Iterator performance enhancements - turn hasNext and peek into element access, and...

diff --git a/auto_tests/tests/utils_test.js b/auto_tests/tests/utils_test.js
index 9c8974c..62b2c63 100644 (file)
--- a/auto_tests/tests/utils_test.js
+++ b/auto_tests/tests/utils_test.js
@@ -80,60 +80,60 @@ UtilsTestCase.prototype.testUpdateDeepDecoupled = function() {
 UtilsTestCase.prototype.testIterator_nopredicate = function() {
   var array = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
   var iter = Dygraph.createIterator(array, 1, 4);
-  assertTrue(iter.hasNext());
-  assertEquals('b', iter.peek());
+  assertTrue(iter.hasNext);
+  assertEquals('b', iter.peek);
   assertEquals('b', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
 
-  assertEquals('c', iter.peek());
+  assertEquals('c', iter.peek);
   assertEquals('c', iter.next());
 
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('d', iter.next());
 
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('e', iter.next());
 
-  assertFalse(iter.hasNext());
+  assertFalse(iter.hasNext);
 }
 
 UtilsTestCase.prototype.testIterator_predicate = function() {
   var array = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h'];
   var iter = Dygraph.createIterator(array, 1, 4,
       function(array, idx) { return array[idx] !== 'd' });
-  assertTrue(iter.hasNext());
-  assertEquals('b', iter.peek());
+  assertTrue(iter.hasNext);
+  assertEquals('b', iter.peek);
   assertEquals('b', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
 
-  assertEquals('c', iter.peek());
+  assertEquals('c', iter.peek);
   assertEquals('c', iter.next());
 
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('e', iter.next());
 
-  assertFalse(iter.hasNext());
+  assertFalse(iter.hasNext);
 }
 
 UtilsTestCase.prototype.testIterator_empty = function() {
   var array = [];
   var iter = Dygraph.createIterator([], 0, 0);
-  assertFalse(iter.hasNext());
+  assertFalse(iter.hasNext);
 }
 
 UtilsTestCase.prototype.testIterator_outOfRange = function() {
   var array = ['a', 'b', 'c'];
   var iter = Dygraph.createIterator(array, 1, 4,
       function(array, idx) { return array[idx] !== 'd' });
-  assertTrue(iter.hasNext());
-  assertEquals('b', iter.peek());
+  assertTrue(iter.hasNext);
+  assertEquals('b', iter.peek);
   assertEquals('b', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
 
-  assertEquals('c', iter.peek());
+  assertEquals('c', iter.peek);
   assertEquals('c', iter.next());
 
-  assertFalse(iter.hasNext());
+  assertFalse(iter.hasNext);
 }
 
 // Makes sure full array is tested, and that the predicate isn't called
@@ -148,25 +148,25 @@ UtilsTestCase.prototype.testIterator_whole_array = function() {
           return true;
         };
       });
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('a', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('b', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('c', iter.next());
-  assertFalse(iter.hasNext());
+  assertFalse(iter.hasNext);
   assertNull(iter.next());
 }
 
 UtilsTestCase.prototype.testIterator_no_args = function() {
   var array = ['a', 'b', 'c'];
   var iter = Dygraph.createIterator(array);
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('a', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('b', iter.next());
-  assertTrue(iter.hasNext());
+  assertTrue(iter.hasNext);
   assertEquals('c', iter.next());
-  assertFalse(iter.hasNext());
+  assertFalse(iter.hasNext);
   assertNull(iter.next());
 }

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index 4a29848..1bd3595 100644 (file)
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -791,7 +791,7 @@ DygraphCanvasRenderer.prototype._drawSeries = function(
 
   strategy.init();
 
-  while(iter.hasNext()) {
+  while(iter.hasNext) {
     point = iter.next();
     if (point.canvasy === null || point.canvasy != point.canvasy) {
       if (stepPlot && prevCanvasX !== null) {
@@ -802,7 +802,7 @@ DygraphCanvasRenderer.prototype._drawSeries = function(
       }
       prevCanvasX = prevCanvasY = null;
     } else {
-      nextCanvasY = iter.hasNext() ? iter.peek().canvasy : null;
+      nextCanvasY = iter.hasNext ? iter.peek.canvasy : null;
       // TODO: we calculate isNullOrNaN for this point, and the next, and then, when
       // we iterate, test for isNullOrNaN again. Why bother?
       var isNextCanvasYNullOrNaN = nextCanvasY === null || nextCanvasY != nextCanvasY;
@@ -811,7 +811,7 @@ DygraphCanvasRenderer.prototype._drawSeries = function(
         // Also consider a point to be "isolated" if it's adjacent to a
         // null point, excluding the graph edges.
         if ((!first && !prevCanvasX) ||
-            (iter.hasNext() && isNextCanvasYNullOrNaN)) {
+            (iter.hasNext && isNextCanvasYNullOrNaN)) {
           isIsolated = true;
         }
       }
@@ -936,7 +936,7 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
                             fillAlpha + ')';
       ctx.fillStyle = err_color;
       ctx.beginPath();
-      while (iter.hasNext()) {
+      while (iter.hasNext) {
         point = iter.next();
         if (point.name == setName) { // TODO(klausw): this is always true
           if (!Dygraph.isOK(point.y)) {
@@ -1005,7 +1005,7 @@ DygraphCanvasRenderer.prototype._renderLineChart = function() {
                             fillAlpha + ')';
       ctx.fillStyle = err_color;
       ctx.beginPath();
-      while(iter.hasNext()) {
+      while(iter.hasNext) {
         point = iter.next();
         if (point.name == setName) { // TODO(klausw): this is always true
           if (!Dygraph.isOK(point.y)) {

diff --git a/dygraph-utils.js b/dygraph-utils.js
index 8cfd861..7aeca8d 100644 (file)
--- a/dygraph-utils.js
+++ b/dygraph-utils.js
@@ -684,46 +684,37 @@ Dygraph.isAndroid = function() {
 Dygraph.Iterator = function(array, start, length, predicate) {
   start = start || 0;
   length = length || array.length;
+  this.hasNext = true; // Use to identify if there's another element.
+  this.peek = null; // Use for look-ahead
   this.array_ = array;
   this.predicate_ = predicate;
   this.end_ = Math.min(array.length, start + length);
-  this.nextIdx_ = start - 1; // use -1 so initial call to advance works.
-  this.hasNext_ = true;
-  this.peek_ = null;
-  this.advance_();
-}
-
-Dygraph.Iterator.prototype.hasNext = function() {
-  return this.hasNext_;
+  this.nextIdx_ = start - 1; // use -1 so initial advance works.
+  this.next(); // ignoring result.
 }
 
 Dygraph.Iterator.prototype.next = function() {
-  if (this.hasNext_) {
-    var obj = this.peek_;
-    this.advance_();
-    return obj;
+  if (!this.hasNext) {
+    return null;
   }
-  return null;
-}
+  var obj = this.peek;
 
-Dygraph.Iterator.prototype.peek = function() {
-  return this.peek_;
-}
-
-Dygraph.Iterator.prototype.advance_ = function() {
-  var nextIdx = this.nextIdx_;
-  nextIdx++;
-  while(nextIdx < this.end_) {
+  var nextIdx = this.nextIdx_ + 1;
+  var found = false;
+  while (nextIdx < this.end_) {
     if (!this.predicate_ || this.predicate_(this.array_, nextIdx)) {
-      this.peek_ = this.array_[nextIdx];
-      this.nextIdx_ = nextIdx;
-      return;
+      this.peek = this.array_[nextIdx];
+      found = true;
+      break;
     }
     nextIdx++;
   }
   this.nextIdx_ = nextIdx;
-  this.hasNext_ = false;
-  this.peek_ = null;
+  if (!found) {
+    this.hasNext = false;
+    this.peek = null;
+  }
+  return obj;
 }
 
 /**