/**
 * @file thread_pool.h
 * 
 * @brief Interface of thread_pool_t.
 * 
 */

/*
 * Copyright (C) 2005-2006 Martin Willi
 * Copyright (C) 2005 Jan Hutter
 * Hochschule fuer Technik Rapperswil
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 */

#ifndef THREAD_POOL_H_
#define THREAD_POOL_H_

typedef struct thread_pool_t thread_pool_t;

#include <stdlib.h>

#include <library.h>

/**
 * @brief A thread_pool consists of a pool of threads processing jobs from the job queue.
 *
 * Current implementation uses as many threads as specified in constructor.
 * A more improved version would dynamically increase thread count if necessary.
 *
 * @b Constructors:
 *  - thread_pool_create()
 *
 * @todo Add support for dynamic thread handling
 * 
 * @ingroup processing
 */
struct thread_pool_t {
	
	/**
	 * @brief Return currently instanciated thread count.
	 *
	 * @param thread_pool	calling object		
	 * @return				size of thread pool
	 */
	u_int (*get_pool_size) (thread_pool_t *thread_pool);
	
	/**
	 * @brief Get the number of threads currently waiting for work.
	 *
	 * @param thread_pool	calling object		
	 * @return				number of idle threads
	 */
	u_int (*get_idle_threads) (thread_pool_t *thread_pool);
	
	/**
	 * @brief Destroy a thread_pool_t object.
	 * 
	 * Sends cancellation request to all threads and AWAITS their termination.
	 * 
	 * @param thread_pool	calling object
	 */
	void (*destroy) (thread_pool_t *thread_pool);
};

/**
 * @brief Create the thread pool using using pool_size of threads.
 * 
 * @param pool_size			desired pool size
 * @return
 *							- thread_pool_t object if one ore more threads could be started, or
 *							- NULL if no threads could be created
 *
 * @ingroup processing
 */
thread_pool_t *thread_pool_create(size_t pool_size);


#endif /*THREAD_POOL_H_*/
