Help me change the CRC lookup method of this C language into PHP code

Help me change the CRC lookup method of this C language to PHP code php c algorithm

Help me change this lookup method to PHP code ,!!!!!!!!!! CRC-ITU lookup algorithm C language segment static const 2010crctab16 [] = {0X0000, 0X1189, 0X2312, 0X329B, 0X4624, 0X57AD, 0X6536, 0X74BF, 0X8C48, expires, 0XAF5A, 0XBED3, 0XCA6C, 0XDBE5, 0XE97E, 0XF8F7, 0X1081, 0X0108, 0X3393, 0X221A, 0X56A5, 0X472C, 0X75B7, 0X643E, salesman, 0X8D40, 0 XBFDB, 0XAE52, 0 XDAED, 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, 0 XBDCB, 0XAC42, 0X9ED9, 0X8F50, 0 unknown, 0XEA66, 0XD8FD, 0XC974, 0X4204, 0X538D, 0X6116, 0X709F, 0X0420, 0X15A9, 0X2732, 0X36BB, 0XCE4C, 0XDFC5, 0XED5E, 0XFCD7, 0X8868, 0X99E1, 0XAB7A, 0XBAF3, 0X5285, 0x0000c, 0X7197, 0X601E, 0X14A1, 0X0528, 0X37B3, 0X263A, 0 XDECD, 0XCF44, 0 XFDDF, 0XEC56, 0X98E9, 0X8960, 0 XBBFB, 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, 0 XFFCF, 0XEE46, 0 fingerprint, 0XCD54, 0XB9EB, 0XA862, 0X9AF9, values, 0X8408, 0X9581, 0XA71A, 0XB693, 0XC22C, 0XD3A5, numbers, 0XF0B7, 0X0840, 0X19C9, numbers, 0X3ADB, 0X4E64, 0X5FED, 0X6D76, 0X7CFF, 0X9489, 0X8500, 0XB79 B, 0XA612, 0XD2AD, 0XC324, 0XF1BF, 0XE036, 0X18C1, 0X0948, 0X3BD3, 0X2A5A, 0X5EE5, primary, 0X7DF7, primary, 0XA50A, 0XB483, 0X8618, 0X9791, 0XE32E, 0XF2A7, 0XC03C, 0XD1B5, 0X2942, 0X38CB, 0X0A50, 0X1BD9, 0X6F66, 0X7EEF, 0X4C74, 0X5DFD, 0XA402, 0X9699, 0X8710, 0XF3AF, 0XE226, 0XD0BD, 0XC134, 0X39C3, 0X284A, 0X1AD1, 0X0B58, primary, 0XD785, 0XE51E, 0XF497, 0X8028, 0X9 1A1, primary, 0XB2B3, primary, 0X5BCD, 0X6956, 0X78DF, 0x0c0, 0X1DE9, 0X2F72, primary, primary, 0XC704, 0XF59F, 0XE416, 0X90A9, 0X8120, 0XB3BB, 0xa133, primary, 0X1CE1, 0X0D68, 0X3FF3, 0X2E7A, 0XE70E, 0XF687, 0XC41C, primary, primary, 0XB0A3, 0X8238, 0X93B1, primary, 0X7ACF, 0X4854, 0X59DD, 0X2D62, 0X3CEB, 0X0E70, 0X1FF9, 0XF78F, 0XE606, 0XD49D, 0XC514, 0XB1AB, 0XA022, 0X92B9, 0X8330, 0X 7BC7, 0X6A4E, 0X58D5, 0X495C, 0X3DE3, 0X2C6A, 0X1EF1, 0X0F78, }; b2getcrc16 (const U8 * pData, int nLength) {b2fcs = 0 xffff; // initialize while (nLength> 0) {fcs = (fcs> 8) ^ crctab16 [(fcs ^ * pData) & 0xff]; nLength --; pData ++ ;} return ~ Fcs; // reverse retrieval}

Reply to discussion (solution)

Verify the correctness by yourself.

$ S = 'abcdefg'; echo GetCrc16 ($ s, strlen ($ s); function GetCrc16 ($ pData, $ nLength) {$ crctab16 = array (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, 0 XBFDB, 0XAE52, 0 XDAED, 0XCB64, 0XF9FF, 0XE876, 0X2102, 0X308B, 0X0210, 0X1399, 0X6726, 0X7 6AF, 0X4434, 0X55BD, 0XAD4A, 0XBCC3, 0X8E58, 0X9FD1, 0XEB6E, 0XFAE7, 0XC87C, 0XD9F5, 0X3183, 0X200A, 0X1291, 0X0318, 0X77A7, 0X662E, 0X54B5, 0X453C, 0 XBDCB, 0XAC42, 0X9ED9, 0X8F50, 0 5e, 0XEA66, 0XD8FD, 0XC974, 0X4204, 0X538D, 0X6116, 0X709F, 0X0420, 0X15A9, 0X2732, 0X36BB, 0XCE4C, 0XDFC5, 0XED5E, 0XFCD7, 0X8868, 0X99E1, 0XAB7A, 0XBAF3, 0X5285, 0x0000c, 0X7197, 0X601E, 0X14A1, 0X0528, 0X37B3, 0X2 63A, 0 XDECD, 0XCF44, 0 XFDDF, 0XEC56, 0X98E9, 0X8960, 0 XBBFB, 0XAA72, 0X6306, 0X728F, 0X4014, 0X519D, 0X2522, 0X34AB, 0X0630, 0X17B9, 0XEF4E, 0XFEC7, 0XCC5C, 0XDDD5, 0XA96A, 0XB8E3, primary, primary, 0X7387, 0X620E, 0X5095, 0X411C, 0X35A3, 0X242A, 0X16B1, 0X0738, 0 XFFCF, 0XEE46, 0 Hour, 0XCD54, 0XB9EB, 0XA862, 0X9AF9, 0X8B70, 0X8408, 0X9581, 0XA71A, 0XB693, 0XC22C, 0XD3A5, 0XE13E, 0XF0B7, 0X0840, 0X1 9C9, 0X2B52, 0X3ADB, 0X4E64, 0X5FED, 0X6D76, California, 0X9489, 0X8500, 0XB79B, California, 0XD2AD, 0XC324, 0XF1BF, 0XE036, 0X18C1, 0X0948, 0X3BD3, 0X2A5A, 0X5EE5, primary, 0X7DF7, primary, primary, 0XB483, 0X8618, 0X9791, 0XE32E, 0XF2A7, 0XC03C, 0XD1B5, 0X2942, 0X38CB, 0X0A50, 0X1BD9, numbers, numbers, 0X4C74, 0X5DFD, 0XB58B, 0XA402, 0X9699, 0X8710, 0XF3AF, 0XE226, 0XD0BD, 0XC134, 0X39C3, 0X284A, 0X1AD1, 0 X B58, 0X7FE7, primary, 0X5CF5, primary, 0XC60C, primary, 0XE51E, 0XF497, 0X8028, 0X91A1, primary, 0XB2B3, 0X4A44, 0X5BCD, 0X6956, 0X78DF, 0X1DE9, 0X2F72, 0X3EFB, 0XD68D, 0XC704, 0XF59F, primary, 0X90A9, 0X8120, 0XB3BB, 0xa133, primary, 0X3FF3, 0X2E7A, 0XE70E, 0XF687, 0XC41C, 0XD595, 0XA12A, 0XB0A3, 0X8238, 0X93B1, 0X6B46, 0X7ACF, 0X4854, 0X59DD, 0X2D62, 0X3 CEB, hour, hour, 0XF78F, 0XE606, 0XD49D, 0XC514, 0XB1AB, 0XA022, 0X92B9, 0X8330, hour, 0X6A4E, 0X58D5, 0X495C, 0X3DE3, 0X2C6A, salesman, 0X0F78,); $ fcs = 0 xffff; // Initialization $ I = 0; while ($ nLength> 0) {$ fcs = ($ fcs> 8) ^ $ crctab16 [($ fcs ^ ord ($ pData {$ I}) & 0xff]; $ nLength --; $ I ++;} return ~ $ Fcs; // reverse retrieval}

-35460

The test value in C language is "0501001A" in hexadecimal notation, and the result is "778E"

char bufdata[]={0x05,0x01,0x00,0x1A};//int main(void){crc = GetCrc16( bufdata, sizeof(bufdata) );}

If php uses the method you have given, it calculates negative numbers and does not get what the C language requires.

No problem!

$s = "\x05\x01\x00\x1A";printf('%X', GetCrc16($s, strlen($s)));

FFFF778E
Only 2 bytes at the lowest position

$s = "\x05\x01\x00\x1A";printf('%X', GetCrc16($s, strlen($s)) &0xffff);

778E

So return ~ $ Fcs; // reverse response writing
Return ~ $ Fcs & 0 xffff;

I can only answer your questions.
You didn't say that. I don't want to be a perfect fan.

Yes, thank you!