[Patches] [ python-Patches-977553 ] Speed up EnumKey call

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Patches item #977553, was opened at 2004-06-22 15:22
Message generated for change (Comment added) made by garth42
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Category: Windows
Group: Python 2.4
Status: Open
Resolution: None
Priority: 5
Submitted By: Garth Bushell (garth42)
Assigned to: Nobody/Anonymous (nobody)
Summary: Speed up EnumKey call

Initial Comment:
This patch removes the RegQueryInfoKey call and
replaces it with a call to EnumKeyEx. This greatly
speeds up this call. 

The script below times 

python 2.3              5531 89.7130000591
python 2.4 +patch   5531 0.0469999313354

start = time.time()
i = 0
try:
  while 1:
    _winreg.EnumKey(_winreg.HKEY_CLASSES_ROOT, i)
    i += 1
except WindowsError:
  pass
print i, time.time() - start


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>Comment By: Garth Bushell (garth42)
Date: 2004-07-14 16:12

Message:
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mmangino: 

Yes you're correct it should be 256 in both cases. Doh! I'll
attach a new patch in a while. but It's easy to mmodify the
patch and up the linit to 256

theller:

The advantage of the latter is it returns the Length of the
string returned so we can pass it straight back to the
string creation funtion in python without a strlen.

also the SDK says this....

Note  This function is provided only for compatibility with
16-bit versions of Windows. Applications should use the
RegEnumKeyEx function.



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Comment By: Thomas Heller (theller)
Date: 2004-07-14 15:54

Message:
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I'm curious: Why did you replace RegEnumKey with
RegEnumKeyEx? Are there any advantages of the latter?

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Comment By: Mike Mangino (mmangino)
Date: 2004-07-14 14:12

Message:
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This looks good to me, but I think the buffer size is off by
one. I read the SDK to say tha they key can be 255
characters. That means you need to allocate 256 characters
to allow for the null terminator. Could you create a test
case for a max length registry key?

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