Cách tính crc16 trong php

Question

Tôi cần trợ giúp trong việc chuyển đổi mã CRC được viết bằng Ojective C thành PHP. Sau đây là mã C Mục tiêu

static UInt16 CRC16_Table[] = 
    { 0x0000, 0x2110, 0x4220, 0x6330, 0x8440, 0xa550, 0xc660, 0xe770, 
    0x0881, 0x2991, 0x4aa1, 0x6bb1, 0x8cc1, 0xadd1, 0xcee1, 0xeff1, 
    0x3112, 0x1002, 0x7332, 0x5222, 0xb552, 0x9442, 0xf772, 0xd662, 
    0x3993, 0x1883, 0x7bb3, 0x5aa3, 0xbdd3, 0x9cc3, 0xfff3, 0xdee3, 
    0x6224, 0x4334, 0x2004, 0x0114, 0xe664, 0xc774, 0xa444, 0x8554, 
    0x6aa5, 0x4bb5, 0x2885, 0x0995, 0xeee5, 0xcff5, 0xacc5, 0x8dd5, 
    0x5336, 0x7226, 0x1116, 0x3006, 0xd776, 0xf666, 0x9556, 0xb446, 
    0x5bb7, 0x7aa7, 0x1997, 0x3887, 0xdff7, 0xfee7, 0x9dd7, 0xbcc7, 
    0xc448, 0xe558, 0x8668, 0xa778, 0x4008, 0x6118, 0x0228, 0x2338, 
    0xccc9, 0xedd9, 0x8ee9, 0xaff9, 0x4889, 0x6999, 0x0aa9, 0x2bb9, 
    0xf55a, 0xd44a, 0xb77a, 0x966a, 0x711a, 0x500a, 0x333a, 0x122a, 
    0xfddb, 0xdccb, 0xbffb, 0x9eeb, 0x799b, 0x588b, 0x3bbb, 0x1aab, 
    0xa66c, 0x877c, 0xe44c, 0xc55c, 0x222c, 0x033c, 0x600c, 0x411c, 
    0xaeed, 0x8ffd, 0xeccd, 0xcddd, 0x2aad, 0x0bbd, 0x688d, 0x499d, 
    0x977e, 0xb66e, 0xd55e, 0xf44e, 0x133e, 0x322e, 0x511e, 0x700e, 
    0x9fff, 0xbeef, 0xdddf, 0xfccf, 0x1bbf, 0x3aaf, 0x599f, 0x788f, 
    0x8891, 0xa981, 0xcab1, 0xeba1, 0x0cd1, 0x2dc1, 0x4ef1, 0x6fe1, 
    0x8010, 0xa100, 0xc230, 0xe320, 0x0450, 0x2540, 0x4670, 0x6760, 
    0xb983, 0x9893, 0xfba3, 0xdab3, 0x3dc3, 0x1cd3, 0x7fe3, 0x5ef3, 
    0xb102, 0x9012, 0xf322, 0xd232, 0x3542, 0x1452, 0x7762, 0x5672, 
    0xeab5, 0xcba5, 0xa895, 0x8985, 0x6ef5, 0x4fe5, 0x2cd5, 0x0dc5, 
    0xe234, 0xc324, 0xa014, 0x8104, 0x6674, 0x4764, 0x2454, 0x0544, 
    0xdba7, 0xfab7, 0x9987, 0xb897, 0x5fe7, 0x7ef7, 0x1dc7, 0x3cd7, 
    0xd326, 0xf236, 0x9106, 0xb016, 0x5766, 0x7676, 0x1546, 0x3456, 
    0x4cd9, 0x6dc9, 0x0ef9, 0x2fe9, 0xc899, 0xe989, 0x8ab9, 0xaba9, 
    0x4458, 0x6548, 0x0678, 0x2768, 0xc018, 0xe108, 0x8238, 0xa328, 
    0x7dcb, 0x5cdb, 0x3feb, 0x1efb, 0xf98b, 0xd89b, 0xbbab, 0x9abb, 
    0x754a, 0x545a, 0x376a, 0x167a, 0xf10a, 0xd01a, 0xb32a, 0x923a, 
    0x2efd, 0x0fed, 0x6cdd, 0x4dcd, 0xaabd, 0x8bad, 0xe89d, 0xc98d, 
    0x267c, 0x076c, 0x645c, 0x454c, 0xa23c, 0x832c, 0xe01c, 0xc10c, 
    0x1fef, 0x3eff, 0x5dcf, 0x7cdf, 0x9baf, 0xbabf, 0xd98f, 0xf89f, 
    0x176e, 0x367e, 0x554e, 0x745e, 0x932e, 0xb23e, 0xd10e, 0xf01e 
    }; 


    +(SInt16) CalculateCRC16 : (Byte*)buffer : (UInt16) length 
    { 
    UInt32 crc=0; 

    while (length--) 
     crc = ((crc>>8) & 0xff)^*(CRC16_Table + ((*buffer++^crc) & 0xff)); 

    return((SInt16)crc); 
    } 

và sau đây là đoạn code tôi đã viết cho đến nay trong php

$CRC16_Table = array 
     ( 0x0000, 0x2110, 0x4220, 0x6330, 0x8440, 0xa550, 0xc660, 0xe770, 
      0x0881, 0x2991, 0x4aa1, 0x6bb1, 0x8cc1, 0xadd1, 0xcee1, 0xeff1, 
      0x3112, 0x1002, 0x7332, 0x5222, 0xb552, 0x9442, 0xf772, 0xd662, 
      0x3993, 0x1883, 0x7bb3, 0x5aa3, 0xbdd3, 0x9cc3, 0xfff3, 0xdee3, 
      0x6224, 0x4334, 0x2004, 0x0114, 0xe664, 0xc774, 0xa444, 0x8554, 
      0x6aa5, 0x4bb5, 0x2885, 0x0995, 0xeee5, 0xcff5, 0xacc5, 0x8dd5, 
      0x5336, 0x7226, 0x1116, 0x3006, 0xd776, 0xf666, 0x9556, 0xb446, 
      0x5bb7, 0x7aa7, 0x1997, 0x3887, 0xdff7, 0xfee7, 0x9dd7, 0xbcc7, 
      0xc448, 0xe558, 0x8668, 0xa778, 0x4008, 0x6118, 0x0228, 0x2338, 
      0xccc9, 0xedd9, 0x8ee9, 0xaff9, 0x4889, 0x6999, 0x0aa9, 0x2bb9, 
      0xf55a, 0xd44a, 0xb77a, 0x966a, 0x711a, 0x500a, 0x333a, 0x122a, 
      0xfddb, 0xdccb, 0xbffb, 0x9eeb, 0x799b, 0x588b, 0x3bbb, 0x1aab, 
      0xa66c, 0x877c, 0xe44c, 0xc55c, 0x222c, 0x033c, 0x600c, 0x411c, 
      0xaeed, 0x8ffd, 0xeccd, 0xcddd, 0x2aad, 0x0bbd, 0x688d, 0x499d, 
      0x977e, 0xb66e, 0xd55e, 0xf44e, 0x133e, 0x322e, 0x511e, 0x700e, 
      0x9fff, 0xbeef, 0xdddf, 0xfccf, 0x1bbf, 0x3aaf, 0x599f, 0x788f, 
      0x8891, 0xa981, 0xcab1, 0xeba1, 0x0cd1, 0x2dc1, 0x4ef1, 0x6fe1, 
      0x8010, 0xa100, 0xc230, 0xe320, 0x0450, 0x2540, 0x4670, 0x6760, 
      0xb983, 0x9893, 0xfba3, 0xdab3, 0x3dc3, 0x1cd3, 0x7fe3, 0x5ef3, 
      0xb102, 0x9012, 0xf322, 0xd232, 0x3542, 0x1452, 0x7762, 0x5672, 
      0xeab5, 0xcba5, 0xa895, 0x8985, 0x6ef5, 0x4fe5, 0x2cd5, 0x0dc5, 
      0xe234, 0xc324, 0xa014, 0x8104, 0x6674, 0x4764, 0x2454, 0x0544, 
      0xdba7, 0xfab7, 0x9987, 0xb897, 0x5fe7, 0x7ef7, 0x1dc7, 0x3cd7, 
      0xd326, 0xf236, 0x9106, 0xb016, 0x5766, 0x7676, 0x1546, 0x3456, 
      0x4cd9, 0x6dc9, 0x0ef9, 0x2fe9, 0xc899, 0xe989, 0x8ab9, 0xaba9, 
      0x4458, 0x6548, 0x0678, 0x2768, 0xc018, 0xe108, 0x8238, 0xa328, 
      0x7dcb, 0x5cdb, 0x3feb, 0x1efb, 0xf98b, 0xd89b, 0xbbab, 0x9abb, 
      0x754a, 0x545a, 0x376a, 0x167a, 0xf10a, 0xd01a, 0xb32a, 0x923a, 
      0x2efd, 0x0fed, 0x6cdd, 0x4dcd, 0xaabd, 0x8bad, 0xe89d, 0xc98d, 
      0x267c, 0x076c, 0x645c, 0x454c, 0xa23c, 0x832c, 0xe01c, 0xc10c, 
      0x1fef, 0x3eff, 0x5dcf, 0x7cdf, 0x9baf, 0xbabf, 0xd98f, 0xf89f, 
      0x176e, 0x367e, 0x554e, 0x745e, 0x932e, 0xb23e, 0xd10e, 0xf01e 
     ); 

    function CalculateCRC16($strMessage) 
    { 
     $hexdata = pack('H*',$strMessage); 
     $nLength = strlen($hexdata); 
     $crc = 0xFFFF; 
     $pos = 0; 
     while($nLength > 0) 
     { 
      $crc = ($crc >> 8)^$CRC16_Table[($crc^ord($hexdata[$pos])) &  0xFF]; 
      $nLength--; 
      $pos++; 
     } 
     return ~$crc; 
    } 

đâu $ strMessage chứa giá trị đóng gói, nhưng nó không cho kết quả chính xác .

Mọi trợ giúp sẽ được đánh giá cao.

Answer 1

Điều này dường như làm việc, thử nghiệm với một số giá trị chống lại this website cho CRC-16-CCITT

Lưu ý rằng nó sử dụng chuỗi PHP như bộ đệm byte trực tiếp, bởi vì nó tương đương gần nhất của PHP để byte[]

<?php 

class CRC16 { 
    private static $CRC16_Table = array 
     ( 0x0000, 0x2110, 0x4220, 0x6330, 0x8440, 0xa550, 0xc660, 0xe770, 
      0x0881, 0x2991, 0x4aa1, 0x6bb1, 0x8cc1, 0xadd1, 0xcee1, 0xeff1, 
      0x3112, 0x1002, 0x7332, 0x5222, 0xb552, 0x9442, 0xf772, 0xd662, 
      0x3993, 0x1883, 0x7bb3, 0x5aa3, 0xbdd3, 0x9cc3, 0xfff3, 0xdee3, 
      0x6224, 0x4334, 0x2004, 0x0114, 0xe664, 0xc774, 0xa444, 0x8554, 
      0x6aa5, 0x4bb5, 0x2885, 0x0995, 0xeee5, 0xcff5, 0xacc5, 0x8dd5, 
      0x5336, 0x7226, 0x1116, 0x3006, 0xd776, 0xf666, 0x9556, 0xb446, 
      0x5bb7, 0x7aa7, 0x1997, 0x3887, 0xdff7, 0xfee7, 0x9dd7, 0xbcc7, 
      0xc448, 0xe558, 0x8668, 0xa778, 0x4008, 0x6118, 0x0228, 0x2338, 
      0xccc9, 0xedd9, 0x8ee9, 0xaff9, 0x4889, 0x6999, 0x0aa9, 0x2bb9, 
      0xf55a, 0xd44a, 0xb77a, 0x966a, 0x711a, 0x500a, 0x333a, 0x122a, 
      0xfddb, 0xdccb, 0xbffb, 0x9eeb, 0x799b, 0x588b, 0x3bbb, 0x1aab, 
      0xa66c, 0x877c, 0xe44c, 0xc55c, 0x222c, 0x033c, 0x600c, 0x411c, 
      0xaeed, 0x8ffd, 0xeccd, 0xcddd, 0x2aad, 0x0bbd, 0x688d, 0x499d, 
      0x977e, 0xb66e, 0xd55e, 0xf44e, 0x133e, 0x322e, 0x511e, 0x700e, 
      0x9fff, 0xbeef, 0xdddf, 0xfccf, 0x1bbf, 0x3aaf, 0x599f, 0x788f, 
      0x8891, 0xa981, 0xcab1, 0xeba1, 0x0cd1, 0x2dc1, 0x4ef1, 0x6fe1, 
      0x8010, 0xa100, 0xc230, 0xe320, 0x0450, 0x2540, 0x4670, 0x6760, 
      0xb983, 0x9893, 0xfba3, 0xdab3, 0x3dc3, 0x1cd3, 0x7fe3, 0x5ef3, 
      0xb102, 0x9012, 0xf322, 0xd232, 0x3542, 0x1452, 0x7762, 0x5672, 
      0xeab5, 0xcba5, 0xa895, 0x8985, 0x6ef5, 0x4fe5, 0x2cd5, 0x0dc5, 
      0xe234, 0xc324, 0xa014, 0x8104, 0x6674, 0x4764, 0x2454, 0x0544, 
      0xdba7, 0xfab7, 0x9987, 0xb897, 0x5fe7, 0x7ef7, 0x1dc7, 0x3cd7, 
      0xd326, 0xf236, 0x9106, 0xb016, 0x5766, 0x7676, 0x1546, 0x3456, 
      0x4cd9, 0x6dc9, 0x0ef9, 0x2fe9, 0xc899, 0xe989, 0x8ab9, 0xaba9, 
      0x4458, 0x6548, 0x0678, 0x2768, 0xc018, 0xe108, 0x8238, 0xa328, 
      0x7dcb, 0x5cdb, 0x3feb, 0x1efb, 0xf98b, 0xd89b, 0xbbab, 0x9abb, 
      0x754a, 0x545a, 0x376a, 0x167a, 0xf10a, 0xd01a, 0xb32a, 0x923a, 
      0x2efd, 0x0fed, 0x6cdd, 0x4dcd, 0xaabd, 0x8bad, 0xe89d, 0xc98d, 
      0x267c, 0x076c, 0x645c, 0x454c, 0xa23c, 0x832c, 0xe01c, 0xc10c, 
      0x1fef, 0x3eff, 0x5dcf, 0x7cdf, 0x9baf, 0xbabf, 0xd98f, 0xf89f, 
      0x176e, 0x367e, 0x554e, 0x745e, 0x932e, 0xb23e, 0xd10e, 0xf01e 
     ); 

    public static function calculate($buffer) { 
     $length = strlen($buffer); 

     $crc = 0; 
     $i = 0; 
     while($length--) { 
      $crc = (($crc >> 8) & 0xff)^(self::$CRC16_Table[(ord($buffer[$i++])^$crc) & 0xFF]); 
     } 

     return (($crc & 0xFFFF)^0x8000) - 0x8000; 
    }  
} 

echo CRC16::calculate("\x74\x65\x73\x74"); 

Answer 2

Đó là CRC- 16 CCITT, có thể nó sẽ giúp bạn

<?php 
function crc16($data) 
{ 
    $crc = 0xFFFF; 
    for ($i = 0; $i < strlen($data); $i++) 
    { 
    $x = (($crc >> 8)^ord($data[$i])) & 0xFF; 
    $x ^= $x >> 4; 
    $crc = (($crc << 8)^($x << 12)^($x << 5)^$x) & 0xFFFF; 
    } 
    return $crc; 
} 
?>