libbb: shrink wget/tftp progress indicator code a bit more

This makes size display 5-char wide instead of 6-char, but now it's smarter
(can show sizes in "12.3M" format).

function                                             old     new   delta
bb_progress_update                                   654     622     -32

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

1 files changed, 27 insertions, 29 deletions

diff --git a/libbb/progress.c b/libbb/progress.c
index 17272fd17..f1d980d68 100644
--- a/libbb/progress.c
+++ b/libbb/progress.c
@@ -71,10 +71,9 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
                 uoff_t transferred,
                 uoff_t totalsize)
 {
-        unsigned beg_and_transferred; /* does not need uoff_t, see scaling code below */
+        char numbuf5[6]; /* 5 + 1 for NUL */
         unsigned since_last_update, elapsed;
         int notty;
-        int kiloscale;
 
         //transferred = 1234; /* use for stall detection testing */
         //totalsize = 0; /* use for unknown size download testing */
@@ -95,24 +94,22 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
                 return;
         }
 
-        kiloscale = 0;
+        /* Before we lose real, unscaled sizes, produce human-readable size string */
+        smart_ulltoa5(beg_size + transferred, numbuf5, " kMGTPEZY")[0] = '\0';
+
         /*
          * Scale sizes down if they are close to overflowing.
          * This allows calculations like (100 * transferred / totalsize)
          * without risking overflow: we guarantee 10 highest bits to be 0.
          * Introduced error is less than 1 / 2^12 ~= 0.025%
          */
-        while (totalsize >= (1 << 22)) {
-                totalsize >>= 10;
-                beg_size >>= 10;
-                transferred >>= 10;
-                kiloscale++;
+        while (totalsize >= (1 << 20)) {
+                totalsize >>= 8;
+                beg_size >>= 8;
+                transferred >>= 8;
         }
-        /* If they were huge, now they are scaled down to [4194303,4096] range.
-         * (N * totalsize) won't overflow 32 bits for N up to 1024.
-         * The downside is that files larger than 4194303 kbytes (>4GB)
-         * never show kbytes download size, they show "0M","1M"... right away
-         * since kiloscale is already >1.
+        /* If they were huge, now they are scaled down to [1048575,4096] range.
+         * (N * totalsize) won't overflow 32 bits for N up to 4096.
          */
 #if ULONG_MAX == 0xffffffff
 /* 32-bit CPU, uoff_t arithmetic is complex on it, cast variables to narrower types */
@@ -124,19 +121,26 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
         notty = !isatty(STDERR_FILENO);
 
         if (ENABLE_UNICODE_SUPPORT)
-                fprintf(stderr, "\r%s" + notty, p->curfile);
+                fprintf(stderr, "\r%s " + notty, p->curfile);
         else
-                fprintf(stderr, "\r%-20.20s" + notty, p->curfile);
-
-        beg_and_transferred = beg_size + transferred;
+                fprintf(stderr, "\r%-20.20s " + notty, p->curfile);
 
         if (totalsize != 0) {
                 int barlength;
-                unsigned ratio = 100 * beg_and_transferred / totalsize;
-                fprintf(stderr, "%4u%%", ratio);
+                unsigned beg_and_transferred; /* does not need uoff_t, see scaling code */
+                unsigned ratio;
+
+                beg_and_transferred = beg_size + transferred;
+                ratio = 100 * beg_and_transferred / totalsize;
+                /* can't overflow ^^^^^^^^^^^^^^^ */
+                fprintf(stderr, "%3u%% ", ratio);
 
-                barlength = get_terminal_width(2) - 49;
-                if (barlength > 0) {
+                barlength = get_terminal_width(2) - 48;
+                /*
+                 * Must reject barlength <= 0 (terminal too narrow). While at it,
+                 * also reject: 1-char bar (useless), 2-char bar (ridiculous).
+                 */
+                if (barlength > 2) {
                         if (barlength > 999)
                                 barlength = 999;
                         {
@@ -147,18 +151,12 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
                                 memset(buf, ' ', barlength);
                                 buf[barlength] = '\0';
                                 memset(buf, '*', stars);
-                                fprintf(stderr, " |%s|", buf);
+                                fprintf(stderr, "|%s| ", buf);
                         }
                 }
         }
 
-        while (beg_and_transferred >= 100000) {
-                beg_and_transferred >>= 10;
-                kiloscale++;
-        }
-        /* see http://en.wikipedia.org/wiki/Tera */
-        fprintf(stderr, "%6u%c", (unsigned)beg_and_transferred, " kMGTPEZY"[kiloscale]);
-#define beg_and_transferred dont_use_beg_and_transferred_below()
+        fputs(numbuf5, stderr); /* "NNNNk" */
 
         since_last_update = elapsed - p->last_change_sec;
         if ((unsigned)transferred != p->last_size) {