bitset

/*	Copyright (C) 2004 Garrett A. Kajmowicz

	This file is part of the uClibc++ Library.

	This library is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public
	License as published by the Free Software Foundation; either
	version 2.1 of the License, or (at your option) any later version.

	This library is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public
	License along with this library; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#include <basic_definitions>
#include <cstddef>
#include <climits>
#include <func_exception>
#include <string>
#include <iosfwd>

#ifndef __STD_BITSET_HEADER
#define __STD_BITSET_HEADER 1

#pragma GCC visibility push(default)

namespace std{
	template <size_t N> class bitset;


	template <size_t N> bitset<N> operator&(const bitset<N>&, const bitset<N>&);
	template <size_t N> bitset<N> operator|(const bitset<N>&, const bitset<N>&);
	template <size_t N> bitset<N> operator^(const bitset<N>&, const bitset<N>&);
	template <class charT, class traits, size_t N> basic_istream<charT, traits>& 
		operator>>(basic_istream<charT, traits>& is, bitset<N>& x);

	template <class charT, class traits, size_t N> basic_ostream<charT, traits>& 
		operator<<(basic_ostream<charT, traits>& os, const bitset<N>& x);
	
	//Actual Code


	template<size_t N> class _UCXXEXPORT bitset {
	private:
		//Number of characters allocated to hold the bits
		static const size_t WORD_SIZE = CHAR_BIT;		//Use int maybe?
		static const size_t num_bytes = (N + WORD_SIZE - 1) / WORD_SIZE;

		//From the bit number, figure out which byte we are working with
		size_t byte_num(size_t bit_num) const{ 
			if(WORD_SIZE == 8){
				return (bit_num >> 3);
			}
			if(WORD_SIZE == 16){
				return (bit_num >> 4);
			}
			if(WORD_SIZE == 32){
				return (bit_num >> 5);
			}
			if(WORD_SIZE == 64){
				return (bit_num >> 6);
			}
			return bit_num / WORD_SIZE;
		}
		//From the bit number, figure out which bit inside the byte we need
		size_t bit_num(const size_t bit_num) const{
			return bit_num % WORD_SIZE;
		}


		//Point to the actual data
		char data[num_bytes];
	public:

		class _UCXXEXPORT reference {
			friend class bitset;
			reference() : bit_num(0), parent(0) {  }
			size_t bit_num;
			bitset * parent;
		public:
			~reference() {  }
			reference& operator=(bool x){			// for b[i] = x;
				parent->set(bit_num, x);
				return *this;
			}
			reference& operator=(const reference& x){	// for b[i] = b[j];
				parent->set(bit_num, x);
				return *this;
			}
			bool operator~() const{				// flips the bit
				return !parent->test(bit_num);
			}
			operator bool() const{				// for x = b[i];
				return parent->test(bit_num);
			}
			reference& flip(){				// for b[i].flip();
				parent->flip(bit_num);
				return *this;
			}
		};

		bitset(){
			reset();
		}
		bitset(unsigned long val){
			reset();
			size_t count = sizeof(val) * CHAR_BIT;
			if(count > N){
				count = N;
			}
			for(size_t i = 0; i < count; ++i){
				set(i, ((val >> i) & 1));
			}
		}

		bitset(const bitset & val){
			for(size_t i = 0; i < num_bytes; ++i){
				data[i] = val.data[i];
			}
		}

		template<class charT, class traits, class Allocator> _UCXXEXPORT
		explicit bitset(
			const basic_string<charT,traits,Allocator>& str,
			typename basic_string<charT,traits,Allocator>::size_type pos = 0,
			typename basic_string<charT,traits,Allocator>::size_type n =
			basic_string<charT>::npos
			
		){
			reset();
			if(n > str.length()){
				n = str.length();
			}
			size_t width = n;
			if (width + pos > str.length()){
				width = str.length() - pos;
			}

			for(size_t i = 0; i < width; ++i){
				switch(str[pos + width - i - 1]){
					case '0':
						break;
					case '1':
						set(i);
						break;
					default:
						__throw_invalid_argument();
				}
			}
		}

		bitset<N>& operator&=(const bitset<N>& rhs){
			for(size_t i =0; i < num_bytes; ++i){
				data[i] &= rhs.data[i];
			}
			return *this;
		}

		bitset<N>& operator|=(const bitset<N>& rhs){
			for(size_t i =0; i < num_bytes; ++i){
				data[i] |= rhs.data[i];
			}
			return *this;
		}
		bitset<N>& operator^=(const bitset<N>& rhs){
			for(size_t i=0; i < num_bytes; ++i){
				data[i] ^= rhs.data[i];
			}
			return *this;
		}

		bitset<N>& operator<<=(size_t pos){
			for(size_t i = N-1; i >=pos; --i){
				set(i, test(i - pos));
			}
			for(size_t i = 0; i < pos; ++i){
				reset(i);
			}
			return *this;
		}

		bitset<N>& operator>>=(size_t pos){
			for(size_t i = 0; i < (N - pos); ++i){
				set(i, test(i + pos));
			}
			for(size_t i = pos; i > 0; --i){
				reset(N - i);
			}
			return *this;
		}

		bitset<N>& set(){
			size_t i;
			for(i = 0; i < N ; ++i){
				data[byte_num(i)] |= (1<<bit_num(i));
			}
			return *this;
		}
		bitset<N>& set(size_t pos, int val = true){
			if(val == true){
				data[byte_num(pos)] |= (1<<bit_num(pos));
			}else{
				data[byte_num(pos)] &= ~(1<<bit_num(pos));
			}
			return *this;
		}
		bitset<N>& reset(){
			for(size_t i = 0; i < num_bytes; ++i){
				data[i] = 0;
			}
			return *this;
		}
		bitset<N>& reset(size_t pos){
			data[byte_num(pos)] &= ~(1<<bit_num(pos));
			return *this;
		}
		bitset<N>  operator~() const{
			bitset<N> retval(*this);
			retval.flip();
			return retval;
		}

		bitset<N>& flip(){
			for(size_t i = 0; i < num_bytes; ++i){
				data[i] =  ~data[i];
			}
			return *this;
		}
		bitset<N>& flip(size_t pos){
			char temp = data[byte_num(pos)] & (1 << bit_num(pos));
			if(temp == 0){	//Bit was 0
				data[byte_num(pos)] |= (1 << bit_num(pos));
			}else{		//Bit was 1
				data[byte_num(pos)] &= ~(1<<bit_num(pos));
			}
			return *this;
		}

		reference operator[](size_t pos){   // for b[i];
			reference retval;
			retval.parent = this;
			retval.bit_num = pos;
			return retval;
		}

		unsigned long to_ulong() const{
			if(N > sizeof(unsigned long) * CHAR_BIT){
				__throw_overflow_error();
			}
			unsigned long retval = 0;
			size_t count = N;
			for(size_t i = count; i > 0; --i){
				if(test(i)){
					retval +=1;
				}
				retval<<=1;
			}
			if(test(0)){
				retval +=1;
			}
			return retval;
		}

		template <class charT, class traits, class Allocator>
			basic_string<charT, traits, Allocator> to_string() const
		{
			basic_string<charT, traits, Allocator> retval;
			retval.reserve(N);
			for(size_t i = N ; i > 0; --i){
				if(test(i-1) == true){
					retval.append("1");
				}else{
					retval.append("0");
				}
			}
			return retval;
		}


		size_t count() const{
			size_t retval = 0;
			for(size_t i =0; i < N; ++i){
				if(test(i)){
					++retval;
				}
			}
			return retval;
		}
		size_t size()  const{
			return N;
		}

		bitset<N>& operator=(const bitset<N> & rhs){
			if(&rhs == this){
				return *this;
			}
			for(size_t i = 0; i <= byte_num(N); ++i){
				data[i] = rhs.data[i];
			}
			return *this;
		}


		bool operator==(const bitset<N>& rhs) const{
			for(size_t i =0; i< N; ++i){
				if(test(i) != rhs.test(i)){
					return false;
				}
			}
			return true;
		}

		bool operator!=(const bitset<N>& rhs) const{
			for(size_t i =0; i< N; ++i){
				if(test(i) != rhs.test(i)){
					return true;
				}
			}
			return false;
		}

		bool test(size_t pos) const{
			return (data[byte_num(pos)] & (1<<bit_num(pos)) ) != 0;
		}

		bool any() const{
			for(size_t i = 0; i< N; ++i){
				if(test(i)==true){
					return true;
				}
			}
			return false;
		}

		bool none() const{
			if(any() == true){
				return false;
			}
			return true;
		}

		bitset<N> operator<<(size_t pos) const{
			bitset retval(*this);
			retval<<=pos;
			return retval;
		}
		bitset<N> operator>>(size_t pos) const{
			bitset retval(*this);
			retval>>=pos;
			return retval;
		}
	};

	//Non-member functions


	template <size_t N> _UCXXEXPORT bitset<N> operator&(const bitset<N>& lhs, const bitset<N>& rhs){
		bitset<N> retval(lhs);
		retval &= rhs;
		return retval;
	}

	template <size_t N> _UCXXEXPORT bitset<N> operator|(const bitset<N>& lhs, const bitset<N>& rhs){
		bitset<N> retval(lhs);
		retval |= rhs;
		return retval;
	}

	template <size_t N> _UCXXEXPORT bitset<N> operator^(const bitset<N>& lhs, const bitset<N>& rhs){
		bitset<N> retval(lhs);
		retval ^= rhs;
		return retval;
	}

	template <class charT, class traits, size_t N> _UCXXEXPORT basic_istream<charT, traits>& 
		operator>>(basic_istream<charT, traits>& is, bitset<N>& x)
	{
		string s;
		charT c;
		for(size_t i = 0; i < N; ++i){
			is.get(c);
			if(!is.good()){
				break;
			}
			if(c != '1' && c !='0'){
				is.putback(c);
				break;
			}
			s+=c;
		}
		bitset<N> temp(s);
		x = temp;
		
		return is;
	}

	template <class charT, class traits, size_t N> _UCXXEXPORT basic_ostream<charT, traits>& 
		operator<<(basic_ostream<charT, traits>& os, const bitset<N>& x)
	{
		for(size_t i = N ; i > 0; --i){
			if(x.test(i-1) == true){
				os << "1";
			}else{
				os << "0";
			}
		}
		return os;
	}




}

#pragma GCC visibility pop

#endif