/*
 * 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
 */

#include <stdio.h>

#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>
#include <sys/times.h>
#include <time.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 amount of CPU time used by the current process,
 * in seconds, or -1.0 if an error occurred.
 */
double proc_stat_getCPUTime(void)
{
#if defined(_WIN32)
    /* Windows -------------------------------------------------- */
    FILETIME createTime;
    FILETIME exitTime;
    FILETIME kernelTime;
    FILETIME userTime;
    if ( GetProcessTimes( GetCurrentProcess( ),
                         &createTime, &exitTime, &kernelTime, &userTime ) != -1 )
    {
        SYSTEMTIME userSystemTime;
        if ( FileTimeToSystemTime( &userTime, &userSystemTime ) != -1 )
            return (double)userSystemTime.wHour * 3600.0 +
            (double)userSystemTime.wMinute * 60.0 +
            (double)userSystemTime.wSecond +
            (double)userSystemTime.wMilliseconds / 1000.0;
    }
    
#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
    /* AIX, BSD, Cygwin, HP-UX, Linux, OSX, and Solaris --------- */
    
#if _POSIX_TIMERS > 0
    /* Prefer high-res POSIX timers, when available. */
    {
        clockid_t id;
        struct timespec ts;
#if _POSIX_CPUTIME > 0
        /* Clock ids vary by OS.  Query the id, if possible. */
        if ( clock_getcpuclockid( 0, &id ) == -1 )
#endif
#if defined(CLOCK_PROCESS_CPUTIME_ID)
        /* Use known clock id for AIX, Linux, or Solaris. */
            id = CLOCK_PROCESS_CPUTIME_ID;
#elif defined(CLOCK_VIRTUAL)
        /* Use known clock id for BSD or HP-UX. */
        id = CLOCK_VIRTUAL;
#else
        id = (clockid_t)-1;
#endif
        if ( id != (clockid_t)-1 && clock_gettime( id, &ts ) != -1 )
            return (double)ts.tv_sec +
            (double)ts.tv_nsec / 1000000000.0;
    }
#endif
    
#if defined(RUSAGE_SELF)
    {
        struct rusage rusage;
        if ( getrusage( RUSAGE_SELF, &rusage ) != -1 )
            return (double)rusage.ru_utime.tv_sec +
            (double)rusage.ru_utime.tv_usec / 1000000.0;
    }
#endif
    
#if defined(_SC_CLK_TCK)
    {
        const double ticks = (double)sysconf( _SC_CLK_TCK );
        struct tms tms;
        if ( times( &tms ) != (clock_t)-1 )
            return (double)tms.tms_utime / ticks;
    }
#endif
    
#if defined(CLOCKS_PER_SEC)
    {
        clock_t cl = clock( );
        if ( cl != (clock_t)-1 )
            return (double)cl / (double)CLOCKS_PER_SEC;
    }
#endif
    
#endif
    
    return -1.0;		/* Failed. */
}

/*
 * 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
 */

/**
 * 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 proc_stat_getPeakRSS(void)
{
#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 proc_stat_getCurrentRSS(void)
{
#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
}

void proc_stat_print_rss(const char *name, size_t x, size_t y, FILE *fh)
{
    fprintf(fh, "%s: %zu byte\n", name, (y - x));
}
