// Ceres Solver - A fast non-linear least squares minimizer
// Copyright 2017 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its contributors may be
//   used to endorse or promote products derived from this software without
//   specific prior written permission.
//
// 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
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//
// Author: yp@photonscore.de (Yury Prokazov)

#include "ceres/thread_token_provider.h"

#ifdef CERES_USE_OPENMP
#include <omp.h>
#endif

namespace ceres {
namespace internal {

ThreadTokenProvider::ThreadTokenProvider(int num_threads) {
  (void)num_threads;
#ifdef CERES_USE_CXX11_THREADS
  for (int i = 0; i < num_threads; i++) {
    pool_.Push(i);
  }
#endif

}

int ThreadTokenProvider::Acquire() {
#ifdef CERES_USE_OPENMP
  return omp_get_thread_num();
#endif

#ifdef CERES_NO_THREADS
  return 0;
#endif

#ifdef CERES_USE_CXX11_THREADS
  int thread_id;
  CHECK(pool_.Wait(&thread_id));
  return thread_id;
#endif

}

void ThreadTokenProvider::Release(int thread_id) {
  (void)thread_id;
#ifdef CERES_USE_CXX11_THREADS
  pool_.Push(thread_id);
#endif

}

}  // namespace internal
}  // namespace ceres