ch02-sysinfo/sysinfolinuximpl.cpp

#include "sysinfolinuximpl.h"

#include <sys/sysinfo.h>
#include <sys/types.h>

SysInfoLinuxImpl::SysInfoLinuxImpl() : SysInfo(), mCpuLoadLastValues() {}

void SysInfoLinuxImpl::init() { mCpuLoadLastValues = cpuRawData(); }

double SysInfoLinuxImpl::cpuLoadAverage() {
  QVector<qulonglong> firstSample = mCpuLoadLastValues;
  QVector<qulonglong> secondSample = cpuRawData();
  mCpuLoadLastValues = secondSample;
  double overall = (secondSample[0] - firstSample[0]) +
                   (secondSample[1] - firstSample[1]) +
                   (secondSample[2] - firstSample[2]);
  double total = overall + (secondSample[3] - firstSample[3]);
  double percent = (overall / total) * 100.0;
  return qBound(0.0, percent, 100.0);
}

double SysInfoLinuxImpl::memoryUsed() {
  struct sysinfo memInfo;
  sysinfo(&memInfo);
  qulonglong totalMemory = memInfo.totalram;
  totalMemory += memInfo.totalswap;
  totalMemory *= memInfo.mem_unit;
  qulonglong totalMemoryUsed = memInfo.totalram - memInfo.freeram;
  totalMemoryUsed += memInfo.totalswap - memInfo.freeswap;
  totalMemoryUsed *= memInfo.mem_unit;
  double percent = (double)totalMemoryUsed / (double)totalMemory * 100.0;
  return qBound(0.0, percent, 100.0);
}

QVector<qulonglong> SysInfoLinuxImpl::cpuRawData() {
  QFile file("/proc/stat");
  file.open(QIODevice::ReadOnly);
  QByteArray line = file.readLine();
  file.close();
  qulonglong totalUser = 0, totalUserNice = 0, totalSystem = 0, totalIdle = 0;
  std::sscanf(line.data(), "cpu %llu %llu %llu %llu", &totalUser,
              &totalUserNice, &totalSystem, &totalIdle);

  QVector<qulonglong> rawData;
  rawData.append(totalUser);
  rawData.append(totalUserNice);
  rawData.append(totalSystem);
  rawData.append(totalIdle);

  return rawData;
}