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- // endian/example/conversion_use_case.cpp
- // Copyright Beman Dawes 2014
- // Distributed under the Boost Software License, Version 1.0.
- // See http://www.boost.org/LICENSE_1_0.txt
- // This program reads a binary file of fixed length records, with a format defined
- // in a header file supplied by a third-party. The records inserted into a vector,
- // and the vector is sorted. The sorted records are then written to an output file.
- // Full I/O error testing omitted for brevity, So don't try this at home.
- #include "third_party_format.hpp"
- #include <boost/endian/conversion.hpp>
- #include <vector>
- #include <fstream>
- #include <algorithm>
- #include <iostream>
- using third_party::record;
- int main()
- {
- std::ifstream in("data.bin", std::ios::binary);
- if (!in) { std::cout << "Could not open data.bin\n"; return 1; }
- std::ofstream out("sorted-data.bin", std::ios::binary);
- if (!out) { std::cout << "Could not open sorted-data.bin\n"; return 1; }
- record rec;
- std::vector<record> recs;
- while (!in.eof()) // read each record
- {
- in.read((char*)&rec, sizeof(rec));
- rec.balance = boost::endian::big_to_native(rec.balance); // reverse if needed
- recs.push_back(rec);
- }
- std::sort(recs.begin(), recs.end(), // decending sort by balance
- [](const record& lhs, const record& rhs) -> bool
- { return lhs.balance > rhs.balance; });
- for (auto &out_rec : recs) // write each record
- {
- out_rec.balance = boost::endian::native_to_big(out_rec.balance); // reverse if needed
- out.write((const char*)&out_rec, sizeof(out_rec));
- }
- }
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