merlin-utils/mapped_file.h

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2019-12-08 18:55:33 +00:00
#ifndef __mapped_file_h__
#define __mapped_file_h__
#include <cstddef>
#include <system_error>
#include <string>
class mapped_file_base {
public:
enum mapmode { readonly, readwrite, priv };
enum createmode { truncate, exclusive };
void close();
bool is_open() const {
return _data != nullptr;
}
size_t size() const {
return _size;
}
operator bool() const { return is_open(); }
bool operator !() const { return !is_open(); }
~mapped_file_base() { close(); }
protected:
void swap(mapped_file_base &rhs);
void open(const std::string &p, mapmode flags, size_t length, size_t offset, std::error_code *ec);
void create(const std::string &p, size_t new_size, std::error_code *ec); // always creates readwrite.
#ifdef _WIN32
void open(const std::wstring &p, mapmode flags, size_t length, size_t offset, std::error_code *ec);
void create(const std::wstring &p, size_t new_size, std::error_code *ec); // always creates readwrite.
template<class S>
void open_common(const S &p, mapmode flags, size_t length, size_t offset, std::error_code *ec);
template<class S>
void create_common(const S &p, size_t new_size, std::error_code *ec); // always creates readwrite.
#endif
void reset();
size_t _size = 0;
void *_data = nullptr;
mapmode _flags = readonly;
#ifdef _WIN32
void *_file_handle = nullptr;
void *_map_handle = nullptr;
#else
int _fd = -1;
#endif
};
class mapped_file : public mapped_file_base {
typedef mapped_file_base base;
public:
typedef unsigned char value_type;
typedef value_type *iterator;
typedef const value_type *const_iterator;
typedef value_type &reference ;
typedef const value_type &const_reference;
mapped_file() = default;
mapped_file(mapped_file &&);
mapped_file(const mapped_file &) = delete;
mapped_file(const std::string &p, mapmode flags = readonly, size_t length = -1, size_t offset = 0) {
open(p, flags, length, offset);
}
mapped_file(const std::string &p, std::error_code &ec) noexcept {
open(p, readonly, -1, 0, ec);
}
mapped_file(const std::string &p, mapmode flags, std::error_code &ec) noexcept {
open(p, flags, -1, 0, ec);
}
mapped_file(const std::string &p, mapmode flags, size_t length, std::error_code &ec) noexcept {
open(p, flags, length, 0, ec);
}
mapped_file(const std::string &p, mapmode flags, size_t length, size_t offset, std::error_code &ec) noexcept {
open(p, flags, length, offset, ec);
}
#ifdef _WIN32
mapped_file(const std::wstring &p, mapmode flags = readonly, size_t length = -1, size_t offset = 0) {
open(p, flags, length, offset);
}
mapped_file(const std::wstring &p, std::error_code &ec) noexcept {
open(p, readonly, -1, 0, ec);
}
mapped_file(const std::wstring &p, mapmode flags, std::error_code &ec) noexcept {
open(p, flags, -1, 0, ec);
}
mapped_file(const std::wstring &p, mapmode flags, size_t length, std::error_code &ec) noexcept {
open(p, flags, length, 0, ec);
}
mapped_file(const std::wstring &p, mapmode flags, size_t length, size_t offset, std::error_code &ec) noexcept {
open(p, flags, length, offset, ec);
}
#endif
mapped_file &operator=(mapped_file &&);
mapped_file &operator=(const mapped_file &) = delete;
void open(const std::string &p, mapmode flags, size_t length = -1, size_t offset = 0) {
base::open(p, flags, length, offset, nullptr);
}
void open(const std::string &p, std::error_code &ec) noexcept {
base::open(p, readonly, -1, 0, &ec);
}
void open(const std::string &p, mapmode flags, std::error_code &ec) noexcept {
base::open(p, flags, -1, 0, &ec);
}
void open(const std::string &p, mapmode flags, size_t length, std::error_code &ec) noexcept {
base::open(p, flags, length, 0, &ec);
}
void open(const std::string &p, mapmode flags, size_t length, size_t offset, std::error_code &ec) noexcept {
base::open(p, flags, length, offset, &ec);
}
#ifdef _WIN32
void open(const std::wstring &p, mapmode flags, size_t length = -1, size_t offset = 0) {
base::open(p, flags, length, offset, nullptr);
}
void open(const std::wstring &p, std::error_code &ec) noexcept {
base::open(p, readonly, -1, 0, &ec);
}
void open(const std::wstring &p, mapmode flags, std::error_code &ec) noexcept {
base::open(p, flags, -1, 0, &ec);
}
void open(const std::wstring &p, mapmode flags, size_t length, std::error_code &ec) noexcept {
base::open(p, flags, length, 0, &ec);
}
void open(const std::wstring &p, mapmode flags, size_t length, size_t offset, std::error_code &ec) noexcept {
base::open(p, flags, length, offset, &ec);
}
#endif
void create(const std::string &p, size_t size) {
base::create(p, size, nullptr);
}
void create(const std::string &p, size_t size, std::error_code &ec) noexcept {
base::create(p, size, &ec);
}
#ifdef _WIN32
void create(const std::wstring &p, size_t size) {
base::create(p, size, nullptr);
}
void create(const std::wstring &p, size_t size, std::error_code &ec) noexcept {
base::create(p, size, &ec);
}
#endif
const value_type *data() const {
return (const value_type *)_data;
}
value_type *data() {
return (value_type *)_data;
}
const_iterator cbegin() const {
return data();
}
const_iterator cend() const {
return data() + size();
}
const_iterator begin() const {
return cbegin();
}
const_iterator end() const {
return cend();
}
iterator begin() {
return (iterator)_data;
}
iterator end() {
return (iterator)_data + size();
}
mapmode flags() const {
return _flags;
}
void swap(mapped_file &rhs) {
base::swap(rhs);
}
};
namespace std {
template<class T>
void swap(mapped_file &a, mapped_file &b) {
a.swap(b);
}
}
#endif