Brainfuckインタプリタ

main.cpp

#include <iostream>
#include <cstring>
#include <memory>
#include <stack>

using std::cout;
using std::cin;
using std::endl;
using std::auto_ptr;
using std::stack;

const int MemorySize=30000,SourceLength=10000;
auto_ptr<unsigned char> Memory;
auto_ptr<char> Source;
unsigned char* Ptr=0;
stack<int> Brackets;

int main(void)
{
    Memory.reset(new unsigned char[MemorySize]);
    Source.reset(new char[SourceLength]);
    while(1){
        for(int i=0;i<MemorySize;i++) *(Memory.get()+i)=0;
        Ptr=Memory.get();
        while(!Brackets.empty()) Brackets.pop();
        cout<<"Please input program.(Max length is "<<SourceLength<<")"<<endl<<">";
        cin>>Source.get();
        if(!strcmp(Source.get(),"x")) break;
        int Length=strlen(Source.get());
        for(int i=0;i<Length;i++){
            char Code=*(Source.get()+i);
            if(Code=='>') Ptr++;
            else if(Code=='<') Ptr--;
            else if(Code=='+') (*Ptr)++;
            else if(Code=='-') (*Ptr)--;
            else if(Code=='.') cout<<*Ptr;
            else if(Code==',') cin>>*Ptr;
            else if(Code=='['){
                Brackets.push(i-1);
                    if(!*Ptr){
                        int Count=1;
                        while(++i<Length&&Count){
                            if(*(Source.get()+i)=='[') Count++;
                            else if(*(Source.get()+i)==']') Count--;
                        }
                    }
            }else if(Code==']'){
                if(*Ptr){
                    i=Brackets.top();
                    Brackets.pop();
                }
            }else{
                cout<<"Oh... \""<<Code<<"\" is an illegal character.";
                break;
            }
        }
        cout<<endl;
    }
    return 0;
}