>Hrvoje Niksic <hn*****@xemacs.orgwrote:It's a bit nice that using cStringIO doesn't rely on a very esoteric> Nick Craig-Wood <ni**@craig-wood.comwrites:
What you are missing is that if the recv ever returns no bytes at all
then the other end has closed the connection. So something like this
is the correct thing to write :-
data = ""
while True:
new = client.recv(256)
if not new:
break
data += new
This is a good case for the iter() function:
buf = cStringIO.StringIO()
for new in iter(partial(client.recv, 256), ''):
buf.write(new)
data = buf.getvalue()
Note that appending to a string is almost never a good idea, since it
can result in quadratic allocation.
My aim was clear exposition rather than the ultimate performance!
Anyway str += was optimised in python 2.4 or 2.5 (forget which) wasn't
it? I'm not convinced it will be any worse performing than
cStringIO.StringIO.write() which effectively appends to a string in
exactly the same way.
This test agrees with me!
$ python -m timeit -s 's = ""' 'for i in xrange(100000): s+="x"'
10 loops, best of 3: 23.8 msec per loop
$ python -m timeit -s 'from cStringIO import StringIO; s=StringIO()' 'for i in xrange(100000): s.write("x")'
10 loops, best of 3: 56 msec per loop
optimization in the CPython eval loop, as well as on what references
happen to exist to what objects. For example, one might want to use a
debugger without falling back to the quadratic behavior of repeated
string concatenation. cStringIO wins out in this case.
Jean-Paul
