top: tweak scroll coordinates msg handling (again)

An earlier commit improved the scroll coordinates
message performance by offloading most of the work
to those occasions when column headers were rebuilt.

The only remaining per-frame costs were the addition
of some terminfo escapes and the Frame_maxtask count.

This commit further reduces those per-frame costs to
the absolute minimum.

Reference:
commit fbfaa868babb0974c799d45e208619412afbdfef

Signed-off-by: Jim Warner <james.warner@comcast.net>

diff --git a/top/top.c b/top/top.c
index debe6cdd89fc1787d380aa59b7c2ad5cf30860a6..2b3fc4204996a2d1deac5b3309ea57c6d2b1d270 100644 (file)
--- a/top/top.c
+++ b/top/top.c
@@ -695,10 +695,7 @@ static int show_pmt (const char *str) {
         /*
          * Show a special coordinate message, in support of scrolling */
 static inline void show_scroll (void) {
-   char tmp[SMLBUFSIZ];
-
-   snprintf(tmp, sizeof(tmp), Scroll_fmts, Frame_maxtask);
-   PUTT("%s%s  %.*s%s", tg2(0, Msg_row), Caps_off, Screen_cols - 2, tmp, Cap_clr_eol);
+   PUTT(Scroll_fmts, tg2(0, Msg_row), Frame_maxtask);
    putp(tg2(0, Msg_row));
 } // end: show_scroll
 
@@ -795,11 +792,9 @@ static void show_special (int interact, const char *glob) {
 
         /*
          * Create a nearly complete scroll coordinates message, but still
-         * technically a format string since we're missing total tasks. */
+         * a format string since we'll be missing a tgoto and total tasks. */
 static void updt_scroll_msg (void) {
-#ifndef SCROLLVAR_NO
-   char tmp[SMLBUFSIZ];
-#endif
+   char tmp1[SMLBUFSIZ], tmp2[SMLBUFSIZ];
    int totpflgs = Curwin->totpflgs;
    int begpflgs = Curwin->begpflg + 1;
 
@@ -811,14 +806,15 @@ static void updt_scroll_msg (void) {
 #endif
    if (1 > totpflgs) totpflgs = 1;
    if (1 > begpflgs) begpflgs = 1;
-   snprintf(Scroll_fmts, sizeof(Scroll_fmts)
-      , N_fmt(SCROLL_coord_fmt)
-      , Curwin->begtask + 1
-      , begpflgs, totpflgs);
+   snprintf(tmp1, sizeof(tmp1)
+      , N_fmt(SCROLL_coord_fmt), Curwin->begtask + 1, begpflgs, totpflgs);
+   strcpy(tmp2, tmp1);
 #ifndef SCROLLVAR_NO
-   snprintf(tmp, sizeof(tmp), Curwin->varcolbeg ? " + %d" : "", Curwin->varcolbeg);
-   scat (Scroll_fmts, tmp);
+   if (Curwin->varcolbeg)
+      snprintf(tmp2, sizeof(tmp2), "%s + %d", tmp1, Curwin->varcolbeg);
 #endif
+   snprintf(Scroll_fmts, sizeof(Scroll_fmts)
+      , "%%s%s  %.*s%s", Caps_off, Screen_cols - 3, tmp2, Cap_clr_eol);
 } // end: updt_scroll_msg
 \f
 /*######  Low Level Memory/Keyboard support  #############################*/