package com.xiaoleilu.hutool.util;
/**
* Hash算法大全<br>
* 推荐使用FNV1算法
*
* @author Goodzzp,Looly
*/
public final class HashUtil {
private HashUtil(){}
/**
* 加法hash
*
* @param key 字符串
* @param prime 一个质数
* @return hash结果
*/
public static int additiveHash(String key, int prime) {
int hash, i;
for (hash = key.length(), i = 0; i < key.length(); i++){
hash += key.charAt(i);
}
return hash % prime;
}
/**
* 旋转hash
*
* @param key 输入字符串
* @param prime 质数
* @return hash值
*/
public static int rotatingHash(String key, int prime) {
int hash, i;
for (hash = key.length(), i = 0; i < key.length(); ++i){
hash = (hash << 4) ^ (hash >> 28) ^ key.charAt(i);
}
// 使用：hash = (hash ^ (hash>>10) ^ (hash>>20)) & mask;
// 替代：hash %= prime;
// return (hash ^ (hash>>10) ^ (hash>>20));
return hash % prime;
}
/**
* 一次一个hash
*
* @param key 输入字符串
* @return 输出hash值
*/
public static int oneByOneHash(String key) {
int hash, i;
for (hash = 0, i = 0; i < key.length(); ++i) {
hash += key.charAt(i);
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
// return (hash & M_MASK);
return hash;
}
/**
* Bernstein's hash
*
* @param key 输入字节数组
* @return 结果hash
*/
public static int bernstein(String key) {
int hash = 0;
int i;
for (i = 0; i < key.length(); ++i){
hash = 33 * hash + key.charAt(i);
}
return hash;
}
/**
* Universal Hashing
*
* @param key 字节数组
* @param mask 掩码
* @param tab tab
* @return hash值
*/
public static int universal(char[] key, int mask, int[] tab) {
int hash = key.length, i, len = key.length;
for (i = 0; i < (len << 3); i += 8) {
char k = key[i >> 3];
if ((k & 0x01) == 0){
hash ^= tab[i + 0];
}
if ((k & 0x02) == 0){
hash ^= tab[i + 1];
}
if ((k & 0x04) == 0){
hash ^= tab[i + 2];
}
if ((k & 0x08) == 0){
hash ^= tab[i + 3];
}
if ((k & 0x10) == 0){
hash ^= tab[i + 4];
}
if ((k & 0x20) == 0){
hash ^= tab[i + 5];
}
if ((k & 0x40) == 0){
hash ^= tab[i + 6];
}
if ((k & 0x80) == 0){
hash ^= tab[i + 7];
}
}
return (hash & mask);
}
/**
* Zobrist Hashing
*
* @param key 字节数组
* @param mask 掩码
* @param tab tab
* @return hash值
*/
public static int zobrist(char[] key, int mask, int[][] tab) {
int hash, i;
for (hash = key.length, i = 0; i < key.length; ++i){
hash ^= tab[i][key[i]];
}
return (hash & mask);
}
/**
* 改进的32位FNV算法1
*
* @param data 数组
* @return hash结果
*/
public static int fnvHash(byte[] data) {
final int p = 16777619;
int hash = (int) 2166136261L;
for (byte b : data){
hash = (hash ^ b) * p;
}
hash += hash << 13;
hash ^= hash >> 7;
hash += hash << 3;
hash ^= hash >> 17;
hash += hash << 5;
return hash;
}
/**
* 改进的32位FNV算法1
*
* @param data 字符串
* @return hash结果
*/
public static int fnvHash(String data) {
final int p = 16777619;
int hash = (int) 2166136261L;
for (int i = 0; i < data.length(); i++){
hash = (hash ^ data.charAt(i)) * p;
}
hash += hash << 13;
hash ^= hash >> 7;
hash += hash << 3;
hash ^= hash >> 17;
hash += hash << 5;
return hash;
}
/**
* Thomas Wang的算法，整数hash
*
* @param key 整数
* @return hash值
*/
public static int intHash(int key) {
key += ~(key << 15);
key ^= (key >>> 10);
key += (key << 3);
key ^= (key >>> 6);
key += ~(key << 11);
key ^= (key >>> 16);
return key;
}
/**
* RS算法hash
*
* @param str 字符串
* @return hash值
*/
public static int rsHash(String str) {
int b = 378551;
int a = 63689;
int hash = 0;
for (int i = 0; i < str.length(); i++) {
hash = hash * a + str.charAt(i);
a = a * b;
}
return hash & 0x7FFFFFFF;
}
/**
* JS算法
*
* @param str 字符串
* @return hash值
*/
public static int jsHash(String str) {
int hash = 1315423911;
for (int i = 0; i < str.length(); i++) {
hash ^= ((hash << 5) + str.charAt(i) + (hash >> 2));
}
return hash & 0x7FFFFFFF;
}
/**
* PJW算法
*
* @param str 字符串
* @return hash值
*/
public static int pjwHash(String str) {
int bitsInUnsignedInt = 32;
int threeQuarters = (bitsInUnsignedInt * 3) / 4;
int oneEighth = bitsInUnsignedInt / 8;
int highBits = 0xFFFFFFFF << (bitsInUnsignedInt - oneEighth);
int hash = 0;
int test = 0;
for (int i = 0; i < str.length(); i++) {
hash = (hash << oneEighth) + str.charAt(i);
if ((test = hash & highBits) != 0) {
hash = ((hash ^ (test >> threeQuarters)) & (~highBits));
}
}
return hash & 0x7FFFFFFF;
}
/**
* ELF算法
*
* @param str 字符串
* @return hash值
*/
public static int elfHash(String str) {
int hash = 0;
int x = 0;
for (int i = 0; i < str.length(); i++) {
hash = (hash << 4) + str.charAt(i);
if ((x = (int) (hash & 0xF0000000L)) != 0) {
hash ^= (x >> 24);
hash &= ~x;
}
}
return hash & 0x7FFFFFFF;
}
/**
* BKDR算法
*
* @param str 字符串
* @return hash值
*/
public static int bkdrHash(String str) {
int seed = 131; // 31 131 1313 13131 131313 etc..
int hash = 0;
for (int i = 0; i < str.length(); i++) {
hash = (hash * seed) + str.charAt(i);
}
return hash & 0x7FFFFFFF;
}
/**
* SDBM算法
*
* @param str 字符串
* @return hash值
*/
public static int sdbmHash(String str) {
int hash = 0;
for (int i = 0; i < str.length(); i++) {
hash = str.charAt(i) + (hash << 6) + (hash << 16) - hash;
}
return hash & 0x7FFFFFFF;
}
/**
* DJB算法
*
* @param str 字符串
* @return hash值
*/
public static int djbHash(String str) {
int hash = 5381;
for (int i = 0; i < str.length(); i++) {
hash = ((hash << 5) + hash) + str.charAt(i);
}
return hash & 0x7FFFFFFF;
}
/**
* DEK算法
*
* @param str 字符串
* @return hash值
*/
public static int dekHash(String str) {
int hash = str.length();
for (int i = 0; i < str.length(); i++) {
hash = ((hash << 5) ^ (hash >> 27)) ^ str.charAt(i);
}
return hash & 0x7FFFFFFF;
}
/**
* AP算法
*
* @param str 字符串
* @return hash值
*/
public static int apHash(String str) {
int hash = 0;
for (int i = 0; i < str.length(); i++) {
hash ^= ((i & 1) == 0) ? ((hash << 7) ^ str.charAt(i) ^ (hash >> 3)) : (~((hash << 11) ^ str.charAt(i) ^ (hash >> 5)));
}
// return (hash & 0x7FFFFFFF);
return hash;
}
/**
* TianL Hash算法
* @param str 字符串
* @return Hash值
*/
public static long tianlHash(String str) {
long hash = 0;
int iLength = str.length();
if (iLength == 0){
return 0;
}
if (iLength <= 256){
hash = 16777216L * (iLength - 1);
}else{
hash = 4278190080L;
}
int i;
char ucChar;
if (iLength <= 96) {
for (i = 1; i <= iLength; i++) {
ucChar = str.charAt(i - 1);
if (ucChar <= 'Z' && ucChar >= 'A') {
ucChar = (char) (ucChar + 32);
}
hash += (3 * i * ucChar * ucChar + 5 * i * ucChar + 7 * i + 11 * ucChar) % 16777216;
}
} else {
for (i = 1; i <= 96; i++) {
ucChar = str.charAt(i + iLength - 96 - 1);
if (ucChar <= 'Z' && ucChar >= 'A'){
ucChar = (char) (ucChar + 32);
}
hash += (3 * i * ucChar * ucChar + 5 * i * ucChar + 7 * i + 11 * ucChar) % 16777216;
}
}
if (hash < 0) {
hash *= -1;
}
return hash;
}
/**
* JAVA自己带的算法
*
* @param str 字符串
* @return hash值
*/
public static int javaDefaultHash(String str) {
int h = 0;
int off = 0;
int len = str.length();
for (int i = 0; i < len; i++) {
h = 31 * h + str.charAt(off++);
}
return h;
}
/**
* 混合hash算法，输出64位的值
*
* @param str 字符串
* @return hash值
*/
public static long mixHash(String str) {
long hash = str.hashCode();
hash <<= 32;
hash |= fnvHash(str);
return hash;
}
}