| /* | 
 |  * The copyright in this software is being made available under the 2-clauses | 
 |  * BSD License, included below. This software may be subject to other third | 
 |  * party and contributor rights, including patent rights, and no such rights | 
 |  * are granted under this license. | 
 |  * | 
 |  * Copyright (c) 2016, Even Rouault | 
 |  * All rights reserved. | 
 |  * | 
 |  * Redistribution and use in source and binary forms, with or without | 
 |  * modification, are permitted provided that the following conditions | 
 |  * are met: | 
 |  * 1. Redistributions of source code must retain the above copyright | 
 |  *    notice, this list of conditions and the following disclaimer. | 
 |  * 2. Redistributions in binary form must reproduce the above copyright | 
 |  *    notice, this list of conditions and the following disclaimer in the | 
 |  *    documentation and/or other materials provided with the distribution. | 
 |  * | 
 |  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS' | 
 |  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | 
 |  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | 
 |  * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | 
 |  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | 
 |  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | 
 |  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | 
 |  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | 
 |  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | 
 |  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | 
 |  * POSSIBILITY OF SUCH DAMAGE. | 
 |  */ | 
 |  | 
 | #ifndef THREAD_H | 
 | #define THREAD_H | 
 |  | 
 | #include "openjpeg.h" | 
 |  | 
 | /** | 
 | @file thread.h | 
 | @brief Thread API | 
 |  | 
 | The functions in thread.c have for goal to manage mutex, conditions, thread | 
 | creation and thread pools that accept jobs. | 
 | */ | 
 |  | 
 | /** @defgroup THREAD THREAD - Mutex, conditions, threads and thread pools */ | 
 | /*@{*/ | 
 |  | 
 | /** @name Mutex */ | 
 | /*@{*/ | 
 |  | 
 | /** Opaque type for a mutex */ | 
 | typedef struct opj_mutex_t opj_mutex_t; | 
 |  | 
 | /** Creates a mutex. | 
 |  * @return the mutex or NULL in case of error (can for example happen if the library | 
 |  * is built without thread support) | 
 |  */ | 
 | opj_mutex_t* opj_mutex_create(void); | 
 |  | 
 | /** Lock/acquire the mutex. | 
 |  * @param mutex the mutex to acquire. | 
 |  */ | 
 | void opj_mutex_lock(opj_mutex_t* mutex); | 
 |  | 
 | /** Unlock/release the mutex. | 
 |  * @param mutex the mutex to release. | 
 |  */ | 
 | void opj_mutex_unlock(opj_mutex_t* mutex); | 
 |  | 
 | /** Destroy a mutex | 
 |  * @param mutex the mutex to destroy. | 
 |  */ | 
 | void opj_mutex_destroy(opj_mutex_t* mutex); | 
 |  | 
 | /*@}*/ | 
 |  | 
 | /** @name Condition */ | 
 | /*@{*/ | 
 |  | 
 | /** Opaque type for a condition */ | 
 | typedef struct opj_cond_t opj_cond_t; | 
 |  | 
 | /** Creates a condition. | 
 |  * @return the condition or NULL in case of error (can for example happen if the library | 
 |  * is built without thread support) | 
 |  */ | 
 | opj_cond_t* opj_cond_create(void); | 
 |  | 
 | /** Wait for the condition to be signaled. | 
 |  * The semantics is the same as the POSIX pthread_cond_wait. | 
 |  * The provided mutex *must* be acquired before calling this function, and | 
 |  * released afterwards. | 
 |  * The mutex will be released by this function while it must wait for the condition | 
 |  * and reacquired afterwards. | 
 |  * In some particular situations, the function might return even if the condition is not signaled | 
 |  * with opj_cond_signal(), hence the need to check with an application level | 
 |  * mechanism. | 
 |  * | 
 |  * Waiting thread : | 
 |  * \code | 
 |  *    opj_mutex_lock(mutex); | 
 |  *    while( !some_application_level_condition ) | 
 |  *    { | 
 |  *        opj_cond_wait(cond, mutex); | 
 |  *    } | 
 |  *    opj_mutex_unlock(mutex); | 
 |  * \endcode | 
 |  * | 
 |  * Signaling thread : | 
 |  * \code | 
 |  *    opj_mutex_lock(mutex); | 
 |  *    some_application_level_condition = TRUE; | 
 |  *    opj_cond_signal(cond); | 
 |  *    opj_mutex_unlock(mutex); | 
 |  * \endcode | 
 |  * | 
 |  * @param cond the condition to wait. | 
 |  * @param mutex the mutex (in acquired state before calling this function) | 
 |  */ | 
 | void opj_cond_wait(opj_cond_t* cond, opj_mutex_t* mutex); | 
 |  | 
 | /** Signal waiting threads on a condition. | 
 |  * One of the thread waiting with opj_cond_wait() will be waken up. | 
 |  * It is strongly advised that this call is done with the mutex that is used | 
 |  * by opj_cond_wait(), in a acquired state. | 
 |  * @param cond the condition to signal. | 
 |  */ | 
 | void opj_cond_signal(opj_cond_t* cond); | 
 |  | 
 | /** Destroy a condition | 
 |  * @param cond the condition to destroy. | 
 |  */ | 
 | void opj_cond_destroy(opj_cond_t* cond); | 
 |  | 
 | /*@}*/ | 
 |  | 
 | /** @name Thread */ | 
 | /*@{*/ | 
 |  | 
 | /** Opaque type for a thread handle */ | 
 | typedef struct opj_thread_t opj_thread_t; | 
 |  | 
 | /** User function to execute in a thread | 
 |  * @param user_data user data provided with opj_thread_create() | 
 |  */ | 
 | typedef void (*opj_thread_fn)(void* user_data); | 
 |  | 
 | /** Creates a new thread. | 
 |  * @param thread_fn Function to run in the new thread. | 
 |  * @param user_data user data provided to the thread function. Might be NULL. | 
 |  * @return a thread handle or NULL in case of failure (can for example happen if the library | 
 |  * is built without thread support) | 
 |  */ | 
 | opj_thread_t* opj_thread_create(opj_thread_fn thread_fn, void* user_data); | 
 |  | 
 | /** Wait for a thread to be finished and release associated resources to the | 
 |  * thread handle. | 
 |  * @param thread the thread to wait for being finished. | 
 |  */ | 
 | void opj_thread_join(opj_thread_t* thread); | 
 |  | 
 | /*@}*/ | 
 |  | 
 | /** @name Thread local storage */ | 
 | /*@{*/ | 
 | /** Opaque type for a thread local storage */ | 
 | typedef struct opj_tls_t opj_tls_t; | 
 |  | 
 | /** Get a thread local value corresponding to the provided key. | 
 |  * @param tls thread local storage handle | 
 |  * @param key key whose value to retrieve. | 
 |  * @return value associated with the key, or NULL is missing. | 
 |  */ | 
 | void* opj_tls_get(opj_tls_t* tls, int key); | 
 |  | 
 | /** Type of the function used to free a TLS value */ | 
 | typedef void (*opj_tls_free_func)(void* value); | 
 |  | 
 | /** Set a thread local value corresponding to the provided key. | 
 |  * @param tls thread local storage handle | 
 |  * @param key key whose value to set. | 
 |  * @param value value to set (may be NULL). | 
 |  * @param free_func function to call currently installed value. | 
 |  * @return OPJ_TRUE if successful. | 
 |  */ | 
 | OPJ_BOOL opj_tls_set(opj_tls_t* tls, int key, void* value, | 
 |                      opj_tls_free_func free_func); | 
 |  | 
 | /*@}*/ | 
 |  | 
 | /** @name Thread pool */ | 
 | /*@{*/ | 
 |  | 
 | /** Opaque type for a thread pool */ | 
 | typedef struct opj_thread_pool_t opj_thread_pool_t; | 
 |  | 
 | /** Create a new thread pool. | 
 |  * num_thread must nominally be >= 1 to create a real thread pool. If num_threads | 
 |  * is negative or null, then a dummy thread pool will be created. All functions | 
 |  * operating on the thread pool will work, but job submission will be run | 
 |  * synchronously in the calling thread. | 
 |  * | 
 |  * @param num_threads the number of threads to allocate for this thread pool. | 
 |  * @return a thread pool handle, or NULL in case of failure (can for example happen if the library | 
 |  * is built without thread support) | 
 |  */ | 
 | opj_thread_pool_t* opj_thread_pool_create(int num_threads); | 
 |  | 
 | /** User function to execute in a thread | 
 |  * @param user_data user data provided with opj_thread_create() | 
 |  * @param tls handle to thread local storage | 
 |  */ | 
 | typedef void (*opj_job_fn)(void* user_data, opj_tls_t* tls); | 
 |  | 
 |  | 
 | /** Submit a new job to be run by one of the thread in the thread pool. | 
 |  * The job ( thread_fn, user_data ) will be added in the queue of jobs managed | 
 |  * by the thread pool, and run by the first thread that is no longer busy. | 
 |  * | 
 |  * @param tp the thread pool handle. | 
 |  * @param job_fn Function to run. Must not be NULL. | 
 |  * @param user_data User data provided to thread_fn. | 
 |  * @return OPJ_TRUE if the job was successfully submitted. | 
 |  */ | 
 | OPJ_BOOL opj_thread_pool_submit_job(opj_thread_pool_t* tp, opj_job_fn job_fn, | 
 |                                     void* user_data); | 
 |  | 
 | /** Wait that no more than max_remaining_jobs jobs are remaining in the queue of | 
 |  * the thread pool. The aim of this function is to avoid submitting too many | 
 |  * jobs while the thread pool cannot cope fast enough with them, which would | 
 |  * result potentially in out-of-memory situations with too many job descriptions | 
 |  * being queued. | 
 |  * | 
 |  * @param tp the thread pool handle | 
 |  * @param max_remaining_jobs maximum number of jobs allowed to be queued without waiting. | 
 |  */ | 
 | void opj_thread_pool_wait_completion(opj_thread_pool_t* tp, | 
 |                                      int max_remaining_jobs); | 
 |  | 
 | /** Return the number of threads associated with the thread pool. | 
 |  * | 
 |  * @param tp the thread pool handle. | 
 |  * @return number of threads associated with the thread pool. | 
 |  */ | 
 | int opj_thread_pool_get_thread_count(opj_thread_pool_t* tp); | 
 |  | 
 | /** Destroy a thread pool. | 
 |  * @param tp the thread pool handle. | 
 |  */ | 
 | void opj_thread_pool_destroy(opj_thread_pool_t* tp); | 
 |  | 
 | /*@}*/ | 
 |  | 
 | /*@}*/ | 
 |  | 
 | #endif /* THREAD_H */ |