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META-INF.assets.rjzjh.zrender.core.arrayDiff.js Maven / Gradle / Ivy
// Hirschberg's algorithm
// http://en.wikipedia.org/wiki/Hirschberg%27s_algorithm
/**
* @module zrender/core/arrayDiff
* @author Yi Shen
*/
define(function (require) {
function defaultCompareFunc(a, b) {
return a === b;
}
function createItem(cmd, idx, idx1) {
var res = {
// cmd explanation
// '=': not change
// '^': replace with a new item in second array. Unused temporary
// '+': add a new item of second array
// '-': del item in first array
cmd: cmd,
// Value index, use index in the first array
// Except '+'. Adding a new item needs value in the second array
idx: idx
};
// Replace need to know both two indices
// if (cmd === '^') {
// res.idx1 = idx1;
// }
if (cmd === '=') {
res.idx1 = idx1;
}
return res;
}
function append(out, cmd, idx, idx1) {
out.push(createItem(cmd, idx, idx1));
}
var abs = Math.abs;
// Needleman-Wunsch score
function score(arr0, arr1, i0, i1, j0, j1, equal, memo) {
var last;
var invM = i0 > i1;
var invN = j0 > j1;
var m = abs(i1 - i0);
var n = abs(j1 - j0);
var i;
var j;
for (i = 0; i <= m; i++) {
for (j = 0; j <= n; j++) {
if (i === 0) {
memo[j] = j;
}
else if (j === 0) {
last = memo[j];
memo[j] = i;
}
else {
// memo[i-1][j-1] + same(arr0[i-1], arr1[j-1]) ? 0 : 1
// Retained or replace
var val0 = arr0[invM ? (i0 - i) : (i - 1 + i0)];
var val1 = arr1[invN ? (j0 - j) : (j - 1 + j0)];
// Because replace is add after remove actually
// It has a higher score than removing or adding
// TODO custom score function
var score0 = last + (equal(val0, val1) ? 0 : 2);
// memo[i-1][j] + 1
// Remove arr0[i-1]
var score1 = memo[j] + 1;
// memo[i][j-1] + 1
// Add arr1[j-1]
var score2 = memo[j - 1] + 1;
last = memo[j];
memo[j] = score0 < score1 ? score0 : score1;
score2 < memo[j] && (memo[j] = score2);
// Math min of three parameters seems slow
// memo[j] = Math.min(score0, score1, score2);
}
}
}
return memo;
}
function hirschberg(arr0, arr1, i0, i1, j0, j1, equal, score0, score1) {
var out = [];
var len0 = i1 - i0;
var len1 = j1 - j0;
var i;
var j;
if (! len0) {
for (j = 0; j < len1; j++) {
append(out, '+', j + j0);
}
}
else if (! len1) {
for (i = 0; i < len0; i++) {
append(out, '-', i + i0);
}
}
else if (len0 === 1) {
var a = arr0[i0];
var matched = false;
for (j = 0; j < len1; j++) {
if (equal(a, arr1[j + j0]) && ! matched) {
matched = true;
// Equal and update use the index in first array
append(out, '=', i0, j + j0);
}
else {
// if (j === len1 - 1 && ! matched) {
// append(out, '^', i0, j + j0);
// }
// else {
append(out, '+', j + j0);
// }
}
}
if (! matched) {
append(out, '-', i0);
}
}
else if (len1 === 1) {
var b = arr1[j0];
var matched = false;
for (i = 0; i < len0; i++) {
if (equal(b, arr0[i + i0]) && ! matched) {
matched = true;
append(out, '=', i + i0, j0);
}
else {
// if (i === len0 - 1 && ! matched) {
// append(out, '^', i + i0, j0);
// }
// else {
append(out, '-', i + i0);
// }
}
}
if (! matched) {
append(out, '+', j0);
}
}
else {
var imid = ((len0 / 2) | 0) + i0;
score(arr0, arr1, i0, imid, j0, j1, equal, score0);
score(arr0, arr1, i1, imid + 1, j1, j0, equal, score1);
var min = Infinity;
var jmid = 0;
var sum;
for (j = 0; j <= len1; j++) {
sum = score0[j] + score1[len1 - j];
if (sum < min) {
min = sum;
jmid = j;
}
}
jmid += j0;
out = hirschberg(arr0, arr1, i0, imid, j0, jmid, equal, score0, score1);
var out1 = hirschberg(arr0, arr1, imid, i1, jmid, j1, equal, score0, score1);
// Concat
for (i = 0; i < out1.length; i++) {
out.push(out1[i]);
}
}
return out;
}
function arrayDiff(arr0, arr1, equal) {
equal = equal || defaultCompareFunc;
// Remove the common head and tail
var i;
var j;
var len0 = arr0.length;
var len1 = arr1.length;
var lenMin = Math.min(len0, len1);
var head = [];
for (i = 0; i < lenMin; i++) {
if (! equal(arr0[i], arr1[i])) {
break;
}
append(head, '=', i, i);
}
for (j = 0; j < lenMin; j++) {
if (! equal(arr0[len0 - j - 1], arr1[len1 - j - 1])) {
break;
}
}
if (len0 - j >= i || len1 - j >= i) {
var middle = hirschberg(arr0, arr1, i, len0 - j, i, len1 - j, equal, [], []);
for (i = 0; i < middle.length; i++) {
head.push(middle[i]);
}
for (i = 0; i < j; i++) {
append(head, '=', len0 - j + i, len1 - j + i);
}
}
return head;
}
return arrayDiff;
});
