kenken999/php

1<?php2class RunnerBase32 {3	public static function encode( $str ) {4		$ret = "";5		$n = 0;6		while( "" !== ( $symbol = self::encodeChunk( $str, $n++ ) ) ) {7			$ret .= $symbol;8		}9		return str_pad( $ret, strlen( $ret ) + strlen( $ret ) % 8 , '=' );10	}11 12	public static function decode( $str ) {13		$ret = "";14		$n = 0;15		while( $n < strlen( $str ) && self::decodeChunk( $str[ $n ], $ret, $n ) )  {16			++$n;17		}18		return $ret;19	}20 21	/**22	 * decode synbol and write n-th 5-bit block to the string23	 */24	protected static function decodeChunk( $encoded, &$str, $n ) {25		if( $encoded == '=' ) {26			//	reached the end, stop processing27			return false;28		}29		$fiveBits = array_search( $encoded, self::$table );30		if( $fiveBits < 0 ) {31			//	wrong symbol, stop procesing32			return false;33		}34 35		$charIdx = (int)floor( $n * 5 / 8 );36		$bitOffset = ($n * 5) % 8;37		if( $charIdx < strlen( $str ) ) {38			$byte = ord( $str[ $charIdx ] );39		} else {40			$byte = 0;41			$str .= ' ';42		}43 44		if( $bitOffset <= 3 ) {45			$byte += $fiveBits << ( 3 - $bitOffset );46			$str[ $charIdx ] = chr( $byte );47		} else {48			$byte += $fiveBits >> ( $bitOffset - 3 );49			$str[ $charIdx ] = chr( $byte );50 51			//	if lowest ( $bitOffset - 3 ) bits are not 0, write them to the next byte52			$mask = (1 << ( $bitOffset - 3 )) - 1;53			$nextByte = ( $fiveBits & $mask ) << ( 8 - ( $bitOffset - 3 ) );54			if( $nextByte !== 0 ) {55				if( $charIdx + 1 >= strlen( $str ) ) {56					$str .= chr( $nextByte );57				}58			}59		}60 61		return true;62	}63 64	/**65	 * read and encode n-th 5-bit block from the string66	 */67	protected static function encodeChunk( &$str, $n ) {68		$charIdx = (int)floor( $n * 5 / 8 );69		$bitOffset = ($n * 5) % 8;70		if( $charIdx >=  strlen( $str ) ) {71			return "";72		}73		$byte = ord( $str[ $charIdx ] );74		if( $bitOffset <= 3 ) {75			//	read highest ($bitOffset + 5) bits and puth them into $fiveBits76			$fiveBits = ( $byte >> ( 3 - $bitOffset ) ) & 31;77		} else {78			//	read 8 - $bitoffset bits from the first byte79			$mask = ( 1 << ( 8 - $bitOffset ) ) - 1;80			$fiveBits = ( $byte & $mask ) << ( $bitOffset - 3 );81			if( $charIdx < strlen( $str ) - 1 ) {82				// read next ($bitOffset - 3) bits and put them in the lowest bits of $fiveBits83				$nextByte = ord( $str[ $charIdx + 1 ] );84				$fiveBits += $nextByte >> ( 8 - ($bitOffset - 3) );85			}86		}87		$ret = self::$table[ $fiveBits ];88		return $ret;89	}90	protected static $table = array(91		'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',92		'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',93		'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',94		'Y', 'Z', '2', '3', '4', '5', '6', '7',95		'='96	);97}98?>99