include/barrett/log/detail/reader-inl.h

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#include <stdexcept>
#include <sstream>
#include <fstream>


namespace barrett {
namespace log {


template<typename T, typename Traits>
Reader<T, Traits>::Reader(const char* fileName) :
        file(fileName, std::ios_base::binary), recordLength(Traits::serializedLength()), recordCount(0)
{
        if (recordLength == 0) {
                throw(std::logic_error("(log::Reader::Reader): The record length "
                                "(Traits::serializedLength()) cannot be zero."));
        }

        file.seekg(0, std::ifstream::end);
        long size = file.tellg();

        if (size % recordLength != 0) {
                std::stringstream ss;
                ss << "(log::Reader::Reader): The file '" << fileName
                                << "' is corrupted or does not contain this type of data. Its "
                                "size is not evenly divisible by the record length ("
                                << recordLength << " bytes).";
                throw(std::runtime_error(ss.str()));
        }
        recordCount = size / recordLength;
        file.seekg(0);

        buffer = new char[recordLength];
}

template<typename T, typename Traits>
Reader<T, Traits>::~Reader()
{
        if (file.is_open()) {
                close();
        }

        delete[] buffer;
        buffer = NULL;
}

template<typename T, typename Traits>
inline size_t Reader<T, Traits>::numRecords() const
{
        return recordCount;
}

template<typename T, typename Traits>
inline T Reader<T, Traits>::getRecord()
{
        file.read(buffer, recordLength);

        if (file.eof()) {
                throw(std::underflow_error("(log::Reader::getRecord()): The end of the file was reached. There are no more records to read."));
        }

        return Traits::unserialize(buffer);
}

template<typename T, typename Traits>
inline void Reader<T, Traits>::exportCSV(const char* outputFileName)
{
        std::ofstream ofs(outputFileName);
        exportCSV(ofs);
        ofs.close();
}

template<typename T, typename Traits>
void Reader<T, Traits>::exportCSV(std::ostream& os)
{
        try {
                for (size_t i = 0; i < numRecords(); ++i) {
                        Traits::asCSV(getRecord(), os);
                        os << std::endl;
                }
        } catch (std::underflow_error) {}
}

template<typename T, typename Traits>
inline void Reader<T, Traits>::close()
{
        file.close();
}


}
}