public static Unicode::substr($text, $start, $length = NULL)
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 $length: The number of characters to read.
Return value
string The shortened string.
File
- core/lib/Drupal/Component/Utility/Unicode.php, line 401
Class
- Unicode
- Provides Unicode-related conversions and operations.
Namespace
Drupal\Component\Utility
Code
public static function substr($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)); } }
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