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/* Copyright (c) the JPEG XL Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style
* license that can be found in the LICENSE file.
*/
/** @addtogroup libjxl_threads
* @{
* @file resizable_parallel_runner.h
* @brief implementation using std::thread of a resizeable ::JxlParallelRunner.
*/
/** Implementation of JxlParallelRunner than can be used to enable
* multithreading when using the JPEG XL library. This uses std::thread
* internally and related synchronization functions. The number of threads
* created can be changed after creation of the thread pool; the threads
* (including the main thread) are re-used for every
* ResizableParallelRunner::Runner call. Only one concurrent
* @ref JxlResizableParallelRunner call per instance is allowed at a time.
*
* This is a scalable, lower-overhead thread pool runner, especially suitable
* for data-parallel computations in the fork-join model, where clients need to
* know when all tasks have completed.
*
* Compared to the implementation in @ref thread_parallel_runner.h, this
* implementation is tuned for execution on lower-powered systems, including
* for example ARM CPUs with big.LITTLE computation models.
*/
#ifndef JXL_RESIZABLE_PARALLEL_RUNNER_H_
#define JXL_RESIZABLE_PARALLEL_RUNNER_H_
#include <jxl/jxl_threads_export.h>
#include <jxl/memory_manager.h>
#include <jxl/parallel_runner.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#ifdef __cplusplus
extern "C" {
#endif
/** Parallel runner internally using std::thread. Use as @ref JxlParallelRunner.
*/
JXL_THREADS_EXPORT JxlParallelRetCode JxlResizableParallelRunner(
void* runner_opaque, void* jpegxl_opaque, JxlParallelRunInit init,
JxlParallelRunFunction func, uint32_t start_range, uint32_t end_range);
/** Creates the runner for @ref JxlResizableParallelRunner. Use as the opaque
* runner. The runner will execute tasks on the calling thread until
* @ref JxlResizableParallelRunnerSetThreads is called.
*/
JXL_THREADS_EXPORT void* JxlResizableParallelRunnerCreate(
const JxlMemoryManager* memory_manager);
/** Changes the number of threads for @ref JxlResizableParallelRunner.
*/
JXL_THREADS_EXPORT void JxlResizableParallelRunnerSetThreads(
void* runner_opaque, size_t num_threads);
/** Suggests a number of threads to use for an image of given size.
*/
JXL_THREADS_EXPORT uint32_t
JxlResizableParallelRunnerSuggestThreads(uint64_t xsize, uint64_t ysize);
/** Destroys the runner created by @ref JxlResizableParallelRunnerCreate.
*/
JXL_THREADS_EXPORT void JxlResizableParallelRunnerDestroy(void* runner_opaque);
#ifdef __cplusplus
}
#endif
#endif /* JXL_RESIZABLE_PARALLEL_RUNNER_H_ */
/** @}*/