Crc16.php

<?php
/**
 * Crc16
 * 在线校验工具及相关说明：http://www.ip33.com/crc.html
 *
 * 使用
 * ```php
 * $byte = Crc16::str2bytes('08643330407105010301ac');
 * echo dechex(Crc16::CRC16_CCITT_FALSE($byte,0x0001));
 * ```
 */
class Crc16 {

  private static $crc16_ccitt_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  bytes2Str ($bytes)
  {
      $str="";
      for   ($i=0;$i<count($bytes);$i++)
          $str.=sprintf("%02X",$bytes[$i]);

      return   $str;
  }

  public static function str2bytes  ($string)
  {
      $bytes=array();
      for($i=0;$i<strlen($string)/2;$i++){
        $bytes[$i]= hexdec($string[$i*2].$string[$i*2+1]);
      }
      return   $bytes;
  }

  /**
   * 采用查表法，根据数据生成CRC校验码
   *
   * @param array $message 校验值，为需要校验的字节
   * @return int
   */
  public static function CRC_X25($message, $init = 0xffff) {
    
      $crc_reg = 0xffff;//CRC校验时初值
      for ($i = 0; $i < count($message); $i++) {
          $crc_reg = ($crc_reg >> 8) ^ self::$crc16_ccitt_table[($crc_reg ^ $message[$i]) & 0xff];
      }
      return ~$crc_reg & 0xffff;
  }

  /**
   * 宽度 : 16
   * 多项式 : 0x1021
   * 初始值 : 0x0000
   * 结果异或值 : 0x0000
   * 输入值反转 : true
   * 输出值反转 : true
   * @param bytes
   * @return int
   */
  public static function CRC16_CCITT($bytes,$init=0x0000,$polynomial=0x8408) {
      $crc = $init; // initial value
      $polynomial = 0x8408;// poly value reversed 0x1021;

      for ($i = 0; $i < count($bytes); $i++) {
          $crc ^= ((int) $bytes[$i] & 0x000000ff);
          for ($j = 0; $j < 8; $j++) {
              if (($crc & 0x00000001) != 0) {
                  $crc >>= 1;
                  $crc ^= $polynomial;
              } else {
                  $crc >>= 1;
              }
          }
      }
      return $crc;
  }

  /**
   * 宽度 : 16
   * 多项式 : 0x1021
   * 初始值 : 0xFFFF
   * 结果异或值 : 0x0000
   * 输入值反转 : false
   * 输出值反转 : false
   * @param bytes
   * @return int
   */
  public static function CRC16_CCITT_FALSE($bytes, $init = 0xffff, $polynomial = 0x1021) {
      $crc = $init; // initial value
      $polynomial = 0x1021; // poly value
      for ($index = 0; $index < count($bytes); $index++) {
          $b = $bytes[$index];
          for ($i = 0; $i < 8; $i++) {
              $bit = (($b >> (7 - $i) & 1) == 1);
              $c15 = (($crc >> 15 & 1) == 1);
              $crc <<= 1;
              if ($c15 ^ $bit)
                  $crc ^= $polynomial;
          }
      }
      $crc &= 0xffff;
      return $crc;
  }

  /**
   * @param bytes $buf
   * @param int $offset
   * @param int $length
   * @return int
   */
  public static function CRC16_MODBUS($buf,$offset, $length) {
      $c = 0xFFFF;
      $crc = 0xFFFF;
      for ($i = $offset; $i < $length; $i++) {
          $c = $buf[$i] & 0x00FF;
          $crc ^= $c;
          for ($j = 0; $j < 8; $j++) {
              if (($crc & 0x0001) != 0) {
                  $crc >>= 1;
                  $crc ^= 0xA001;
              } else
                  $crc >>= 1;
          }
      }
      return $crc;
  }

  /**
   * @param bytes $buf
   * @param int $offset
   * @param int $length
   * @return int
   */
  public static function CRC16_XMODEM($bytes) {
      $crc = 0x0000;          // initial value
      $polynomial = 0x1021;
      for ($index = 0; $index < count($bytes); $index++) {
          $b = $bytes[$index];
          for ($i = 0; $i < 8; $i++) {
              $bit = (($b >> (7 - $i) & 1) == 1);
              $c15 = (($crc >> 15 & 1) == 1);
              $crc <<= 1;
              if ($c15 ^ $bit) $crc ^= $polynomial;
          }
      }
      $crc &= 0xffff;
      return $crc;
  }
}