Java Long Number Create toLong(byte[] bytes)

Description

Converts a byte array to a long value.

License

Apache License

Parameter

Parameter	Description
bytes	array

Return

the long value

Declaration

public static long toLong(byte[] bytes) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

public class Main {
    /**// ww w.j  a va  2s . com
     * Size of long in bytes
     */
    public static final int SIZEOF_LONG = Long.SIZE / Byte.SIZE;

    /**
     * Converts a byte array to a long value. Reverses
     * {@link #toBytes(long)}
     *
     * @param bytes array
     * @return the long value
     */
    public static long toLong(byte[] bytes) {
        return toLong(bytes, 0, SIZEOF_LONG);
    }

    /**
     * Converts a byte array to a long value. Assumes there will be
     * {@link #SIZEOF_LONG} bytes available.
     *
     * @param bytes  bytes
     * @param offset offset
     * @return the long value
     */
    public static long toLong(byte[] bytes, int offset) {
        return toLong(bytes, offset, SIZEOF_LONG);
    }

    /**
     * Converts a byte array to a long value.
     *
     * @param bytes  array of bytes
     * @param offset offset into array
     * @param length length of data (must be {@link #SIZEOF_LONG})
     * @return the long value
     * @throws IllegalArgumentException if length is not {@link #SIZEOF_LONG} or
     *                                  if there's not enough room in the array at the offset indicated.
     */
    public static long toLong(byte[] bytes, int offset, final int length) {
        if (length != SIZEOF_LONG || offset + length > bytes.length) {
            throw explainWrongLengthOrOffset(bytes, offset, length, SIZEOF_LONG);
        }
        long l = 0;
        for (int i = offset; i < offset + length; i++) {
            l <<= 8;
            l ^= bytes[i] & 0xFF;
        }
        return l;
    }

    private static IllegalArgumentException explainWrongLengthOrOffset(final byte[] bytes, final int offset,
            final int length, final int expectedLength) {
        String reason;
        if (length != expectedLength) {
            reason = "Wrong length: " + length + ", expected " + expectedLength;
        } else {
            reason = "offset (" + offset + ") + length (" + length + ") exceed the" + " capacity of the array: "
                    + bytes.length;
        }
        return new IllegalArgumentException(reason);
    }
}

Related

1. toLong(byte[] bytes)
2. toLong(byte[] bytes)
3. toLong(byte[] bytes)
4. toLong(byte[] bytes)
5. toLong(byte[] bytes)
6. toLong(byte[] bytes)
7. toLong(byte[] bytes)
8. toLong(byte[] bytes)
9. toLong(byte[] bytes, boolean bigEndian)