/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at https://curl.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * SPDX-License-Identifier: curl
 *
 ***************************************************************************/
#include "curl_setup.h"
#include <curl/curl.h>
#include "testutil.h"
#include "memdebug.h"

#if defined(WIN32) && !defined(MSDOS)

struct timeval tutil_tvnow(void)
{
  /*
  ** GetTickCount() is available on _all_ Windows versions from W95 up
  ** to nowadays. Returns milliseconds elapsed since last system boot,
  ** increases monotonically and wraps once 49.7 days have elapsed.
  */
  struct timeval now;
  DWORD milliseconds = GetTickCount();
  now.tv_sec = milliseconds / 1000;
  now.tv_usec = (milliseconds % 1000) * 1000;
  return now;
}

#elif defined(HAVE_CLOCK_GETTIME_MONOTONIC)

struct timeval tutil_tvnow(void)
{
  /*
  ** clock_gettime() is granted to be increased monotonically when the
  ** monotonic clock is queried. Time starting point is unspecified, it
  ** could be the system start-up time, the Epoch, or something else,
  ** in any case the time starting point does not change once that the
  ** system has started up.
  */
  struct timeval now;
  struct timespec tsnow;
  if(0 == clock_gettime(CLOCK_MONOTONIC, &tsnow)) {
    now.tv_sec = tsnow.tv_sec;
    now.tv_usec = (int)(tsnow.tv_nsec / 1000);
  }
  /*
  ** Even when the configure process has truly detected monotonic clock
  ** availability, it might happen that it is not actually available at
  ** run-time. When this occurs simply fallback to other time source.
  */
#ifdef HAVE_GETTIMEOFDAY
  else
    (void)gettimeofday(&now, NULL);
#else
  else {
    now.tv_sec = time(NULL);
    now.tv_usec = 0;
  }
#endif
  return now;
}

#elif defined(HAVE_GETTIMEOFDAY)

struct timeval tutil_tvnow(void)
{
  /*
  ** gettimeofday() is not granted to be increased monotonically, due to
  ** clock drifting and external source time synchronization it can jump
  ** forward or backward in time.
  */
  struct timeval now;
  (void)gettimeofday(&now, NULL);
  return now;
}

#else

struct timeval tutil_tvnow(void)
{
  /*
  ** time() returns the value of time in seconds since the Epoch.
  */
  struct timeval now;
  now.tv_sec = time(NULL);
  now.tv_usec = 0;
  return now;
}

#endif

/*
 * Make sure that the first argument is the more recent time, as otherwise
 * we'll get a weird negative time-diff back...
 *
 * Returns: the time difference in number of milliseconds.
 */
long tutil_tvdiff(struct timeval newer, struct timeval older)
{
  return (long)(newer.tv_sec-older.tv_sec)*1000+
    (long)(newer.tv_usec-older.tv_usec)/1000;
}

/*
 * Same as tutil_tvdiff but with full usec resolution.
 *
 * Returns: the time difference in seconds with subsecond resolution.
 */
double tutil_tvdiff_secs(struct timeval newer, struct timeval older)
{
  if(newer.tv_sec != older.tv_sec)
    return (double)(newer.tv_sec-older.tv_sec)+
      (double)(newer.tv_usec-older.tv_usec)/1000000.0;
  return (double)(newer.tv_usec-older.tv_usec)/1000000.0;
}

#ifdef WIN32
HMODULE win32_load_system_library(const TCHAR *filename)
{
  size_t filenamelen = _tcslen(filename);
  size_t systemdirlen = GetSystemDirectory(NULL, 0);
  size_t written;
  TCHAR *path;

  if(!filenamelen || filenamelen > 32768 ||
     !systemdirlen || systemdirlen > 32768)
    return NULL;

  /* systemdirlen includes null character */
  path = malloc(sizeof(TCHAR) * (systemdirlen + 1 + filenamelen));
  if(!path)
    return NULL;

  /* if written >= systemdirlen then nothing was written */
  written = GetSystemDirectory(path, (unsigned int)systemdirlen);
  if(!written || written >= systemdirlen)
    return NULL;

  if(path[written - 1] != _T('\\'))
    path[written++] = _T('\\');

  _tcscpy(path + written, filename);

  return LoadLibrary(path);
}
#endif
