Nicer ETA display

This patch changes the ETA display to show its units more explicitly,
so that instead of things like "03:12:32" or "08:12", you get "3h 12m"
and "8m 12s" respectively.  The old ETA refused to display times
longer than 100 hours, which was unfortunate for downloads of DVD's.
This one will happily display the ETA of up to 1,000,000 days.

For me it's a definite improvement.


2005-06-25  Hrvoje Niksic  <[email protected]>

	* progress.c (eta_to_human): New logic for more human-readable
	ETA.

Index: src/progress.c
===================================================================
--- src/progress.c	(revision 1807)
+++ src/progress.c	(working copy)
@@ -486,7 +486,7 @@
   double last_eta_time;		/* time of the last update to download
 				   speed and ETA, measured since the
 				   beginning of download. */
-  wgint last_eta_value;
+  int last_eta_value;
 };
 
 static void create_image (struct bar_progress *, double);
@@ -700,6 +700,8 @@
 #endif
 }
 
+static const char *eta_to_human (int);
+
 #define APPEND_LITERAL(s) do {			\
   memcpy (p, s, sizeof (s) - 1);		\
   p += sizeof (s) - 1;				\
@@ -721,7 +723,7 @@
   struct bar_progress_hist *hist = &bp->hist;
 
   /* The progress bar should look like this:
-     xx% [=======>             ] nn,nnn 12.34K/s ETA 00:00
+     xx% [=======>             ] nn,nnn 12.34K/s  eta 36m 51s
 
      Calculate the geometry.  The idea is to assign as much room as
      possible to the progress bar.  The other idea is to never let
@@ -734,7 +736,7 @@
      "[]"              - progress bar decorations - 2 chars
      " nnn,nnn,nnn"    - downloaded bytes         - 12 chars or very rarely more
      " 1012.56K/s"     - dl rate                  - 11 chars
-     " ETA xx:xx:xx"   - ETA                      - 13 chars
+     "  eta 36m 51s"   - ETA                      - 13 chars
 
      "=====>..."       - progress bar             - the rest
   */
@@ -748,7 +750,6 @@
   if (bp->total_length > 0)
     {
       int percentage = (int)(100.0 * size / bp->total_length);
-
       assert (percentage <= 100);
 
       if (percentage < 100)
@@ -841,13 +842,12 @@
   else
     APPEND_LITERAL ("   --.--K/s");
 
-  /* " ETA xx:xx:xx"; wait for three seconds before displaying the ETA.
+  /* "  ETA ..m ..s"; wait for three seconds before displaying the ETA.
      That's because the ETA value needs a while to become
      reliable.  */
   if (bp->total_length > 0 && bp->count > 0 && dl_total_time > 3000)
     {
-      wgint eta;
-      int eta_hrs, eta_min, eta_sec;
+      int eta;
 
       /* Don't change the value of ETA more than approximately once
 	 per second; doing so would cause flashing without providing
@@ -864,38 +864,18 @@
 	     hist->total_time and bp->count with hist->total_bytes.
 	     I found that doing that results in a very jerky and
 	     ultimately unreliable ETA.  */
-	  double time_sofar = (double)dl_total_time / 1000;
+	  double time_sofar = (double) dl_total_time / 1000;
 	  wgint bytes_remaining = bp->total_length - size;
-	  eta = (wgint) (time_sofar * bytes_remaining / bp->count);
+	  eta = (int) (time_sofar * bytes_remaining / bp->count + 0.5);
 	  bp->last_eta_value = eta;
 	  bp->last_eta_time = dl_total_time;
 	}
 
-      eta_hrs = eta / 3600, eta %= 3600;
-      eta_min = eta / 60,   eta %= 60;
-      eta_sec = eta;
-
-      if (eta_hrs > 99)
-	goto no_eta;
-
-      if (eta_hrs == 0)
-	{
-	  /* Hours not printed: pad with three spaces. */
-	  APPEND_LITERAL ("   ");
-	  sprintf (p, " ETA %02d:%02d", eta_min, eta_sec);
-	}
-      else
-	{
-	  if (eta_hrs < 10)
-	    /* Hours printed with one digit: pad with one space. */
-	    *p++ = ' ';
-	  sprintf (p, " ETA %d:%02d:%02d", eta_hrs, eta_min, eta_sec);
-	}
+      sprintf (p, "  eta %s", eta_to_human (eta));
       p += strlen (p);
     }
   else if (bp->total_length > 0)
     {
-    no_eta:
       APPEND_LITERAL ("             ");
     }
 
@@ -961,3 +941,34 @@
   signal (SIGWINCH, progress_handle_sigwinch);
 }
 #endif
+
+/* Provide a human-readable rendition of the ETA.  It never occupies
+   more than 7 characters of screen space.  */
+
+static const char *
+eta_to_human (int secs)
+{
+  static char buf[10];		/* 8 is enough, but just in case */
+  static int last = -1;
+
+  /* Trivial optimization.  This function can be called every 200
+     msecs (see bar_update) for fast downloads, but ETA will only
+     change once per 900 msecs (see create_image).  */
+  if (secs == last)
+    return buf;
+  last = secs;
+
+  if (secs < 100)
+    sprintf (buf, "%ds", secs);
+  else if (secs < 100 * 60)
+    sprintf (buf, "%dm %ds", secs / 60, secs % 60);
+  else if (secs < 100 * 3600)
+    sprintf (buf, "%dh %dm", secs / 3600, (secs / 60) % 60);
+  else if (secs < 100 * 86400)
+    sprintf (buf, "%dd %dh", secs / 86400, (secs / 3600) % 60);
+  else
+    /* (2^31-1)/86400 doesn't overflow BUF. */
+    sprintf (buf, "%dd", secs / 86400);
+
+  return buf;
+}