dlib.container.stack source code

1 /*
2 Copyright (c) 2011-2021 Timur Gafarov
3 
4 Boost Software License - Version 1.0 - August 17th, 2003
5 
6 Permission is hereby granted, free of charge, to any person or organization
7 obtaining a copy of the software and accompanying documentation covered by
8 this license (the "Software") to use, reproduce, display, distribute,
9 execute, and transmit the Software, and to prepare derivative works of the
10 Software, and to permit third-parties to whom the Software is furnished to
11 do so, all subject to the following:
12 
13 The copyright notices in the Software and this entire statement, including
14 the above license grant, this restriction and the following disclaimer,
15 must be included in all copies of the Software, in whole or in part, and
16 all derivative works of the Software, unless such copies or derivative
17 works are solely in the form of machine-executable object code generated by
18 a source language processor.
19 
20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
23 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
24 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
25 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 DEALINGS IN THE SOFTWARE.
27 */
28 
29 /**
30  * Stack (based on Array)
31  *
32  * Copyright: Timur Gafarov 2011-2021.
33  * License: $(LINK2 boost.org/LICENSE_1_0.txt, Boost License 1.0).
34  * Authors: Timur Gafarov, Andrey Penechko, Roman Chistokhodov
35  */
36 module dlib.container.stack;
37 
38 import dlib.container.array;
39 
40 /**
41  * Stack implementation based on Array.
42  */
43 struct Stack(T)
44 {
45     private Array!T array;
46 
47     public:
48     /**
49      * Push element to stack.
50      */
51     void push(T v)
52     {
53         array.insertBack(v);
54     }
55 
56     /**
57      * Pop top element out.
58      * Returns: Removed element.
59      * Throws: Exception on underflow.
60      */
61     T pop()
62     {
63         if (empty)
64             throw new Exception("Stack!(T): underflow");
65 
66         T res = array[$-1];
67         array.removeBack(1);
68         return res;
69     }
70 
71     /**
72      * Non-throwing version of pop.
73      * Returns: true on success, false on failure.
74      * Element is stored in value.
75      */
76     bool pop(ref T value)
77     {
78         if (empty)
79             return false;
80 
81         value = array[$-1];
82         array.removeBack(1);
83         return true;
84     }
85 
86     /**
87      * Top stack element.
88      * Note: Stack must be non-empty.
89      */
90     T top()
91     {
92         return array[$-1];
93     }
94 
95     /**
96      * Pointer to top stack element.
97      * Note: Stack must be non-empty.
98      */
99     T* topPtr()
100     {
101         return &array.data[$-1];
102     }
103 
104     /**
105      * Check if stack has no elements.
106      */
107     @property bool empty() nothrow
108     {
109         return array.length == 0;
110     }
111 
112     /**
113      * Free memory allocated by Stack.
114      */
115     void free()
116     {
117         array.free();
118     }
119 }
120 
121 ///
122 unittest
123 {
124     import std.exception: assertThrown;
125 
126     Stack!int s;
127     assertThrown(s.pop());
128     s.push(100);
129     s.push(3);
130     s.push(76);
131     assert(s.top() == 76);
132     int v;
133     s.pop(v);
134     assert(v == 76);
135     assert(s.pop() == 3);
136     assert(s.pop() == 100);
137     assert(s.empty);
138     s.free();
139 }