Help to change the C-language CRC table method to PHP code

PHP C algorithm

Help to change this table method to PHP code,!!!!!!!!!! Crc-itu Search Table algorithm C language fragment static const U16 crctab16[] ={0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,0x8c48, 0X9DC 1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0X643E,0X9CC9, 0 X8D40, 0XBFDB, 0xae52, 0XDAED, 0xcb64, 0xf9ff, 0xe876,0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0X55BD,0XAD4 A, 0XBCC3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0X54B5, 0X453C,0 XBDCB, 0xac42, 0x9ed9, 0x8f50, 0XFBEF, 0xea66, 0XD8FD, 0xc974,0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0X2732, 0X36 BB,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, 0x06 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, 0X D3A5, 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, 0X e32e, 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, 0X F497, 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, 0X c41c, 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,}; U16 GETCRC16 (const u8* pData, int nlength) {U16 FCS = 0xFFFF;//Initialize while (nlength>0) {FCS = (FCS &G        T;> 8) ^ crctab16[(FCS ^ *pdata) & 0xFF];        nlength--;     pdata++; } return ~fcs;//}

Reply to discussion (solution)

Self-validating correctness

$s = ' abcdefg '; Echo GetCrc16 ($s, strlen ($s)), function GetCrc16 ($pData, $nLength) {$crctab = Array (0X0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0X74BF, 0x8c48, 0X9DC1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0XF8F7, 0X10 Bayi, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 0X9CC9, 0X8D40, 0XBFDB, 0xae52, 0XDAED, 0xcb64, 0xf9ff, 0XE  876, 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, 0XF  BEF, 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, 0XC    F44, 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, 0XE    E46, 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, 0X F2a7, 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, 0X E51E, 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, 0X2E7 A, 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, 0X0F7  8,); $fcs = 0xFFFF;  Initialize $i = 0;    while ($nLength >0) {$fcs = ($fcs >> 8) ^ $crctab 16[($fcs ^ ord ($pData {$i})) & 0xFF];    $nLength--;  $i + +; } return ~ $fcs;//Take counter}

-35460

The test value given by the C language is "0501001A" hexadecimal, resulting in "778E"

Char Bufdata[]={0x05,0x01,0x00,0x1a};//int main (void) {CRC = GETCRC16 (Bufdata, sizeof (Bufdata));}

and PHP If you give the method, the calculation is negative, completely can not get C language to

No problem!

$s = "\x05\x01\x00\x1a";p rintf ('%x ', GetCrc16 ($s, strlen ($s)));

ffff778e
Take low 2 bytes only

$s = "\x05\x01\x00\x1a";p rintf ('%x ', GetCrc16 ($s, strlen ($s)) &0xffff);

778E

So return ~ $fcs;//Take reaction writing
return ~ $fcs & 0xFFFF;

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