mem_str.cpp

Go to the documentation of this file.

// Conversions of memory amounts and strings
// Author: Max Schwarz <max.schwarz@ais.uni-bonn.de>
 
#include "mem_str.h"
 
#include <fmt/format.h>
 
#include <regex>
 
namespace rosbag_fancy
{
namespace mem_str
{
 
std::string memoryToString(uint64_t memory)
{
        if(memory < static_cast<uint64_t>(1<<10))
                return fmt::format("{}.0   B", memory);
        else if(memory < static_cast<uint64_t>(1<<20))
                return fmt::format("{:.1f} KiB", static_cast<double>(memory) / static_cast<uint64_t>(1<<10));
        else if(memory < static_cast<uint64_t>(1<<30))
                return fmt::format("{:.1f} MiB", static_cast<double>(memory) / static_cast<uint64_t>(1<<20));
        else if(memory < static_cast<uint64_t>(1ull<<40))
                return fmt::format("{:.1f} GiB", static_cast<double>(memory) / static_cast<uint64_t>(1ull<<30));
        else
                return fmt::format("{:.1f} TiB", static_cast<double>(memory) / static_cast<uint64_t>(1ull<<40));
}
 
uint64_t stringToMemory(std::string humanSize)
{
        // format should be "10MB" or "3 GB" or "10 B" or "10GiB"
        static std::regex memoryRegex{R"EOS((\d+)\s*(K|M|G|T|E|)i?B?)EOS"};
 
        std::smatch match;
        if(!std::regex_match(humanSize, match, memoryRegex))
        {
                fmt::print(stderr, "Could not parse memory string '{}' - it should be something like '120B' or '10GB'\n",
                        humanSize
                );
                std::exit(1);
        }
 
        std::string number = match[1].str();
        std::string unit = match[2].str();
 
        std::uint64_t multiplier = [&]() -> std::uint64_t {
                if(unit.empty())
                        return 1;
 
                switch(unit[0])
                {
                        case 'K': return 1ULL << 10;
                        case 'M': return 1ULL << 20;
                        case 'G': return 1ULL << 30;
                        case 'T': return 1ULL << 40;
                        case 'E': return 1ULL << 50;
                }
 
                throw std::logic_error{"I got regexes wrong :("};
        }();
 
        return std::stoull(humanSize) * multiplier;
}
 
}
}