public static void getBytes(long i, final int index, final byte[] buf) {
        long q;
        int r;
        int pos = index;
        byte sign = 0;

        if (i < 0) {
            sign = '-';
            i = -i;
        }

        // Get 2 digits/iteration using longs until quotient fits into an int
        while (i > Integer.MAX_VALUE) {
            q = i / 100;
            // really: r = i - (q * 100);
            r = (int) (i - ((q << 6) + (q << 5) + (q << 2)));
            i = q;
            buf[--pos] = DigitOnes[r];
            buf[--pos] = DigitTens[r];
        }

        // Get 2 digits/iteration using ints
        int q2;
        int i2 = (int) i;
        while (i2 >= 65536) {
            q2 = i2 / 100;
            // really: r = i2 - (q * 100);
            r = i2 - ((q2 << 6) + (q2 << 5) + (q2 << 2));
            i2 = q2;
            buf[--pos] = DigitOnes[r];
            buf[--pos] = DigitTens[r];
        }

        // Fall thru to fast mode for smaller numbers
        // assert(i2 <= 65536, i2);
        for (;;) {
            q2 = i2 * 52429 >>> 16 + 3;
            r = i2 - ((q2 << 3) + (q2 << 1)); // r = i2-(q2*10) ...
            buf[--pos] = digits[r];
            i2 = q2;
            if (i2 == 0) {
                break;
            }
        }
        if (sign != 0) {
            buf[--pos] = sign;
        }
    }
Utilities for byte process

@author dennis
metamorphosis-commons/src/main/java/com/taobao/metamorphosis/network/ByteUtils.java