primer cambio

node_modules/amqplib/lib/bitset.js

@@ -0,0 +1,130 @@
+//
+//
+//
+
+'use strict';
+
+/**
+ * A bitset implementation, after that in java.util.  Yes there
+ * already exist such things, but none implement next{Clear|Set}Bit or
+ * equivalent, and none involved me tooling about for an evening.
+ */
+class BitSet {
+  /**
+   * @param {number} [size]
+   */
+  constructor(size) {
+    if (size) {
+      const numWords = Math.ceil(size / 32);
+      this.words = new Array(numWords);
+    }
+    else {
+      this.words = [];
+    }
+    this.wordsInUse = 0; // = number, not index
+  }
+
+  /**
+   * @param {number} numWords
+   */
+  ensureSize(numWords) {
+    const wordsPresent = this.words.length;
+    if (wordsPresent < numWords) {
+      this.words = this.words.concat(new Array(numWords - wordsPresent));
+    }
+  }
+
+  /**
+   * @param {number} bitIndex
+   */
+  set(bitIndex) {
+    const w = wordIndex(bitIndex);
+    if (w >= this.wordsInUse) {
+      this.ensureSize(w + 1);
+      this.wordsInUse = w + 1;
+    }
+    const bit = 1 << bitIndex;
+    this.words[w] |= bit;
+  }
+
+  /**
+   * @param {number} bitIndex
+   */
+  clear(bitIndex) {
+    const w = wordIndex(bitIndex);
+    if (w >= this.wordsInUse) return;
+    const mask = ~(1 << bitIndex);
+    this.words[w] &= mask;
+  }
+
+  /**
+   * @param {number} bitIndex
+   */
+  get(bitIndex) {
+    const w = wordIndex(bitIndex);
+    if (w >= this.wordsInUse) return false; // >= since index vs size
+    const bit = 1 << bitIndex;
+    return !!(this.words[w] & bit);
+  }
+
+  /**
+   * Give the next bit that is set on or after fromIndex, or -1 if no such bit
+   *
+   * @param {number} fromIndex
+   */
+  nextSetBit(fromIndex) {
+    let w = wordIndex(fromIndex);
+    if (w >= this.wordsInUse) return -1;
+
+    // the right-hand side is shifted to only test the bits of the first
+    // word that are > fromIndex
+    let word = this.words[w] & (0xffffffff << fromIndex);
+    while (true) {
+      if (word) return (w * 32) + trailingZeros(word);
+      w++;
+      if (w === this.wordsInUse) return -1;
+      word = this.words[w];
+    }
+  }
+
+  /**
+   * @param {number} fromIndex
+   */
+  nextClearBit(fromIndex) {
+    let w = wordIndex(fromIndex);
+    if (w >= this.wordsInUse) return fromIndex;
+
+    let word = ~(this.words[w]) & (0xffffffff << fromIndex);
+    while (true) {
+      if (word) return (w * 32) + trailingZeros(word);
+      w++;
+      if (w == this.wordsInUse) return w * 32;
+      word = ~(this.words[w]);
+    }
+  }
+}
+
+/**
+ * @param {number} bitIndex
+ */
+function wordIndex(bitIndex) {
+  return Math.floor(bitIndex / 32);
+}
+
+/**
+ * @param {number} i
+ */
+function trailingZeros(i) {
+  // From Hacker's Delight, via JDK. Probably far less effective here,
+  // since bit ops are not necessarily the quick way to do things in
+  // JS.
+  if (i === 0) return 32;
+  let y, n = 31;
+  y = i << 16; if (y != 0) { n = n -16; i = y; }
+  y = i << 8;  if (y != 0) { n = n - 8; i = y; }
+  y = i << 4;  if (y != 0) { n = n - 4; i = y; }
+  y = i << 2;  if (y != 0) { n = n - 2; i = y; }
+  return n - ((i << 1) >>> 31);
+}
+
+module.exports.BitSet = BitSet;