Port CRC implementation - Java Security

Java examples for Security:CRC

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Description

Port CRC implementation

Demo Code


//package com.java2s;

public class Main {
    /**//  w  ww .  ja v a 2 s  .  c o  m
     * Port of the following C implementation:
     * <pre>
     * WORD crc16(BYTE *buf, WORD num) {
     *    int i;
     *    WORD crc = 0xffff;
     *    while(num--) {
     *        crc ^= *buf++;
     *        i = 8;
     *        do {
     *           if (crc & 1)
     *             crc = ( crc >> 1 ) ^ 0x8408;
     *           else
     *             crc >>= 1;
     *        } while(--i);
     *    }
     *    return crc;
     * }
     * </pre>
     *
     * @param buf bytes buffer
     * @return crc16 code
     */
    public static char crc16(byte[] buf) {

        char crc = 0xffff;
        for (byte b : buf) {
            crc ^= b;
            for (int j = 0; j < 8; ++j) {
                if ((crc & 1) != 0)
                    crc = (char) ((crc >> 1) ^ 0x8408);
                else
                    crc >>= 1;
            }
        }
        return crc;
    }
}

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