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// SPDX-License-Identifier: MIT
#ifndef RGBDS_FILE_HPP
#define RGBDS_FILE_HPP
#include <fcntl.h>
#include <fstream>
#include <ios>
#include <iostream>
#include <streambuf>
#include <string>
#include <variant>
#include "helpers.hpp" // assume
#include "platform.hpp"
class File {
std::variant<std::streambuf *, std::filebuf> _file;
public:
File() : _file(nullptr) {}
// This should only be called once, and before doing any `->` operations.
// Returns `nullptr` on error, and a non-null pointer otherwise.
File *open(std::string const &path, std::ios_base::openmode mode) {
if (path != "-") {
return _file.emplace<std::filebuf>().open(path, mode) ? this : nullptr;
} else if (mode & std::ios_base::in) {
assume(!(mode & std::ios_base::out));
_file.emplace<std::streambuf *>(std::cin.rdbuf());
if (setmode(STDIN_FILENO, (mode & std::ios_base::binary) ? O_BINARY : O_TEXT) == -1) {
return nullptr;
}
} else {
assume(mode & std::ios_base::out);
_file.emplace<std::streambuf *>(std::cout.rdbuf());
}
return this;
}
std::streambuf &operator*() {
return std::holds_alternative<std::filebuf>(_file) ? std::get<std::filebuf>(_file)
: *std::get<std::streambuf *>(_file);
}
std::streambuf const &operator*() const {
// The non-`const` version does not perform any modifications, so it's okay.
return **const_cast<File *>(this);
}
std::streambuf *operator->() { return &**this; }
std::streambuf const *operator->() const {
// See the `operator*` equivalent.
return const_cast<File *>(this)->operator->();
}
char const *c_str(std::string const &path) const {
return std::holds_alternative<std::filebuf>(_file) ? path.c_str()
: std::get<std::streambuf *>(_file) == std::cin.rdbuf() ? "<stdin>"
: "<stdout>";
}
};
#endif // RGBDS_FILE_HPP
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