it-works/brainfuck/brainfuck.hpp

//
//  brainfuck.hpp
//
//  Created by Joshua Moerman on 05/22/11.
//  Copyright 2011 Vadovas. All rights reserved.
//

/*
 T is the memory-type (normally bytes aka char)
 OutputIterator is where to write (normally cout)
 */

#ifndef BRAINFUCK_HPP
#define BRAINFUCK_HPP

#include <iostream>
#include <iterator>
#include <algorithm>

namespace brainfuck_details {

// recursive funtion (from http://www.xs4all.nl/~weegen/eelis/geordi/) but templated
template <typename T, typename InputIterator, typename OutputIterator>
void b(char * c, InputIterator& in, T * & p, OutputIterator out){
        for(; *c && *c != ']'; ++c) {
		switch(*c){
			case '>' : ++p; break;
			case '<' : --p; break;
			case '+' : ++*p; break;
			case '-' : --*p; break;
			case '.' : *out++ = *p; break;
			case ',' : *p = *in++; break;
			case '[' :
                        	for(++c; *p;) b(c, in, p, out);
                        	for(int d = 0; *c!=']' || d--; ++c) if(*c == '[') d++;
				break;
                }   
        } 
}

// normally we want a comma between values
template <typename T>
std::ostream_iterator<T> default_ostream_iterator(std::ostream& os = std::cout){
	return std::ostream_iterator<T>(os, ", ");
}

// except for char's
template <>
std::ostream_iterator<char> default_ostream_iterator<char>(std::ostream& os){
	return std::ostream_iterator<char>(os);
}

}

// Would be better if we used a smarter iterator for p... it is of fixed size now :(
template <typename T = char, typename OutputIterator = std::ostream_iterator<T>>
void brainfuck(std::string prg, std::basic_string<T> inp = std::basic_string<T>(), OutputIterator it = brainfuck_details::default_ostream_iterator<T>()) {
	char * c = new char[prg.length() + 1];
	std::copy(prg.begin(), prg.end(), c);

	T * i = new T[inp.length() + 1];
	std::copy(inp.begin(), inp.end(), i);

	T * p = new T[512];
	std::fill_n(p, 512, T(0));

	brainfuck_details::b(c,i,p,it);
}

// we can't put a default on the InputIterator, because that would be ambigious
template <typename T = char, typename InputIterator = std::istream_iterator<T>, typename OutputIterator = std::ostream_iterator<T>>
void brainfuck(std::string prg, InputIterator inp, OutputIterator it = brainfuck_details::default_ostream_iterator<T>()) {
	char * c = new char[prg.length() + 1];
	std::copy(prg.begin(), prg.end(), c);

	T * p = new T[512];
	std::fill_n(p, 512, T(0));

	brainfuck_details::b(c,inp,p,it);
}

#endif	// BRAINFUCK_HPP