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libbb: shrink wget/tftp progress indicator code for 32-bit

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function                                             old     new   delta
bb_progress_update                                   756     654    -102

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2018-02-07 17:47:39 +01:00
parent 2bd5b4e9a0
commit ab843e3244
1 changed files with 38 additions and 40 deletions
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78
libbb/progress.c
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@ -71,7 +71,7 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
uoff_t transferred,
uoff_t totalsize)
{
uoff_t beg_and_transferred;
unsigned beg_and_transferred; /* does not need uoff_t, see scaling code below */
unsigned since_last_update, elapsed;
int notty;
int kiloscale;
@ -102,33 +102,24 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
* without risking overflow: we guarantee 10 highest bits to be 0.
* Introduced error is less than 1 / 2^12 ~= 0.025%
*/
if (ULONG_MAX > 0xffffffff || sizeof(off_t) == 4 || sizeof(off_t) != 8) {
/*
* 64-bit CPU || small off_t: in either case,
* >> is cheap, single-word operation.
* ... || 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;
kiloscale = 1;
}
} else {
/* 32-bit CPU and 64-bit off_t.
* Use a 40-bit shift, it is easier to do on 32-bit CPU.
*/
/* ONE suppresses "warning: shift count >= width of type" */
#define ONE (sizeof(off_t) > 4)
if (totalsize >= (uoff_t)(1ULL << 54*ONE)) {
totalsize = (uint32_t)(totalsize >> 32*ONE) >> 8;
beg_size = (uint32_t)(beg_size >> 32*ONE) >> 8;
transferred = (uint32_t)(transferred >> 32*ONE) >> 8;
kiloscale = 4;
}
while (totalsize >= (1 << 22)) {
totalsize >>= 10;
beg_size >>= 10;
transferred >>= 10;
kiloscale++;
}
/* 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 ULONG_MAX == 0xffffffff
/* 32-bit CPU, uoff_t arithmetic is complex on it, cast variables to narrower types */
# define totalsize ((unsigned)totalsize)
# define beg_size ((unsigned)beg_size)
# define transferred ((unsigned)transferred)
#endif
notty = !isatty(STDERR_FILENO);
@ -146,13 +137,18 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
barlength = get_terminal_width(2) - 49;
if (barlength > 0) {
/* god bless gcc for variable arrays :) */
char buf[barlength + 1];
unsigned stars = (unsigned)barlength * beg_and_transferred / totalsize;
memset(buf, ' ', barlength);
buf[barlength] = '\0';
memset(buf, '*', stars);
fprintf(stderr, " |%s|", buf);
if (barlength > 999)
barlength = 999;
{
/* god bless gcc for variable arrays :) */
char buf[barlength + 1];
unsigned stars = (unsigned)barlength * beg_and_transferred / totalsize;
/* can't overflow ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ */
memset(buf, ' ', barlength);
buf[barlength] = '\0';
memset(buf, '*', stars);
fprintf(stderr, " |%s|", buf);
}
}
}
@ -184,16 +180,18 @@ void FAST_FUNC bb_progress_update(bb_progress_t *p,
fprintf(stderr, " --:--:-- ETA");
} else {
unsigned eta, secs, hours;
unsigned bytes;
totalsize -= beg_size; /* now it's "total to upload" */
bytes = totalsize - beg_size;
/* Estimated remaining time =
* estimated_sec_to_dl_totalsize_bytes - elapsed_sec =
* totalsize / average_bytes_sec_so_far - elapsed =
* totalsize / (transferred/elapsed) - elapsed =
* totalsize * elapsed / transferred - elapsed
* estimated_sec_to_dl_bytes - elapsed_sec =
* bytes / average_bytes_sec_so_far - elapsed =
* bytes / (transferred/elapsed) - elapsed =
* bytes * elapsed / transferred - elapsed
*/
eta = totalsize * elapsed / transferred - elapsed;
eta = (unsigned long)bytes * elapsed / transferred - elapsed;
/* if 32bit, can overflow ^^^^^^^^^^, but this would only show bad ETA */
if (eta >= 1000*60*60)
eta = 1000*60*60 - 1;
secs = eta % 3600;