/***************************************************************************************[System.cc]
Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
Copyright (c) 2007-2010, Niklas Sorensson

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
associated documentation files (the "Software"), to deal in the Software without restriction,
including without limitation the rights to use, copy, modify, merge, publish, distribute,
sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or
substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
**************************************************************************************************/

#include "System.h"

#include <signal.h>
#include <stdio.h>

#if defined(__linux__)

#include <stdlib.h>

using namespace Glucose;

static inline int memReadStat(int field) {
    char  name[256];
    pid_t pid = getpid();
    int   value;

    sprintf(name, "/proc/%d/statm", pid);
    FILE* in = fopen(name, "rb");
    if(in == NULL) return 0;

    for(; field >= 0; field--)
        if(fscanf(in, "%d", &value) != 1) printf("ERROR! Failed to parse memory statistics from \"/proc\".\n"), exit(1);
    fclose(in);
    return value;
}


static inline int memReadPeak(void) {
    char  name[256];
    pid_t pid = getpid();

    sprintf(name, "/proc/%d/status", pid);
    FILE* in = fopen(name, "rb");
    if(in == NULL) return 0;

    // Find the correct line, beginning with "VmPeak:":
    int peak_kb = 0;
    while(!feof(in) && fscanf(in, "VmPeak: %d kB", &peak_kb) != 1)
        while(!feof(in) && fgetc(in) != '\n')
            ;
    fclose(in);

    return peak_kb;
}

double Glucose::memUsed() { return (double)memReadStat(0) * (double)getpagesize() / (1024 * 1024); }
double Glucose::memUsedPeak(bool strictlyPeak) {
    double peak = memReadPeak() / (double)1024;
    return peak == 0 && !strictlyPeak ? memUsed() : peak;
}

#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || defined(__gnu_hurd__)

double Glucose::memUsed() {
    struct rusage ru;
    getrusage(RUSAGE_SELF, &ru);
    return (double)ru.ru_maxrss / 1024;
}
double Glucose::memUsedPeak() { return memUsed(); }


#elif defined(__APPLE__)

#include <malloc/malloc.h>


double Glucose::memUsed() {
    malloc_statistics_t t;
    malloc_zone_statistics(NULL, &t);
    return (double)t.max_size_in_use / (1024 * 1024);
}


double Glucose::memUsedPeak(bool strictlyPeak) { return memUsed(); }


#else
double Glucose::memUsed() { return 0; }
double Glucose::memUsedPeak() { return 0; }
#endif


void Glucose::setX86FPUPrecision() {
#if defined(__linux__) && defined(_FPU_EXTENDED) && defined(_FPU_DOUBLE) && defined(_FPU_GETCW)
    // Only correct FPU precision on Linux architectures that needs and supports it:
    fpu_control_t oldcw, newcw;
    _FPU_GETCW(oldcw);
    newcw = (oldcw & ~_FPU_EXTENDED) | _FPU_DOUBLE;
    _FPU_SETCW(newcw);
    printf("WARNING: for repeatability, setting FPU to use double precision\n");
#endif
}


#if !defined(_MSC_VER) && !defined(__MINGW32__)


void Glucose::limitMemory(uint64_t max_mem_mb) {
// FIXME: OpenBSD does not support RLIMIT_AS. Not sure how well RLIMIT_DATA works instead.
#if defined(__OpenBSD__)
#define RLIMIT_AS RLIMIT_DATA
#endif

    // Set limit on virtual memory:
    if(max_mem_mb != 0) {
        rlim_t new_mem_lim = (rlim_t)max_mem_mb * 1024 * 1024;
        rlimit rl;
        getrlimit(RLIMIT_AS, &rl);
        if(rl.rlim_max == RLIM_INFINITY || new_mem_lim < rl.rlim_max) {
            rl.rlim_cur = new_mem_lim;
            if(setrlimit(RLIMIT_AS, &rl) == -1) printf("WARNING! Could not set resource limit: Virtual memory.\n");
        }
    }

#if defined(__OpenBSD__)
#undef RLIMIT_AS
#endif
}


#else
void Glucose::limitMemory(uint64_t /*max_mem_mb*/) { printf("WARNING! Memory limit not supported on this architecture.\n"); }
#endif


#if !defined(_MSC_VER) && !defined(__MINGW32__)


void Glucose::limitTime(uint32_t max_cpu_time) {
    if(max_cpu_time != 0) {
        rlimit rl;
        getrlimit(RLIMIT_CPU, &rl);
        if(rl.rlim_max == RLIM_INFINITY || (rlim_t)max_cpu_time < rl.rlim_max) {
            rl.rlim_cur = max_cpu_time;
            if(setrlimit(RLIMIT_CPU, &rl) == -1) printf("WARNING! Could not set resource limit: CPU-time.\n");
        }
    }
}


#else
void Glucose::limitTime(uint32_t /*max_cpu_time*/) { printf("WARNING! CPU-time limit not supported on this architecture.\n"); }
#endif


void Glucose::sigTerm(void handler(int)) {
    signal(SIGINT, handler);
    signal(SIGTERM, handler);
#ifdef SIGXCPU
    signal(SIGXCPU, handler);
#endif
}