PHTimer.cc

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// $Id: PHTimer.C,v 1.2 2010/12/05 02:30:28 bbannier Exp $
 
#include "PHTimer.h"
 
#include <cmath>
#include <climits>
#include <stdexcept>
#include <fstream>
 
//______________________________________________________________________
// static members
PHTimer::Frequency PHTimer::_frequency = PHTimer::Frequency();
const double PHTimer::_twopower32 = pow(2,32);
 
//______________________________________________________________________
void PHTimer::Frequency::set_cpu_freq(const char * path)
{
    // Set the default to 2 GHz
    _frequency = 2e9;
 
    // Open the cpuinfo file
    std::ifstream cpuProcFile(path);
    if ( !cpuProcFile.is_open())
        throw std::runtime_error(std::string("cpu info. unavailable"));
    else {
        // Now parse it looking for the string "cpu MHz"
        char readLine[1024];
        std::string searchString("cpu MHz");
        while ((cpuProcFile.rdstate() & std::ios::failbit) == 0 ) {
            // Read into the raw char array and then construct a std::string
            // (std::string) to do the searching
            cpuProcFile.getline(readLine, 1024);
            std::string readLineString(readLine);
            if (readLineString.find(searchString) != std::string::npos) {
 
                // Now look for the :, the clock frequency will follow it
                size_t semicolonPosition = readLineString.find(':', 0);
                if( semicolonPosition == std::string::npos ) throw std::runtime_error(std::string("wrong format for cpu info file"));
                std::string frequencyString(readLineString.substr(semicolonPosition + 1));
 
                // Make a string stream for the conversion to floating number
                double freqMHz = 0;
                std::istringstream frequencySstream(frequencyString);
 
                frequencySstream >> freqMHz;
                _frequency = freqMHz*1e6;
 
            }
        }
    }
}
 
//______________________________________________________________________
double PHTimer::get_difference( const PHTimer::time_struct &t0, const PHTimer::time_struct &t1 )
{
    unsigned long diff_high = t0._high - t1._high;
    unsigned long diff_low;
    if (t0._low < t1._low) {
        --diff_high;
        diff_low = (UINT_MAX - t1._low) + t0._low + 1;
    } else diff_low = t0._low - t1._low;
 
    return (_twopower32*diff_high + diff_low)*_frequency.period();
}
 
//_______________________________________________________
void PHTimer::PRINT(std::ostream& os, const std::string& message)
{
    const int max_col=80;
    if(!message.size()) {
        os << std::string(max_col,'-') << std::endl;
        return;
    }
    int fill = max_col - message.size() - 2;
    int pre = static_cast<int>(std::floor(fill/2.0));
    int post = fill - pre;
    os << std::string(pre,'-') << " ";
    os << message << " ";
    os << std::string(post,'-') << std::endl;
}