Message 195240 - Python tracker

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Author	vstinner
Recipients	christian.heimes, eric.snow, lemburg, pitrou, rhettinger, serhiy.storchaka, vstinner
Date	2013-08-15.09:22:11
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1376558531.72.0.562797703026.issue17628@psf.upfronthosting.co.za>
In-reply-to

Content
In issue #18719, Raymond modified Python 2.7, but he didn't touch the following macro: #define Py_UNICODE_MATCH(string, offset, substring) \ ((((string)->str + (offset)) == ((substring)->str)) && \ ((((string)->str + (offset) + (substring)->length-1) == ((substring)->str + (substring)->length-1))) && \ !memcmp((string)->str + (offset), (substring)->str, (substring)->length*sizeof(Py_UNICODE))) It was said that looking for the last character before calling memcmp() is inefficient for the CPU cache. This macro should also be modified.

In issue #18719, Raymond modified Python 2.7, but he didn't touch the following macro:

#define Py_UNICODE_MATCH(string, offset, substring) \
    ((*((string)->str + (offset)) == *((substring)->str)) && \
    ((*((string)->str + (offset) + (substring)->length-1) == *((substring)->str + (substring)->length-1))) && \
     !memcmp((string)->str + (offset), (substring)->str, (substring)->length*sizeof(Py_UNICODE)))

It was said that looking for the last character before calling memcmp() is inefficient for the CPU cache. This macro should also be modified.

History
Date	User	Action	Args
2013-08-15 09:22:11	vstinner	set	recipients: + vstinner, lemburg, rhettinger, pitrou, christian.heimes, eric.snow, serhiy.storchaka
2013-08-15 09:22:11	vstinner	set	messageid: <1376558531.72.0.562797703026.issue17628@psf.upfronthosting.co.za>
2013-08-15 09:22:11	vstinner	link	issue17628 messages
2013-08-15 09:22:11	vstinner	create