libc/src/__support/time/linux/clock_conversion.h

//===--- clock conversion linux implementation ------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H
#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H

#include "src/__support/macros/config.h"
#include "src/__support/time/linux/clock_gettime.h"
#include "src/__support/time/units.h"

namespace LIBC_NAMESPACE_DECL {
namespace internal {

LIBC_INLINE timespec convert_clock(timespec input, clockid_t from,
                                   clockid_t to) {
  using namespace time_units;
  timespec from_time;
  timespec to_time;
  timespec output;
  internal::clock_gettime(from, &from_time);
  internal::clock_gettime(to, &to_time);
  output.tv_sec = input.tv_sec - from_time.tv_sec + to_time.tv_sec;
  output.tv_nsec = input.tv_nsec - from_time.tv_nsec + to_time.tv_nsec;

  if (output.tv_nsec > 1_s_ns) {
    output.tv_sec++;
    output.tv_nsec -= 1_s_ns;
  } else if (output.tv_nsec < 0) {
    output.tv_sec--;
    output.tv_nsec += 1_s_ns;
  }
  return output;
}

} // namespace internal
} // namespace LIBC_NAMESPACE_DECL

#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H