patch 9.1.1151: too many strlen() calls in getchar.c

Problem:  too many strlen() calls in getchar.c
Solution: store last inserted and recorded lengths,
          add functions to retrieve those and use those
          functions (John Marriott)

closes: #16720

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/getchar.c b/src/getchar.c
index 83a9861..3b4aad0 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -88,6 +88,11 @@
 
 static size_t	last_recorded_len = 0;	// number of last recorded chars
 
+static size_t	last_get_recorded_len = 0;	// length of the string returned from the
+						// last call to get_recorded()
+static size_t	last_get_inserted_len = 0;	// length of the string returned from the
+						// last call to get_inserted()
+
 #ifdef FEAT_EVAL
 mapblock_T	*last_used_map = NULL;
 int		last_used_sid = -1;
@@ -168,39 +173,63 @@
 get_recorded(void)
 {
     char_u	*p;
-    size_t	len;
 
-    p = get_buffcont(&recordbuff, TRUE, &len);
+    p = get_buffcont(&recordbuff, TRUE, &last_get_recorded_len);
+    if (p == NULL)
+	return NULL;
+
     free_buff(&recordbuff);
 
     /*
      * Remove the characters that were added the last time, these must be the
      * (possibly mapped) characters that stopped the recording.
      */
-    if (len >= last_recorded_len)
+    if (last_get_recorded_len >= last_recorded_len)
     {
-	len -= last_recorded_len;
-	p[len] = NUL;
+	last_get_recorded_len -= last_recorded_len;
+	p[last_get_recorded_len] = NUL;
     }
 
     /*
      * When stopping recording from Insert mode with CTRL-O q, also remove the
      * CTRL-O.
      */
-    if (len > 0 && restart_edit != 0 && p[len - 1] == Ctrl_O)
-	p[len - 1] = NUL;
+    if (last_get_recorded_len > 0 && restart_edit != 0
+				    && p[last_get_recorded_len - 1] == Ctrl_O)
+    {
+	--last_get_recorded_len;
+	p[last_get_recorded_len] = NUL;
+    }
 
     return (p);
 }
 
 /*
+ * Return the length of string returned from the last call of get_recorded().
+ */
+    size_t
+get_recorded_len(void)
+{
+    return last_get_recorded_len;
+}
+
+/*
  * Return the contents of the redo buffer as a single string.
  * K_SPECIAL and CSI in the returned string are escaped.
  */
     char_u *
 get_inserted(void)
 {
-    return get_buffcont(&redobuff, FALSE, NULL);
+    return get_buffcont(&redobuff, FALSE, &last_get_inserted_len);
+}
+
+/*
+ * Return the length of string returned from the last call of get_inserted().
+ */
+    size_t
+get_inserted_len(void)
+{
+    return last_get_inserted_len;
 }
 
 /*