Replace unused entries with NaNs

src/ol/structs/buffer.js

@@ -3,6 +3,12 @@ goog.provide('ol.structs.Buffer');
 goog.require('ol.structs.IntegerSet');
 
 
+/**
+ * @define {boolean} Replace unused entries with NaNs.
+ */
+ol.BUFFER_REPLACE_UNUSED_ENTRIES_WITH_NANS = goog.DEBUG;
+
+
 
 /**
  * @constructor
@@ -37,6 +43,14 @@ ol.structs.Buffer = function(opt_arr, opt_used, opt_dirty) {
   if (opt_dirty && used !== 0) {
     this.dirtySet_.addRange(0, used);
   }
+  if (ol.BUFFER_REPLACE_UNUSED_ENTRIES_WITH_NANS) {
+    var arr = this.arr_;
+    var n = arr.length;
+    var i;
+    for (i = used; i < n; ++i) {
+      arr[i] = NaN;
+    }
+  }
 
 };
 
@@ -111,6 +125,13 @@ ol.structs.Buffer.prototype.getFreeSet = function() {
 ol.structs.Buffer.prototype.remove = function(index, size) {
   this.freeSet_.addRange(index, index + size);
   this.dirtySet_.removeRange(index, index + size);
+  if (ol.BUFFER_REPLACE_UNUSED_ENTRIES_WITH_NANS) {
+    var arr = this.arr_;
+    var i;
+    for (i = 0; i < size; ++i) {
+      arr[index + i] = NaN;
+    }
+  }
 };
 
 

test/spec/ol/structs/buffer.test.js

@@ -247,28 +247,32 @@ describe('ol.structs.Buffer', function() {
     it('allows multiple adds and removes', function() {
       var b = new ol.structs.Buffer(new Array(8), 0);
       expect(b.add([0, 1])).to.be(0);
-      expect(b.getArray()).to.equalArray([
+      expect(b.getArray()).to.equalArray([0, 1, NaN, NaN, NaN, NaN, NaN, NaN]);
-        0, 1,
-        undefined, undefined,
-        undefined, undefined,
-        undefined, undefined
-      ]);
       expect(b.getCount()).to.be(2);
       expect(b.add([2, 3, 4, 5])).to.be(2);
+      expect(b.getArray()).to.equalArray([0, 1, 2, 3, 4, 5, NaN, NaN]);
       expect(b.getCount()).to.be(6);
       expect(b.add([6, 7])).to.be(6);
-      expect(b.getCount()).to.be(8);
       expect(b.getArray()).to.equalArray([0, 1, 2, 3, 4, 5, 6, 7]);
+      expect(b.getCount()).to.be(8);
       b.remove(2, 2);
+      expect(b.getArray()).to.equalArray([0, 1, NaN, NaN, 4, 5, 6, 7]);
       expect(b.getCount()).to.be(6);
       expect(b.add([8, 9])).to.be(2);
       expect(b.getArray()).to.equalArray([0, 1, 8, 9, 4, 5, 6, 7]);
+      expect(b.getCount()).to.be(8);
       b.remove(1, 1);
+      expect(b.getArray()).to.equalArray([0, NaN, 8, 9, 4, 5, 6, 7]);
+      expect(b.getCount()).to.be(7);
       b.remove(4, 4);
+      expect(b.getArray()).to.equalArray([0, NaN, 8, 9, NaN, NaN, NaN, NaN]);
+      expect(b.getCount()).to.be(3);
       expect(b.add([10, 11, 12])).to.be(4);
-      expect(b.getArray()).to.equalArray([0, 1, 8, 9, 10, 11, 12, 7]);
+      expect(b.getArray()).to.equalArray([0, NaN, 8, 9, 10, 11, 12, NaN]);
+      expect(b.getCount()).to.be(6);
       expect(b.add([13])).to.be(1);
-      expect(b.getArray()).to.equalArray([0, 13, 8, 9, 10, 11, 12, 7]);
+      expect(b.getArray()).to.equalArray([0, 13, 8, 9, 10, 11, 12, NaN]);
+      expect(b.getCount()).to.be(7);
     });
 
   });