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212 lines
7.2 KiB
212 lines
7.2 KiB
3 years ago
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'use strict';
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var GOOD_LEAF_SIZE = 200;
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// :: class<T> A rope sequence is a persistent sequence data structure
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// that supports appending, prepending, and slicing without doing a
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// full copy. It is represented as a mostly-balanced tree.
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var RopeSequence = function RopeSequence () {};
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RopeSequence.prototype.append = function append (other) {
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if (!other.length) { return this }
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other = RopeSequence.from(other);
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return (!this.length && other) ||
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(other.length < GOOD_LEAF_SIZE && this.leafAppend(other)) ||
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(this.length < GOOD_LEAF_SIZE && other.leafPrepend(this)) ||
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this.appendInner(other)
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};
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// :: (union<[T], RopeSequence<T>>) → RopeSequence<T>
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// Prepend an array or other rope to this one, returning a new rope.
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RopeSequence.prototype.prepend = function prepend (other) {
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if (!other.length) { return this }
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return RopeSequence.from(other).append(this)
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};
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RopeSequence.prototype.appendInner = function appendInner (other) {
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return new Append(this, other)
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};
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// :: (?number, ?number) → RopeSequence<T>
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// Create a rope repesenting a sub-sequence of this rope.
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RopeSequence.prototype.slice = function slice (from, to) {
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if ( from === void 0 ) from = 0;
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if ( to === void 0 ) to = this.length;
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if (from >= to) { return RopeSequence.empty }
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return this.sliceInner(Math.max(0, from), Math.min(this.length, to))
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};
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// :: (number) → T
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// Retrieve the element at the given position from this rope.
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RopeSequence.prototype.get = function get (i) {
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if (i < 0 || i >= this.length) { return undefined }
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return this.getInner(i)
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};
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// :: ((element: T, index: number) → ?bool, ?number, ?number)
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// Call the given function for each element between the given
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// indices. This tends to be more efficient than looping over the
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// indices and calling `get`, because it doesn't have to descend the
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// tree for every element.
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RopeSequence.prototype.forEach = function forEach (f, from, to) {
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if ( from === void 0 ) from = 0;
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if ( to === void 0 ) to = this.length;
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if (from <= to)
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{ this.forEachInner(f, from, to, 0); }
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else
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{ this.forEachInvertedInner(f, from, to, 0); }
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};
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// :: ((element: T, index: number) → U, ?number, ?number) → [U]
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// Map the given functions over the elements of the rope, producing
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// a flat array.
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RopeSequence.prototype.map = function map (f, from, to) {
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if ( from === void 0 ) from = 0;
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if ( to === void 0 ) to = this.length;
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var result = [];
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this.forEach(function (elt, i) { return result.push(f(elt, i)); }, from, to);
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return result
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};
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// :: (?union<[T], RopeSequence<T>>) → RopeSequence<T>
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// Create a rope representing the given array, or return the rope
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// itself if a rope was given.
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RopeSequence.from = function from (values) {
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if (values instanceof RopeSequence) { return values }
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return values && values.length ? new Leaf(values) : RopeSequence.empty
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};
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var Leaf = /*@__PURE__*/(function (RopeSequence) {
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function Leaf(values) {
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RopeSequence.call(this);
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this.values = values;
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}
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if ( RopeSequence ) Leaf.__proto__ = RopeSequence;
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Leaf.prototype = Object.create( RopeSequence && RopeSequence.prototype );
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Leaf.prototype.constructor = Leaf;
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var prototypeAccessors = { length: { configurable: true },depth: { configurable: true } };
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Leaf.prototype.flatten = function flatten () {
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return this.values
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};
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Leaf.prototype.sliceInner = function sliceInner (from, to) {
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if (from == 0 && to == this.length) { return this }
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return new Leaf(this.values.slice(from, to))
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};
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Leaf.prototype.getInner = function getInner (i) {
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return this.values[i]
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};
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Leaf.prototype.forEachInner = function forEachInner (f, from, to, start) {
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for (var i = from; i < to; i++)
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{ if (f(this.values[i], start + i) === false) { return false } }
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};
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Leaf.prototype.forEachInvertedInner = function forEachInvertedInner (f, from, to, start) {
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for (var i = from - 1; i >= to; i--)
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{ if (f(this.values[i], start + i) === false) { return false } }
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};
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Leaf.prototype.leafAppend = function leafAppend (other) {
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if (this.length + other.length <= GOOD_LEAF_SIZE)
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{ return new Leaf(this.values.concat(other.flatten())) }
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};
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Leaf.prototype.leafPrepend = function leafPrepend (other) {
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if (this.length + other.length <= GOOD_LEAF_SIZE)
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{ return new Leaf(other.flatten().concat(this.values)) }
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};
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prototypeAccessors.length.get = function () { return this.values.length };
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prototypeAccessors.depth.get = function () { return 0 };
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Object.defineProperties( Leaf.prototype, prototypeAccessors );
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return Leaf;
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}(RopeSequence));
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// :: RopeSequence
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// The empty rope sequence.
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RopeSequence.empty = new Leaf([]);
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var Append = /*@__PURE__*/(function (RopeSequence) {
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function Append(left, right) {
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RopeSequence.call(this);
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this.left = left;
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this.right = right;
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this.length = left.length + right.length;
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this.depth = Math.max(left.depth, right.depth) + 1;
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}
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if ( RopeSequence ) Append.__proto__ = RopeSequence;
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Append.prototype = Object.create( RopeSequence && RopeSequence.prototype );
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Append.prototype.constructor = Append;
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Append.prototype.flatten = function flatten () {
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return this.left.flatten().concat(this.right.flatten())
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};
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Append.prototype.getInner = function getInner (i) {
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return i < this.left.length ? this.left.get(i) : this.right.get(i - this.left.length)
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};
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Append.prototype.forEachInner = function forEachInner (f, from, to, start) {
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var leftLen = this.left.length;
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if (from < leftLen &&
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this.left.forEachInner(f, from, Math.min(to, leftLen), start) === false)
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{ return false }
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if (to > leftLen &&
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this.right.forEachInner(f, Math.max(from - leftLen, 0), Math.min(this.length, to) - leftLen, start + leftLen) === false)
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{ return false }
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};
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Append.prototype.forEachInvertedInner = function forEachInvertedInner (f, from, to, start) {
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var leftLen = this.left.length;
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if (from > leftLen &&
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this.right.forEachInvertedInner(f, from - leftLen, Math.max(to, leftLen) - leftLen, start + leftLen) === false)
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{ return false }
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if (to < leftLen &&
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this.left.forEachInvertedInner(f, Math.min(from, leftLen), to, start) === false)
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{ return false }
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};
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Append.prototype.sliceInner = function sliceInner (from, to) {
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if (from == 0 && to == this.length) { return this }
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var leftLen = this.left.length;
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if (to <= leftLen) { return this.left.slice(from, to) }
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if (from >= leftLen) { return this.right.slice(from - leftLen, to - leftLen) }
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return this.left.slice(from, leftLen).append(this.right.slice(0, to - leftLen))
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};
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Append.prototype.leafAppend = function leafAppend (other) {
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var inner = this.right.leafAppend(other);
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if (inner) { return new Append(this.left, inner) }
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};
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Append.prototype.leafPrepend = function leafPrepend (other) {
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var inner = this.left.leafPrepend(other);
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if (inner) { return new Append(inner, this.right) }
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};
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Append.prototype.appendInner = function appendInner (other) {
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if (this.left.depth >= Math.max(this.right.depth, other.depth) + 1)
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{ return new Append(this.left, new Append(this.right, other)) }
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return new Append(this, other)
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};
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return Append;
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}(RopeSequence));
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var ropeSequence = RopeSequence;
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module.exports = ropeSequence;
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