/* Authors: Lutong Wang and Bangqi Xu */
/*
 * Copyright (c) 2019, The Regents of the University of California
 * All rights reserved.
 *
 * 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 the University 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 REGENTS 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 INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Author:  David Robert Nadeau
 * Site:    http://NadeauSoftware.com/
 * License: Creative Commons Attribution 3.0 Unported License
 *          http://creativecommons.org/licenses/by/3.0/deed.en_US
 */

#if defined(_WIN32)
#include <psapi.h>
#include <windows.h>

#elif defined(__unix__) || defined(__unix) || defined(unix) \
    || (defined(__APPLE__) && defined(__MACH__))
#include <sys/resource.h>
#include <unistd.h>

#if defined(__APPLE__) && defined(__MACH__)
#include <mach/mach.h>

#elif (defined(_AIX) || defined(__TOS__AIX__)) \
    || (defined(__sun__) || defined(__sun)     \
        || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
#include <fcntl.h>
#include <procfs.h>

#elif defined(__linux__) || defined(__linux) || defined(linux) \
    || defined(__gnu_linux__)
#include <stdio.h>

#endif

#else
#error "Cannot define getPeakRSS( ) or getCurrentRSS( ) for an unknown OS."
#endif

/**
 * Returns the peak (maximum so far) resident set size (physical
 * memory use) measured in bytes, or zero if the value cannot be
 * determined on this OS.
 */
size_t getPeakRSS()
{
#if defined(_WIN32)
  /* Windows -------------------------------------------------- */
  PROCESS_MEMORY_COUNTERS info;
  GetProcessMemoryInfo(GetCurrentProcess(), &info, sizeof(info));
  return (size_t) info.PeakWorkingSetSize;

#elif (defined(_AIX) || defined(__TOS__AIX__)) \
    || (defined(__sun__) || defined(__sun)     \
        || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
  /* AIX and Solaris ------------------------------------------ */
  struct psinfo psinfo;
  int fd = -1;
  if ((fd = open("/proc/self/psinfo", O_RDONLY)) == -1)
    return (size_t) 0L; /* Can't open? */
  if (read(fd, &psinfo, sizeof(psinfo)) != sizeof(psinfo)) {
    close(fd);
    return (size_t) 0L; /* Can't read? */
  }
  close(fd);
  return (size_t)(psinfo.pr_rssize * 1024L);

#elif defined(__unix__) || defined(__unix) || defined(unix) \
    || (defined(__APPLE__) && defined(__MACH__))
  /* BSD, Linux, and OSX -------------------------------------- */
  struct rusage rusage;
  getrusage(RUSAGE_SELF, &rusage);
#if defined(__APPLE__) && defined(__MACH__)
  return (size_t) rusage.ru_maxrss;
#else
  return (size_t)(rusage.ru_maxrss * 1024L);
#endif

#else
  /* Unknown OS ----------------------------------------------- */
  return (size_t) 0L; /* Unsupported. */
#endif
}

/**
 * Returns the current resident set size (physical memory use) measured
 * in bytes, or zero if the value cannot be determined on this OS.
 */
size_t getCurrentRSS()
{
#if defined(_WIN32)
  /* Windows -------------------------------------------------- */
  PROCESS_MEMORY_COUNTERS info;
  GetProcessMemoryInfo(GetCurrentProcess(), &info, sizeof(info));
  return (size_t) info.WorkingSetSize;

#elif defined(__APPLE__) && defined(__MACH__)
  /* OSX ------------------------------------------------------ */
  struct mach_task_basic_info info;
  mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
  if (task_info(mach_task_self(),
                MACH_TASK_BASIC_INFO,
                (task_info_t) &info,
                &infoCount)
      != KERN_SUCCESS)
    return (size_t) 0L; /* Can't access? */
  return (size_t) info.resident_size;

#elif defined(__linux__) || defined(__linux) || defined(linux) \
    || defined(__gnu_linux__)
  /* Linux ---------------------------------------------------- */
  long rss = 0L;
  FILE* fp = NULL;
  if ((fp = fopen("/proc/self/statm", "r")) == NULL)
    return (size_t) 0L; /* Can't open? */
  if (fscanf(fp, "%*s%ld", &rss) != 1) {
    fclose(fp);
    return (size_t) 0L; /* Can't read? */
  }
  fclose(fp);
  return (size_t) rss * (size_t) sysconf(_SC_PAGESIZE);

#else
  /* AIX, BSD, Solaris, and Unknown OS ------------------------ */
  return (size_t) 0L; /* Unsupported. */
#endif
}