mildew.util.stack source code

1 /**
2 This module implements Stack
3 
4 ────────────────────────────────────────────────────────────────────────────────
5 
6 Copyright (C) 2021 pillager86.rf.gd
7 
8 This program is free software: you can redistribute it and/or modify it under 
9 the terms of the GNU General Public License as published by the Free Software 
10 Foundation, either version 3 of the License, or (at your option) any later 
11 version.
12 
13 This program is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
15 PARTICULAR PURPOSE.  See the GNU General Public License for more details.
16 
17 You should have received a copy of the GNU General Public License along with 
18 this program.  If not, see <https://www.gnu.org/licenses/>.
19 */
20 module mildew.util.stack;
21 
22 /// Stack data structure wrapper around dynamic D arrays
23 struct Stack(T)
24 {
25 public:
26     /// push an item to the stack and return its position
27     size_t push(T item)
28     {
29         _data ~= item;
30         return _data.length - 1;
31     }
32     /// pushes multiple items to the stack such that the last element is on the top
33     void push(T[] items)
34     {
35         _data ~= items;
36     }
37     /// pops one item from the stack
38     auto pop()
39     {
40         auto item = _data[$-1];
41         _data = _data[0..$-1];
42         return item;
43     }
44     /// pops multiple items from the stack
45     auto pop(size_t n)
46     {
47         auto items = _data[$-n..$];
48         _data = _data[0..$-n];
49         return items;
50     }
51     /// peek element at the top of array
52     auto peek()
53     {
54         return _data[$-1];
55     }
56     /// number of stack elements
57     auto size() const
58     {
59         return _data.length;
60     }
61 
62     /// set the size directly
63     auto size(size_t sz)
64     {
65         return _data.length = sz;
66     }
67 
68     /// direct access to array. TODO: replace with an opIndex and opIndexAssign
69     auto array() { return _data; }
70 
71     /// calls reserve on array
72     void reserve(size_t size)
73     {
74         _data.reserve(size);
75     }
76 
77     /// the top element by reference
78     ref auto top() { return _data[$-1]; }
79 private:
80     T[] _data;
81 }