<?php
/**
 * Created by PhpStorm.
 * User: Mead
 * Date: 2019/9/5
 * Time: 9:33 AM
 */

namespace App\Handlers;
trait Crc16Handler
{
    protected static $crc_table = [
        0x0000, 0x1189, 0x2312, 0x329B, 0x4624, 0x57AD,
        0x6536, 0x74BF, 0x8C48, 0x9DC1, 0xAF5A, 0xBED3,
        0xCA6C, 0xDBE5, 0xE97E, 0xF8F7, 0x1081, 0x0108,
        0x3393, 0x221A, 0x56A5, 0x472C, 0x75B7, 0x643E,
        0x9CC9, 0x8D40, 0xBFDB, 0xAE52, 0xDAED, 0xCB64,
        0xF9FF, 0xE876, 0x2102, 0x308B, 0x0210, 0x1399,
        0x6726, 0x76AF, 0x4434, 0x55BD, 0xAD4A, 0xBCC3,
        0x8E58, 0x9FD1, 0xEB6E, 0xFAE7, 0xC87C, 0xD9F5,
        0x3183, 0x200A, 0x1291, 0x0318, 0x77A7, 0x662E,
        0x54B5, 0x453C, 0xBDCB, 0xAC42, 0x9ED9, 0x8F50,
        0xFBEF, 0xEA66, 0xD8FD, 0xC974, 0x4204, 0x538D,
        0x6116, 0x709F, 0x0420, 0x15A9, 0x2732, 0x36BB,
        0xCE4C, 0xDFC5, 0xED5E, 0xFCD7, 0x8868, 0x99E1,
        0xAB7A, 0xBAF3, 0x5285, 0x430C, 0x7197, 0x601E,
        0x14A1, 0x0528, 0x37B3, 0x263A, 0xDECD, 0xCF44,
        0xFDDF, 0xEC56, 0x98E9, 0x8960, 0xBBFB, 0xAA72,
        0x6306, 0x728F, 0x4014, 0x519D, 0x2522, 0x34AB,
        0x0630, 0x17B9, 0xEF4E, 0xFEC7, 0xCC5C, 0xDDD5,
        0xA96A, 0xB8E3, 0x8A78, 0x9BF1, 0x7387, 0x620E,
        0x5095, 0x411C, 0x35A3, 0x242A, 0x16B1, 0x0738,
        0xFFCF, 0xEE46, 0xDCDD, 0xCD54, 0xB9EB, 0xA862,
        0x9AF9, 0x8B70, 0x8408, 0x9581, 0xA71A, 0xB693,
        0xC22C, 0xD3A5, 0xE13E, 0xF0B7, 0x0840, 0x19C9,
        0x2B52, 0x3ADB, 0x4E64, 0x5FED, 0x6D76, 0x7CFF,
        0x9489, 0x8500, 0xB79B, 0xA612, 0xD2AD, 0xC324,
        0xF1BF, 0xE036, 0x18C1, 0x0948, 0x3BD3, 0x2A5A,
        0x5EE5, 0x4F6C, 0x7DF7, 0x6C7E, 0xA50A, 0xB483,
        0x8618, 0x9791, 0xE32E, 0xF2A7, 0xC03C, 0xD1B5,
        0x2942, 0x38CB, 0x0A50, 0x1BD9, 0x6F66, 0x7EEF,
        0x4C74, 0x5DFD, 0xB58B, 0xA402, 0x9699, 0x8710,
        0xF3AF, 0xE226, 0xD0BD, 0xC134, 0x39C3, 0x284A,
        0x1AD1, 0x0B58, 0x7FE7, 0x6E6E, 0x5CF5, 0x4D7C,
        0xC60C, 0xD785, 0xE51E, 0xF497, 0x8028, 0x91A1,
        0xA33A, 0xB2B3, 0x4A44, 0x5BCD, 0x6956, 0x78DF,
        0x0C60, 0x1DE9, 0x2F72, 0x3EFB, 0xD68D, 0xC704,
        0xF59F, 0xE416, 0x90A9, 0x8120, 0xB3BB, 0xA232,
        0x5AC5, 0x4B4C, 0x79D7, 0x685E, 0x1CE1, 0x0D68,
        0x3FF3, 0x2E7A, 0xE70E, 0xF687, 0xC41C, 0xD595,
        0xA12A, 0xB0A3, 0x8238, 0x93B1, 0x6B46, 0x7ACF,
        0x4854, 0x59DD, 0x2D62, 0x3CEB, 0x0E70, 0x1FF9,
        0xF78F, 0xE606, 0xD49D, 0xC514, 0xB1AB, 0xA022,
        0x92B9, 0x8330, 0x7BC7, 0x6A4E, 0x58D5, 0x495C,
        0x3DE3, 0x2C6A, 0x1EF1, 0x0F78,
    ];


    public static function crc16($data)
    {
        $crc = 0xFFFF;

        foreach ($data as $d) {
            $d = hexdec($d);
            $crc = self::$crc_table[($d ^ $crc) & 0xFF] ^ ($crc >> 8 & 0xFF);
        }

        $crc = $crc ^ 0xFFFF;
        $crc = $crc & 0xFFFF;

        return str_pad(dechex($crc), 4, '0', STR_PAD_LEFT);
    }
}