Fix BLI_path_frame_strip

The `BLI_path_frame_strip` function was completely broken, unless the
number of digits in the sequence number was the same as the length of
the extension. In other words, it would work fine for `file.0001.abc` (4
digit `0001` and 4 char `.abc`), but other combinations would truncate
to the shortest (`file.001.abc` would become `file.###.ab` and
`file.00001.a` would become `file.##.a`). The dependency between the
sequence number and the file extension is now removed.

The behaviour has changed a little bit in the case where there are no
numbers in the filename. Previously, `path="filename.abc"` would result
in `path="filename.abc"` and `ext=""`, but now it results in
`path="filename"` and `ext=".abc"`. This way `ext` always contains the
extension, and the behaviour is consistent regardless of whether there
were any numbers found.

Furthermore, I've removed the `bool set_frame_char` parameter, because
it was unclear, probably also buggy, and most importantly, never used.

I've also added a unit test for the `BLI_path_frame_strip` function.

1 files changed, 8 insertions, 10 deletions

diff --git a/source/blender/blenlib/intern/path_util.c b/source/blender/blenlib/intern/path_util.c
index 77b137a9d6d..6d69f29a228 100644
--- a/source/blender/blenlib/intern/path_util.c
+++ b/source/blender/blenlib/intern/path_util.c
@@ -862,7 +862,7 @@ bool BLI_path_frame_get(char *path, int *r_frame, int *r_numdigits)
 	return false;
 }
 
-void BLI_path_frame_strip(char *path, bool set_frame_char, char *ext)
+void BLI_path_frame_strip(char *path, char *r_ext)
 {
 	if (*path) {
 		char *file = (char *)BLI_last_slash(path);
@@ -896,16 +896,14 @@ void BLI_path_frame_strip(char *path, bool set_frame_char, char *ext)
 
 		c++;
 
-		if (numdigits) {
-			/* replace the number with the suffix and terminate the string */
-			while (numdigits--) {
-				*ext++ = *suffix;
-				*c++ = set_frame_char ? '#' : *suffix;
-				suffix++;
-			}
-			*c = '\0';
-			*ext = '\0';
+		int suffix_length = len - (suffix - file);
+		BLI_strncpy(r_ext, suffix, suffix_length+1);
+
+		/* replace the number with the suffix and terminate the string */
+		while (numdigits--) {
+			*c++ = '#';
 		}
+		*c = '\0';
 	}
 }