annotate pytouhou/utils/bitstream.py @ 56:299de3a9b69f

Filter out off-screen enemies (the same way the official game does)
author Thibaut Girka <thib@sitedethib.com>
date Tue, 23 Aug 2011 00:15:22 +0200
parents ab826bc29aa2
children ac2e5e1c2c3c
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1 # -*- encoding: utf-8 -*-
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2 ##
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3 ## Copyright (C) 2011 Thibaut Girka <thib@sitedethib.com>
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4 ##
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5 ## This program is free software; you can redistribute it and/or modify
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6 ## it under the terms of the GNU General Public License as published
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7 ## by the Free Software Foundation; version 3 only.
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8 ##
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9 ## This program is distributed in the hope that it will be useful,
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10 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
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11 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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12 ## GNU General Public License for more details.
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13 ##
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14
0
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15 class BitStream(object):
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16 def __init__(self, io):
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17 self.io = io
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18 self.bits = 0
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19 self.byte = 0
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20
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21
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22 def seek(self, offset, whence=0):
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23 self.io.seek(offset, whence)
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24 self.byte = 0
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25 self.bits = 0
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26
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27
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28 def tell(self):
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29 return self.io.tell()
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30
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31
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32 def tell2(self):
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33 return self.io.tell(), self.bits
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34
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35
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36 def read_bit(self):
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37 if not self.bits:
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38 self.byte = ord(self.io.read(1))
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39 self.bits = 8
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40 self.bits -= 1
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41 return (self.byte >> self.bits) & 0x01
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42
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43
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44 def read(self, nb_bits):
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45 value = 0
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46 for i in range(nb_bits - 1, -1, -1):
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47 value |= self.read_bit() << i
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48 return value
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49
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50
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51 def write_bit(self, bit):
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52 if self.bits == 8:
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53 self.io.write(chr(self.byte))
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54 self.bits = 0
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55 self.byte = 0
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56 self.byte &= ~(1 << (7 - self.bits))
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57 self.byte |= bit << (7 - self.bits)
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58 self.bits += 1
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59
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60
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61 def write(self, bits, nb_bits):
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62 for i in range(nb_bits):
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63 self.write_bit(bits >> (nb_bits - 1 - i) & 0x01)
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64
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65
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66 def flush(self):
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67 self.io.write(chr(self.byte))
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68 self.bits = 0
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69 self.byte = 0
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70 self.io.flush()
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