diff --git a/MoreLinq.Test/WindowLeftTest.cs b/MoreLinq.Test/WindowLeftTest.cs
index c63dc071c..765cbd1e4 100644
--- a/MoreLinq.Test/WindowLeftTest.cs
+++ b/MoreLinq.Test/WindowLeftTest.cs
@@ -19,6 +19,7 @@ namespace MoreLinq.Test
{
using System.Collections.Generic;
using NUnit.Framework;
+ using NUnit.Framework.Interfaces;
[TestFixture]
public class WindowLeftTest
@@ -138,5 +139,25 @@ public void WindowLeftWithWindowSizeSmallerThanSequence()
reader.ReadEnd();
}
}
+
+ static IEnumerable<T> Seq<T>(params T[] values) => values;
+
+ public static readonly IEnumerable<ITestCaseData> TestData =
+ from e in new[]
+ {
+ new {Source = Enumerable.Range(0, 4), Size = 1, Result = new[] {Seq(0), Seq(1), Seq(2), Seq(3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 2, Result = new[] {Seq(0, 1), Seq(1, 2), Seq(2, 3), Seq(3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 3, Result = new[] {Seq(0, 1, 2), Seq(1, 2, 3), Seq(2, 3), Seq(3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 4, Result = new[] {Seq(0, 1, 2, 3), Seq(1, 2, 3), Seq(2, 3), Seq(3)}}
+ }
+ select new TestCaseData(e.Source, e.Size).Returns(e.Result);
+
+ [Test, TestCaseSource(nameof(TestData))]
+ public IEnumerable<IEnumerable<int>> TestWindowLeftOnKnownResults(IEnumerable<int> sequence, int sizes)
+ {
+ using var testingSequence = sequence.AsTestingSequence();
+ var r = testingSequence.WindowLeft(sizes).ToList();
+ return r;
+ }
}
}
diff --git a/MoreLinq.Test/WindowRightTest.cs b/MoreLinq.Test/WindowRightTest.cs
index d5296e307..ac3aa0c6e 100644
--- a/MoreLinq.Test/WindowRightTest.cs
+++ b/MoreLinq.Test/WindowRightTest.cs
@@ -19,6 +19,7 @@ namespace MoreLinq.Test
{
using System.Collections.Generic;
using NUnit.Framework;
+ using NUnit.Framework.Interfaces;
[TestFixture]
public class WindowRightTest
@@ -138,5 +139,25 @@ public void WindowRightWithWindowSizeSmallerThanSequence()
reader.ReadEnd();
}
}
+
+ static IEnumerable<T> Seq<T>(params T[] values) => values;
+
+ public static readonly IEnumerable<ITestCaseData> TestData =
+ from e in new[]
+ {
+ new {Source = Enumerable.Range(0, 4), Size = 1, Result = new[] {Seq(0), Seq(1), Seq(2), Seq(3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 2, Result = new[] {Seq(0), Seq(0, 1), Seq(1, 2), Seq(2, 3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 3, Result = new[] {Seq(0), Seq(0, 1), Seq(0, 1, 2), Seq(1, 2, 3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 4, Result = new[] {Seq(0), Seq(0, 1), Seq(0, 1, 2), Seq(0, 1, 2, 3)}}
+ }
+ select new TestCaseData(e.Source, e.Size).Returns(e.Result);
+
+ [Test, TestCaseSource(nameof(TestData))]
+ public IEnumerable<IEnumerable<int>> TestWindowRightOnKnownResults(IEnumerable<int> sequence, int sizes)
+ {
+ using var testingSequence = sequence.AsTestingSequence();
+ var r = testingSequence.WindowRight(sizes).ToList();
+ return r;
+ }
}
}
diff --git a/MoreLinq.Test/WindowTest.cs b/MoreLinq.Test/WindowTest.cs
index 2fc765be9..9c7d49717 100644
--- a/MoreLinq.Test/WindowTest.cs
+++ b/MoreLinq.Test/WindowTest.cs
@@ -17,7 +17,9 @@
namespace MoreLinq.Test
{
+ using System.Collections.Generic;
using NUnit.Framework;
+ using NUnit.Framework.Interfaces;
/// <summary>
/// Verify the behavior of the Window operator
@@ -176,5 +178,24 @@ public void TestWindowWindowsImmutability()
reader.ReadEnd();
}
}
+
+ static IEnumerable<T> Seq<T>(params T[] values) => values;
+
+ public static readonly IEnumerable<ITestCaseData> TestData =
+ from e in new[]
+ {
+ new {Source = Enumerable.Range(0, 4), Size = 1, Result = new[] {Seq(0), Seq(1), Seq(2), Seq(3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 2, Result = new[] {Seq(0, 1), Seq(1, 2), Seq(2, 3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 3, Result = new[] {Seq(0, 1, 2), Seq(1, 2, 3)}},
+ new {Source = Enumerable.Range(0, 4), Size = 4, Result = new[] {Seq(0, 1, 2, 3)}}
+ }
+ select new TestCaseData(e.Source, e.Size).Returns(e.Result);
+
+ [Test, TestCaseSource(nameof(TestData))]
+ public IEnumerable<IEnumerable<int>> TestWindowOnKnownResults(IEnumerable<int> sequence, int sizes)
+ {
+ using var testingSequence = sequence.AsTestingSequence();
+ return testingSequence.Window(sizes).ToList();
+ }
}
}
diff --git a/MoreLinq/Window.cs b/MoreLinq/Window.cs
index a3c5375f6..32fa9b7ae 100644
--- a/MoreLinq/Window.cs
+++ b/MoreLinq/Window.cs
@@ -39,34 +39,7 @@ public static IEnumerable<IList<TSource>> Window<TSource>(this IEnumerable<TSour
if (source == null) throw new ArgumentNullException(nameof(source));
if (size <= 0) throw new ArgumentOutOfRangeException(nameof(size));
- return _(); IEnumerable<IList<TSource>> _()
- {
- using var iter = source.GetEnumerator();
-
- // generate the first window of items
- var window = new TSource[size];
- int i;
- for (i = 0; i < size && iter.MoveNext(); i++)
- window[i] = iter.Current;
-
- if (i < size)
- yield break;
-
- while (iter.MoveNext())
- {
- // generate the next window by shifting forward by one item
- // and do that before exposing the data
- var newWindow = new TSource[size];
- Array.Copy(window, 1, newWindow, 0, size - 1);
- newWindow[size - 1] = iter.Current;
-
- yield return window;
- window = newWindow;
- }
-
- // return the last window.
- yield return window;
- }
+ return Window(source, size, false, false);
}
/// <summary>
@@ -84,5 +57,106 @@ public static IEnumerable<IList<TSource>> Window<TSource>(this IEnumerable<TSour
[Obsolete("Use " + nameof(Window) + " instead.")]
public static IEnumerable<IEnumerable<TSource>> Windowed<TSource>(this IEnumerable<TSource> source, int size) =>
source.Window(size);
+
+ private static IEnumerable<IList<TSource>> Window<TSource>(IEnumerable<TSource> source, int size,
+ bool hasPartialBegin, bool hasPartialEnd)
+ {
+ using var iter = source.GetEnumerator();
+
+ var hasNext = iter.MoveNext();
+
+ // early break
+ if (!hasNext)
+ yield break;
+
+ // Store the window to be yield.
+ // In any cases we build the next window (if any) before yielding
+ // Loops do not have to yield the last window they created.
+ TSource[] window;
+
+ // Warm-up
+ if (hasPartialBegin)
+ {
+ // build first partial window;
+ window = new[] {iter.Current};
+ hasNext = iter.MoveNext();
+
+ // build other partial windows
+ while (window.Length < size && hasNext)
+ {
+ // Prepare next window, bigger than the previous one
+ var nextWindow = new TSource[window.Length + 1];
+ Array.Copy(window, nextWindow, window.Length);
+
+ // window ready to ship, we forget it immediately
+ yield return window;
+
+ nextWindow[nextWindow.Length - 1] = iter.Current;
+ hasNext = iter.MoveNext();
+ window = nextWindow;
+ }
+ }
+ else
+ {
+ // build first window
+ window = new TSource[size];
+ int i;
+ for (i = 0; i < size && hasNext; i++)
+ {
+ window[i] = iter.Current;
+ hasNext = iter.MoveNext();
+ }
+
+ // Ensure correct size on partial window cases
+ if (i != size)
+ {
+ if (hasPartialEnd)
+ Array.Resize(ref window, i);
+ else
+ yield break;
+ }
+ }
+
+ // Main loop
+ if (window.Length == size)
+ {
+ // build windows of given size
+ while (hasNext)
+ {
+ // Prepare next window, same size as the previous one
+ var nextWindow = new TSource[size];
+ Array.Copy(window, 1, nextWindow, 0, size - 1);
+
+ // window ready to ship, we forget it immediately
+ yield return window;
+
+ nextWindow[size - 1] = iter.Current;
+ hasNext = iter.MoveNext();
+ window = nextWindow;
+ }
+ }
+
+ // Cool down
+ if (hasPartialEnd)
+ {
+ // build final partial windows
+ while (window.Length > 1)
+ {
+ // Prepare next window, smaller than the previous one
+ var nextWindow = new TSource[window.Length - 1];
+ Array.Copy(window, 1, nextWindow, 0, nextWindow.Length);
+
+ // window ready to ship, we forget it immediately
+ yield return window;
+ window = nextWindow;
+ }
+ }
+
+ // No more windows to build, we can finally yield this one
+ if (hasPartialBegin || hasPartialEnd || window.Length == size)
+ {
+ yield return window;
+ }
+ }
}
}
diff --git a/MoreLinq/WindowLeft.cs b/MoreLinq/WindowLeft.cs
index fdcd72803..589425cc9 100644
--- a/MoreLinq/WindowLeft.cs
+++ b/MoreLinq/WindowLeft.cs
@@ -19,7 +19,6 @@ namespace MoreLinq
{
using System;
using System.Collections.Generic;
- using System.Linq;
public static partial class MoreEnumerable
{
@@ -63,28 +62,7 @@ public static IEnumerable<IList<TSource>> WindowLeft<TSource>(this IEnumerable<T
if (source == null) throw new ArgumentNullException(nameof(source));
if (size <= 0) throw new ArgumentOutOfRangeException(nameof(size));
- return _(); IEnumerable<IList<TSource>> _()
- {
- var window = new List<TSource>();
- foreach (var item in source)
- {
- window.Add(item);
- if (window.Count < size)
- continue;
-
- // prepare next window before exposing data
- var nextWindow = new List<TSource>(window.Skip(1));
- yield return window;
- window = nextWindow;
- }
- while (window.Count > 0)
- {
- // prepare next window before exposing data
- var nextWindow = new List<TSource>(window.Skip(1));
- yield return window;
- window = nextWindow;
- }
- }
+ return Window(source, size, false, true);
}
}
}
diff --git a/MoreLinq/WindowRight.cs b/MoreLinq/WindowRight.cs
index 4172c3d6d..8231a97d7 100644
--- a/MoreLinq/WindowRight.cs
+++ b/MoreLinq/WindowRight.cs
@@ -19,7 +19,6 @@ namespace MoreLinq
{
using System;
using System.Collections.Generic;
- using System.Linq;
public static partial class MoreEnumerable
{
@@ -63,34 +62,7 @@ public static IEnumerable<IList<TSource>> WindowRight<TSource>(this IEnumerable<
if (source == null) throw new ArgumentNullException(nameof(source));
if (size < 0) throw new ArgumentOutOfRangeException(nameof(size));
- return source.WindowRightWhile((_, i) => i < size);
- }
-
- /// <summary>
- /// Creates a right-aligned sliding window over the source sequence
- /// with a predicate function determining the window range.
- /// </summary>
-
- static IEnumerable<IList<TSource>> WindowRightWhile<TSource>(
- this IEnumerable<TSource> source,
- Func<TSource, int, bool> predicate)
- {
- if (source == null) throw new ArgumentNullException(nameof(source));
- if (predicate == null) throw new ArgumentNullException(nameof(predicate));
-
- return _(); IEnumerable<IList<TSource>> _()
- {
- var window = new List<TSource>();
- foreach (var item in source)
- {
- window.Add(item);
-
- // prepare next window before exposing data
- var nextWindow = new List<TSource>(predicate(item, window.Count) ? window : window.Skip(1));
- yield return window;
- window = nextWindow;
- }
- }
+ return Window(source, size, true, false);
}
}
}