114 lines
3.5 KiB
Python
114 lines
3.5 KiB
Python
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'''brainfuck interpreter adapted from (public domain) code at
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http://brainfuck.sourceforge.net/brain.py'''
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import re
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import random
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BUFFER_SIZE = 5000
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#command
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def bf(bot, inp, input=None, max_steps=1000000, no_input=0):
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"""Runs a Brainfuck program given as a string.
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The string must contain nothing but "<>[]+-.,", i.e.
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be already filtered.
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If 'input' is None, stdin is used. 'input' can be
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a string or a tuple; tuples are only used if
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extended_interpretation is non-zero, and should
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be more or less obvious in that case.
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if max_steps is < 0, there is no restriction."""
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program = re.sub('[^][<>+-.,]', '', inp.inp)
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# create a dict of brackets pairs, for speed later on
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parens={}
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open_parens=[]
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for pos in range(len(program)):
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if program[pos] == '[':
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open_parens.append(pos)
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elif program[pos] == ']':
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if len(open_parens) > 0:
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parens[pos] = open_parens[-1]
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parens[open_parens[-1]] = pos
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open_parens.pop()
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else:
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return 'unbalanced brackets'
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# if len(open_parens) != 0:
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# return 'unbalanced brackets'
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# now we can start interpreting
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pc = 0 # program counter
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mp = 0 # memory pointer
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steps = 0
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memory = [0] * BUFFER_SIZE #initial memory area
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rightmost = 0
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if input != None:
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if type(input) == type(()):
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# we'll only be using input[0] right now
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inputs, input = input, input[0]
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input_pointer = 0
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output = "" #we'll save the output here
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if no_input:
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eof_reached = 1
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else:
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eof_reached = 0
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# the main program loop:
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while pc < len(program):
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c = program[pc]
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if c == '+':
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memory[mp] = memory[mp] + 1 % 256
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elif c == '-':
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memory[mp] = memory[mp] - 1 % 256
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elif c == '>':
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mp = mp + 1
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if mp > rightmost:
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rightmost = mp
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if mp >= len(memory):
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memory = memory + [0]*BUFFER_SIZE # no restriction on memory growth!
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elif c == '<':
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mp = mp - 1 % len(memory)
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elif c == '.':
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output += chr(memory[mp])
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if len(output) > 500:
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break
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elif program[pc] == ',':
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if eof_reached:
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raise Exception, "Program tries reading past EOF"
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if input == None:
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#char = sys.stdin.read(1)
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char = chr(random.randint(1,255))
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if char == '': # EOF
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memory[mp] = 0
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eof_reached = 1
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else:
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memory[mp] = ord(char)
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else:
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if input_pointer == len(input): # EOF
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memory[mp] = 0
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eof_reached = 1
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else:
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memory[mp] = ord(input[input_pointer])
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input_pointer = input_pointer + 1
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elif program[pc] == '[':
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if memory[mp] == 0:
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pc = parens[pc]
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elif program[pc] == ']':
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if memory[mp] != 0:
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pc = parens[pc]
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pc += 1
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steps += 1
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if max_steps >= 0 and steps > max_steps:
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output += "Maximum number of steps exceeded"
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break
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# end of while loop
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return unicode(re.sub('[\r\n\x00]', '/', output), 'iso-8859-1')[:400]
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