/*
 * Acess2 C++ Library
 * - By John Hodge (thePowersGang)
 *
 * string (header)
 * - C++'s String type
 */
#ifndef _LIBCXX_STRING_
#define _LIBCXX_STRING_

#include "_libcxx_helpers.h"
#include <allocator>

namespace std {

template <class charT>
struct char_traits
{
};

template <>
struct char_traits<char>
{
	typedef char	char_type;
	typedef int	int_type;
	//typedef streamoff	off_type;
	//typedef streampos	pos_type;
	//typedef mbstate_t	state_type;
	
	static bool eq(const char_type& c, const char_type& d) {
		return c == d;
	}
	static bool lt(const char_type& c, const char_type& d) {
		return c < d;
	}
	static size_t length(const char_type* s) {
		size_t	ret = 0;
		while(*s++)	ret ++;
		return ret;
	}
};

template <>
struct char_traits<wchar_t>
{
	typedef wchar_t	char_type;
	typedef int	int_type;
	//typedef streamoff	off_type;
	//typedef streampos	pos_type;
	//typedef mbstate_t	state_type;
	
	static size_t length(const char_type* s) {
		size_t	ret = 0;
		while(*s++)	ret ++;
		return ret;
	}
	static bool eq(const char_type& c, const char_type& d) {
		return c == d;
	}
	static bool lt(const char_type& c, const char_type& d) {
		return c < d;
	}
};

extern void _throw_out_of_range(const char *message);

template < class charT, class traits=char_traits<charT>, class Alloc=allocator<charT> >
class basic_string
{
public:
	typedef traits	traits_type;
	typedef Alloc	allocator_type;
	typedef charT	value_type;
	typedef typename allocator_type::reference	reference;
	typedef typename allocator_type::const_reference	const_reference;
	typedef size_t	size_type;

private:
	struct dynamic_info
	{
		allocator_type	m_allocator;
		 int	m_ref_count = 1;
		size_type	m_capacity = 0;
		size_type	m_size = 0;
		typename allocator_type::pointer m_data = 0;
		dynamic_info(const allocator_type& alloc):
			m_allocator(alloc)
		{
		}
		dynamic_info(const dynamic_info& other):
			m_allocator(other.m_allocator),
			m_ref_count(1),
			m_capacity(other.m_capacity),
			m_size(other.m_size)
		{
			m_data = m_allocator.allocate(m_capacity);
			for( size_type i = 0; i < m_size; i ++ )
				m_data[i] = other.m_data[i];
		}
	};

	allocator_type	m_allocator;
	dynamic_info	*m_content;

public:
	basic_string(const allocator_type& alloc = allocator_type()):
		m_allocator(alloc),
		m_content(0)
	{
	}
	basic_string(const basic_string& str) throw():
		basic_string(allocator_type())
	{
		*this = str;
	}
	#if _CXX11_AVAIL
	basic_string(basic_string&& str):
		m_allocator(str.m_allocator),
		m_content(str.m_content)
	{
		str.m_content = 0;
		::_sys::debug("basic_string(move) %p %s", m_content, c_str());
	}
	#endif
	basic_string(const basic_string& str, const allocator_type& alloc):
		basic_string(str, 0, str.length(), alloc)
	{
	}
	basic_string(const basic_string& str, size_type pos, size_type len = npos, const allocator_type& alloc = allocator_type()):
		basic_string(alloc)
	{
		if( pos < str.length() )
		{
			if( len > str.length() - pos )
				len = str.length() - pos;
			reserve(len);
			for( size_type i = 0; i < len; i ++ )
				m_content->m_data[i] = str.m_content->m_data[pos+i];
			m_content->m_size = len;
		}
	}
	basic_string(const charT *s, const allocator_type& alloc = allocator_type()):
		basic_string(s, traits::length(s), alloc)
	{
	}
	basic_string(const charT *s, size_type n, const allocator_type& alloc = allocator_type()):
		basic_string(alloc)
	{
		if( n > 0 )
		{
			reserve(n);
			for( size_type i = 0; i < n; i ++ )
				m_content->m_data[i] = s[i];
			m_content->m_data[n] = 0;
			m_content->m_size = n;
		}
	}
	basic_string(size_type n, charT c, const allocator_type& alloc = allocator_type()):
		basic_string(alloc)
	{
		if( n > 0 )
		{
			reserve(n);
			for( size_type i = 0; i < n; i ++ )
				m_content->m_data[i] = c;
			m_content->m_data[n] = 0;
			m_content->m_size = n;
		}
	}
	#if __cplusplus < 199711L
	basic_string(basic_string&& str) noexcept:
		basic_string(allocator_type())
	{
	}
	basic_string(basic_string&& str, const allocator_type& alloc) noexcept:
		basic_string(alloc)
	{
		m_content = str.m_content;
		str.m_content = 0;
	}
	#endif
	~basic_string()
	{
		release_content();
	}
	basic_string& operator=(const basic_string& str) throw() {
		return assign(str);
	}
	basic_string& operator=(const charT* s) {
		return assign(s);
	}
	basic_string& operator=(charT c) {
		return assign(c);
	}
	
	// iterators
	
	// capacity
	size_type size() const {
		return m_content ? m_content->m_size : 0;
	}
	size_type length() const {
		return size();
	}
	size_type max_size() const {
		return -1;
	}
	void resize(size_type size, charT c = 0) {
		reserve(size);
		if( m_content->m_size < size ) {
			for( size_type ofs = m_content->m_size; ofs < size; ofs ++ )
				m_content->m_data[ofs] = c;
			m_content->m_data[size] = 0;
		}
		m_content->m_size = size;
		m_content->m_data[size] = 0;
	}
	size_type capacity() const {
		return m_content ? m_content->m_capacity : 0;
	}
	void reserve(size_type size) {
		own_content();
		size = (size+1 + 31) & ~31;
		if( size > m_content->m_capacity ) {
			auto new_area = m_allocator.allocate(size);
			for( size_type i = 0; i < m_content->m_size; i ++ )
				new_area[i] = m_content->m_data[i];
			m_allocator.deallocate(m_content->m_data, m_content->m_capacity);
			m_content->m_data = new_area;
			m_content->m_capacity = size;
		}
	}
	void clear() {
		own_content();
		m_content->m_size = 0;
	}
	bool empty() const {
		return length() == 0;
	}
	
	// Access
	reference operator[] (size_type pos) {
		own_content();
		return m_content->m_data[pos];
	}
	const_reference operator[] (size_type pos) const {
		return (m_content ? m_content->m_data[pos] : *(const charT*)0);
	}
	reference at(size_type pos) {
		own_content();
		if(pos >= m_content->m_size)
			_throw_out_of_range("basic_string - at");
		return m_content->m_data[pos];
	}
	const_reference at(size_type pos) const {
		if(!m_content || pos >= m_content.m_size)
			_throw_out_of_range("basic_string - at");
		return m_content->m_data[pos];
	}
	
	// Modifiers
	basic_string& operator +=(const basic_string& str) {
		return append(str);
	}
	basic_string& operator +=(const charT* s) {
		return append(s);
	}
	basic_string& operator +=(charT c) {
		push_back(c);
		return *this;
	}
	basic_string& append(const basic_string& str) {
		return append(str, 0, npos);
	}
	basic_string& append(const basic_string& str, size_type subpos, size_type sublen) {
		if(subpos >= str.size())
			_throw_out_of_range("basic_string - assign source");
		if( sublen > str.size() - subpos )
			sublen = str.size() - subpos;
		append( str.data() + subpos, sublen );
		return *this;
	}
	basic_string& append(const charT* s) {
		return append(s, traits::length(s));
	}
	basic_string& append(const charT* s, size_type n) {
		reserve(size() + n);
		for( size_type i = 0; i < n; i ++ )
			m_content->m_data[size() + i] = s[i];
		m_content->m_data[size()+n] = '\0';
		m_content->m_size += n;
		return *this;
	}
	basic_string& append(size_type n, charT c) {
		reserve(size() + n);
		for( size_type i = 0; i < n; i ++ )
			m_content->m_data[size() + i] = c;
		m_content->m_data[size()+n] = '\0';
		m_content->m_size += n;
		return *this;
	}
	void push_back(charT c) {
		append(1, c);
	}
	basic_string& assign(const basic_string& str) throw() {
		// Special case, triggers copy-on-write.
		release_content();
		m_content = str.m_content;
		m_content->m_ref_count ++;
		return *this;
	}
	basic_string& assign(const basic_string& str, size_type subpos, size_type sublen) {
		if(subpos >= str.size())
			_throw_out_of_range("basic_string - assign source");
		if( sublen > str.size() - subpos )
			sublen = str.size() - subpos;
		
		return assign(str.data() + subpos, sublen);
	}
	basic_string& assign(const charT* s) {
		return assign(s, traits::length(s));
	}
	basic_string& assign(const charT* s, size_type n) {
		release_content();
		reserve(n);
		for( size_type i = 0; i < n; i ++ )
			m_content->m_data[i] = s[i];
		m_content->m_data[n] = '\0';
		m_content->m_size = n;
		return *this;
	}
	basic_string& assign(size_type n, charT c) {
		release_content();
		reserve(n);
		for( size_type i = 0; i < n; i ++ )
			m_content->m_data[i] = c;
		m_content->m_data[n] = '\0';
		m_content->m_size = n;
		return *this;
	}
	
	// String operations
	const char *c_str() const {
		// TODO: this is const, but also might need to do processing
		if(m_content) {
			_libcxx_assert(m_content->m_data[m_content->m_size] == '\0');
		}
		return (m_content ? m_content->m_data : "");
	}
	const char *data() const {
		return (m_content ? m_content->m_data : NULL);
	}
	
	static const size_type npos = -1;
private:
	void own_content() {
		if(!m_content)
		{
			m_content = new dynamic_info(m_allocator);
		}
		else if( m_content->m_ref_count > 1 )
		{
			dynamic_info *new_cont = new dynamic_info(*m_content);
			m_content->m_ref_count --;
			m_content = new_cont;
		}
		else
		{
			// already owned
		}
	}
	void release_content() {
		if( m_content )
		{
			m_content->m_ref_count --;
			if( m_content->m_ref_count == 0 ) {
				m_allocator.deallocate(m_content->m_data, m_content->m_capacity);
				delete m_content;
			}
			m_content = NULL;
		}
	}
};

typedef basic_string<char>	string;

template <class charT, class traits, class Alloc>
basic_string<charT,traits,Alloc> operator+(const basic_string<charT,traits,Alloc>& lhs, const basic_string<charT,traits,Alloc>& rhs)
{
	basic_string<charT,traits,Alloc>	ret;
	ret.reserve(lhs.size() + rhs.size());
	ret += lhs;
	ret += rhs;
	return ret;
}
template <class charT, class traits, class Alloc>
basic_string<charT,traits,Alloc> operator+(const basic_string<charT,traits,Alloc>& lhs, const charT* rhs)
{
	basic_string<charT,traits,Alloc>	ret;
	ret.reserve(lhs.size() + traits::length(rhs));
	ret += lhs;
	ret += rhs;
	return ret;
}
template <class charT, class traits, class Alloc>
basic_string<charT,traits,Alloc> operator+(const charT* lhs, const basic_string<charT,traits,Alloc>& rhs)
{
	basic_string<charT,traits,Alloc>	ret;
	ret.reserve(traits::length(lhs) + rhs.size());
	ret += lhs;
	ret += rhs;
	return ret;
}
template <class charT, class traits, class Alloc>
basic_string<charT,traits,Alloc> operator+(const basic_string<charT,traits,Alloc>& lhs, const charT rhs)
{
	basic_string<charT,traits,Alloc>	ret;
	ret.reserve(lhs.size() + 1);
	ret += lhs;
	ret += rhs;
	return ret;
}
template <class charT, class traits, class Alloc>
basic_string<charT,traits,Alloc> operator+(const charT lhs, const basic_string<charT,traits,Alloc>& rhs)
{
	basic_string<charT,traits,Alloc>	ret;
	ret.reserve(1 + rhs.size());
	ret += lhs;
	ret += rhs;
	return ret;
}

};

#endif

// vim: ft=cpp