[PATCH v3 05/13] match_{base,path}name: replace strncmp_icase with memequal_icase

["Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>]

treat_leading_path:   0.000  0.000
read_directory:       3.578  3.501
+treat_one_path:      2.323  2.257
++is_excluded:        2.117  2.056
+++prep_exclude:      0.224  0.216
+++matching:          1.544  1.493
++dir_exist:          0.035  0.035
++index_name_exists:  0.290  0.292
lazy_init_name_hash:  0.258  0.256
+simplify_away:       0.087  0.084
+dir_add_name:        0.445  0.447

Suggested-by: Fredrik Gustafsson <iveqy@iveqy.com>
Suggested-by: Antoine Pelisse <apelisse@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 dir.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/dir.c b/dir.c
index a2ab200..26c3b3a 100644
--- a/dir.c
+++ b/dir.c
@@ -47,6 +47,29 @@ static int read_directory_recursive(struct dir_struct *dir, const char *path, in
 	int check_only, const struct path_simplify *simplify);
 static int get_dtype(struct dirent *de, const char *path, int len);
 
+static inline int memequal_icase(const char *a, const char *b, int n)
+{
+	if (!memcmp(a, b, n))
+		return 1;
+
+	if (!ignore_case)
+		return 0;
+
+	/*
+	 * This assumes that ASCII is used in most repositories. We
+	 * try the ascii-only version first (i.e. Git's
+	 * toupper). Failing that, fall back to normal strncasecmp.
+	 */
+	while (n && toupper(*a) == toupper(*b)) {
+		a++;
+		b++;
+		n--;
+	}
+	if (!n)
+		return 1;
+	return !strncasecmp(a, b, n);
+}
+
 inline int git_fnmatch(const char *pattern, const char *string,
 		       int flags, int prefix)
 {
@@ -637,11 +660,11 @@ int match_basename(const char *basename, int basenamelen,
 {
 	if (prefix == patternlen) {
 		if (patternlen == basenamelen &&
-		    !strncmp_icase(pattern, basename, patternlen))
+		    memequal_icase(pattern, basename, patternlen))
 			return 1;
 	} else if (flags & EXC_FLAG_ENDSWITH) {
 		if (patternlen - 1 <= basenamelen &&
-		    !strncmp_icase(pattern + 1,
+		    memequal_icase(pattern + 1,
 				   basename + basenamelen - patternlen + 1,
 				   patternlen - 1))
 			return 1;
@@ -675,7 +698,7 @@ int match_pathname(const char *pathname, int pathlen,
 	 */
 	if (pathlen < baselen + 1 ||
 	    (baselen && (pathname[baselen] != '/' ||
-			 strncmp_icase(pathname, base, baselen))))
+			 !memequal_icase(pathname, base, baselen))))
 		return 0;
 
 	namelen = baselen ? pathlen - baselen - 1 : pathlen;
@@ -689,7 +712,7 @@ int match_pathname(const char *pathname, int pathlen,
 		if (prefix > namelen)
 			return 0;
 
-		if (strncmp_icase(pattern, name, prefix))
+		if (!memequal_icase(pattern, name, prefix))
 			return 0;
 		pattern += prefix;
 		name    += prefix;
-- 
1.8.1.2.536.gf441e6d