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// Copyright (c) 2019 Egor Tensin <Egor.Tensin@gmail.com>
// This file is part of the "math-server" project.
// For details, see https://github.com/egor-tensin/math-server.
// Distributed under the MIT License.
#pragma once
#include "error.hpp"
#include <exception>
#include <fstream>
#include <functional>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
namespace math::client::input {
class Error : public client::Error {
public:
explicit Error(const std::string& what) : client::Error{"input error: " + what} {}
};
class Reader {
public:
using InputHandler = std::function<bool(const std::string&)>;
virtual ~Reader() = default;
virtual bool for_each_input(const InputHandler& process) const = 0;
};
using ReaderPtr = std::unique_ptr<input::Reader>;
class FileReader : public Reader {
public:
explicit FileReader(const std::string& path) : m_path{path} {}
bool for_each_input(const InputHandler& process) const override { return enum_lines(process); }
private:
bool enum_lines(const InputHandler& process) const {
std::ifstream ifs;
ifs.exceptions(std::ifstream::badbit);
try {
ifs.open(m_path);
if (!ifs.is_open()) {
throw Error{"couldn't open file: " + m_path};
}
for (std::string line; std::getline(ifs, line);) {
if (!process(line)) {
return false;
}
}
} catch (const std::exception& e) {
throw Error{e.what()};
}
return true;
}
const std::string m_path;
};
class MultiFileReader : public Reader {
public:
explicit MultiFileReader(const std::vector<std::string>& paths) : m_paths{paths} {}
bool for_each_input(const InputHandler& process) const override {
for (const auto& path : m_paths) {
const FileReader reader{path};
if (!reader.for_each_input(process)) {
return false;
}
}
return true;
}
private:
const std::vector<std::string> m_paths;
};
inline input::ReaderPtr make_file_reader(const std::string& path) {
return std::make_unique<input::FileReader>(path);
}
inline input::ReaderPtr make_file_reader(const std::vector<std::string>& paths) {
return std::make_unique<input::MultiFileReader>(paths);
}
class StringReader : public Reader {
public:
explicit StringReader(const std::string& input) : m_input{input} {}
bool for_each_input(const InputHandler& process) const override { return process(m_input); }
private:
const std::string m_input;
};
inline input::ReaderPtr make_string_reader(const std::string& input) {
return std::make_unique<input::StringReader>(input);
}
class ConsoleReader : public Reader {
public:
ConsoleReader() = default;
bool for_each_input(const InputHandler& process) const override {
std::string line;
while (read_line(line)) {
if (!process(line)) {
return false;
}
}
return true;
}
private:
static bool read_line(std::string& dest) {
return static_cast<bool>(std::getline(std::cin, dest));
}
};
inline input::ReaderPtr make_console_reader() {
return std::make_unique<input::ConsoleReader>();
}
} // namespace math::client::input
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