// wink-distance
// Distance functions for Bag of Words, Strings,
// Vectors and more.
//
// Copyright (C) GRAYPE Systems Private Limited
//
// This file is part of “wink-distance”.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the "Software"),
// to deal in the Software without restriction, including without limitation
// the rights to use, copy, modify, merge, publish, distribute, sublicense,
// and/or sell copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
// ## string
// ### hamming
/**
*
* Computes the hamming distance between two strings of identical length.
* This distance is always `>= 0`.
*
* @method string.hamming
* @param {string} str1 first string.
* @param {string} str2 second string.
* @return {number} hamming distance between `str1` and `str2`.
* @example
* hamming( 'john', 'john' );
* // -> 0
* hamming( 'sam', 'sat' );
* // -> 1
* hamming( 'summer', 'samuel' );
* // -> 3
* hamming( 'saturn', 'urn' );
* // -> throws error
*/
var hamming = function ( str1, str2 ) {
// As we may need to swap values!
var s1 = str1,
s2 = str2;
// String lengths.
var s1Length = s1.length,
s2Length = s2.length;
// Absolute distance between `s1` & `s2`.
var distance = 0;
if ( s1Length !== s2Length ) {
throw Error( 'wink-distance: hamming requires identical length input strings.' );
}
// Compute distance.
for ( var i = 0; i < s1Length; i += 1 ) {
if ( s1[ i ] !== s2[ i ] ) distance += 1;
}
// Normalize the distance & return.
return distance;
}; // hamming()
module.exports = hamming;
