mpw-shell/cxx/mapped_file.h
2016-02-11 15:46:40 -05:00

147 lines
2.5 KiB
C++

#ifndef __mapped_file_h__
#define __mapped_file_h__
#ifdef HAVE_TSFS
#include <filesystem>
#else
#include <string>
#endif
#include <cstddef>
class mapped_file_base {
public:
#ifdef HAVE_TSFS
typedef std::filesystem::path path_type ;
#else
typedef std::string path_type ;
#endif
enum mapmode { readonly, readwrite, priv };
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 path_type& p, mapmode flags, size_t length, size_t offset);
void create(const path_type &p, size_t new_size); // always creates readwrite.
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(const path_type& p, mapmode flags = readonly, size_t length = -1, size_t offset = 0) {
open(p, flags, length, offset);
}
mapped_file(mapped_file &&);
mapped_file(const mapped_file &) = delete;
mapped_file &operator=(mapped_file &&);
mapped_file &operator=(const mapped_file &) = delete;
void open(const path_type& p, mapmode flags, size_t length = -1, size_t offset = 0) {
base::open(p, flags, length, offset);
}
const value_type *data() const {
return (const value_type *)_data;
}
value_type *data() {
return _flags == readonly ? (value_type *)nullptr : (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 _flags == readonly ? (iterator)nullptr : (iterator)_data;
}
iterator end() {
return _flags == readonly ? (iterator)nullptr : (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