brainfuck.sol.js

//compiles to 2820 bytes unoptimized, 1524 optimized
//using remix version "soljson-v0.4.18+commit.9cf6e910.js"

pragma solidity ^0.4.15;

contract BrainFucker{
    function interpret(bytes s, bytes1[128] input) public returns (bytes1[128] output) {
        uint256 ptr=0;
        uint256 i=0;
        uint256 right = s.length;
        uint256 BUFSIZE=1000;
        uint256 loop;
        bytes memory buf = new bytes(1000);
        uint256 inpos = 0;
        uint256 outpos = 0;
        while(i < right){
            bytes1 c = s[i];
            if(c == '>'){
                ptr++;
                if(ptr >= BUFSIZE){
                    ptr = 0;
                }
            }else if(c == '<'){
                ptr--;
                if(ptr < 0){
                    ptr = BUFSIZE-1;
                }
            }else if(c == '+'){
                buf[ptr] = bytes1(uint8(buf[ptr]) + 1);
            }else if(c == '-'){
                buf[ptr] = bytes1(uint8(buf[ptr]) - 1);
            }else if(c == '['){
                if(buf[ptr] == 0){
                    loop = 1;
                    while(loop > 0){
                        i++;
                        c = s[i];
                        if(c == '['){
                            loop++;
                        }else if(c == ']'){
                            loop--;
                        }
                    }
                }
            }else if(c == ']'){
                loop = 1;
                while(loop > 0){
                    i--;
                    c = s[i];
                    if(c == '['){
                        loop--;
                    }else if(c == ']'){
                        loop++;
                    }
                }
                i--;
            }else if(c == '.'){
                output[outpos] = buf[ptr];
                outpos++;
            }else if(c == ','){
                buf[ptr] = input[inpos];
                inpos++;
            }
            i++;
        }
    }
}