139 lines
4.6 KiB
Python
Executable File
139 lines
4.6 KiB
Python
Executable File
# The contents of this file are subject to the BitTorrent Open Source License
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# Version 1.1 (the License). You may not copy or use this file, in either
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# source code or executable form, except in compliance with the License. You
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# may obtain a copy of the License at http://www.bittorrent.com/license/.
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#
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# Software distributed under the License is distributed on an AS IS basis,
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# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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# for the specific language governing rights and limitations under the
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# License.
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# Written by Bram Cohen
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from random import randrange, shuffle, choice
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class PiecePicker(object):
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def __init__(self, numpieces, config):
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self.config = config
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self.numpieces = numpieces
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self.interests = [range(numpieces)]
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self.pos_in_interests = range(numpieces)
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self.numinterests = [0] * numpieces
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self.have = [False] * numpieces
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self.crosscount = [numpieces]
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self.started = []
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self.seedstarted = []
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self.numgot = 0
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self.scrambled = range(numpieces)
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shuffle(self.scrambled)
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def got_have(self, piece):
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numint = self.numinterests[piece]
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self.crosscount[numint + self.have[piece]] -= 1
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self.numinterests[piece] += 1
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try:
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self.crosscount[numint + 1 + self.have[piece]] += 1
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except IndexError:
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self.crosscount.append(1)
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if self.have[piece]:
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return
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if numint == len(self.interests) - 1:
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self.interests.append([])
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self._shift_over(piece, self.interests[numint], self.interests[numint + 1])
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def lost_have(self, piece):
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numint = self.numinterests[piece]
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self.crosscount[numint + self.have[piece]] -= 1
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self.numinterests[piece] -= 1
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self.crosscount[numint - 1 + self.have[piece]] += 1
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if self.have[piece]:
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return
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self._shift_over(piece, self.interests[numint], self.interests[numint - 1])
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def _shift_over(self, piece, l1, l2):
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p = self.pos_in_interests[piece]
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l1[p] = l1[-1]
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self.pos_in_interests[l1[-1]] = p
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del l1[-1]
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newp = randrange(len(l2) + 1)
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if newp == len(l2):
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self.pos_in_interests[piece] = len(l2)
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l2.append(piece)
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else:
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old = l2[newp]
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self.pos_in_interests[old] = len(l2)
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l2.append(old)
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l2[newp] = piece
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self.pos_in_interests[piece] = newp
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def requested(self, piece, seed = False):
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if piece not in self.started:
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self.started.append(piece)
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if seed and piece not in self.seedstarted:
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self.seedstarted.append(piece)
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def complete(self, piece):
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assert not self.have[piece]
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self.have[piece] = True
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self.crosscount[self.numinterests[piece]] -= 1
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try:
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self.crosscount[self.numinterests[piece] + 1] += 1
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except IndexError:
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self.crosscount.append(1)
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self.numgot += 1
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l = self.interests[self.numinterests[piece]]
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p = self.pos_in_interests[piece]
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l[p] = l[-1]
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self.pos_in_interests[l[-1]] = p
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del l[-1]
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try:
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self.started.remove(piece)
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self.seedstarted.remove(piece)
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except ValueError:
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pass
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def next(self, havefunc, seed = False):
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bests = None
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bestnum = 2 ** 30
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if seed:
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s = self.seedstarted
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else:
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s = self.started
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for i in s:
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if havefunc(i):
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if self.numinterests[i] < bestnum:
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bests = [i]
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bestnum = self.numinterests[i]
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elif self.numinterests[i] == bestnum:
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bests.append(i)
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if bests:
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return choice(bests)
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if self.numgot < self.config['rarest_first_cutoff']:
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for i in self.scrambled:
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if havefunc(i):
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return i
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return None
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for i in xrange(1, min(bestnum, len(self.interests))):
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for j in self.interests[i]:
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if havefunc(j):
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return j
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return None
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def am_I_complete(self):
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return self.numgot == self.numpieces
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def bump(self, piece):
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l = self.interests[self.numinterests[piece]]
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pos = self.pos_in_interests[piece]
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del l[pos]
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l.append(piece)
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for i in range(pos,len(l)):
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self.pos_in_interests[l[i]] = i
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try:
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self.started.remove(piece)
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self.seedstarted.remove(piece)
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except ValueError:
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pass
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