forstio/source/forstio/buffer.h

#pragma once

#include "error.h"

#include <array>
#include <cstdint>
#include <deque>
#include <list>
#include <string>
#include <vector>

namespace saw {
/*
 * Access class to reduce templated BufferSegments bloat
 */
class buffer {
protected:
	~buffer() = default;

public:
	virtual size_t read_position() const = 0;
	virtual size_t read_composite_length() const = 0;
	virtual size_t read_segment_length(size_t offset = 0) const = 0;
	virtual void read_advance(size_t bytes) = 0;

	virtual uint8_t &read(size_t i = 0) = 0;
	virtual const uint8_t &read(size_t i = 0) const = 0;

	virtual size_t write_position() const = 0;
	virtual size_t write_composite_length() const = 0;
	virtual size_t write_segment_length(size_t offset = 0) const = 0;
	virtual void write_advance(size_t bytes) = 0;

	virtual uint8_t &write(size_t i = 0) = 0;
	virtual const uint8_t &write(size_t i = 0) const = 0;

	/*
	 * Sometime buffers need to grow with a little more control
	 * than with push and pop for more efficient calls.
	 * There is nothing you can do if read hasn't been filled, but at
	 * least write can be increased if it is demanded.
	 */
	virtual error write_require_length(size_t bytes) = 0;

	error push(const uint8_t &value);
	error push(const uint8_t &buffer, size_t size);
	error pop(uint8_t &value);
	error pop(uint8_t &buffer, size_t size);

	/*
	 * Subject to change
	 */
	std::string to_string() const;
	std::string to_hex() const;
};

/*
 *	A viewer class for buffers.
 *	Working on the reference buffer invalidates the buffer view
 */
class buffer_view : public buffer {
private:
	buffer &buffer_;
	size_t read_offset_;
	size_t write_offset_;

public:
	buffer_view(buffer &);

	size_t read_position() const override;
	size_t read_composite_length() const override;
	size_t read_segment_length(size_t offset = 0) const override;
	void read_advance(size_t bytes) override;

	uint8_t &read(size_t i = 0) override;
	const uint8_t &read(size_t i = 0) const override;

	size_t write_position() const override;
	size_t write_composite_length() const override;
	size_t write_segment_length(size_t offset = 0) const override;
	void write_advance(size_t bytes) override;

	uint8_t &write(size_t i = 0) override;
	const uint8_t &write(size_t i = 0) const override;

	error write_require_length(size_t bytes) override;

	size_t read_offset() const;
	size_t write_offset() const;
};

/*
 * Buffer size meant for default allocation size of the ringbuffer since
 * this class currently doesn't support proper resizing
 */
constexpr size_t RING_BUFFER_MAX_SIZE = 4096;
/*
 * Buffer wrapping around if read caught up
 */
class ring_buffer final : public buffer {
private:
	std::vector<uint8_t> buffer_;
	size_t read_position_;
	size_t write_position_;
	bool write_reached_read_ = false;

public:
	ring_buffer();
	ring_buffer(size_t size);

	inline size_t size() const { return buffer_.size(); }

	inline uint8_t &operator[](size_t i) { return buffer_[i]; }
	inline const uint8_t &operator[](size_t i) const { return buffer_[i]; }

	size_t read_position() const override;
	size_t read_composite_length() const override;
	size_t read_segment_length(size_t offset = 0) const override;
	void read_advance(size_t bytes) override;

	uint8_t &read(size_t i = 0) override;
	const uint8_t &read(size_t i = 0) const override;

	size_t write_position() const override;
	size_t write_composite_length() const override;
	size_t write_segment_length(size_t offset = 0) const override;
	void write_advance(size_t bytes) override;

	uint8_t &write(size_t i = 0) override;
	const uint8_t &write(size_t i = 0) const override;

	error write_require_length(size_t bytes) override;
};

/*
 * One time buffer
 */
class array_buffer : public buffer {
private:
	std::vector<uint8_t> buffer_;

	size_t read_position_;
	size_t write_position_;

public:
	array_buffer(size_t size);

	size_t read_position() const override;
	size_t read_composite_length() const override;
	size_t read_segment_length(size_t offset = 0) const override;
	void read_advance(size_t bytes) override;

	uint8_t &read(size_t i = 0) override;
	const uint8_t &read(size_t i = 0) const override;

	size_t write_position() const override;
	size_t write_composite_length() const override;
	size_t write_segment_length(size_t offset = 0) const override;
	void write_advance(size_t bytes) override;

	uint8_t &write(size_t i = 0) override;
	const uint8_t &write(size_t i = 0) const override;

	error write_require_length(size_t bytes) override;
};

class chain_array_buffer : public buffer {
private:
	std::deque<array_buffer> buffer_;

	size_t read_position_;
	size_t write_position_;

public:
	chain_array_buffer();

	size_t read_position() const override;
	size_t read_composite_length() const override;
	size_t read_segment_length(size_t offset = 0) const override;
	void read_advance(size_t bytes) override;

	uint8_t &read(size_t i = 0) override;
	const uint8_t &read(size_t i = 0) const override;

	size_t write_position() const override;
	size_t write_composite_length() const override;
	size_t write_segment_length(size_t offset = 0) const override;
	void write_advance(size_t bytes) override;

	uint8_t &write(size_t i = 0) override;
	const uint8_t &write(size_t i = 0) const override;

	error write_require_length(size_t bytes) override;
};
} // namespace saw