Calculates a low collision hash code for the passed string - Java java.lang

Java examples for java.lang:String Hash

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Description

Calculates a low collision hash code for the passed string

Demo Code

//package com.java2s;

import java.util.Arrays;

public class Main {
    public static void main(String[] argv) {
        String s = "java2s.com";
        System.out.println(longHashCode(s));
    }/*w w w. ja va  2 s . com*/

    /**
     * Calculates a low collision hash code for the passed string
     * @param s The string to calculate the hash code for
     * @return the long hashcode
     */
    public static long longHashCode(String s) {
        long h = 0;
        int len = s.length();
        int off = 0;
        int hashPrime = s.hashCode();
        char val[] = s.toCharArray();
        for (int i = 0; i < len; i++) {
            h = (31 * h + val[off++] + (hashPrime * h));
        }
        return h;
    }

    /**
     * Calculates a low collision hash code for the passed byte array
     * @param arr The byte array to calculate the hash code for
     * @return the long hashcode
     */
    public static long longHashCode(byte[] arr) {
        long h = 0;
        int len = arr.length;
        int off = 0;
        int hashPrime = Arrays.hashCode(arr);
        for (int i = 0; i < len; i++) {
            h = (31 * h + arr[off++] + (hashPrime * h));
        }
        return h;
    }
}

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