#define CAML_NAME_SPACE

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <errno.h>
#include <stdint.h>

#include <caml/mlvalues.h>
#include <caml/memory.h>
#include <caml/alloc.h>
#include <caml/fail.h>

#ifndef __unused
#define __unused(x) x __attribute((unused))
#endif
#define __unit() value __unused(unit)

CAMLprim value
clock_linux_get_time_byte(__unit ())
{
  struct timespec ts;

  if (clock_gettime(CLOCK_MONOTONIC, &ts))
    caml_invalid_argument("clock: unsupported clock");

  return caml_copy_int64(ts.tv_sec * 1000000000LL + ts.tv_nsec);
}

// XXX(dinosaure): commented because to be able to compile the test into any
// platform (ARM)
//
// uint64_t
// clock_linux_get_tick(__unit ())
// {
//   // struct timespec ts;
//   unsigned hi, lo;
//   __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
// 
//   // XXX(dinosaure): [clock_gettime] costs a lot and are
//   // not really precise. [rdtsc] (Read Time Stamp Counter)
//   // is more reliable.
// 
//   return (((unsigned long long) lo) | (((unsigned long long) hi) << 32));
// }

uint64_t
clock_linux_get_time_native(__unit ())
{
  struct timespec ts;

  (void) clock_gettime(CLOCK_MONOTONIC, &ts);
  // XXX(dinosaure): assume that it will never fail.
  // [caml_invalid_argument] allocs.

  return (ts.tv_sec * 1000000000LL + ts.tv_nsec);
}