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>

diff --git a/libbb/progress.c b/libbb/progress.c
index 17272fd175864717ac1e734766363416747f6f57..f1d980d68b25f51f6f3953ee030ba4eedcb1d18b 100644 (file)
--- 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) {