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Current Path : /lib64/python2.7/Demo/threads/ |
Current File : //lib64/python2.7/Demo/threads/Generator.py |
# Generator implementation using threads import sys import thread class Killed(Exception): pass class Generator: # Constructor def __init__(self, func, args): self.getlock = thread.allocate_lock() self.putlock = thread.allocate_lock() self.getlock.acquire() self.putlock.acquire() self.func = func self.args = args self.done = 0 self.killed = 0 thread.start_new_thread(self._start, ()) # Internal routine def _start(self): try: self.putlock.acquire() if not self.killed: try: apply(self.func, (self,) + self.args) except Killed: pass finally: if not self.killed: self.done = 1 self.getlock.release() # Called by producer for each value; raise Killed if no more needed def put(self, value): if self.killed: raise TypeError, 'put() called on killed generator' self.value = value self.getlock.release() # Resume consumer thread self.putlock.acquire() # Wait for next get() call if self.killed: raise Killed # Called by producer to get next value; raise EOFError if no more def get(self): if self.killed: raise TypeError, 'get() called on killed generator' self.putlock.release() # Resume producer thread self.getlock.acquire() # Wait for value to appear if self.done: raise EOFError # Say there are no more values return self.value # Called by consumer if no more values wanted def kill(self): if self.killed: raise TypeError, 'kill() called on killed generator' self.killed = 1 self.putlock.release() # Clone constructor def clone(self): return Generator(self.func, self.args) def pi(g): k, a, b, a1, b1 = 2L, 4L, 1L, 12L, 4L while 1: # Next approximation p, q, k = k*k, 2L*k+1L, k+1L a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1 # Print common digits d, d1 = a//b, a1//b1 while d == d1: g.put(int(d)) a, a1 = 10L*(a%b), 10L*(a1%b1) d, d1 = a//b, a1//b1 def test(): g = Generator(pi, ()) g.kill() g = Generator(pi, ()) for i in range(10): print g.get(), print h = g.clone() g.kill() while 1: print h.get(), sys.stdout.flush() test()