progress meter: add disabled code for a more stable ETA

Compiles to ~25 bytes if enabled.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 14 insertions, 0 deletions

diff --git a/include/libbb.h b/include/libbb.h
index 2c34859a2..c02621d94 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1949,6 +1949,7 @@ typedef struct bb_progress_t {
         unsigned last_update_sec;
         unsigned last_change_sec;
         unsigned start_sec;
+        /*unsigned last_eta;*/
         const char *curfile;
 } bb_progress_t;
 
diff --git a/libbb/progress.c b/libbb/progress.c
index f1d980d68..23e974ce7 100644
--- a/libbb/progress.c
+++ b/libbb/progress.c
@@ -57,6 +57,9 @@ void FAST_FUNC bb_progress_init(bb_progress_t *p, const char *curfile)
         p->last_update_sec = p->start_sec;
         p->last_change_sec = p->start_sec;
         p->last_size = 0;
+#if 0
+        p->last_eta = INT_MAX;
+#endif
 }
 
 /* File already had beg_size bytes.
@@ -192,6 +195,16 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
                 /* if 32bit, can overflow ^^^^^^^^^^, but this would only show bad ETA */
                 if (eta >= 1000*60*60)
                         eta = 1000*60*60 - 1;
+#if 0
+                /* To prevent annoying "back-and-forth" estimation jitter,
+                 * if new ETA is larger than the last just by a few seconds,
+                 * disregard it, and show last one. The end result is that
+                 * ETA usually only decreases, unless download slows down a lot.
+                 */
+                if ((unsigned)(eta - p->last_eta) < 10)
+                        eta = p->last_eta;
+                p->last_eta = eta;
+#endif
                 secs = eta % 3600;
                 hours = eta / 3600;
                 fprintf(stderr, "%3u:%02u:%02u ETA", hours, secs / 60, secs % 60);