bf_io.cpp

#include "bf_instruction.hpp"

#include <map>

namespace bf {

    std::vector<Instruction> read_instructions(std::istream& is)
    {
	static std::map<char,int>
	    direction = { {'>',  1},
			  {'<', -1},
			  {'+',  1},
			  {'-', -1} };
	
	static std::map<char,Action>
	    charActions = { { '>', MOVE },
			    { '<', MOVE },
			    { '+', INCR },
			    { '-', INCR },
			    { '[', FALSEJUMP },
			    { ']', TRUEJUMP },
			    { '.', PRINT },
			    { ',', READ } };

	std::vector<Instruction> instrs;
	char c;

	while(is >> c){
	    switch(c){
	    case '<':
	    case '>':
	    case '+':
	    case '-':
		{
		    int increment = direction.at(c);
		    Action action = charActions.at(c);
		    if(instrs.empty() || instrs.back().action != action){
			instrs.push_back({ action });
		    }
		    instrs.back().val += increment;
		}
		break;
	    case '.':
	    case ',':
	    case '[':
	    case ']':
		instrs.push_back({ charActions.at(c) });
		break;
	    }
	}
	
	return instrs;
    }

}