1 files changed, 89 insertions, 0 deletions
diff --git a/libs/rs/rsLocklessFifo.h b/libs/rs/rsLocklessFifo.h
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+++ b/libs/rs/rsLocklessFifo.h
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+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_RS_LOCKLESS_FIFO_H
+#define ANDROID_RS_LOCKLESS_FIFO_H
+
+
+#include "rsUtils.h"
+
+namespace android {
+
+
+// A simple FIFO to be used as a producer / consumer between two
+// threads.  One is writer and one is reader.  The common cases
+// will not require locking.  It is not threadsafe for multiple 
+// readers or writers by design.
+
+class LocklessCommandFifo 
+{
+public:
+    bool init(uint32_t size);
+
+    LocklessCommandFifo();
+    ~LocklessCommandFifo();
+
+
+protected:
+    class Signal {
+    public:
+        Signal();
+        ~Signal();
+
+        bool init();
+
+        void set();
+        void wait();
+
+    protected:
+        bool mSet;
+        pthread_mutex_t mMutex;
+        pthread_cond_t mCondition;
+    };
+
+    uint8_t * volatile mPut;
+    uint8_t * volatile mGet;
+    uint8_t * mBuffer;
+    uint8_t * mEnd;
+    uint8_t mSize;
+
+    Signal mSignalToWorker;
+    Signal mSignalToControl;
+
+
+
+public:
+    void * reserve(uint32_t bytes);
+    void commit(uint32_t command, uint32_t bytes);
+    void commitSync(uint32_t command, uint32_t bytes);
+
+    void flush();
+    const void * get(uint32_t *command, uint32_t *bytesData);
+    void next();
+
+    void makeSpace(uint32_t bytes);
+
+    bool isEmpty() const;
+    uint32_t getFreeSpace() const;
+
+
+private:
+    void dumpState(const char *) const;
+};
+
+
+}
+#endif