On 31 May 2015 at 11:46, Lex Trotman elextr@gmail.com wrote:
On 31 May 2015 at 08:05, Thomas Martitz kugel@rockbox.org wrote:
Am 30.05.2015 um 03:19 schrieb Matthew Brush:
Just because it's such a trivial search algorithm, using strstr() is much more simple and probably more efficient than using Scintilla's API to find text, but if manual and automatic mode is supported, it would make sense to share the existing code, and that beats out advantage having a redundant (yet simpler/faster) routine to do same, IMO. +1 (if it's not too much hassle to refactor "Mark All").
What makes you think naive strstr() based search is faster/more efficient than whatever Scintilla does?
I haven't looked actually, but I'd think it does the same (probably using C++ strings), or something smarter like KMP mentioned in this thread or whatever the C++ template library provides. But I don't think it does anything slower than the most trivial strstr() method.
Scintilla uses its own home rolled gap buffer, not C++ strings (for the text and styles). For plain case sensitive "find text" it uses the naive algorithm, but each char from the buffer is accessed by Document::charat() which will probably inline as its in the header and its only a call to CellBuffer::charat() which probably won't inline since its in the cxx file not the header and which calls SplitVector::charat() which is in the header and may or may not inline due to its size (15 lines).
So its almost certainly slower than strstr().
And on my system strstr() is a builtin that can use any hardware support available.
But to be able to use strstr() (or any other algorithm that needs contiguous text) the gap needs to be closed, so a large block of text and styles need copying, which is done by memmove() which I think uses intrinsics if available so it probably runs at memory speed so its fast. But its something else that complicates comparing speeds :)
Essentially the only way to tell is to try benchmarks for a (hopefully) representative set of cases.
Cheers Lex
Best regards.
Devel mailing list Devel@lists.geany.org https://lists.geany.org/cgi-bin/mailman/listinfo/devel