blob: e3ae013c88c12518ff4c60a59a3395466968064f [file] [log] [blame]
'use strict';
module.exports = (function()
{
function _min(d0, d1, d2, bx, ay)
{
return d0 < d1 || d2 < d1
? d0 > d2
? d2 + 1
: d0 + 1
: bx === ay
? d1
: d1 + 1;
}
return function(a, b)
{
if (a === b) {
return 0;
}
if (a.length > b.length) {
var tmp = a;
a = b;
b = tmp;
}
var la = a.length;
var lb = b.length;
while (la > 0 && (a.charCodeAt(la - 1) === b.charCodeAt(lb - 1))) {
la--;
lb--;
}
var offset = 0;
while (offset < la && (a.charCodeAt(offset) === b.charCodeAt(offset))) {
offset++;
}
la -= offset;
lb -= offset;
if (la === 0 || lb < 3) {
return lb;
}
var x = 0;
var y;
var d0;
var d1;
var d2;
var d3;
var dd;
var dy;
var ay;
var bx0;
var bx1;
var bx2;
var bx3;
var vector = [];
for (y = 0; y < la; y++) {
vector.push(y + 1);
vector.push(a.charCodeAt(offset + y));
}
var len = vector.length - 1;
for (; x < lb - 3;) {
bx0 = b.charCodeAt(offset + (d0 = x));
bx1 = b.charCodeAt(offset + (d1 = x + 1));
bx2 = b.charCodeAt(offset + (d2 = x + 2));
bx3 = b.charCodeAt(offset + (d3 = x + 3));
dd = (x += 4);
for (y = 0; y < len; y += 2) {
dy = vector[y];
ay = vector[y + 1];
d0 = _min(dy, d0, d1, bx0, ay);
d1 = _min(d0, d1, d2, bx1, ay);
d2 = _min(d1, d2, d3, bx2, ay);
dd = _min(d2, d3, dd, bx3, ay);
vector[y] = dd;
d3 = d2;
d2 = d1;
d1 = d0;
d0 = dy;
}
}
for (; x < lb;) {
bx0 = b.charCodeAt(offset + (d0 = x));
dd = ++x;
for (y = 0; y < len; y += 2) {
dy = vector[y];
vector[y] = dd = _min(dy, d0, dd, bx0, vector[y + 1]);
d0 = dy;
}
}
return dd;
};
})();