ex14_18_String.h

#ifndef CP5_STRING_H__
#define CP5_STRING_H__

#include <memory>
#include <iostream>

#ifndef _MSC_VER
#define NOEXCEPT noexcept
#else
#define NOEXCEPT
#endif

//===================================================================================
//
//		|s|t|r|i|n|g|\0|-------------------|
//		 ^			 ^  ^ first_free       ^
//		elements	 last_elem			   cap
//
//===================================================================================

class String
{
	friend std::ostream& operator<<(std::ostream&, const String&);
	friend std::istream& operator>>(std::istream&, String&);
	friend bool operator==(const String&, const String&);
	friend bool operator!=(const String&, const String&);
	friend bool operator< (const String&, const String&);
	friend bool operator> (const String&, const String&);
	friend bool operator<=(const String&, const String&);
	friend bool operator>=(const String&, const String&);

public:
	String() : String("") {}
	String(const char *);
	String(const String&);
	String& operator=(const String&);
	String(String &&) NOEXCEPT;
	String& operator=(String&&) NOEXCEPT;
	~String();

	void push_back(const char);

	char* begin() const { return elements; }
	char* end() const { return last_elem; }

	const char *c_str() const { return elements; }
	size_t size() const { return last_elem - elements; }
	size_t length() const { return size(); }
	size_t capacity() const { return cap - elements; }

	void reserve(size_t);
	void resize(size_t);
	void resize(size_t, char);

private:
	std::pair<char*, char*> alloc_n_copy(const char*, const char*);
	void range_initializer(const char*, const char*);
	void free();
	void reallocate();
	void alloc_n_move(size_t new_cap);
	void chk_n_alloc() { if (first_free == cap) reallocate(); }

private:
	char *elements;
	char *last_elem;
	char *first_free;
	char *cap;
	std::allocator<char> alloc;
};

std::ostream& operator<<(std::ostream&, const String&);
std::istream& operator>>(std::istream&, String&);
bool operator==(const String&, const String&);
bool operator!=(const String&, const String&);
bool operator< (const String&, const String&);
bool operator> (const String&, const String&);
bool operator<=(const String&, const String&);
bool operator>=(const String&, const String&);

#endif