Oboe FIFO: general purpose FIFO
Bug: 33347409
Test: test_oboe_api
Change-Id: I764fe372f00b98364e4d36e7841cb00fc8af5695
Signed-off-by: Phil Burk <philburk@google.com>
diff --git a/media/liboboe/src/fifo/FifoControllerBase.h b/media/liboboe/src/fifo/FifoControllerBase.h
new file mode 100644
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+++ b/media/liboboe/src/fifo/FifoControllerBase.h
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+/*
+ * Copyright 2015 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 FIFO_FIFO_CONTROLLER_BASE_H
+#define FIFO_FIFO_CONTROLLER_BASE_H
+
+#include <stdint.h>
+
+typedef int64_t fifo_counter_t;
+typedef int32_t fifo_frames_t;
+
+/**
+ * Manage the read/write indices of a circular buffer.
+ *
+ * The caller is responsible for reading and writing the actual data.
+ * Note that the span of available frames may not be contiguous. They
+ * may wrap around from the end to the beginning of the buffer. In that
+ * case the data must be read or written in at least two blocks of frames.
+ *
+ */
+class FifoControllerBase {
+
+public:
+ /**
+ * Constructor for FifoControllerBase
+ * @param capacity Total size of the circular buffer in frames.
+ * @param threshold Number of frames to fill. Must be less than capacity.
+ */
+ FifoControllerBase(fifo_frames_t capacity, fifo_frames_t threshold);
+
+ virtual ~FifoControllerBase();
+
+ // Abstract methods to be implemented in subclasses.
+ /**
+ * @return Counter used by the reader of the FIFO.
+ */
+ virtual fifo_counter_t getReadCounter() = 0;
+
+ /**
+ * This is normally only used internally.
+ * @param count Number of frames that have been read.
+ */
+ virtual void setReadCounter(fifo_counter_t count) = 0;
+
+ /**
+ * @return Counter used by the reader of the FIFO.
+ */
+ virtual fifo_counter_t getWriteCounter() = 0;
+
+ /**
+ * This is normally only used internally.
+ * @param count Number of frames that have been read.
+ */
+ virtual void setWriteCounter(fifo_counter_t count) = 0;
+
+ /**
+ * This may be negative if an unthrottled reader has read beyond the available data.
+ * @return number of valid frames available to read. Never read more than this.
+ */
+ fifo_frames_t getFullFramesAvailable();
+
+ /**
+ * The index in a circular buffer of the next frame to read.
+ */
+ fifo_frames_t getReadIndex();
+
+ /**
+ * @param numFrames number of frames to advance the read index
+ */
+ void advanceReadIndex(fifo_frames_t numFrames);
+
+ /**
+ * @return number of frames that can be written. Never write more than this.
+ */
+ fifo_frames_t getEmptyFramesAvailable();
+
+ /**
+ * The index in a circular buffer of the next frame to write.
+ */
+ fifo_frames_t getWriteIndex();
+
+ /**
+ * @param numFrames number of frames to advance the write index
+ */
+ void advanceWriteIndex(fifo_frames_t numFrames);
+
+ /**
+ * You can request that the buffer not be filled above a maximum
+ * number of frames.
+ * @param threshold effective size of the buffer
+ */
+ void setThreshold(fifo_frames_t threshold);
+
+ fifo_frames_t getThreshold() const {
+ return mThreshold;
+ }
+
+ fifo_frames_t getCapacity() const {
+ return mCapacity;
+ }
+
+
+private:
+ fifo_frames_t mCapacity;
+ fifo_frames_t mThreshold;
+};
+
+#endif // FIFO_FIFO_CONTROLLER_BASE_H