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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.
#ifndef LIB_JXL_FAKE_PARALLEL_RUNNER_TESTONLY_H_
#define LIB_JXL_FAKE_PARALLEL_RUNNER_TESTONLY_H_
#include <jxl/parallel_runner.h>
#include <cstdint>
#include <vector>
#include "lib/jxl/base/compiler_specific.h"
#include "lib/jxl/base/random.h"
namespace jxl {
// A parallel runner implementation that runs all the jobs in a single thread
// (the caller thread) but runs them pretending to use multiple threads and
// potentially out of order. This is useful for testing conditions that only
// occur under heavy load where the order of operations is different.
class FakeParallelRunner {
public:
FakeParallelRunner(uint32_t order_seed, uint32_t num_threads)
: order_seed_(order_seed), rng_(order_seed), num_threads_(num_threads) {
if (num_threads_ < 1) num_threads_ = 1;
}
JxlParallelRetCode Run(void* jxl_opaque, JxlParallelRunInit init,
JxlParallelRunFunction func, uint32_t start,
uint32_t end) {
JxlParallelRetCode ret = init(jxl_opaque, num_threads_);
if (ret != 0) return ret;
if (order_seed_ == 0) {
for (uint32_t i = start; i < end; i++) {
func(jxl_opaque, i, i % num_threads_);
}
} else {
std::vector<uint32_t> order(end - start);
for (uint32_t i = start; i < end; i++) {
order[i - start] = i;
}
rng_.Shuffle(order.data(), order.size());
for (uint32_t i = start; i < end; i++) {
func(jxl_opaque, order[i - start], i % num_threads_);
}
}
return ret;
}
private:
// Seed for the RNG for defining the execution order. A value of 0 means
// sequential order from start to end.
uint32_t order_seed_;
// The PRNG object, initialized with the order_seed_. Only used if the seed is
// not 0.
Rng rng_;
// Number of fake threads. All the tasks are run on the same thread, but using
// different thread_id values based on this num_threads.
uint32_t num_threads_;
};
} // namespace jxl
extern "C" {
// Function to pass as the parallel runner.
JXL_INLINE JxlParallelRetCode JxlFakeParallelRunner(
void* runner_opaque, void* jpegxl_opaque, JxlParallelRunInit init,
JxlParallelRunFunction func, uint32_t start_range, uint32_t end_range) {
return static_cast<jxl::FakeParallelRunner*>(runner_opaque)
->Run(jpegxl_opaque, init, func, start_range, end_range);
}
}
#endif // LIB_JXL_FAKE_PARALLEL_RUNNER_TESTONLY_H_