/* -*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*- */
/* vim: set filetype=c tabstop=8 shiftwidth=4 expandtab: */

/*
    time.c -- Time routines.
*/
/*
    Copyright (c) 1984, Taiichi Yuasa and Masami Hagiya.
    Copyright (c) 1990, Giuseppe Attardi.
    Copyright (c) 2001, Juan Jose Garcia Ripoll.

    ECL is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    See file '../Copyright' for full details.
*/

#include <limits.h>
#include <time.h>
#ifndef _MSC_VER
# include <unistd.h>
# include <errno.h>
#endif
#if defined(_MSC_VER) || defined(__MINGW32__)
# include <windows.h>
# include <winsock.h>
#endif

#define ECL_INCLUDE_MATH_H
#include <ecl/ecl.h>
#include <ecl/internal.h>
#include <ecl/number.h>
#ifdef HAVE_TIMES
# include <sys/times.h>
#endif
#ifdef HAVE_GETRUSAGE
# include <sys/time.h>
# include <sys/resource.h>
#endif
#ifdef HAVE_GETTIMEOFDAY
# include <sys/time.h>
#endif
#include <ecl/impl/math_fenv.h>

static struct ecl_timeval beginning;

void
ecl_get_internal_real_time(struct ecl_timeval *tv)
{
#if defined(HAVE_GETTIMEOFDAY) && !defined(ECL_MS_WINDOWS_HOST)
        struct timezone tz;
        struct timeval aux;
        gettimeofday(&aux, &tz);
        tv->tv_usec = aux.tv_usec;
        tv->tv_sec = aux.tv_sec;
#else
# if defined(ECL_MS_WINDOWS_HOST)
        union {
                FILETIME filetime;
                DWORDLONG hundred_ns;
        } system_time;
        GetSystemTimeAsFileTime(&system_time.filetime);
        system_time.hundred_ns /= 10000;
        tv->tv_sec = system_time.hundred_ns / 1000;
        tv->tv_usec = (system_time.hundred_ns % 1000) * 1000;
# else
        time_t = time(0);
        tv->tv_sec = time_t;
        tv->tv_usec = 0;
# endif
#endif
}

void
ecl_get_internal_run_time(struct ecl_timeval *tv)
{
#ifdef HAVE_GETRUSAGE
        struct rusage r;
        getrusage(RUSAGE_SELF, &r);
        tv->tv_usec = r.ru_utime.tv_usec;
        tv->tv_sec = r.ru_utime.tv_sec;
#else
# ifdef HAVE_TIMES
        struct tms buf;
        times(&buf);
        tv->tv_sec = buf.tms_utime / CLK_TCK;
        tv->tv_usec = (buf.tms_utime % CLK_TCK) * 1000000;
# else
#  if defined(ECL_MS_WINDOWS_HOST)
        union {
                FILETIME filetime;
                DWORDLONG hundred_ns;
        } kernel_time, user_time, creation_time, exit_time;
        if (!GetProcessTimes(GetCurrentProcess(),
                             &creation_time.filetime,
                             &exit_time.filetime,
                             &kernel_time.filetime,
                             &user_time.filetime))
            FEwin32_error("GetProcessTimes() failed", 0);
        kernel_time.hundred_ns += user_time.hundred_ns;
        kernel_time.hundred_ns /= 10000;
        tv->tv_sec = kernel_time.hundred_ns / 1000;
        tv->tv_usec = (kernel_time.hundred_ns % 1000) * 1000;
#  else
        ecl_get_internal_real_time(tv);
#  endif
# endif
#endif
}

void
ecl_musleep(double time, bool alertable)
{
#ifdef HAVE_NANOSLEEP
        struct timespec tm;
        int code;
        tm.tv_sec = (time_t)floor(time);
        tm.tv_nsec = (long)((time - floor(time)) * 1e9);
 AGAIN:
        code = nanosleep(&tm, &tm);
        {
                int old_errno = errno;
                if (code < 0 && old_errno == EINTR && !alertable) {
                        goto AGAIN;
                }
        }
#else
#if defined (ECL_MS_WINDOWS_HOST)
        /* Maximum waiting time that fits in SleepEx. This is the
         * largest integer that fits safely in DWORD in milliseconds
         * and has to be converted to 100ns (1e-3 / 100e-9 = 1e4) */
        const DWORDLONG maxtime = (DWORDLONG)0xfffffff * (DWORDLONG)10000;
        DWORDLONG wait = time * 1e7;
        union {
                FILETIME filetime;
                DWORDLONG hundred_ns;
        } end, now;
        if (alertable) {
                GetSystemTimeAsFileTime(&end.filetime);
                end.hundred_ns += wait;
        }
        do {
                DWORDLONG interval;
                if (wait > maxtime) {
                        interval = maxtime;
                        wait -= maxtime;
                } else {
                        interval = wait;
                        wait = 0;
                }
                if (SleepEx(interval/10000, alertable) != 0) {
                        if (alertable) {
                                break;
                        } else {
                                GetSystemTimeAsFileTime(&now.filetime);
                                if (now.hundred_ns >= end.hundred_ns)
                                        break;
                                else
                                        wait = end.hundred_ns - now.hundred_ns;
                        }
                }
        } while (wait);
#else
        int t = (int)time;
        for (t = (time + 0.5); t > 1000; t -= 1000)
                sleep(1000);
        sleep(t);
#endif
#endif
}

cl_fixnum
ecl_runtime(void)
{
        struct ecl_timeval tv;
        ecl_get_internal_run_time(&tv);
        return tv.tv_sec * 1000 + tv.tv_usec / 1000;
}

cl_object
cl_sleep(cl_object z)
{
        double time;
        /* INV: ecl_minusp() makes sure `z' is real */
        if (ecl_minusp(z))
                cl_error(9, @'simple-type-error', @':format-control',
                            make_constant_base_string("Not a non-negative number ~S"),
                            @':format-arguments', cl_list(1, z),
                            @':expected-type', @'real', @':datum', z);
        /* Compute time without overflows */
        ECL_WITHOUT_FPE_BEGIN {
                time = ecl_to_double(z);
                if (isnan(time) || !isfinite(time) || (time > INT_MAX)) {
                        time = INT_MAX;
                } else if (time < 1e-9) {
                        time = 1e-9;
                }
        } ECL_WITHOUT_FPE_END;
        ecl_musleep(time, 0);
        @(return ECL_NIL)
}

static cl_object
timeval_to_time(long sec, long usec)
{
        cl_object milliseconds = ecl_plus(ecl_times(ecl_make_integer(sec),
                                                    ecl_make_fixnum(1000)),
                                          ecl_make_integer(usec / 1000));
        @(return milliseconds);
}

cl_object
cl_get_internal_run_time()
{
        struct ecl_timeval tv;
        ecl_get_internal_run_time(&tv);
        return timeval_to_time(tv.tv_sec, tv.tv_usec);
}

cl_object
cl_get_internal_real_time()
{
        struct ecl_timeval tv;
        ecl_get_internal_real_time(&tv);
        return timeval_to_time(tv.tv_sec - beginning.tv_sec,
                               tv.tv_usec - beginning.tv_usec);
}

cl_object
cl_get_universal_time()
{
        cl_object utc = ecl_make_integer(time(0));
        @(return ecl_plus(utc, cl_core.Jan1st1970UT))
}

void
init_unixtime(void)
{
        ecl_get_internal_real_time(&beginning);

        ECL_SET(@'internal-time-units-per-second', ecl_make_fixnum(1000));

        cl_core.Jan1st1970UT =
            ecl_times(ecl_make_fixnum(24 * 60 * 60),
                         ecl_make_fixnum(17 + 365 * 70));
}
