Online PHP editor | rfc for cfa0n

<?php function lzw_compress($string) { // compression $dictionary = array_flip(range("\0", "\xFF")); $word = ""; $codes = array(); for ($i=0; $i <= strlen($string); $i++) { $x = substr($string, $i, 1); if (strlen($x) && isset($dictionary[$word . $x])) { $word .= $x; } elseif ($i) { $codes[] = $dictionary[$word]; $dictionary[$word . $x] = count($dictionary); $word = $x; } } // convert codes to binary string $dictionary_count = 256; $bits = 8; // ceil(log($dictionary_count, 2)) $return = ""; $rest = 0; $rest_length = 0; foreach ($codes as $code) { $rest = ($rest << $bits) + $code; $rest_length += $bits; $dictionary_count++; if ($dictionary_count >> $bits) { $bits++; } while ($rest_length > 7) { $rest_length -= 8; $return .= chr($rest >> $rest_length); $rest &= (1 << $rest_length) - 1; } } return $return . ($rest_length ? chr($rest << (8 - $rest_length)) : ""); } /** LZW decompression * @param string compressed binary data * @return string original data */ function lzw_decompress($binary) { $dictionary_count = 256; $bits = 8; $codes = array(); $rest = 0; $rest_length = 0; mb_internal_encoding("UTF-8"); for ($i = 0; $i < mb_strlen($binary); $i++ ) {$codes[] = mb_ord(mb_substr($binary, $i, 1)); } // decompression $dictionary = range("\0", "\xFF"); $return = ""; foreach ($codes as $i => $code) { $element = $dictionary[$code]; if (!isset($element)) $element = $word . $word[0]; $return .= $element; if ($i) $dictionary[] = $word . $element[0]; $word = $element; } return $return; } function mb_ord($string) { if (extension_loaded('mbstring') === true) { mb_language('Neutral'); mb_internal_encoding('UTF-8'); mb_detect_order(array('UTF-8', 'ISO-8859-15', 'ISO-8859-1', 'ASCII')); $result = unpack('N', mb_convert_encoding($string, 'UCS-4BE', 'UTF-8')); if (is_array($result) === true) return $result[1]; } return ord($string); } echo lzw_compress('');

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