solanaceae_util/solanaceae/file/file2_std.cpp
2024-03-28 15:34:43 +01:00

130 lines
2.7 KiB
C++

#include "./file2_std.hpp"
#include <limits>
#include <vector>
// why is this so ugly?
// WARNING: has g pos side effect
static uint64_t get_file_size(std::fstream& f) {
// figure out size
f.seekg(0, f.end);
uint64_t file_size = f.tellg();
f.seekg(0, f.beg);
return file_size;
}
File2WFile::File2WFile(std::string_view file_path, bool trunc) :
File2I(true, false),
_file(
static_cast<std::string>(file_path),
std::ios::out |
(trunc ? std::ios::trunc | std::ios::binary : std::ios::binary) // hacky but type safe
)
{
_file_size = get_file_size(_file);
if (!_file.is_open()) {
return; // TODO: error
}
}
bool File2WFile::isGood(void) {
return _file.is_open() && _file.good();
}
//bool write(const ByteSpan data, int64_t pos = -1) override;
bool File2WFile::write(const ByteSpan data, int64_t pos) {
if (pos != -1) {
//std::cerr << "invalid pos\n";
return false;
}
if (data.empty()) {
//std::cerr << "no data\n";
return false; // true instead?
}
_file.write(reinterpret_cast<const char*>(data.ptr), data.size);
return _file.good();
}
std::variant<ByteSpan, std::vector<uint8_t>> File2WFile::read(uint64_t, int64_t) {
return ByteSpan{};
}
File2RWFile::File2RWFile(std::string_view file_path, uint64_t file_size, bool trunc) :
File2I(true, true),
_file(
static_cast<std::string>(file_path),
std::ios::in |
std::ios::out |
(trunc ? std::ios::trunc | std::ios::binary : std::ios::binary) // hacky but type safe
)
{
if (file_size == -1) {
_file_size = get_file_size(_file);
} else {
_file_size = file_size;
}
if (!_file.is_open()) {
return; // TODO: error
}
}
bool File2RWFile::isGood(void) {
return _file.is_open() && _file.good();
}
bool File2RWFile::write(const ByteSpan data, int64_t pos) {
if (pos >= _file_size) {
return false;
}
if (data.empty()) {
return false; // true instead?
}
// if out-of-order, seek
if (pos >= 0 && _file.tellp() != int64_t(pos)) {
// TODO: error check
if (_file.seekp(pos, std::ios::beg).fail()) {
return false;
}
} else if (pos < -1) {
// error !!!!
return false;
}
_file.write(reinterpret_cast<const char*>(data.ptr), data.size);
return _file.good();
}
std::variant<ByteSpan, std::vector<uint8_t>> File2RWFile::read(uint64_t size, int64_t pos) {
if (pos >= int64_t(_file_size)) {
return ByteSpan{};
}
if (pos != -1) {
// TODO: error check
_file.seekg(pos, std::ios::beg);
} else if (pos < -1) {
// error !!!!
return ByteSpan{};
}
// we copy the data from file (not mapped)
std::vector<uint8_t> chunk(size);
const auto nread = _file.read(reinterpret_cast<char*>(chunk.data()), chunk.size()).gcount();
if (nread != std::numeric_limits<std::streamsize>::max()) {
chunk.resize(nread); // usually a noop
} else {
chunk.clear();
}
return chunk;
}