@a-s8h/liblevenshtein/lib/liblevenshtein/collection/max-heap.js

Various utilities regarding Levenshtein transducers.

// Generated by CoffeeScript 1.7.1
(function() {
  var MaxHeap, global;

  MaxHeap = (function() {
    MaxHeap.prototype._parent = function(i) {
      if (i > 0) {
        return ((i + 1) >> 1) - 1;
      } else {
        return 0;
      }
    };

    MaxHeap.prototype._left_child = function(i) {
      return (i << 1) + 1;
    };

    MaxHeap.prototype._right_child = function(i) {
      return (i << 1) + 2;
    };

    MaxHeap.prototype._heapify = function(i) {
      var heap, l, largest, r, tmp;
      l = this._left_child(i);
      r = this._right_child(i);
      heap = this['heap'];
      if (l < this['length'] && this.f(heap[l], heap[i]) > 0) {
        largest = l;
      } else {
        largest = i;
      }
      if (r < this['length'] && this.f(heap[r], heap[largest]) > 0) {
        largest = r;
      }
      if (largest !== i) {
        tmp = heap[i];
        heap[i] = heap[largest];
        heap[largest] = tmp;
        this._heapify(largest);
      }
      return null;
    };

    MaxHeap.prototype._build = function() {
      var i;
      i = this['length'] >> 1;
      while (i >= 0) {
        this._heapify(i);
        i -= 1;
      }
      return null;
    };

    MaxHeap.prototype['increase_key'] = function(i, key) {
      var f, heap, p, parent, tmp;
      f = this.f;
      heap = this['heap'];
      if (f(key, heap[i]) < 0) {
        throw new Error("Expected " + key + " to be at least heap[" + i + "] = " + heap[i]);
      }
      heap[i] = key;
      parent = this._parent;
      p = parent(i);
      while (i && f(heap[p], heap[i]) < 0) {
        tmp = heap[i];
        heap[i] = heap[p];
        heap[p] = tmp;
        i = p;
        p = parent(i);
      }
      return null;
    };

    MaxHeap.prototype['sort'] = function() {
      var heap, i, tmp;
      this._build();
      i = this['length'] - 1;
      heap = this['heap'];
      while (i >= 0) {
        tmp = heap[0];
        heap[0] = heap[i];
        heap[i] = tmp;
        this['length'] -= 1;
        this._heapify(0);
        i -= 1;
      }
      return null;
    };

    MaxHeap.prototype['peek'] = function() {
      if (this['length']) {
        return this['heap'][0];
      } else {
        return null;
      }
    };

    MaxHeap.prototype['pop'] = function() {
      var heap, max;
      if (this['length']) {
        heap = this['heap'];
        max = heap[0];
        heap[0] = heap[this['length'] - 1];
        this['length'] -= 1;
        this._heapify(0);
        return max;
      } else {
        return null;
      }
    };

    MaxHeap.prototype['push'] = function(key) {
      var f, heap, i, p, parent;
      i = this['length'];
      this['length'] += 1;
      parent = this._parent;
      p = parent(i);
      heap = this['heap'];
      f = this.f;
      while (i > 0 && f(heap[p], key) < 0) {
        heap[i] = heap[p];
        i = p;
        p = parent(i);
      }
      heap[i] = key;
      return null;
    };

    function MaxHeap(f, heap, length) {
      if (!heap) {
        heap = [];
      }
      if (typeof heap.length !== 'number') {
        throw new Error("heap must be array-like");
      }
      if (typeof length !== 'number') {
        length = heap ? heap.length : 0;
      }
      if (typeof f !== 'function') {
        throw new Error("f must be a function");
      }
      if (!((0 <= length && length <= heap.length))) {
        throw new Error("Expected 0 <= heap length = " + length + " <= " + heap.length + " = heap size");
      }
      this.f = f;
      this['heap'] = heap;
      this['length'] = length;
      this._build();
    }

    return MaxHeap;

  })();

  global = typeof exports === 'object' ? exports : typeof window === 'object' ? window : this;

  global['levenshtein'] || (global['levenshtein'] = {});

  global['levenshtein']['MaxHeap'] = MaxHeap;

}).call(this);