stdex/queue.d at master · Poita/stdex · GitHub

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
module stdex.queue;

import std.array;
import stdex.heap;

struct Queue(T)
{
public:
    @property bool empty() const
    {
        return m_first == m_last;
    }

    @property size_t length() const
    {
        return m_length;
    }

    @property ref const(T) front() const
    {
        assert(m_length, "Queue is empty.");
        assert(m_first < m_buffer.length, "Internal error: m_first is out of range.");
        return m_buffer[m_first];
    }

    void push(T value)
    {
        if (m_length == m_buffer.length)
        {
            // Resize
            size_t n = m_length;
            m_buffer.length = n == 0 ? 8 : n * 2;
            size_t m = n - m_first;
            if (m)
            {
                m_buffer[$-m..$] = m_buffer[m_first..n];
                m_first = m_buffer.length - m;
            }
        }
        m_buffer[m_last++] = value;
        ++m_length;
        if (m_last == m_buffer.length)
            m_last = 0;
    }

    void pop()
    {
        assert(m_length, "Queue is empty.");
        ++m_first;
        if (m_first == m_buffer.length)
            m_first = 0;
        --m_length;
    }

private:
    T[] m_buffer = [];
    size_t m_first = 0;
    size_t m_last = 0;
    size_t m_length = 0;
}

unittest
{
    import std.stdio;
    writeln("testing stdex.queue.Queue");

    Queue!int q;
    foreach (i; 0..1000)
    {
        q.push(2*i);
        q.push(2*i+1);
        assert(q.front == i);
        q.pop();
        assert(q.length == i+1);
    }
}

struct PriorityQueue(T, alias compare = "a < b")
{
public:
    @property bool empty() const
    {
        return m_heap.empty;
    }

    @property size_t length() const
    {
        return m_heap.length;
    }

    @property ref const(T) front() const
    {
        return m_heap[0];
    }

    void push(T value)
    {
        m_heap ~= value;
        pushHeap!compare(m_heap);
    }

    void pop()
    {
        popHeap!compare(m_heap);
        m_heap = m_heap[0..$-1];
    }

private:
    T[] m_heap;
}

unittest
{
    import std.stdio;
    writeln("testing stdex.queue.PriorityQueue");

    PriorityQueue!int q;
    int[] a = [5, 4, 6, 3, 7, 2, 8, 1, 9];
    int[] b = [5, 5, 6, 6, 7, 7, 8, 8, 9];
    foreach (i; 0..9)
    {
        q.push(a[i]);
        assert(q.front == b[i]);
    }
    foreach (i; 0..9)
    {
        assert(q.front == 9 - i);
        q.pop();
    }
}