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Diffstat (limited to 'node_modules/async/internal/Heap.js')
-rw-r--r-- | node_modules/async/internal/Heap.js | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/node_modules/async/internal/Heap.js b/node_modules/async/internal/Heap.js new file mode 100644 index 0000000..80762fe --- /dev/null +++ b/node_modules/async/internal/Heap.js @@ -0,0 +1,120 @@ +"use strict"; + +Object.defineProperty(exports, "__esModule", { + value: true +}); +// Binary min-heap implementation used for priority queue. +// Implementation is stable, i.e. push time is considered for equal priorities +class Heap { + constructor() { + this.heap = []; + this.pushCount = Number.MIN_SAFE_INTEGER; + } + + get length() { + return this.heap.length; + } + + empty() { + this.heap = []; + return this; + } + + percUp(index) { + let p; + + while (index > 0 && smaller(this.heap[index], this.heap[p = parent(index)])) { + let t = this.heap[index]; + this.heap[index] = this.heap[p]; + this.heap[p] = t; + + index = p; + } + } + + percDown(index) { + let l; + + while ((l = leftChi(index)) < this.heap.length) { + if (l + 1 < this.heap.length && smaller(this.heap[l + 1], this.heap[l])) { + l = l + 1; + } + + if (smaller(this.heap[index], this.heap[l])) { + break; + } + + let t = this.heap[index]; + this.heap[index] = this.heap[l]; + this.heap[l] = t; + + index = l; + } + } + + push(node) { + node.pushCount = ++this.pushCount; + this.heap.push(node); + this.percUp(this.heap.length - 1); + } + + unshift(node) { + return this.heap.push(node); + } + + shift() { + let [top] = this.heap; + + this.heap[0] = this.heap[this.heap.length - 1]; + this.heap.pop(); + this.percDown(0); + + return top; + } + + toArray() { + return [...this]; + } + + *[Symbol.iterator]() { + for (let i = 0; i < this.heap.length; i++) { + yield this.heap[i].data; + } + } + + remove(testFn) { + let j = 0; + for (let i = 0; i < this.heap.length; i++) { + if (!testFn(this.heap[i])) { + this.heap[j] = this.heap[i]; + j++; + } + } + + this.heap.splice(j); + + for (let i = parent(this.heap.length - 1); i >= 0; i--) { + this.percDown(i); + } + + return this; + } +} + +exports.default = Heap; +function leftChi(i) { + return (i << 1) + 1; +} + +function parent(i) { + return (i + 1 >> 1) - 1; +} + +function smaller(x, y) { + if (x.priority !== y.priority) { + return x.priority < y.priority; + } else { + return x.pushCount < y.pushCount; + } +} +module.exports = exports["default"];
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