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+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ * 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.
+ */
+
+/**
+ * @file parc_RingBuffer.h
+ * @ingroup threading
+ * @brief A thread-safe ring buffer.
+ *
+ * A fixed size, thread safe ring buffer. It can have multiple producers and multiple
+ * consumers. All exclusion is done inside the ring buffer.
+ *
+ * This is a non-blocking data structure.
+ *
+ * If the user knows there is only one producer and one consumer, you can create the ring buffer with
+ * `parcRingBuffer_CreateSingleProducerSingleConsumer`. Such a ring buffer can have at most 2 references.
+ *
+ */
+
+#ifndef libparc_parc_RingBuffer_h
+#define libparc_parc_RingBuffer_h
+
+#include <stdbool.h>
+#include <stdint.h>
+
+struct parc_ringbuffer;
+typedef struct parc_ringbuffer PARCRingBuffer;
+
+/**< Will be called for each data item on destroy */
+typedef void (RingBufferEntryDestroyer)(void **entryPtr);
+
+struct parc_ringbuffer_impl;
+typedef struct parc_ringbuffer_interface PARCRingBufferInterface;
+
+struct parc_ringbuffer_interface {
+    void *instance;
+    void * (*acquire)(PARCRingBufferInterface *ring);
+    void (*release)(PARCRingBufferInterface **ring);
+    bool (*put)(PARCRingBufferInterface *ring, void *data);
+    bool (*get)(PARCRingBufferInterface *ring, void *outputDataPtr);
+    bool (*remaining)(PARCRingBufferInterface *ring);
+};
+
+/**
+ * Creates a ring buffer of the given size, which must be a power of 2.
+ *
+ * The ring buffer can store up to (elements-1) items in the buffer.  The buffer can
+ * be shared between multiple producers and consumers.  Each of them should be
+ * given out from a call to {@link parcRingBuffer_Acquire} to create reference counted
+ * copies.
+ *
+ * The reference count is "1" on return.
+ *
+ * @param [in] interface A pointer to the underlying instance and the interface functions for acquire,
+ * release,put,get,and remaining.
+ *
+ * @return non-null An pointer to a new allocated `PARCRingBuffer`.
+ *
+ * Example:
+ * @code
+ * <#example#>
+ * @endcode
+ */
+PARCRingBuffer *parcRingBuffer_Create(PARCRingBufferInterface *interface);
+
+/**
+ * Acquire a new reference to an instance of `PARCRingBuffer`.
+ *
+ * A RING WITHOUT LOCKS CAN ONLY HAVE 2 REFERENCES.
+ * The reference count to the instance is incremented.
+ *
+ * @param [in] ring The instance of `PARCRingBuffer` to which to refer.
+ *
+ * @return The same value as the input parameter @p ring
+ *
+ * Example:
+ * @code
+ * {
+ *     <#example#>
+ * }
+ * @endcode
+ */
+
+PARCRingBuffer *parcRingBuffer_Acquire(const PARCRingBuffer *ring);
+
+/**
+ * Releases a reference.  The buffer will be destroyed after the last release.
+ *
+ * If the destroyer was specified on create, it will be called on each entry in the buffer
+ * when the buffer is destroyed.
+ *
+ * @param [in,out] ringPtr The pointer to the pointer of the `PARCRingBuffer` to be destroyed.
+ *
+ * Example:
+ * @code
+ * <#example#>
+ * @endcode
+ */
+void parcRingBuffer_Release(PARCRingBuffer **ringPtr);
+
+/**
+ * Non-blocking attempt to put item on ring.  May return false if ring is full.
+ *
+ * @param [in,out] ring The instance of `PARCRingBuffer` to modify'
+ * @param [in] data A pointer to teh data to put on the ring.
+ *
+ * @return true Data was put on the queue
+ * @return false Would have blocked, the queue was full
+ *
+ * Example:
+ * @code
+ * <#example#>
+ * @endcode
+ */
+bool parcRingBuffer_Put(PARCRingBuffer *ring, void *data);
+
+/**
+ * Gets the next item off the ring, or returns false if would have blocked.
+ *
+ * Non-blocking, gets an item off the ring, or returns false if would block
+ *
+ * @param [in] ring The pointer to the `PARCRingBuffer`
+ * @param [out] outputDataPtr The output pointer
+ *
+ * @return true Data returned in the output argument
+ * @return false Ring is empty, no data returned.
+ *
+ * Example:
+ * @code
+ * <#example#>
+ * @endcode
+ */
+bool parcRingBuffer_Get(PARCRingBuffer *ring, void **outputDataPtr);
+
+/**
+ * Returns the remaining capacity of the ring
+ *
+ * Returns the remaining capacity of the ring.  This does not guarantee the next
+ * Put will not block, as other producers might consumer the space between calls.
+ *
+ * @param [in] ring The pointer to the `PARCRingBuffer`
+ *
+ * @return  The uint32_t remaining capacity of the ring.
+ *
+ * Example:
+ * @code
+ * <#example#>
+ * @endcode
+ */
+uint32_t parcRingBuffer_Remaining(PARCRingBuffer *ring);
+#endif // libparc_parc_RingBuffer_h