RAMInfo.cc

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#include "RAMInfo.hh"

#include <QString>
#include <stdio.h>

// Main Memory information
#ifdef WIN32
#include <Windows.h>
#elif defined ARCH_DARWIN
#include <mach/mach_host.h>
#include <mach/vm_statistics.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#endif
// private struct to get ram information
namespace{
struct MemoryVacancy{
  uint64_t totalRamMB;
  uint64_t freeRamMB;
  uint64_t bufferRamMB;
};

void parseMeminfo(uint64_t& _total, uint64_t& _free, uint64_t& _buffer)
{
  //use the specific type for scanf so we have at least 64 bit to read memory information
  //this way we support memory information for max 9,223,372,036,854,775,807 byte of memory (that is 8 exa byte)
  unsigned long long memcache, memfree, total, free, buffer;

  FILE* info = fopen("/proc/meminfo","r");
  if(fscanf (info, "MemTotal: %19llu kB MemFree: %19llu kB Buffers: %19llu kB Cached: %19llu kB",&total, &memfree, &buffer, &memcache) < 4) //try to parse the old meminfo format
  {
    fclose(info);
    info = fopen("/proc/meminfo","r");
    //parsing the old format failed so we try to parse using the new format
    if(fscanf(info, "MemTotal: %19llu kB MemFree: %19llu kB MemAvailable: %19llu kB Buffers: %19llu kB Cached: %19llu kB",&total, &memfree, &free, &buffer, &memcache) < 5)
    {
      //parsing failed overall so return 0 for all values
      total = 0;
      free = 0;
      buffer = 0;
    }
    else
    {
      free = memfree + (buffer + memcache);  //everything is fine
    }

  }
  else  //compute available memory
  {
    free = memfree + (buffer + memcache);
  }
  fclose(info);
  _total = total;
  _free = free;
  _buffer = buffer;
}

}
namespace Utils
{
  namespace Memory
  {
    void MemoryInfoUpdate(MemoryVacancy & _outMemoryVacancy) {

      //initialize to 0 just in case something fails or cant be read
      _outMemoryVacancy.totalRamMB = 0;
      _outMemoryVacancy.freeRamMB = 0;
      _outMemoryVacancy.bufferRamMB = 0;

      // Main Memory information
    #ifdef WIN32 //Windows
      // Define memory structure
      MEMORYSTATUSEX ms;
      // Set the size ( required according to spec ... why???? )
      ms.dwLength = sizeof(ms);
      // Get the info
      GlobalMemoryStatusEx(&ms);

      _outMemoryVacancy.totalRamMB = ms.ullTotalPhys / 1024 / 1024;
      _outMemoryVacancy.freeRamMB = ms.ullAvailPhys / 1024 / 1024;

    #elif defined ARCH_DARWIN // Apple (sadly cant query free memory)
      mach_msg_type_number_t count = HOST_VM_INFO_COUNT;
      vm_statistics_data_t vmstat;
      if(KERN_SUCCESS != host_statistics(mach_host_self(), HOST_VM_INFO, (host_info_t)&vmstat, &count))
      {  // An error occurred
      }
      else
      {
          //retrieve real physical memory
          int mib[2];
          uint64_t physical_memory;
          size_t length;
          mib[0] = CTL_HW;
          mib[1] = HW_MEMSIZE;
          length = sizeof(uint64_t);
          if( sysctl(mib, 2, &physical_memory, &length, NULL, 0) == -1 )
          {
              physical_memory = 0;
          }
          // retrieve free memory
          _outMemoryVacancy.totalRamMB = physical_memory / 1024 / 1024;
          unsigned long active = vmstat.active_count * PAGE_SIZE / 1024 / 1024;
          _outMemoryVacancy.freeRamMB =  _outMemoryVacancy.totalRamMB - active;
          _outMemoryVacancy.bufferRamMB =0;
      }

    #else // Linux

      uint64_t total, free, buffer;
      parseMeminfo(total, free, buffer);

      // Unit in kbytes ; /1024 -> MB
      _outMemoryVacancy.totalRamMB = total / 1024;
      _outMemoryVacancy.freeRamMB = free / 1024;
      _outMemoryVacancy.bufferRamMB = buffer / 1024; // Buffers get freed, if we don't have enough free ram
    #endif
    }

   uint64_t queryFreeRAM()
   {
     MemoryVacancy vac;
     MemoryInfoUpdate(vac);
     return vac.freeRamMB;
   }

   uint64_t queryTotalRAM()
   {
     MemoryVacancy vac;
     MemoryInfoUpdate(vac);
     return vac.totalRamMB;
   }

   uint64_t queryBufferedRAM()
   {
     MemoryVacancy vac;
     MemoryInfoUpdate(vac);
     return vac.bufferRamMB;
   }
  }
}