file_sorting/sort.cpp
2025-11-14 00:20:58 +01:00

56 lines
1.5 KiB
C++

#pragma once
#include "buffer.hpp"
#include "config.hpp"
#include "reader.hpp"
#include "writer.hpp"
#include <fstream>
// returns amount of records read
size_t read_chunk(Reader& reader, SubBuffer& buff)
{
for (size_t i = 0; i < buff.size(); i++) {
std::optional<Record> in = reader.read();
if (!in.has_value()) {
return i;
}
buff[i] = in.value();
}
return buff.size();
}
void write_to_file(const std::string& filename, SubBuffer& buff, size_t n)
{
std::filesystem::path dirPath = std::filesystem::path(filename).parent_path();
std::filesystem::create_directories(dirPath);
std::ofstream out_stream(filename);
Writer output_writer(out_stream);
for (size_t j = 0; j < n; j++) {
output_writer.write(buff[j]);
}
}
void create_initial_runs(const std::string& input_filename, const std::string& directory, Buffer& main_buffer)
{
auto buff = main_buffer.divide(1)[0];
std::ifstream in_stream(input_filename);
Reader input_reader(in_stream);
for (size_t run_index = 0;; run_index++) {
size_t size = read_chunk(input_reader, buff);
if (size == 0) {
break;
}
std::sort(buff.begin(), buff.begin() + size);
write_to_file(directory + "/" + std::to_string(run_index) + ".run", buff, size);
}
}
int sort_file(const Configuration& opts)
{
Buffer main_buffer(opts.n * opts.b);
create_initial_runs(opts.input_file, opts.directory, main_buffer);
return 0;
}