libbb/progress.c: make sure we never get negative ETA

function                                             old     new   delta
bb_progress_update                                   738     733      -5

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

1 files changed, 17 insertions, 16 deletions

diff --git a/libbb/progress.c b/libbb/progress.c
index 3999e0f38..1062e9a0d 100644
--- a/libbb/progress.c
+++ b/libbb/progress.c
@@ -79,16 +79,20 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
         int barlength;
         int kiloscale;
 
-        beg_and_transferred = beg_size + transferred;
-
         elapsed = monotonic_sec();
         since_last_update = elapsed - p->lastupdate_sec;
-        /*
-         * Do not update on every call
-         * (we can be called on every network read!)
-         */
-        if (since_last_update == 0 && beg_and_transferred < totalsize)
+
+        if (totalsize != 0 && transferred >= totalsize - beg_size) {
+                /* Last call. Do not skip this update */
+                transferred = totalsize - beg_size; /* sanitize just in case */
+        }
+        else if (since_last_update == 0) {
+                /*
+                 * Do not update on every call
+                 * (we can be called on every network read!)
+                 */
                 return;
+        }
 
         kiloscale = 0;
         /*
@@ -101,32 +105,29 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
                 /*
                  * 64-bit CPU || small off_t: in either case,
                  * >> is cheap, single-word operation.
-                 * ... || strange off_t: also use this code (it is safe,
-                 * even if suboptimal), because 32/64 optimized one
-                 * works only for 64-bit off_t.
+                 * ... || strange off_t: also use this code
+                 * (it is safe, just suboptimal wrt code size),
+                 * because 32/64 optimized one works only for 64-bit off_t.
                  */
                 if (totalsize >= (1 << 22)) {
                         totalsize >>= 10;
                         beg_size >>= 10;
                         transferred >>= 10;
-                        beg_and_transferred >>= 10;
                         kiloscale = 1;
                 }
         } else {
                 /* 32-bit CPU and 64-bit off_t.
-                 * Pick a shift (40 bits) which is easier to do on 32-bit CPU.
+                 * Use a 40-bit shift, it is easier to do on 32-bit CPU.
                  */
                 if (totalsize >= (uoff_t)(1ULL << 54)) {
                         totalsize = (uint32_t)(totalsize >> 32) >> 8;
                         beg_size = (uint32_t)(beg_size >> 32) >> 8;
                         transferred = (uint32_t)(transferred >> 32) >> 8;
-                        beg_and_transferred = (uint32_t)(beg_and_transferred >> 32) >> 8;
                         kiloscale = 4;
                 }
         }
 
-        if (beg_and_transferred > totalsize)
-                beg_and_transferred = totalsize;
+        beg_and_transferred = beg_size + transferred;
 
         ratio = 100 * beg_and_transferred / totalsize;
 #if ENABLE_UNICODE_SUPPORT
@@ -163,7 +164,7 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
                 p->lastupdate_sec = elapsed;
                 p->lastsize = transferred;
                 if (since_last_update >= STALLTIME) {
-                        /* We "cut off" these seconds from elapsed time
+                        /* We "cut out" these seconds from elapsed time
                          * by adjusting start time */
                         p->start_sec += since_last_update;
                 }