Guido van Rossum | 70dc86f | 1994-05-03 14:15:01 +0000 | [diff] [blame] | 1 | # Generator implementation using threads |
| 2 | |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 3 | import sys |
Guido van Rossum | 70dc86f | 1994-05-03 14:15:01 +0000 | [diff] [blame] | 4 | import thread |
| 5 | |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 6 | class Killed(Exception): |
| 7 | pass |
Guido van Rossum | 70dc86f | 1994-05-03 14:15:01 +0000 | [diff] [blame] | 8 | |
| 9 | class Generator: |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 10 | # Constructor |
| 11 | def __init__(self, func, args): |
| 12 | self.getlock = thread.allocate_lock() |
| 13 | self.putlock = thread.allocate_lock() |
| 14 | self.getlock.acquire() |
| 15 | self.putlock.acquire() |
| 16 | self.func = func |
| 17 | self.args = args |
| 18 | self.done = 0 |
| 19 | self.killed = 0 |
| 20 | thread.start_new_thread(self._start, ()) |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 21 | |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 22 | # Internal routine |
| 23 | def _start(self): |
| 24 | try: |
| 25 | self.putlock.acquire() |
| 26 | if not self.killed: |
| 27 | try: |
| 28 | apply(self.func, (self,) + self.args) |
| 29 | except Killed: |
| 30 | pass |
| 31 | finally: |
| 32 | if not self.killed: |
| 33 | self.done = 1 |
| 34 | self.getlock.release() |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 35 | |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 36 | # Called by producer for each value; raise Killed if no more needed |
| 37 | def put(self, value): |
| 38 | if self.killed: |
| 39 | raise TypeError, 'put() called on killed generator' |
| 40 | self.value = value |
| 41 | self.getlock.release() # Resume consumer thread |
| 42 | self.putlock.acquire() # Wait for next get() call |
| 43 | if self.killed: |
| 44 | raise Killed |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 45 | |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 46 | # Called by producer to get next value; raise EOFError if no more |
| 47 | def get(self): |
| 48 | if self.killed: |
| 49 | raise TypeError, 'get() called on killed generator' |
| 50 | self.putlock.release() # Resume producer thread |
| 51 | self.getlock.acquire() # Wait for value to appear |
| 52 | if self.done: |
| 53 | raise EOFError # Say there are no more values |
| 54 | return self.value |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 55 | |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 56 | # Called by consumer if no more values wanted |
| 57 | def kill(self): |
| 58 | if self.killed: |
| 59 | raise TypeError, 'kill() called on killed generator' |
| 60 | self.killed = 1 |
| 61 | self.putlock.release() |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 62 | |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 63 | # Clone constructor |
| 64 | def clone(self): |
| 65 | return Generator(self.func, self.args) |
Guido van Rossum | 70dc86f | 1994-05-03 14:15:01 +0000 | [diff] [blame] | 66 | |
| 67 | def pi(g): |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 68 | k, a, b, a1, b1 = 2L, 4L, 1L, 12L, 4L |
| 69 | while 1: |
| 70 | # Next approximation |
| 71 | p, q, k = k*k, 2L*k+1L, k+1L |
| 72 | a, b, a1, b1 = a1, b1, p*a+q*a1, p*b+q*b1 |
| 73 | # Print common digits |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 74 | d, d1 = a//b, a1//b1 |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 75 | while d == d1: |
| 76 | g.put(int(d)) |
| 77 | a, a1 = 10L*(a%b), 10L*(a1%b1) |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 78 | d, d1 = a//b, a1//b1 |
Guido van Rossum | 70dc86f | 1994-05-03 14:15:01 +0000 | [diff] [blame] | 79 | |
| 80 | def test(): |
Tim Peters | 68a323c | 2004-07-18 16:56:37 +0000 | [diff] [blame] | 81 | g = Generator(pi, ()) |
| 82 | g.kill() |
| 83 | g = Generator(pi, ()) |
| 84 | for i in range(10): print g.get(), |
| 85 | print |
| 86 | h = g.clone() |
| 87 | g.kill() |
| 88 | while 1: |
| 89 | print h.get(), |
Andrew M. Kuchling | c2dc269 | 2008-09-13 01:27:33 +0000 | [diff] [blame] | 90 | sys.stdout.flush() |
Guido van Rossum | 70dc86f | 1994-05-03 14:15:01 +0000 | [diff] [blame] | 91 | |
| 92 | test() |