netdev - [PATCH net-next 5/5] lib/ts_bm: add helper to reduce indentation and improve readability

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Message-ID: <20230727133604.8275-6-fw@strlen.de>
Date: Thu, 27 Jul 2023 15:36:00 +0200
From: Florian Westphal <fw@...len.de>
To: <netdev@...r.kernel.org>
Cc: Paolo Abeni <pabeni@...hat.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	<netfilter-devel@...r.kernel.org>,
	Jeremy Sowden <jeremy@...zel.net>
Subject: [PATCH net-next 5/5] lib/ts_bm: add helper to reduce indentation and improve readability

From: Jeremy Sowden <jeremy@...zel.net>

The flow-control of `bm_find` is very deeply nested with a conditional
comparing a ternary expression against the pattern inside a for-loop
inside a while-loop inside a for-loop.

Move the inner for-loop into a helper function to reduce the amount of
indentation and make the code easier to read.

Fix indentation and trailing white-space in preceding debug logging
statement.

Signed-off-by: Jeremy Sowden <jeremy@...zel.net>
Signed-off-by: Florian Westphal <fw@...len.de>
---
 lib/ts_bm.c | 43 ++++++++++++++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 13 deletions(-)

diff --git a/lib/ts_bm.c b/lib/ts_bm.c
index c8ecbf74ef29..e5f30f9177df 100644
--- a/lib/ts_bm.c
+++ b/lib/ts_bm.c
@@ -55,6 +55,24 @@ struct ts_bm
 	unsigned int	good_shift[];
 };
 
+static unsigned int matchpat(const u8 *pattern, unsigned int patlen,
+			     const u8 *text, bool icase)
+{
+	unsigned int i;
+
+	for (i = 0; i < patlen; i++) {
+		u8 t = *(text-i);
+
+		if (icase)
+			t = toupper(t);
+
+		if (t != *(pattern-i))
+			break;
+	}
+
+	return i;
+}
+
 static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)
 {
 	struct ts_bm *bm = ts_config_priv(conf);
@@ -72,19 +90,18 @@ static unsigned int bm_find(struct ts_config *conf, struct ts_state *state)
 			break;
 
 		while (shift < text_len) {
-			DEBUGP("Searching in position %d (%c)\n", 
-				shift, text[shift]);
-			for (i = 0; i < bm->patlen; i++) 
-				if ((icase ? toupper(text[shift-i])
-				    : text[shift-i])
-					!= bm->pattern[bm->patlen-1-i])
-				     goto next;
-
-			/* London calling... */
-			DEBUGP("found!\n");
-			return consumed + (shift-(bm->patlen-1));
-
-next:			bs = bm->bad_shift[text[shift-i]];
+			DEBUGP("Searching in position %d (%c)\n",
+			       shift, text[shift]);
+
+			i = matchpat(&bm->pattern[bm->patlen-1], bm->patlen,
+				     &text[shift], icase);
+			if (i == bm->patlen) {
+				/* London calling... */
+				DEBUGP("found!\n");
+				return consumed + (shift-(bm->patlen-1));
+			}
+
+			bs = bm->bad_shift[text[shift-i]];
 
 			/* Now jumping to... */
 			shift = max_t(int, shift-i+bs, shift+bm->good_shift[i]);
-- 
2.41.0