Created
December 4, 2014 06:38
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BrainFuck 解释器
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function getMatchingBra(code) { | |
var stack = []; | |
var bra = []; | |
for(var i = 0; i < code.length; i++) bra.push(-1); | |
for(var i = 0; i < code.length; i++) { | |
if(code[i] === '[') { | |
stack.push(i); | |
} else if(code[i] === ']') { | |
bra[i] = stack.pop(); | |
bra[bra[i]] = i; | |
} | |
} | |
return bra; | |
} | |
function brainFuck(code, input) { | |
var inputPos = 0; | |
var commandPos = 0; | |
var pointerPos = 0; | |
var bytes = [ 0 ]; | |
var output = ""; | |
var matching = getMatchingBra(code); | |
while(commandPos < code.length) { | |
switch(code[commandPos]) { | |
case '>': { | |
pointerPos++; | |
if(undefined === bytes[pointerPos]) { | |
bytes.push(0); | |
} | |
break; | |
} | |
case '<': { | |
pointerPos--; | |
if(0 > pointerPos) { | |
bytes.unshift(0); | |
pointerPos = 0; | |
} | |
break; | |
} | |
case '+': { | |
bytes[pointerPos] = (bytes[pointerPos] + 1) % 256; | |
break; | |
} | |
case '-': { | |
bytes[pointerPos]--; | |
if(bytes[pointerPos] < 0) bytes[pointerPos] = 0; | |
break; | |
} | |
case '.': { | |
output += String.fromCharCode(bytes[pointerPos]); | |
break; | |
} | |
case ',': { | |
var temp = input.charCodeAt(inputPos++); | |
bytes[pointerPos] = temp; | |
break; | |
} | |
case '[': { | |
if(!bytes[pointerPos]) { | |
commandPos = matching[commandPos]; | |
} | |
break; | |
} | |
case ']': { | |
if(bytes[pointerPos]) { | |
commandPos = matching[commandPos]; | |
} | |
break; | |
} | |
} | |
commandPos++; | |
} | |
return output; | |
} | |
var out = brainFuck('+++++++[>+++++[>++>+<<-]>>>+>++>++<<<<<<-]>>+++.[->+<]>.+++.[->+<]>.>[-<->]<---.>>[-<<->>]<<--.'); | |
console.log(out); |
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