progress bar: better overflow protection; more precise bar

function                                             old     new   delta
bb_progress_update                                   639     749    +110

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

diff --git a/include/libbb.h b/include/libbb.h
index d390e68..c017880 100644 (file)
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -1592,8 +1592,9 @@ typedef struct bb_progress_t {
 
 void bb_progress_init(bb_progress_t *p) FAST_FUNC;
 void bb_progress_update(bb_progress_t *p, const char *curfile,
-                       off_t beg_range, off_t transferred,
-                       off_t totalsize) FAST_FUNC;
+                       uoff_t beg_range,
+                       uoff_t transferred,
+                       uoff_t totalsize) FAST_FUNC;
 
 extern const char *applet_name;
 

diff --git a/libbb/progress.c b/libbb/progress.c
index 40608b0..ced04ac 100644 (file)
--- a/libbb/progress.c
+++ b/libbb/progress.c
@@ -62,35 +62,45 @@ void FAST_FUNC bb_progress_init(bb_progress_t *p)
 
 void FAST_FUNC bb_progress_update(bb_progress_t *p,
                const char *curfile,
-               off_t beg_range,
-               off_t transferred,
-               off_t totalsize)
+               uoff_t beg_range,
+               uoff_t transferred,
+               uoff_t totalsize)
 {
        uoff_t beg_and_transferred;
        unsigned since_last_update, elapsed;
        unsigned ratio;
-       int barlength, i;
+       int barlength;
+       int kiloscale;
 
        /* totalsize == 0 if it is unknown */
 
+       beg_and_transferred = beg_range + 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 && !totalsize)
+       if (since_last_update == 0 && beg_and_transferred < totalsize)
                return;
 
-       beg_and_transferred = beg_range + transferred;
-       ratio = 100;
-       if (beg_and_transferred < totalsize) {
-               /* Do not update on every call
-                * (we can be called on every network read!) */
-               if (since_last_update == 0)
-                       return;
-               /* long long helps to have it working even if !LFS */
-               ratio = 100ULL * beg_and_transferred / (uoff_t)totalsize;
+       /* Scale sizes down if they are close to overflowing.
+        * If off_t is only 32 bits, this allows calculations
+        * like (100 * transferred / totalsize) without risking overflow.
+        * Introduced error is < 0.1%
+        */
+       kiloscale = 0;
+       if (totalsize >= (1 << 20)) {
+               totalsize >>= 10;
+               beg_range >>= 10;
+               transferred >>= 10;
+               beg_and_transferred >>= 10;
+               kiloscale++;
        }
 
+       if (beg_and_transferred >= totalsize)
+               beg_and_transferred = totalsize;
+
+       ratio = 100 * beg_and_transferred / totalsize;
 #if ENABLE_UNICODE_SUPPORT
        init_unicode();
        {
@@ -106,21 +116,20 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
        if (barlength > 0) {
                /* god bless gcc for variable arrays :) */
                char buf[barlength + 1];
-               unsigned stars = (unsigned)barlength * ratio / (unsigned)100;
+               unsigned stars = (unsigned)barlength * beg_and_transferred / totalsize;
                memset(buf, ' ', barlength);
                buf[barlength] = '\0';
                memset(buf, '*', stars);
                fprintf(stderr, "|%s|", buf);
        }
 
-       i = 0;
        while (beg_and_transferred >= 100000) {
-               i++;
+               kiloscale++;
                beg_and_transferred >>= 10;
        }
        /* see http://en.wikipedia.org/wiki/Tera */
-       fprintf(stderr, "%6u%c ", (unsigned)beg_and_transferred, " kMGTPEZY"[i]);
-#define beg_and_transferred dont_use_beg_and_transferred_below
+       fprintf(stderr, "%6u%c ", (unsigned)beg_and_transferred, " kMGTPEZY"[kiloscale]);
+#define beg_and_transferred dont_use_beg_and_transferred_below()
 
        if (transferred > p->lastsize) {
                p->lastupdate_sec = elapsed;
@@ -137,13 +146,12 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
        if (since_last_update >= STALLTIME) {
                fprintf(stderr, " - stalled -");
        } else {
-               off_t to_download = totalsize - beg_range;
-               if (!totalsize || transferred <= 0 || (int)elapsed <= 0 || transferred > to_download) {
+               uoff_t to_download = totalsize - beg_range;
+               if (!totalsize || (int)elapsed <= 0 || transferred > to_download) {
                        fprintf(stderr, "--:--:-- ETA");
                } else {
                        /* to_download / (transferred/elapsed) - elapsed: */
-                       /* (long long helps to have working ETA even if !LFS) */
-                       unsigned eta = (unsigned long long)to_download*elapsed/(uoff_t)transferred - elapsed;
+                       unsigned eta = to_download * elapsed / transferred - elapsed;
                        unsigned secs = eta % 3600;
                        unsigned hours = eta / 3600;
                        fprintf(stderr, "%02u:%02u:%02u ETA", hours, secs / 60, secs % 60);