Java Byte Array to Endian bytesToNumberLittleEndian(byte[] buffer, int start, int length)

Description

Reconstructs a number that is represented by more than one byte in a network packet in little-endian order, for the very few protocol values that are sent in this quirky way.

License

Open Source License

Parameter

Parameter	Description
buffer	the byte array containing the packet data
start	the index of the first byte containing a numeric value
length	the number of bytes making up the value

Return

the reconstructed number

Declaration

@SuppressWarnings("SameParameterValue")
public static long bytesToNumberLittleEndian(byte[] buffer, int start, int length)

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /**/*  w w w.  j a  v a2s .  c  om*/
     * Reconstructs a number that is represented by more than one byte in a network packet in little-endian order, for
     * the very few protocol values that are sent in this quirky way.
     *
     * @param buffer the byte array containing the packet data
     * @param start the index of the first byte containing a numeric value
     * @param length the number of bytes making up the value
     * @return the reconstructed number
     */
    @SuppressWarnings("SameParameterValue")
    public static long bytesToNumberLittleEndian(byte[] buffer, int start, int length) {
        long result = 0;
        for (int index = start + length - 1; index >= start; index--) {
            result = (result << 8) + unsign(buffer[index]);
        }
        return result;
    }

    /**
     * Converts a signed byte to its unsigned int equivalent in the range 0-255.
     *
     * @param b a byte value to be considered an unsigned integer
     *
     * @return the unsigned version of the byte
     */
    public static int unsign(byte b) {
        return b & 0xff;
    }
}