aboutsummaryrefslogtreecommitdiff
path: root/src/FIFO.h
blob: 7f71a7269da32c9eff449b47e639192482321d07 (plain)
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
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
/*
    Copyright 2016-2021 Arisotura

    This file is part of melonDS.

    melonDS is free software: you can redistribute it and/or modify it under
    the terms of the GNU General Public License as published by the Free
    Software Foundation, either version 3 of the License, or (at your option)
    any later version.

    melonDS is distributed in the hope that it will be useful, but WITHOUT ANY
    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
    FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

    You should have received a copy of the GNU General Public License along
    with melonDS. If not, see http://www.gnu.org/licenses/.
*/

#ifndef FIFO_H
#define FIFO_H

#include "types.h"

template<typename T, u32 NumEntries>
class FIFO
{
public:
    void Clear()
    {
        NumOccupied = 0;
        ReadPos = 0;
        WritePos = 0;
        memset(&Entries[ReadPos], 0, sizeof(T));
    }


    void DoSavestate(Savestate* file)
    {
        file->Var32(&NumOccupied);
        file->Var32(&ReadPos);
        file->Var32(&WritePos);

        file->VarArray(Entries, sizeof(T)*NumEntries);
    }


    void Write(T val)
    {
        if (IsFull()) return;

        Entries[WritePos] = val;

        WritePos++;
        if (WritePos >= NumEntries)
            WritePos = 0;

        NumOccupied++;
    }

    T Read()
    {
        T ret = Entries[ReadPos];
        if (IsEmpty())
            return ret;

        ReadPos++;
        if (ReadPos >= NumEntries)
            ReadPos = 0;

        NumOccupied--;
        return ret;
    }

    T Peek()
    {
        return Entries[ReadPos];
    }

    T Peek(u32 offset)
    {
        u32 pos = ReadPos + offset;
        if (pos >= NumEntries)
            pos -= NumEntries;

        return Entries[pos];
    }

    u32 Level() { return NumOccupied; }
    bool IsEmpty() { return NumOccupied == 0; }
    bool IsFull() { return NumOccupied >= NumEntries; }

    bool CanFit(u32 num) { return ((NumOccupied + num) <= NumEntries); }

private:
    T Entries[NumEntries] = {0};
    u32 NumOccupied = 0;
    u32 ReadPos = 0, WritePos = 0;
};


template<typename T>
class DynamicFIFO
{
public:
    DynamicFIFO(u32 num)
    {
        NumEntries = num;
        Entries = new T[num];
        Clear();
    }

    ~DynamicFIFO()
    {
        delete[] Entries;
    }


    void Clear()
    {
        NumOccupied = 0;
        ReadPos = 0;
        WritePos = 0;
        memset(&Entries[ReadPos], 0, sizeof(T));
    }


    void DoSavestate(Savestate* file)
    {
        file->Var32(&NumOccupied);
        file->Var32(&ReadPos);
        file->Var32(&WritePos);

        file->VarArray(Entries, sizeof(T)*NumEntries);
    }


    void Write(T val)
    {
        if (IsFull()) return;

        Entries[WritePos] = val;

        WritePos++;
        if (WritePos >= NumEntries)
            WritePos = 0;

        NumOccupied++;
    }

    T Read()
    {
        T ret = Entries[ReadPos];
        if (IsEmpty())
            return ret;

        ReadPos++;
        if (ReadPos >= NumEntries)
            ReadPos = 0;

        NumOccupied--;
        return ret;
    }

    T Peek()
    {
        return Entries[ReadPos];
    }

    T Peek(u32 offset)
    {
        u32 pos = ReadPos + offset;
        if (pos >= NumEntries)
            pos -= NumEntries;

        return Entries[pos];
    }

    u32 Level() { return NumOccupied; }
    bool IsEmpty() { return NumOccupied == 0; }
    bool IsFull() { return NumOccupied >= NumEntries; }

    bool CanFit(u32 num) { return ((NumOccupied + num) <= NumEntries); }

private:
    u32 NumEntries;
    T* Entries;
    u32 NumOccupied;
    u32 ReadPos, WritePos;
};

#endif