branch: externals/compat
commit a6a33ee2fae38857624fc43143a73bcddc9814b7
Author: Daniel Mendler <[email protected]>
Commit: Philip Kaludercic <[email protected]>
string-width: Optimize computation of whole string width
This optimization is important since the allocation is avoided in
particular if no FROM and TO arguments are passed.
---
compat-28.el | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/compat-28.el b/compat-28.el
index 862dd08b71..e94ac9750e 100644
--- a/compat-28.el
+++ b/compat-28.el
@@ -145,7 +145,12 @@ continuing as if the error did not occur."
Optional arguments FROM and TO specify the substring of STRING to
consider, and are interpreted as in `substring'."
:prefix t
- (string-width (substring string (or from 0) to)))
+ (let* ((len (length string))
+ (from (or from 0))
+ (to (or to len)))
+ (if (and (= from 0) (= to len))
+ (string-width string)
+ (string-width (substring string from to)))))
;;;; Defined in dired.c
