1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
// Copyright (c) 2014 AlphaSierraPapa for the SharpDevelop Team
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
namespace Mono.TextEditor.Utils
{
/// <summary>
/// An immutable stack.
///
/// Using 'foreach' on the stack will return the items from top to bottom (in the order they would be popped).
/// </summary>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1710:IdentifiersShouldHaveCorrectSuffix")]
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1711:IdentifiersShouldNotHaveIncorrectSuffix")]
[Serializable]
public sealed class ImmutableStack<T> : IEnumerable<T>
{
/// <summary>
/// Gets the empty stack instance.
/// </summary>
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2104:DoNotDeclareReadOnlyMutableReferenceTypes", Justification = "ImmutableStack is immutable")]
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1000:DoNotDeclareStaticMembersOnGenericTypes")]
public static readonly ImmutableStack<T> Empty = new ImmutableStack<T>();
readonly T value;
readonly ImmutableStack<T> next;
private ImmutableStack()
{
}
private ImmutableStack(T value, ImmutableStack<T> next)
{
this.value = value;
this.next = next;
}
/// <summary>
/// Pushes an item on the stack. This does not modify the stack itself, but returns a new
/// one with the value pushed.
/// </summary>
public ImmutableStack<T> Push(T item)
{
return new ImmutableStack<T>(item, this);
}
/// <summary>
/// Gets the item on the top of the stack.
/// </summary>
/// <exception cref="InvalidOperationException">The stack is empty.</exception>
public T Peek()
{
if (IsEmpty)
throw new InvalidOperationException("Operation not valid on empty stack.");
return value;
}
/// <summary>
/// Gets the item on the top of the stack.
/// Returns <c>default(T)</c> if the stack is empty.
/// </summary>
public T PeekOrDefault()
{
return value;
}
/// <summary>
/// Gets the stack with the top item removed.
/// </summary>
/// <exception cref="InvalidOperationException">The stack is empty.</exception>
public ImmutableStack<T> Pop()
{
if (IsEmpty)
throw new InvalidOperationException("Operation not valid on empty stack.");
return next;
}
/// <summary>
/// Gets if this stack is empty.
/// </summary>
public bool IsEmpty {
get { return next == null; }
}
/// <summary>
/// Gets an enumerator that iterates through the stack top-to-bottom.
/// </summary>
public IEnumerator<T> GetEnumerator()
{
ImmutableStack<T> t = this;
while (!t.IsEmpty) {
yield return t.value;
t = t.next;
}
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return this.GetEnumerator();
}
/// <inheritdoc/>
public override string ToString()
{
StringBuilder b = new StringBuilder("[Stack");
foreach (T val in this) {
b.Append(' ');
b.Append(val);
}
b.Append(']');
return b.ToString();
}
}
}
|
