50 lines
1.6 KiB
C#
50 lines
1.6 KiB
C#
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using System.Collections.Generic;
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using System.Diagnostics;
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namespace Microsoft.Msagl.Routing.Rectilinear {
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/// <summary>
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/// Used in merge-type operations to track whether MoveNext has returned false.
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/// </summary>
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/// <typeparam name="T"></typeparam>
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internal class EnumeratorWrapper<T> {
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/// <summary>
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/// False iff MoveNext has not been called, or has returned false.
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/// </summary>
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internal bool HasCurrent { get { return this.state == MoveNextState.True; } }
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/// <summary>
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/// State of MoveNext. MoveNext is not automatically called on ctor for consistency with unwrapped enumerators.
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/// </summary>
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private enum MoveNextState {
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NotCalled,
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True,
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False
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}
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private MoveNextState state = MoveNextState.NotCalled;
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private readonly IEnumerator<T> enumerator;
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internal EnumeratorWrapper(IEnumerable<T> enumerable) {
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this.enumerator = enumerable.GetEnumerator();
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}
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internal T Current
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{
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get {
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Debug.Assert(this.HasCurrent, "MoveNext has not been called or has returned false");
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return this.enumerator.Current;
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}
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}
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internal bool MoveNext() {
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Debug.Assert(this.state != MoveNextState.False, "MoveNext has returned false");
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if (this.enumerator.MoveNext()) {
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this.state = MoveNextState.True;
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return true;
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}
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this.state = MoveNextState.False;
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return false;
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}
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}
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}
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