mirror of
https://github.com/TomHarte/CLK.git
synced 2024-11-25 16:31:42 +00:00
254 lines
6.3 KiB
C++
254 lines
6.3 KiB
C++
//
|
|
// FileHolder.hpp
|
|
// Clock Signal
|
|
//
|
|
// Created by Thomas Harte on 21/11/2016.
|
|
// Copyright 2016 Thomas Harte. All rights reserved.
|
|
//
|
|
|
|
#ifndef FileHolder_hpp
|
|
#define FileHolder_hpp
|
|
|
|
#include <sys/stat.h>
|
|
#include <array>
|
|
#include <cstdio>
|
|
#include <cstdint>
|
|
#include <mutex>
|
|
#include <string>
|
|
#include <vector>
|
|
|
|
namespace Storage {
|
|
|
|
class FileHolder final {
|
|
public:
|
|
enum class Error {
|
|
CantOpen = -1
|
|
};
|
|
|
|
enum class FileMode {
|
|
ReadWrite,
|
|
Read,
|
|
Rewrite
|
|
};
|
|
|
|
~FileHolder();
|
|
|
|
/*!
|
|
Attempts to open the file indicated by @c file_name. @c ideal_mode nominates how the file would
|
|
most ideally be opened. It can be one of:
|
|
|
|
ReadWrite attempt to open this file for random access reading and writing. If that fails,
|
|
will attept to open in Read mode.
|
|
Read attempts to open this file for reading only.
|
|
Rewrite opens the file for rewriting; none of the original content is preserved; whatever
|
|
the caller outputs will replace the existing file.
|
|
|
|
@raises ErrorCantOpen if the file cannot be opened.
|
|
*/
|
|
FileHolder(const std::string &file_name, FileMode ideal_mode = FileMode::ReadWrite);
|
|
|
|
/*!
|
|
Performs @c get8 four times on @c file, casting each result to a @c uint32_t
|
|
and returning the four assembled in little endian order.
|
|
*/
|
|
uint32_t get32le();
|
|
|
|
/*!
|
|
Writes @c value using successive @c put8s, in little endian order.
|
|
*/
|
|
template <typename T> void put_le(T value) {
|
|
auto bytes = sizeof(T);
|
|
while(bytes--) {
|
|
put8(value&0xff);
|
|
value >>= 8;
|
|
}
|
|
}
|
|
|
|
/*!
|
|
Writes @c value using successive @c put8s, in big endian order.
|
|
*/
|
|
template <typename T> void put_be(T value) {
|
|
auto shift = sizeof(T) * 8;
|
|
while(shift) {
|
|
shift -= 8;
|
|
put8((value >> shift)&0xff);
|
|
}
|
|
}
|
|
|
|
/*!
|
|
Performs @c get8 four times on @c file, casting each result to a @c uint32_t
|
|
and returning the four assembled in big endian order.
|
|
*/
|
|
uint32_t get32be();
|
|
|
|
/*!
|
|
Performs @c get8 three times on @c file, casting each result to a @c uint32_t
|
|
and returning the three assembled in little endian order.
|
|
*/
|
|
uint32_t get24le();
|
|
|
|
/*!
|
|
Performs @c get8 three times on @c file, casting each result to a @c uint32_t
|
|
and returning the three assembled in big endian order.
|
|
*/
|
|
uint32_t get24be();
|
|
|
|
/*!
|
|
Performs @c get8 two times on @c file, casting each result to a @c uint32_t
|
|
and returning the two assembled in little endian order.
|
|
*/
|
|
uint16_t get16le();
|
|
|
|
/*!
|
|
Writes @c value using two successive @c put8s, in little endian order.
|
|
*/
|
|
void put16le(uint16_t value);
|
|
|
|
/*!
|
|
Performs @c get8 two times on @c file, casting each result to a @c uint32_t
|
|
and returning the two assembled in big endian order.
|
|
*/
|
|
uint16_t get16be();
|
|
|
|
/*!
|
|
Writes @c value using two successive @c put8s, in big endian order.
|
|
*/
|
|
void put16be(uint16_t value);
|
|
|
|
/*! Reads a single byte from @c file. */
|
|
uint8_t get8();
|
|
|
|
/*! Writes a single byte from @c file. */
|
|
void put8(uint8_t value);
|
|
|
|
/*! Writes @c value a total of @c repeats times. */
|
|
void putn(std::size_t repeats, uint8_t value);
|
|
|
|
/*! Reads @c size bytes and returns them as a vector. */
|
|
std::vector<uint8_t> read(std::size_t size);
|
|
|
|
/*! Reads @c a.size() bytes into @c a.data(). */
|
|
template <size_t size> std::size_t read(std::array<uint8_t, size> &a) {
|
|
return read(a.data(), a.size());
|
|
}
|
|
|
|
/*! Reads @c size bytes and writes them to @c buffer. */
|
|
std::size_t read(uint8_t *buffer, std::size_t size);
|
|
|
|
/*! Writes @c buffer one byte at a time in order. */
|
|
std::size_t write(const std::vector<uint8_t> &buffer);
|
|
|
|
/*! Writes @c buffer one byte at a time in order, writing @c size bytes in total. */
|
|
std::size_t write(const uint8_t *buffer, std::size_t size);
|
|
|
|
/*! Moves @c bytes from the anchor indicated by @c whence: SEEK_SET, SEEK_CUR or SEEK_END. */
|
|
void seek(long offset, int whence);
|
|
|
|
/*! @returns The current cursor position within this file. */
|
|
long tell();
|
|
|
|
/*! Flushes any queued content that has not yet been written to disk. */
|
|
void flush();
|
|
|
|
/*! @returns @c true if the end-of-file indicator is set, @c false otherwise. */
|
|
bool eof();
|
|
|
|
class BitStream {
|
|
public:
|
|
uint8_t get_bits(int q) {
|
|
uint8_t result = 0;
|
|
while(q--) {
|
|
result = static_cast<uint8_t>((result << 1) | get_bit());
|
|
}
|
|
return result;
|
|
}
|
|
|
|
private:
|
|
BitStream(FILE *file, bool lsb_first) :
|
|
file_(file),
|
|
lsb_first_(lsb_first),
|
|
next_value_(0),
|
|
bits_remaining_(0) {}
|
|
friend FileHolder;
|
|
|
|
FILE *file_;
|
|
bool lsb_first_;
|
|
uint8_t next_value_;
|
|
int bits_remaining_;
|
|
|
|
uint8_t get_bit() {
|
|
if(!bits_remaining_) {
|
|
bits_remaining_ = 8;
|
|
next_value_ = static_cast<uint8_t>(fgetc(file_));
|
|
}
|
|
|
|
uint8_t bit;
|
|
if(lsb_first_) {
|
|
bit = next_value_ & 1;
|
|
next_value_ >>= 1;
|
|
} else {
|
|
bit = next_value_ >> 7;
|
|
next_value_ <<= 1;
|
|
}
|
|
|
|
bits_remaining_--;
|
|
|
|
return bit;
|
|
}
|
|
};
|
|
|
|
/*!
|
|
Obtains a BitStream for reading from the file from the current reading cursor.
|
|
*/
|
|
BitStream get_bitstream(bool lsb_first);
|
|
|
|
/*!
|
|
Reads @c length bytes from the file and compares them to the first
|
|
@c length bytes of @c signature. If @c length is 0, it is computed
|
|
as the length of @c signature not including the terminating null.
|
|
|
|
@returns @c true if the bytes read match the signature; @c false otherwise.
|
|
*/
|
|
bool check_signature(const char *signature, std::size_t length = 0);
|
|
|
|
/*!
|
|
Determines and returns the file extension: everything from the final character
|
|
back to the first dot. The string is converted to lowercase before being returned.
|
|
*/
|
|
std::string extension();
|
|
|
|
/*!
|
|
Ensures the file is at least @c length bytes long, appending 0s until it is
|
|
if necessary.
|
|
*/
|
|
void ensure_is_at_least_length(long length);
|
|
|
|
/*!
|
|
@returns @c true if an attempt was made to read this file in ReadWrite mode but it could be opened only for reading; @c false otherwise.
|
|
*/
|
|
bool get_is_known_read_only();
|
|
|
|
/*!
|
|
@returns the stat struct describing this file.
|
|
*/
|
|
struct stat &stats();
|
|
|
|
/*!
|
|
@returns a mutex owned by the file that can be used to serialise file access.
|
|
*/
|
|
std::mutex &get_file_access_mutex();
|
|
|
|
private:
|
|
FILE *file_ = nullptr;
|
|
const std::string name_;
|
|
|
|
struct stat file_stats_;
|
|
bool is_read_only_ = false;
|
|
|
|
std::mutex file_access_mutex_;
|
|
};
|
|
|
|
}
|
|
|
|
#endif /* FileHolder_hpp */
|