/**
 * @file System.cc originally from Minisat.
 * (see https://github.com/niklasso/minisat, commit 37dc6c6)
 */

/* **************************************************************************************[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 <csignal>
#include <cstdio>

#include "Minisat/utils/System.h"

#if defined(__linux__)

#include <cstdlib>

using namespace Minisat;

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

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

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


#elif defined(__APPLE__)
#include <malloc/malloc.h>

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

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


void Minisat::setX86FPUPrecision()
{
#if defined(__GLIBC__) && 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 Minisat::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 Minisat::limitMemory(uint64_t /*max_mem_mb*/)
{
    printf("WARNING! Memory limit not supported on this architecture.\n");
}
#endif


#if !defined(_MSC_VER) && !defined(__MINGW32__)
void Minisat::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 Minisat::limitTime(uint32_t /*max_cpu_time*/)
{
    printf("WARNING! CPU-time limit not supported on this architecture.\n");
}
#endif


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