Create internal strcmp variants for function ptrs

Using the builtin strcmp and strcasecmp as function pointers is
problematic on win32.  This adds internal implementations and
divorces us from the platform linkage.

4 files changed, 43 insertions, 8 deletions

diff --git a/src/diff.c b/src/diff.c
index 6f48d72a2..d944c65e2 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -551,15 +551,15 @@ static int diff_list_init_from_iterators(
 	if (!old_iter->ignore_case && !new_iter->ignore_case) {
 		diff->opts.flags &= ~GIT_DIFF_DELTAS_ARE_ICASE;
 
-		diff->strcomp    = strcmp;
-		diff->strncomp   = strncmp;
+		diff->strcomp    = git__strcmp;
+		diff->strncomp   = git__strncmp;
 		diff->pfxcomp    = git__prefixcmp;
 		diff->entrycomp  = git_index_entry__cmp;
 	} else {
 		diff->opts.flags |= GIT_DIFF_DELTAS_ARE_ICASE;
 
-		diff->strcomp    = strcasecmp;
-		diff->strncomp   = strncasecmp;
+		diff->strcomp    = git__strcasecmp;
+		diff->strncomp   = git__strncasecmp;
 		diff->pfxcomp    = git__prefixcmp_icase;
 		diff->entrycomp  = git_index_entry__cmp_icase;
 	}
diff --git a/src/pathspec.c b/src/pathspec.c
index 9632f5f13..fc6547afe 100644
--- a/src/pathspec.c
+++ b/src/pathspec.c
@@ -122,11 +122,11 @@ bool git_pathspec_match_path(
 		fnmatch_flags = FNM_CASEFOLD;
 
 	if (casefold) {
-		use_strcmp  = strcasecmp;
-		use_strncmp = strncasecmp;
+		use_strcmp  = git__strcasecmp;
+		use_strncmp = git__strncasecmp;
 	} else {
-		use_strcmp  = strcmp;
-		use_strncmp = strncmp;
+		use_strcmp  = git__strcmp;
+		use_strncmp = git__strncmp;
 	}
 
 	git_vector_foreach(vspec, i, match) {
diff --git a/src/util.c b/src/util.c
index 7f5043817..3a08d4554 100644
--- a/src/util.c
+++ b/src/util.c
@@ -174,6 +174,36 @@ int git__strtol32(int32_t *result, const char *nptr, const char **endptr, int ba
 	return error;
 }
 
+int git__strcmp(const char *a, const char *b)
+{
+	while (*a && *b && *a == *b)
+		++a, ++b;
+	return (int)(*(const unsigned char *)a) - (int)(*(const unsigned char *)b);
+}
+
+int git__strcasecmp(const char *a, const char *b)
+{
+	while (*a && *b && tolower(*a) == tolower(*b))
+		++a, ++b;
+	return (tolower(*a) - tolower(*b));
+}
+
+int git__strncmp(const char *a, const char *b, size_t sz)
+{
+	while (sz && *a && *b && *a == *b)
+		--sz, ++a, ++b;
+	if (!sz)
+		return 0;
+	return (int)(*(const unsigned char *)a) - (int)(*(const unsigned char *)b);
+}
+
+int git__strncasecmp(const char *a, const char *b, size_t sz)
+{
+	while (sz && *a && *b && tolower(*a) == tolower(*b))
+		--sz, ++a, ++b;
+	return !sz ? 0 : (tolower(*a) - tolower(*b));
+}
+
 void git__strntolower(char *str, size_t len)
 {
 	size_t i;
diff --git a/src/util.h b/src/util.h
index 23d4bc6e9..cb1c4fdc2 100644
--- a/src/util.h
+++ b/src/util.h
@@ -134,6 +134,11 @@ extern int git__bsearch(
 
 extern int git__strcmp_cb(const void *a, const void *b);
 
+extern int git__strcmp(const char *a, const char *b);
+extern int git__strcasecmp(const char *a, const char *b);
+extern int git__strncmp(const char *a, const char *b, size_t sz);
+extern int git__strncasecmp(const char *a, const char *b, size_t sz);
+
 typedef struct {
 	short refcount;
 	void *owner;