/*
 * 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 <windows.h>
#include <psapi.h>

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