[PATCH 6/8] grep: continue case insensitive fixed string search after NUL chars

["René Scharfe" <rene.scharfe@lsrfire.ath.cx>]

Functions for C strings, like strcasestr(), can't see beyond NUL
characters.  Check if there is such an obstacle on the line and try
again behind it.

Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx>
---
 grep.c                 |   12 +++++++++---
 t/t7008-grep-binary.sh |    4 ++++
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/grep.c b/grep.c
index c3affb6..b95803b 100644
--- a/grep.c
+++ b/grep.c
@@ -334,9 +334,15 @@ static int fixmatch(const char *pattern, char *line, char *eol,
 {
 	char *hit;
 
-	if (ignore_case)
-		hit = strcasestr(line, pattern);
-	else
+	if (ignore_case) {
+		char *s = line;
+		do {
+			hit = strcasestr(s, pattern);
+			if (hit)
+				break;
+			s += strlen(s) + 1;
+		} while (s < eol);
+	} else
 		hit = memmem(line, eol - line, pattern, strlen(pattern));
 
 	if (!hit) {
diff --git a/t/t7008-grep-binary.sh b/t/t7008-grep-binary.sh
index 9adc9ed..9660842 100755
--- a/t/t7008-grep-binary.sh
+++ b/t/t7008-grep-binary.sh
@@ -55,4 +55,8 @@ test_expect_success 'git grep -F ile a' '
 	git grep -F ile a
 '
 
+test_expect_success 'git grep -Fi iLE a' '
+	git grep -Fi iLE a
+'
+
 test_done
-- 
1.7.1