Merge 7a85c95 into c081197

morelinq · Jan 20, 2023 · e3c5560 · e3c5560
2 parents c081197 + 7a85c95
commit e3c5560
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Showing 2 changed files with 31 additions and 16 deletions.
diff --git a/MoreLinq.Test/ExcludeTest.cs b/MoreLinq.Test/ExcludeTest.cs
@@ -60,7 +60,7 @@ public void TestExcludeNegativeCountException()
         [Test]
         public void TestExcludeWithCountEqualsZero()
         {
-            var sequence = Enumerable.Range(1, 10);
+            using var sequence = Enumerable.Range(1, 10).AsTestingSequence();
             var resultA = sequence.Exclude(5, 0);
 
             Assert.That(resultA, Is.SameAs(sequence));
@@ -88,10 +88,11 @@ public void TestExcludeEmptySequence()
         public void TestExcludeSequenceHead()
         {
             const int count = 10;
-            var sequence = Enumerable.Range(1, count);
+            var xs = Enumerable.Range(1, count);
+            using var sequence = xs.AsTestingSequence();
             var result = sequence.Exclude(0, count / 2);
 
-            Assert.That(result, Is.EqualTo(sequence.Skip(count / 2)));
+            Assert.That(result, Is.EqualTo(xs.Skip(count / 2)));
         }
 
         /// <summary>
@@ -101,10 +102,11 @@ public void TestExcludeSequenceHead()
         public void TestExcludeSequenceTail()
         {
             const int count = 10;
-            var sequence = Enumerable.Range(1, count);
+            var xs = Enumerable.Range(1, count);
+            using var sequence = xs.AsTestingSequence();
             var result = sequence.Exclude(count / 2, count);
 
-            Assert.That(result, Is.EqualTo(sequence.Take(count / 2)));
+            Assert.That(result, Is.EqualTo(xs.Take(count / 2)));
         }
 
         /// <summary>
@@ -116,10 +118,11 @@ public void TestExcludeSequenceMiddle()
             const int count = 10;
             const int startIndex = 3;
             const int excludeCount = 5;
-            var sequence = Enumerable.Range(1, count);
+            var xs = Enumerable.Range(1, count);
+            using var sequence = xs.AsTestingSequence();
             var result = sequence.Exclude(startIndex, excludeCount);
 
-            Assert.That(result, Is.EqualTo(sequence.Take(startIndex).Concat(sequence.Skip(startIndex + excludeCount))));
+            Assert.That(result, Is.EqualTo(xs.Take(startIndex).Concat(xs.Skip(startIndex + excludeCount))));
         }
 
         /// <summary>
@@ -129,7 +132,7 @@ public void TestExcludeSequenceMiddle()
         public void TestExcludeEntireSequence()
         {
             const int count = 10;
-            var sequence = Enumerable.Range(1, count);
+            using var sequence = Enumerable.Range(1, count).AsTestingSequence();
             var result = sequence.Exclude(0, count);
 
             Assert.That(result, Is.Empty);
@@ -142,10 +145,11 @@ public void TestExcludeEntireSequence()
         public void TestExcludeCountGreaterThanSequenceLength()
         {
             const int count = 10;
-            var sequence = Enumerable.Range(1, count);
+            var xs = Enumerable.Range(1, count);
+            using var sequence = xs.AsTestingSequence();
             var result = sequence.Exclude(1, count * 10);
 
-            Assert.That(result, Is.EqualTo(sequence.Take(1)));
+            Assert.That(result, Is.EqualTo(xs.Take(1)));
         }
 
         /// <summary>
@@ -155,10 +159,11 @@ public void TestExcludeCountGreaterThanSequenceLength()
         public void TestExcludeStartIndexGreaterThanSequenceLength()
         {
             const int count = 10;
-            var sequence = Enumerable.Range(1, count);
+            var xs = Enumerable.Range(1, count);
+            using var sequence = xs.AsTestingSequence();
             var result = sequence.Exclude(count + 5, count);
 
-            Assert.That(result, Is.EqualTo(sequence));
+            Assert.That(result, Is.EqualTo(xs));
         }
     }
 }
diff --git a/MoreLinq/Exclude.cs b/MoreLinq/Exclude.cs
@@ -46,15 +46,25 @@ public static IEnumerable<T> Exclude<T>(this IEnumerable<T> sequence, int startI
 
             IEnumerable<T> _()
             {
-                var index = -1;
+                var index = 0;
                 var endIndex = startIndex + count;
                 using var iter = sequence.GetEnumerator();
+
                 // yield the first part of the sequence
-                while (iter.MoveNext() && ++index < startIndex)
+                for (; index < startIndex; index++)
+                {
+                    if (!iter.MoveNext())
+                        yield break;
                     yield return iter.Current;
+                }
+
                 // skip the next part (up to count items)
-                while (++index < endIndex && iter.MoveNext())
-                    continue;
+                for (; index < endIndex; index++)
+                {
+                    if (!iter.MoveNext())
+                        yield break;
+                }
+
                 // yield the remainder of the sequence
                 while (iter.MoveNext())
                     yield return iter.Current;