New asynchat.py from Sam Rushing: this foregoes using the regex module
to find the prefix of strings, thus removing a warning, and simply
uses straightforward string slicing.
diff --git a/Lib/asynchat.py b/Lib/asynchat.py
index cc5fc38..0ce5f43 100644
--- a/Lib/asynchat.py
+++ b/Lib/asynchat.py
@@ -1,5 +1,5 @@
# -*- Mode: Python; tab-width: 4 -*-
-# Id: asynchat.py,v 2.25 1999/11/18 11:01:08 rushing Exp
+# Id: asynchat.py,v 2.26 2000/09/07 22:29:26 rushing Exp
# Author: Sam Rushing <rushing@nightmare.com>
# ======================================================================
@@ -279,40 +279,16 @@
# f_p_a_e ("qwertydkjf", "\r\n") => 0
# this could maybe be made faster with a computed regex?
-
-##def find_prefix_at_end (haystack, needle):
-## nl = len(needle)
-## result = 0
-## for i in range (1,nl):
-## if haystack[-(nl-i):] == needle[:(nl-i)]:
-## result = nl-i
-## break
-## return result
-
-# yes, this is about twice as fast, but still seems
-# to be negligible CPU. The previous version could do about 290
-# searches/sec. the new one about 555/sec.
-
-import regex
-
-prefix_cache = {}
-
-def prefix_regex (needle):
- if prefix_cache.has_key (needle):
- return prefix_cache[needle]
- else:
- reg = needle[-1]
- for i in range(1,len(needle)):
- reg = '%c\(%s\)?' % (needle[-(i+1)], reg)
- reg = regex.compile (reg+'$')
- prefix_cache[needle] = reg, len(needle)
- return reg, len(needle)
+# [answer: no; circa Python-2.0, Jan 2001]
+# python: 18307/s
+# re: 12820/s
+# regex: 14035/s
def find_prefix_at_end (haystack, needle):
- reg, length = prefix_regex (needle)
- lh = len(haystack)
- result = reg.search (haystack, max(0,lh-length))
- if result >= 0:
- return (lh - result)
- else:
- return 0
+ nl = len(needle)
+ result = 0
+ for i in range (1,nl):
+ if haystack[-(nl-i):] == needle[:(nl-i)]:
+ result = nl-i
+ break
+ return result