<?php
/* au CRCチェックバリュークラス ver1.0 poor-script.com */
class auCRC{
	# CRC 固定データテーブル
	protected $crcTable = Array(
		0x0000,0x1021,0x2042,0x3063,0x4084,0x50A5,0x60C6,0x70E7,
		0x8108,0x9129,0xA14A,0xB16B,0xC18C,0xD1AD,0xE1CE,0xF1EF,
		0x1231,0x0210,0x3273,0x2252,0x52B5,0x4294,0x72F7,0x62D6,
		0x9339,0x8318,0xB37B,0xA35A,0xD3BD,0xC39C,0xF3FF,0xE3DE,
		0x2462,0x3443,0x0420,0x1401,0x64E6,0x74C7,0x44A4,0x5485,
		0xA56A,0xB54B,0x8528,0x9509,0xE5EE,0xF5CF,0xC5AC,0xD58D,
		0x3653,0x2672,0x1611,0x0630,0x76D7,0x66F6,0x5695,0x46B4,
		0xB75B,0xA77A,0x9719,0x8738,0xF7DF,0xE7FE,0xD79D,0xC7BC,
		0x48C4,0x58E5,0x6886,0x78A7,0x0840,0x1861,0x2802,0x3823,
		0xC9CC,0xD9ED,0xE98E,0xF9AF,0x8948,0x9969,0xA90A,0xB92B,
		0x5AF5,0x4AD4,0x7AB7,0x6A96,0x1A71,0x0A50,0x3A33,0x2A12,
		0xDBFD,0xCBDC,0xFBBF,0xEB9E,0x9B79,0x8B58,0xBB3B,0xAB1A,
		0x6CA6,0x7C87,0x4CE4,0x5CC5,0x2C22,0x3C03,0x0C60,0x1C41,
		0xEDAE,0xFD8F,0xCDEC,0xDDCD,0xAD2A,0xBD0B,0x8D68,0x9D49,
		0x7E97,0x6EB6,0x5ED5,0x4EF4,0x3E13,0x2E32,0x1E51,0x0E70,
		0xFF9F,0xEFBE,0xDFDD,0xCFFC,0xBF1B,0xAF3A,0x9F59,0x8F78,
		0x9188,0x81A9,0xB1CA,0xA1EB,0xD10C,0xC12D,0xF14E,0xE16F,
		0x1080,0x00A1,0x30C2,0x20E3,0x5004,0x4025,0x7046,0x6067,
		0x83B9,0x9398,0xA3FB,0xB3DA,0xC33D,0xD31C,0xE37F,0xF35E,
		0x02B1,0x1290,0x22F3,0x32D2,0x4235,0x5214,0x6277,0x7256,
		0xB5EA,0xA5CB,0x95A8,0x8589,0xF56E,0xE54F,0xD52C,0xC50D,
		0x34E2,0x24C3,0x14A0,0x0481,0x7466,0x6447,0x5424,0x4405,
		0xA7DB,0xB7FA,0x8799,0x97B8,0xE75F,0xF77E,0xC71D,0xD73C,
		0x26D3,0x36F2,0x0691,0x16B0,0x6657,0x7676,0x4615,0x5634,
		0xD94C,0xC96D,0xF90E,0xE92F,0x99C8,0x89E9,0xB98A,0xA9AB,
		0x5844,0x4865,0x7806,0x6827,0x18C0,0x08E1,0x3882,0x28A3,
		0xCB7D,0xDB5C,0xEB3F,0xFB1E,0x8BF9,0x9BD8,0xABBB,0xBB9A,
		0x4A75,0x5A54,0x6A37,0x7A16,0x0AF1,0x1AD0,0x2AB3,0x3A92,
		0xFD2E,0xED0F,0xDD6C,0xCD4D,0xBDAA,0xAD8B,0x9DE8,0x8DC9,
		0x7C26,0x6C07,0x5C64,0x4C45,0x3CA2,0x2C83,0x1CE0,0x0CC1,
		0xEF1F,0xFF3E,0xCF5D,0xDF7C,0xAF9B,0xBFBA,0x8FD9,0x9FF8,
		0x6E17,0x7E36,0x4E55,0x5E74,0x2E93,0x3EB2,0x0ED1,0x1EF0 
	);
	# 正常なファイルか
	public $isFile = false;
	# ファイルサイズ
	protected $fileSize = 0;
	# ファイルパス
	protected $filePath = "";
	# ファイル中身
	protected $fileContents;
	# CRC付加したファイルサイズ
	protected $fileAddCRCSize = 0;
	# CRC
	protected $crc_char = "";
	
	## コンストラクター
	// @param string $fileName
	public function __construct($fileName){
		$this->filePath = $fileName;
		if(is_file($fileName) === true){
			$this->fileSize = filesize($fileName);
			if($this->fileSize > 0){
				$this->isFile = true;
				//CRC取得
				$this->crc_char = $this->crc();
				//CRC付加ファイルサイズ
				$this->fileAddCRCSize = $this->fileSize + strlen($this->crc_char);
			}
		}
	}
	## CRC付加サイズ
	// @return int
	public function fileSize(){
		if($this->isFile === false){
			return 0;
		}
		return $this->fileAddCRCSize
	}
	## CRC付加データ
	// @return string
	public function fileContents(){
		if($this->isFile === false){
			return null;
		}
		if($this->crc_char === null){
			return $this->fileContents;
		}else{
			return $this->fileContents . $this->crc_char;
		}
	}
	## CRCチェックバリュー
	// @return string
	protected function crc(){
		if($this->isFile === false){
			return null;
		}
		/* データファイル オープン */
		$fp = fopen($this->filePath, "rb");
		/* データファイル リード */
		$this->fileContents = fread($fp, $this->fileSize);
		if($this->fileContents === false){
			return null;
		}
		$buff = unpack("C*", $this->fileContents);
		$crc = 0xFFFF;
		/* チェックバリュー計算 */
		for($i = 1; $i <= $this->fileSize; $i++){
			$ch = $buff[$i];
			$crc = $this->crcTable[($crc >> 8 ^ $ch) & 0xFF] ^ ($crc << 8);
		}
		$crc_str = pack("n*", $crc);
		if($crc_str == "\x00\x00"){
			return null;
		}
		return $crc_str;
	}
}
?>