/*

 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.

 * All rights reserved.

 *

 * This source code is licensed under both the BSD-style license (found in the

 * LICENSE file in the root directory of this source tree) and the GPLv2 (found

 * in the COPYING file in the root directory of this source tree).

 * You may select, at your option, one of the above-listed licenses.

 */

#ifndef POOL_H

#define POOL_H

#if defined (__cplusplus)

extern "C" {

#endif

#include <stddef.h>   /* size_t */

#define ZSTD_STATIC_LINKING_ONLY   /* ZSTD_customMem */

#include "zstd.h"

typedef struct POOL_ctx_s POOL_ctx;

/*! POOL_create() :

 *  Create a thread pool with at most `numThreads` threads.

 * `numThreads` must be at least 1.

 *  The maximum number of queued jobs before blocking is `queueSize`.

 * @return : POOL_ctx pointer on success, else NULL.

*/

POOL_ctx* POOL_create(size_t numThreads, size_t queueSize);

POOL_ctx* POOL_create_advanced(size_t numThreads, size_t queueSize,

                               ZSTD_customMem customMem);

/*! POOL_free() :

 *  Free a thread pool returned by POOL_create().

 */

void POOL_free(POOL_ctx* ctx);

/*! POOL_resize() :

 *  Expands or shrinks pool's number of threads.

 *  This is more efficient than releasing + creating a new context,

 *  since it tries to preserve and re-use existing threads.

 * `numThreads` must be at least 1.

 * @return : 0 when resize was successful,

 *           !0 (typically 1) if there is an error.

 *    note : only numThreads can be resized, queueSize remains unchanged.

 */

int POOL_resize(POOL_ctx* ctx, size_t numThreads);

/*! POOL_sizeof() :

 * @return threadpool memory usage

 *  note : compatible with NULL (returns 0 in this case)

 */

size_t POOL_sizeof(POOL_ctx* ctx);

/*! POOL_function :

 *  The function type that can be added to a thread pool.

 */

typedef void (*POOL_function)(void*);

/*! POOL_add() :

 *  Add the job `function(opaque)` to the thread pool. `ctx` must be valid.

 *  Possibly blocks until there is room in the queue.

 *  Note : The function may be executed asynchronously,

 *         therefore, `opaque` must live until function has been completed.

 */

void POOL_add(POOL_ctx* ctx, POOL_function function, void* opaque);

/*! POOL_tryAdd() :

 *  Add the job `function(opaque)` to thread pool _if_ a worker is available.

 *  Returns immediately even if not (does not block).

 * @return : 1 if successful, 0 if not.

 */

int POOL_tryAdd(POOL_ctx* ctx, POOL_function function, void* opaque);

#if defined (__cplusplus)

}

#endif

#endif