Calculate CRC16 X25 in php

Question

I need help in calculating CRC X25 variation, i have a Java tool and also an online tool that give the correct conversion, but i haven't been able to reproduce it myself.

Online Tool

Github for online tool

String: 40402900033231334C323031373030313839360000000000009001FFFFFFFF0000D656B759 Input type: Hex -> Calc CRC16

Result: CRC-16/X-25 
0x6C49 <-- this is the value im trying to get in php from that string above.

My Php code so far

private static $CRC16_Table = 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, 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 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;
}

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

    foreach ($data as $d) {
        $crc = self::$CRC16_Table[($d ^ $crc) & 0xFF] ^ ($crc >> 8 & 0xFF);
    }

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

    return $crc;
}

This gives me results as follows

ComputeCrc(str_split("40402900033231334C323031373030313839360000000000009001FFFFFFFF0000D656B759", 2));
Result = ec71 <-- decHex result

calculate("40402900033231334C323031373030313839360000000000009001FFFFFFFF0000D656B759");
Result = 48d7; <-- decHex result

Any help will be very appreciated

Answer 1

Solved it applying hexdec before the calculation, may be useful in the future.

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

    foreach ($data as $d) {
        $d = hexdec($d); <-- This did the trick
        $crc = self::$CRC16_Table[($d ^ $crc) & 0xFF] ^ ($crc >> 8 & 0xFF);
    }

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

    return $crc;
}