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	sfeed.c: optimize tag lookup by reverting the binary search to a linear lookup …
	git clone git://git.codemadness.org/sfeed
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	---
	commit 4d445d3e47de2d3e5b101c1a6520690d306a5d6c
	parent c2231c4b4f91a86df6192c9830235f3ca499810e
	Author: Hiltjo Posthuma <[email protected]>
	Date: Tue, 7 Jan 2025 19:51:15 +0100

	sfeed.c: optimize tag lookup by reverting the binary search to a linear lookup

	This removes an intended optimization.
	It was changed to bsearch() in commit 3031d855807de20fc86cd3dd2375ce9473e86947

	After some more testing: because the tags table is so small doing a linear scan
	over the table by first checking the length, and then (if needed) the tag name
	comparison is bit faster (6-11%), but of course depends on the input) in common
	cases than a binary search.

	In practise there is no noticable difference though.

	This simplifies the code a bit.

	Diffstat:
	M sfeed.c \| 33 +++++++++++++++--------------…

	1 file changed, 16 insertions(+), 17 deletions(-)
	---
	diff --git a/sfeed.c b/sfeed.c
	@@ -125,7 +125,7 @@ static void xmltagstart(XMLParser , const char , size_t);
	static void xmltagstartparsed(XMLParser , const char , size_t, int);

	/* map tag name to TagId type */
	-/* RSS, must be alphabetical order */
	+/* RSS, keep this in alphabetical order */
	static const FeedTag rsstags[] = {
	{ STRP("author"), RSSTagAuthor },
	{ STRP("category"), RSSTagCategory },
	@@ -142,7 +142,7 @@ static const FeedTag rsstags[] = {
	{ STRP("title"), RSSTagTitle }
	};

	-/* Atom, must be alphabetical order */
	+/* Atom, keep this in alphabetical order */
	static const FeedTag atomtags[] = {
	{ STRP("author"), AtomTagAuthor },
	{ STRP("category"), AtomTagCategory },
	@@ -212,34 +212,33 @@ static FeedContext ctx;
	static XMLParser parser; /* XML parser state */
	static String attrispermalink, attrrel, attrtype, tmpstr;

	-static int
	-tagcmp(const void v1, const void v2)
	-{
	- return strcasecmp(((FeedTag )v1)->name, ((FeedTag )v2)->name);
	-}
	-
	-/* Unique tagid for parsed tag name. */
	+/* Unique tag(id) for parsed tag name. */
	static FeedTag *
	gettag(enum FeedType feedtype, const char *name, size_t namelen)
	{
	- FeedTag f, *r = NULL;
	-
	- f.name = (char *)name;
	+ FeedTag *r;
	+ size_t i;

	switch (feedtype) {
	case FeedTypeRSS:
	- r = bsearch(&f, rsstags, sizeof(rsstags) / sizeof(rsstags[0]),
	- sizeof(rsstags[0]), tagcmp);
	+ for (i = 0; i < sizeof(rsstags) / sizeof(rsstags[0]); i++) {
	+ r = (FeedTag *)&rsstags[i];
	+ if (r->len == namelen && !strcasecmp(r->name, name))
	+ return r;
	+ }
	break;
	case FeedTypeAtom:
	- r = bsearch(&f, atomtags, sizeof(atomtags) / sizeof(atomtags[0…
	- sizeof(atomtags[0]), tagcmp);
	+ for (i = 0; i < sizeof(atomtags) / sizeof(atomtags[0]); i++) {
	+ r = (FeedTag *)&atomtags[i];
	+ if (r->len == namelen && !strcasecmp(r->name, name))
	+ return r;
	+ }
	break;
	default:
	break;
	}

	- return r;
	+ return NULL;
	}

	static char *