1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_RS_LOCKLESS_FIFO_H
18#define ANDROID_RS_LOCKLESS_FIFO_H
19
20
21#include "rsUtils.h"
22#include "rsSignal.h"
23
24namespace android {
25namespace renderscript {
26
27
28// A simple FIFO to be used as a producer / consumer between two
29// threads.  One is writer and one is reader.  The common cases
30// will not require locking.  It is not threadsafe for multiple
31// readers or writers by design.
32
33class LocklessCommandFifo {
34public:
35    bool init(uint32_t size);
36    void shutdown();
37    void setTimoutCallback(void (*)(void *), void *, uint64_t timeout);
38
39    void printDebugData() const;
40
41    LocklessCommandFifo();
42    ~LocklessCommandFifo();
43
44protected:
45    uint8_t * volatile mPut;
46    uint8_t * volatile mGet;
47    uint8_t * mBuffer;
48    uint8_t * mEnd;
49    uint8_t mSize;
50    bool mInShutdown;
51    bool mInitialized;
52
53    Signal mSignalToWorker;
54    Signal mSignalToControl;
55
56public:
57    void * reserve(uint32_t bytes);
58    void commit(uint32_t command, uint32_t bytes);
59    void commitSync(uint32_t command, uint32_t bytes);
60
61    void flush();
62    bool wait(uint64_t timeout = 0);
63
64    const void * get(uint32_t *command, uint32_t *bytesData, uint64_t timeout = 0);
65    void next();
66
67    void makeSpace(uint32_t bytes);
68    bool makeSpaceNonBlocking(uint32_t bytes);
69
70    bool isEmpty() const;
71    uint32_t getFreeSpace() const;
72
73private:
74    void dumpState(const char *) const;
75
76    void (*mTimeoutCallback)(void *);
77    void * mTimeoutCallbackData;
78    uint64_t mTimeoutWait;
79};
80
81
82}
83}
84#endif
85