core: add get_picture_idx() function

A function that gets the index of a picture in a picture table
given its filename. Since we are going to identify pictures by
their filename, we will need this function in the undo code.

Use the function in the remove_picture() function.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

2 files changed, 15 insertions, 7 deletions

diff --git a/core/picture.c b/core/picture.c
index 727500afd..df1304ab8 100644
--- a/core/picture.c
+++ b/core/picture.c
@@ -58,14 +58,21 @@ void add_picture(struct picture_table *t, struct picture newpic)
 	add_to_picture_table(t, idx, newpic);
 }
 
-// Return true if picture was found and deleted
-bool remove_picture(struct picture_table *t, const char *filename)
+int get_picture_idx(const struct picture_table *t, const char *filename)
 {
 	for (int i = 0; i < t->nr; ++i) {
-		if (same_string(t->pictures[i].filename, filename)) {
-			remove_from_picture_table(t, i);
-			return true;
-		}
+		if (same_string(t->pictures[i].filename, filename))
+			return i;
 	}
-	return false;
+	return -1;
+}
+
+// Return true if picture was found and deleted
+bool remove_picture(struct picture_table *t, const char *filename)
+{
+	int idx = get_picture_idx(t, filename);
+	if (idx < 0)
+		return false;
+	remove_from_picture_table(t, idx);
+	return true;
 }
diff --git a/core/picture.h b/core/picture.h
index da1a42acd..4e42052a4 100644
--- a/core/picture.h
+++ b/core/picture.h
@@ -34,6 +34,7 @@ extern void add_to_picture_table(struct picture_table *, int idx, struct picture
 extern void copy_pictures(const struct picture_table *s, struct picture_table *d);
 extern void add_picture(struct picture_table *, struct picture newpic);
 extern bool remove_picture(struct picture_table *, const char *filename);
+extern int get_picture_idx(const struct picture_table *, const char *filename); /* Return -1 if not found */
 
 #ifdef __cplusplus
 }