Merge branch 'master' into linkedlist2deque

CHANGELOG.md

@@ -1,12 +1,14 @@
 # Changelog
 
-## Unreleased
+## 0.39.8
 
 * Adding ESM named exports support (@jerome-benoit).
 * Fixing `Set` operations CommonJS named export collision by renaming it to `set` (@jerome-benoit).
 * Fixing missing `Uint8Vector`, `Uint8ClampedVector`, `Int8Vector`, `Uint16Vector`, `Int16Vector`, `Uint32Vector`, `Int32Vector`, `Float32Vector`, `Float64Vector`, `PointerVector` CommonJS named exports (@jerome-benoit).
 * Fixing missing `PointerVector` TS exports (@jerome-benoit).
 * Fixing `Float64Vector` TS exports (@atombrenner).
+* Improving performance of `FixedDeque` `#.push` & `#.pop` methods (@jerome-benoit).
+* Fixing some `FixedDeque` & `CircularBuffer` methods.
 
 ## 0.39.7
 

circular-buffer.js

@@ -45,15 +45,24 @@ if (typeof Symbol !== 'undefined')
  * @return {number}      - Returns the new size of the buffer.
  */
 CircularBuffer.prototype.push = function(item) {
-  var index = (this.start + this.size) % this.capacity;
+  var index = this.start + this.size;
+
+  if (index >= this.capacity)
+    index -= this.capacity;
 
   this.items[index] = item;
 
   // Overwriting?
   if (this.size === this.capacity) {
-
-    // If start is at the end, we wrap around the buffer
-    this.start = (index + 1) % this.capacity;
+    index++;
+
+    // Wrapping around?
+    if (index >= this.capacity) {
+      this.start = 0;
+    }
+    else {
+      this.start = index;
+    }
 
     return this.size;
   }

fixed-deque.js

@@ -48,7 +48,10 @@ FixedDeque.prototype.push = function(item) {
   if (this.size === this.capacity)
     throw new Error('mnemonist/fixed-deque.push: deque capacity (' + this.capacity + ') exceeded!');
 
-  var index = (this.start + this.size) % this.capacity;
+  var index = this.start + this.size;
+
+  if (index >= this.capacity)
+    index -= this.capacity;
 
   this.items[index] = item;
 
@@ -85,10 +88,13 @@ FixedDeque.prototype.pop = function() {
   if (this.size === 0)
     return;
 
-  const index = (this.start + this.size - 1) % this.capacity;
-
   this.size--;
 
+  var index = this.start + this.size;
+
+  if (index >= this.capacity)
+    index -= this.capacity;
+
   return this.items[index];
 };
 
@@ -135,7 +141,7 @@ FixedDeque.prototype.peekLast = function() {
 
   var index = this.start + this.size - 1;
 
-  if (index > this.capacity)
+  if (index >= this.capacity)
     index -= this.capacity;
 
   return this.items[index];
@@ -148,12 +154,12 @@ FixedDeque.prototype.peekLast = function() {
  * @return {any}
  */
 FixedDeque.prototype.get = function(index) {
-  if (this.size === 0)
+  if (this.size === 0 || index >= this.capacity)
     return;
 
   index = this.start + index;
 
-  if (index > this.capacity)
+  if (index >= this.capacity)
     index -= this.capacity;
 
   return this.items[index];

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mnemonist",
-  "version": "0.39.7",
+  "version": "0.39.8",
   "description": "Curated collection of data structures for the JavaScript/TypeScript.",
   "scripts": {
     "lint": "eslint --cache --ext .js,.mjs ./*.js ./*.mjs ./utils ./test",

test/circular-buffer.js

@@ -126,6 +126,22 @@ describe('CircularBuffer', function() {
     assert.strictEqual(buffer.get(3), undefined);
   });
 
+  it('peekLast should not be subject to one-off errors (#223).', function() {
+    var buffer = new CircularBuffer(Array, 2);
+
+    buffer.push(true);
+    buffer.push(true);
+    buffer.push(true);
+
+    buffer.push(false);
+    buffer.push(true);
+
+    assert.deepStrictEqual(buffer.toArray(), [false, true]);
+    assert.strictEqual(buffer.peekFirst(), false);
+    assert.strictEqual(buffer.peekLast(), true);
+    assert.strictEqual(buffer.get(1), true);
+  });
+
   it('should be possible to pop the buffer.', function() {
     var buffer = new CircularBuffer(Array, 3);