cityhash

node-cityhash

A NodeJS binding for Google CityHash.

Install

npm install cityhash

Functions

64-bit hash object:
{
    low:    {unsigned long}, eg 1727229466.
    high:   {unsigned long}, eg 1535838579.
    uint64: {boolean} true if hash object is uint64. Otherwise undefined.
    value:  {string}, eg "6596376470467341850".
}

128-bit hash object:
{
    low:     {64-bit hash object}.
    high:    {64-bit hash object}.
    uint128: {boolean} true if hash object is uint128. Otherwise undefined.
    value:   {string}, "low64,high64", eg "9138004313465017137,12242971252332641544".
}

/**
 * convert string or number to hash object.
 * @param {unsigned long long | string} the string or number to be convered to hash object.
 * @return {hash} 64-bit hash object or 128-bit hash object.
**/
function objectify(obj);

/**
 * stringify the hash object.
 * @param {hash} 64-bit hash object or 128-bit hash object.
 * @return {string} the hash string value, eg "6596376470467341850" or "9138004313465017137,12242971252332641544".
**/
function stringify(obj);

/**
 * Compute hash for str by CityHash64().
 * @param {string} str The string to compute hash.
 * @param {unsigned long long | string | 64-bit hash object} [seed0] The hash seed.
 * @param {unsigned long long | string | 64-bit hash object} [seed1] The hash seed.
 * @return {hash} 64-bit hash value.
**/
function hash64(str, [seed0], [seed1]);

/**
 * Compute hash for str by CityHash128().
 * @param {string} str The string to compute hash.
 * @param {string | 128-bit hash object} [seed0] The hash seed.
 * @return {hash} 128-bit hash value.
**/
function hash128(str, [seed0]);

/**
 * Compute hash crc for str by CityHashCrc128().
 * @param {string} str The string to compute hash.
 * @param {string | 128-bit hash object} [seed0] The hash seed.
 * @return {hash} 128-bit hash value.
**/
function crc128(str, [seed0]);

/**
 * Compute hash crc for str by CityHashCrc256().
 * @param {string} str The string to compute hash.
 * @return {array} 4 64-bit hash object in an array, eg [hash1, hash2, hash3, hash4].
**/
function crc256(str);

Usage

var cityhash = require('node-cityhash');
var hash;

hash = cityhash.stringify({low:1727229466, high:1535838579});
// hash = '6596376470467341850'

hash = cityhash.objectify('6596376470467341850');
// hash = {low: 1727229466, high: 1535838579, uint64: true}

hash = cityhash.hash64('Hello');
// hash = {
//    low: 1727229466,
//    high: 1535838579,
//    uint64: true,
//    value:'6596376470467341850'
//    }

hash = cityhash.hash64('Hello', 87392039);
// hash = {
//        low: 2569634289,
//        high: 3664379964,
//        uint64: true,
//        value: '15738392108067291633'
//    }

hash = cityhash.hash64('Hello', cityhash.objectify(87392039));
// hash = {
//        low: 2569634289,
//        high: 3664379964,
//        uint64: true,
//        value: '15738392108067291633'
//    }

hash = cityhash.hash64('Hello', 87392039, 1230234);
// hash = {
//        low: 2389520903,
//        high: 3787608545,
//        value: '16267654833214665223',
//        uint64: true,
//    }

hash = cityhash.hash128('Hello');
// hash = {
//        "low": {
//            "low": 68277041,
//            "high": 2127607426,
//            "value": "9138004313465017137",
//            "uint64": true
//        },
//        "high": {
//            "low": 3936042248,
//            "high": 2850538876,
//            "value": "12242971252332641544",
//            "uint64": true
//        },
//        "value": "9138004313465017137,12242971252332641544",
//        "uint128": true
//    }

hash = cityhash.hash128('Hello', '12343,30293');
// hash = {
//        "low": {
//            "low": 3184066266,
//            "high": 3674042232,
//            "value": "15779891233746910938",
//            "uint64": true
//        },
//        "high": {
//            "low": 4196783977,
//            "high": 3519958761,
//            "value": "15118107765960464233",
//            "uint64": true
//        },
//        "value": "15779891233746910938,15118107765960464233",
//        "uint128": true
//    }

hash = cityhash.hash128('Hello', cityhash.objectify('12343,30293'));
// hash = {
//        "low": {
//            "low": 3184066266,
//            "high": 3674042232,
//            "value": "15779891233746910938",
//            "uint64": true
//        },
//        "high": {
//            "low": 4196783977,
//            "high": 3519958761,
//            "value": "15118107765960464233",
//            "uint64": true
//        },
//        "value": "15779891233746910938,15118107765960464233",
//        "uint128": true
//    }

hash = cityhash.crc128('Hello');
// hash = {
//        "low": {
//            "low": 68277041,
//            "high": 2127607426,
//            "value": "9138004313465017137",
//            "uint64": true
//        },
//        "high": {
//            "low": 3936042248,
//            "high": 2850538876,
//            "value": "12242971252332641544",
//            "uint64": true
//        },
//        "value": "9138004313465017137,12242971252332641544",
//        "uint128": true
//    }

hash = cityhash.crc128('Hello', '12343,30293');
// hash = {
//        "low": {
//            "low": 3184066266,
//            "high": 3674042232,
//            "value": "15779891233746910938",
//            "uint64": true
//        },
//        "high": {
//            "low": 4196783977,
//            "high": 3519958761,
//            "value": "15118107765960464233",
//            "uint64": true
//        },
//        "value": "15779891233746910938,15118107765960464233",
//        "uint128": true
//    }

Benchmark

todo