forked from lix-project/lix-website
137 lines
3.8 KiB
JavaScript
137 lines
3.8 KiB
JavaScript
|
(function() {
|
||
|
'use strict';
|
||
|
|
||
|
var collator;
|
||
|
try {
|
||
|
collator = (typeof Intl !== "undefined" && typeof Intl.Collator !== "undefined") ? Intl.Collator("generic", { sensitivity: "base" }) : null;
|
||
|
} catch (err){
|
||
|
console.log("Collator could not be initialized and wouldn't be used");
|
||
|
}
|
||
|
// arrays to re-use
|
||
|
var prevRow = [],
|
||
|
str2Char = [];
|
||
|
|
||
|
/**
|
||
|
* Based on the algorithm at http://en.wikipedia.org/wiki/Levenshtein_distance.
|
||
|
*/
|
||
|
var Levenshtein = {
|
||
|
/**
|
||
|
* Calculate levenshtein distance of the two strings.
|
||
|
*
|
||
|
* @param str1 String the first string.
|
||
|
* @param str2 String the second string.
|
||
|
* @param [options] Additional options.
|
||
|
* @param [options.useCollator] Use `Intl.Collator` for locale-sensitive string comparison.
|
||
|
* @return Integer the levenshtein distance (0 and above).
|
||
|
*/
|
||
|
get: function(str1, str2, options) {
|
||
|
var useCollator = (options && collator && options.useCollator);
|
||
|
|
||
|
var str1Len = str1.length,
|
||
|
str2Len = str2.length;
|
||
|
|
||
|
// base cases
|
||
|
if (str1Len === 0) return str2Len;
|
||
|
if (str2Len === 0) return str1Len;
|
||
|
|
||
|
// two rows
|
||
|
var curCol, nextCol, i, j, tmp;
|
||
|
|
||
|
// initialise previous row
|
||
|
for (i=0; i<str2Len; ++i) {
|
||
|
prevRow[i] = i;
|
||
|
str2Char[i] = str2.charCodeAt(i);
|
||
|
}
|
||
|
prevRow[str2Len] = str2Len;
|
||
|
|
||
|
var strCmp;
|
||
|
if (useCollator) {
|
||
|
// calculate current row distance from previous row using collator
|
||
|
for (i = 0; i < str1Len; ++i) {
|
||
|
nextCol = i + 1;
|
||
|
|
||
|
for (j = 0; j < str2Len; ++j) {
|
||
|
curCol = nextCol;
|
||
|
|
||
|
// substution
|
||
|
strCmp = 0 === collator.compare(str1.charAt(i), String.fromCharCode(str2Char[j]));
|
||
|
|
||
|
nextCol = prevRow[j] + (strCmp ? 0 : 1);
|
||
|
|
||
|
// insertion
|
||
|
tmp = curCol + 1;
|
||
|
if (nextCol > tmp) {
|
||
|
nextCol = tmp;
|
||
|
}
|
||
|
// deletion
|
||
|
tmp = prevRow[j + 1] + 1;
|
||
|
if (nextCol > tmp) {
|
||
|
nextCol = tmp;
|
||
|
}
|
||
|
|
||
|
// copy current col value into previous (in preparation for next iteration)
|
||
|
prevRow[j] = curCol;
|
||
|
}
|
||
|
|
||
|
// copy last col value into previous (in preparation for next iteration)
|
||
|
prevRow[j] = nextCol;
|
||
|
}
|
||
|
}
|
||
|
else {
|
||
|
// calculate current row distance from previous row without collator
|
||
|
for (i = 0; i < str1Len; ++i) {
|
||
|
nextCol = i + 1;
|
||
|
|
||
|
for (j = 0; j < str2Len; ++j) {
|
||
|
curCol = nextCol;
|
||
|
|
||
|
// substution
|
||
|
strCmp = str1.charCodeAt(i) === str2Char[j];
|
||
|
|
||
|
nextCol = prevRow[j] + (strCmp ? 0 : 1);
|
||
|
|
||
|
// insertion
|
||
|
tmp = curCol + 1;
|
||
|
if (nextCol > tmp) {
|
||
|
nextCol = tmp;
|
||
|
}
|
||
|
// deletion
|
||
|
tmp = prevRow[j + 1] + 1;
|
||
|
if (nextCol > tmp) {
|
||
|
nextCol = tmp;
|
||
|
}
|
||
|
|
||
|
// copy current col value into previous (in preparation for next iteration)
|
||
|
prevRow[j] = curCol;
|
||
|
}
|
||
|
|
||
|
// copy last col value into previous (in preparation for next iteration)
|
||
|
prevRow[j] = nextCol;
|
||
|
}
|
||
|
}
|
||
|
return nextCol;
|
||
|
}
|
||
|
|
||
|
};
|
||
|
|
||
|
// amd
|
||
|
if (typeof define !== "undefined" && define !== null && define.amd) {
|
||
|
define(function() {
|
||
|
return Levenshtein;
|
||
|
});
|
||
|
}
|
||
|
// commonjs
|
||
|
else if (typeof module !== "undefined" && module !== null && typeof exports !== "undefined" && module.exports === exports) {
|
||
|
module.exports = Levenshtein;
|
||
|
}
|
||
|
// web worker
|
||
|
else if (typeof self !== "undefined" && typeof self.postMessage === 'function' && typeof self.importScripts === 'function') {
|
||
|
self.Levenshtein = Levenshtein;
|
||
|
}
|
||
|
// browser main thread
|
||
|
else if (typeof window !== "undefined" && window !== null) {
|
||
|
window.Levenshtein = Levenshtein;
|
||
|
}
|
||
|
}());
|
||
|
|