From: Ralph Corderoy <ralph@inputplus.co.uk>
Date: Sun, 13 Aug 2017 15:33:06 +0000 (+0100)
Subject: scan(): Don't ioctl(2) for TTY's width every call.
X-Git-Url: https://diplodocus.org/git/nmh/commitdiff_plain/7d81fd0ae7fc14189d7758c78a5168921c7ef11b?ds=inline

scan(): Don't ioctl(2) for TTY's width every call.

Saves a system call per message scanned.  Does mean it won't adjust
should the terminal width change mid scan, but that seems fine;  after
all, the retrieved width could be out of date by the time a message's
output is written anyway.
---

diff --git a/uip/scansbr.c b/uip/scansbr.c
index df9ef645..24609d26 100644
--- a/uip/scansbr.c
+++ b/uip/scansbr.c
@@ -48,6 +48,8 @@ int
 scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
       int unseen, char *folder, long size, int noisy, charstring_t *scanl)
 {
+    static bool deja_vu;
+    static int tty_width;
     int i, compnum, encrypted, state;
     char *cp, *tmpbuf, *startbody, **nxtbuf;
     char *saved_c_text = NULL;
@@ -64,9 +66,12 @@ scan (FILE *inb, int innum, int outnum, char *nfs, int width, int curflg,
        scanl used to be a global. */
     if (! *scanl) {
 	if (width == -1) {
-	    /* Default:  width of the terminal, but at least WIDTH/2. */
-	    if ((width = sc_width ()) < WIDTH/2)
-		width = WIDTH/2;
+            if (!deja_vu) {
+                deja_vu = true;
+                tty_width = sc_width();
+            }
+
+            width = max(tty_width, WIDTH / 2);
 	} else if (width == 0) {
 	    /* Unlimited width. */
 	    width = INT_MAX;