to start reading.

int $length: The number of characters to read.

Return value

string The shortened string.

33 calls to Unicode::substr()

AttachedAssetsTest::testSettings in core/modules/system/src/Tests/Common/AttachedAssetsTest.php

Tests JavaScript settings.

ConfigInstaller::installCollectionDefaultConfig in core/lib/Drupal/Core/Config/ConfigInstaller.php

Installs all default configuration in the specified collection.

CssOptimizer::loadFile in core/lib/Drupal/Core/Asset/CssOptimizer.php

Loads the stylesheet and resolves all @import commands.

DbLogTest::doUser in core/modules/dblog/src/Tests/DbLogTest.php

Generates and then verifies some user events.

DedupeBase::transform in core/modules/migrate/src/Plugin/migrate/process/DedupeBase.php

Performs the associated process.

... See full list

File

core/lib/Drupal/Component/Utility/Unicode.php, line 406

Contains \Drupal\Component\Utility\Unicode.

Class

Unicode

Provides Unicode-related conversions and operations.

Namespace

Drupal\Component\Utility

Code

public static function substr($text, $start, $length = NULL) {
  if (static::getStatus() == static::STATUS_MULTIBYTE) {
    return $length === NULL ? mb_substr($text, $start) : mb_substr($text, $start, $length);
  }
  else {
    $strlen = strlen($text);

    // Find the starting byte offset.
    $bytes = 0;
    if ($start > 0) {

      // Count all the characters except continuation bytes from the start
      // until we have found $start characters or the end of the string.
      $bytes = -1;
      $chars = -1;
      while ($bytes < $strlen - 1 && $chars < $start) {
        $bytes++;
        $c = ord($text[$bytes]);
        if ($c < 0x80 || $c >= 0xc0) {
          $chars++;
        }
      }
    }
    elseif ($start < 0) {

      // Count all the characters except continuation bytes from the end
      // until we have found abs($start) characters.
      $start = abs($start);
      $bytes = $strlen;
      $chars = 0;
      while ($bytes > 0 && $chars < $start) {
        $bytes--;
        $c = ord($text[$bytes]);
        if ($c < 0x80 || $c >= 0xc0) {
          $chars++;
        }
      }
    }
    $istart = $bytes;

    // Find the ending byte offset.
    if ($length === NULL) {
      $iend = $strlen;
    }
    elseif ($length > 0) {

      // Count all the characters except continuation bytes from the starting
      // index until we have found $length characters or reached the end of
      // the string, then backtrace one byte.
      $iend = $istart - 1;
      $chars = -1;
      $last_real = FALSE;
      while ($iend < $strlen - 1 && $chars < $length) {
        $iend++;
        $c = ord($text[$iend]);
        $last_real = FALSE;
        if ($c < 0x80 || $c >= 0xc0) {
          $chars++;
          $last_real = TRUE;
        }
      }

      // Backtrace one byte if the last character we found was a real
      // character and we don't need it.
      if ($last_real && $chars >= $length) {
        $iend--;
      }
    }
    elseif ($length < 0) {

      // Count all the characters except continuation bytes from the end
      // until we have found abs($start) characters, then backtrace one byte.
      $length = abs($length);
      $iend = $strlen;
      $chars = 0;
      while ($iend > 0 && $chars < $length) {
        $iend--;
        $c = ord($text[$iend]);
        if ($c < 0x80 || $c >= 0xc0) {
          $chars++;
        }
      }

      // Backtrace one byte if we are not at the beginning of the string.
      if ($iend > 0) {
        $iend--;
      }
    }
    else {

      // $length == 0, return an empty string.
      return '';
    }
    return substr($text, $istart, max(0, $iend - $istart + 1));
  }
}