1 files changed, 24 insertions, 0 deletions
diff --git a/compat/win32/path-utils.c b/compat/win32/path-utils.c
index d9d3641de85..ebf2f12eb66 100644
--- a/compat/win32/path-utils.c
+++ b/compat/win32/path-utils.c
@@ -1,5 +1,29 @@
 #include "../../git-compat-util.h"
 
+int win32_has_dos_drive_prefix(const char *path)
+{
+	int i;
+
+	/*
+	 * Does it start with an ASCII letter (i.e. highest bit not set),
+	 * followed by a colon?
+	 */
+	if (!(0x80 & (unsigned char)*path))
+		return *path && path[1] == ':' ? 2 : 0;
+
+	/*
+	 * While drive letters must be letters of the English alphabet, it is
+	 * possible to assign virtually _any_ Unicode character via `subst` as
+	 * a drive letter to "virtual drives". Even `1`, or `ä`. Or fun stuff
+	 * like this:
+	 *
+	 *      subst ֍: %USERPROFILE%\Desktop
+	 */
+	for (i = 1; i < 4 && (0x80 & (unsigned char)path[i]); i++)
+		; /* skip first UTF-8 character */
+	return path[i] == ':' ? i + 1 : 0;
+}
+
 int win32_skip_dos_drive_prefix(char **path)
 {
 	int ret = has_dos_drive_prefix(*path);