1 files changed, 344 insertions, 0 deletions
diff --git a/libparc/parc/memory/parc_BufferPool.h b/libparc/parc/memory/parc_BufferPool.h
new file mode 100644
index 00000000..33028920
--- /dev/null
+++ b/libparc/parc/memory/parc_BufferPool.h
@@ -0,0 +1,344 @@
+/*
+ * 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_BufferPool.h
+ * @ingroup memory
+ * @brief A simple pool of uniformly sized PARCBuffer instances.
+ *
+ * The client uses `parcBufferPool_GetInstance` to obtain instances which are placed attempted to be placed
+ * into the pool when the `PARCBuffer_Release` function is called.
+ * The pool has a maxmimum number of instances that it will cache.
+ *
+ */
+#ifndef PARCLibrary_parc_BufferPool
+#define PARCLibrary_parc_BufferPool
+#include <stdbool.h>
+
+#include <parc/algol/parc_Object.h>
+
+parcObject_Declare(PARCBufferPool);
+
+/**
+ * Increase the number of references to a `PARCBufferPool` instance.
+ *
+ * Note that new `PARCBufferPool` is not created,
+ * only that the given `PARCBufferPool` reference count is incremented.
+ * Discard the reference by invoking `parcBufferPool_Release`.
+ *
+ * @param [in] instance A pointer to a valid PARCBufferPool instance.
+ *
+ * @return The same value as the parameter @p instance.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_Create(5, 10);
+ *
+ *     PARCBufferPool *b = parcBufferPool_Acquire(a);
+ *
+ *     parcBufferPool_Release(&a);
+ *     parcBufferPool_Release(&b);
+ * }
+ * @endcode
+ */
+PARCBufferPool *parcBufferPool_Acquire(const PARCBufferPool *instance);
+
+#ifdef PARCLibrary_DISABLE_VALIDATION
+#  define parcBufferPool_OptionalAssertValid(_instance_)
+#else
+#  define parcBufferPool_OptionalAssertValid(_instance_) parcBufferPool_AssertValid(_instance_)
+#endif
+
+/**
+ * Assert that the given `PARCBufferPool` instance is valid.
+ *
+ * @param [in] instance A pointer to a valid PARCBufferPool instance.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_Create(5, 10);
+ *
+ *     parcBufferPool_AssertValid(a);
+ *
+ *     parcBufferPool_Release(&a);
+ * }
+ * @endcode
+ */
+void parcBufferPool_AssertValid(const PARCBufferPool *instance);
+
+/**
+ * Create an instance of PARCBufferPool containing instances of `PARCBuffer`.
+ *
+ * This function is equivalent to invoking
+ * @code
+ *     PARCBufferPool *a = parcBufferPool_CreateExtending(&parcObject_DescriptorName(PARCBuffer), 5, 10);
+ * @endcode
+ *
+ * The value of @p limit is the maximum number of instances that the pool will cache,
+ * and @p bufferSize is the size of the `PARCBuffer` instances cached.
+ *
+ * @return non-NULL A pointer to a valid PARCBufferPool instance.
+ * @return NULL An error occurred.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_Create(5, 10);
+ *
+ *     parcBufferPool_Release(&a);
+ * }
+ * @endcode
+ */
+PARCBufferPool *parcBufferPool_Create(size_t limit, size_t bufferSize);
+
+/**
+ * Create an instance of PARCBufferPool containing instances of object specified by the given `PARCObjectDescriptor`.
+ *
+ * The value of @p limit is the maximum number of instances that the pool will cache,
+ * and @p bufferSize is the size of the `PARCBuffer` instances cached.
+ *
+ * This function creates a PARCBufferPool that creates and manages instances of PARCBuffer which may have been extended.
+ *
+ * @return non-NULL A pointer to a valid PARCBufferPool instance.
+ * @return NULL An error occurred.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_CreateExtending(&parcObject_DescriptorName(MyPARCBuffer), 5, 10);
+ *
+ *     parcBufferPool_Release(&a);
+ * }
+ * @endcode
+ */
+PARCBufferPool *parcBufferPool_CreateExtending(const PARCObjectDescriptor *originalDescriptor, size_t limit, size_t bufferSize);
+
+/**
+ * Print a human readable representation of the given `PARCBufferPool`.
+ *
+ * @param [in] instance A pointer to a valid PARCBufferPool instance.
+ * @param [in] indentation The indentation level to use for printing.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_Create(5, 10);
+ *
+ *     parcBufferPool_Display(a, 0);
+ *
+ *     parcBufferPool_Release(&a);
+ * }
+ * @endcode
+ */
+void parcBufferPool_Display(const PARCBufferPool *instance, int indentation);
+
+/**
+ * Determine if an instance of `PARCBufferPool` is valid.
+ *
+ * Valid means the internal state of the type is consistent with its required current or future behaviour.
+ * This may include the validation of internal instances of types.
+ *
+ * @param [in] instance A pointer to a valid PARCBufferPool instance.
+ *
+ * @return true The instance is valid.
+ * @return false The instance is not valid.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_Create(5, 10);
+ *
+ *     if (parcBufferPool_IsValid(a)) {
+ *         printf("Instance is valid.\n");
+ *     }
+ *
+ *     parcBufferPool_Release(&a);
+ * }
+ * @endcode
+ *
+ */
+bool parcBufferPool_IsValid(const PARCBufferPool *instance);
+
+/**
+ * Release a previously acquired reference to the given `PARCBufferPool` instance,
+ * decrementing the reference count for the instance.
+ *
+ * The pointer to the instance is set to NULL as a side-effect of this function.
+ *
+ * If the invocation causes the last reference to the instance to be released,
+ * the instance is deallocated and the instance's implementation will perform
+ * additional cleanup and release other privately held references.
+ *
+ * @param [in,out] instancePtr A pointer to a pointer to the instance to release.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *a = parcBufferPool_Create(5, 10);
+ *
+ *     parcBufferPool_Release(&a);
+ * }
+ * @endcode
+ */
+void parcBufferPool_Release(PARCBufferPool **instancePtr);
+
+/**
+ * Get an instance of a `PARCBuffer`.
+ *
+ * If the PARCBufferPool contains a cached instance, it will be returned.
+ * Otherwise a new instance will be created.
+ *
+ * Any `PARCBuffer` instance which is later released, will be a candidate for caching by the given `PARCBufferPool`.
+ *
+ * @param [in] bufferPool A pointer to a valid PARCBufferPool instance.
+ *
+ * @return non-NULL A pointer to a valid `PARCBuffer`.
+ * @return NULL An error occurred.
+ *
+ * Example:
+ * @code
+ * {
+ *
+ *     PARCBufferPool *pool = parcBufferPool_Create(5, 10);
+ *     ...
+ *
+ *     parcBufferPool_Release(&pool);
+ * }
+ * @endcode
+ */
+PARCBuffer *parcBufferPool_GetInstance(PARCBufferPool *bufferPool);
+
+/**
+ * Set the largest number of buffers the pool will cache.
+ *
+ * If the new limit is less than the current limit, and the current pool size is greater than the new limit,
+ * the number of buffers the pool will cache will decay as they are obtained and released from the pool during use.
+ *
+ * @param [in] bufferPool A pointer to a valid PARCBufferPool instance.
+ * @param [in] limit the largest number of buffers the pool will cache.
+ *
+ * @return The previous value of the largest number of buffers the pool cached.
+ *
+ * Example:
+ * @code
+ * {
+ *
+ *     PARCBufferPool *pool = parcBufferPool_Create(5, 10);
+ *     ...
+ *
+ *     size_t limit = parcBufferPool_SetLimit(pool, 3);
+ *
+ *     parcBufferPool_Release(&pool);
+ * }
+ * @endcode
+ */
+size_t parcBufferPool_SetLimit(PARCBufferPool *bufferPool, size_t limit);
+
+/**
+ * Get the largest number of buffers the pool will cache.
+ *
+ * @param [in] bufferPool A pointer to a valid PARCBufferPool instance.
+ *
+ * @return The value of the largest number of buffers the pool will cache.
+ *
+ * Example:
+ * @code
+ * {
+ *
+ *     PARCBufferPool *pool = parcBufferPool_Create(5, 10);
+ *     ...
+ *
+ *     size_t limit = parcBufferPool_GetLimit(pool);
+ *
+ *     parcBufferPool_Release(&pool);
+ * }
+ * @endcode
+ */
+size_t parcBufferPool_GetLimit(const PARCBufferPool *bufferPool);
+
+/**
+ * Get the current number of buffers the pool has cached.
+ *
+ * The value is always greater than or equal to 0 and less than or equal to the limit.
+ *
+ * @param [in] bufferPool A pointer to a valid PARCBufferPool instance.
+ *
+ * @return the largest number of buffers the pool has ever cached.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *pool = parcBufferPool_Create(5, 10);
+ *     ...
+ *
+ *     size_t poolSize = parcBufferPool_GetCurrentPoolSize(pool);
+ *
+ *     parcBufferPool_Release(&pool);
+ * }
+ * @endcode
+ */
+size_t parcBufferPool_GetCurrentPoolSize(const PARCBufferPool *bufferPool);
+
+/**
+ * Get the largest number of buffers the pool has ever cached.
+ *
+ * The value is always greater than or equal to 0 and less than or equal to the limit.
+ *
+ * @param [in] bufferPool A pointer to a valid PARCBufferPool instance.
+ *
+ * @return the largest number of buffers the pool has ever cached.
+ *
+ * Example:
+ * @code
+ * {
+ *     PARCBufferPool *pool = parcBufferPool_Create(5, 10);
+ *     ...
+ *
+ *     size_t allTimeHigh = parcBufferPool_GetLargestPoolSize(pool);
+ *
+ *     parcBufferPool_Release(&pool);
+ * }
+ * @endcode
+ */
+size_t parcBufferPool_GetLargestPoolSize(const PARCBufferPool *bufferPool);
+
+/**
+ * Forcibly drain the PARCBufferPool of an excess (more than the pool's limit) `PARCBuffer` instances.
+ *
+ * The number of PARCBuffer instances can exceed the PARCBufferPool's limit if `parcBufferPool_SetLimit` is used to set the limit
+ * to less than Pool's current pool size.
+ *
+ * @param [in] bufferPool A pointer to a valid PARCBufferPool instance.
+ *
+ * @return the largest number of buffers released from the Pool's cache.
+ *
+ * Example:
+ * @code
+ * {
+ *
+ *     PARCBufferPool *pool = parcBufferPool_Create(5, 10);
+ *     ...
+ *
+ *     size_t limit = parcBufferPool_SetLimit(pool, 3);
+ *     size_t drained = parcBufferPool_Drain(pool);
+ *
+ *     parcBufferPool_Release(&pool);
+ * }
+ * @endcode
+ */
+size_t parcBufferPool_Drain(PARCBufferPool *bufferPool);
+#endif