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busybox/coreutils
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Ron Yorston 8817e285b7 shuf: speed-up when limited output is requested 
A user noted that the following command was slower than they
expected:

   busybox shuf -i "1500000000-$(date +%s)" -n 5

At time of writing the range contains 128 million values.  On my
system this takes 7.7s whereas 'shuf' from coreutils takes a
handful of milliseconds.

Optimise BusyBox 'shuf' for cases where -n is specified by stopping
shuffling once the required number of lines have been processed.
On my system the time for the example is reduced to 0.4s.

function                                             old     new   delta
shuf_main                                            520     540     +20
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/0 up/down: 20/0)               Total: 20 bytes

v2: Code shrink.  Since outlines <= numlines:
    - the loop in shuffle_lines() only needs to test the value of
      outlines;
    - shuffle_lines() can be called unconditionally.
    Update timing to allow for the 13 million seconds elapsed since v1.

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2021-08-22 15:40:21 +02:00
..
libcoreutils whitespace and comment format fixes, no code changes 2017-10-05 15:19:25 +02:00
basename.c config: update size information 2018-12-28 03:20:17 +01:00
cat.c libbb: introduce and use fputs_stdout 2021-02-03 20:52:40 +01:00
chgrp.c *: --help tweaks 2021-06-14 20:47:20 +02:00
chmod.c *: --help tweaks 2021-06-14 20:47:20 +02:00
chown.c *: --help tweaks 2021-06-14 20:47:20 +02:00
chroot.c make 17 state-changing execing applets (ex: "nice PROG ARGS") noexec 2017-08-04 19:55:01 +02:00
cksum.c crc32: code shrink for !CKSUM config 2021-06-22 10:24:06 +02:00
comm.c config: update size information 2018-12-28 03:20:17 +01:00
Config.src restore documentation on the build config language 2018-06-06 15:16:48 +02:00
cp.c cp: fix build failure with long options disabled 2021-08-15 18:26:56 +02:00
cut.c cut: add toybox-compatible options -O OUTSEP, -D, -F LIST 2021-07-20 16:29:22 +02:00
date.c libbb: in @SECONDS date format, use 64-bit time if libc allows 2020-11-28 23:21:13 +01:00
dd.c dd: tweak --help 2021-08-15 23:05:30 +02:00
df.c df: support -t TYPE 2021-06-20 15:03:21 +02:00
dirname.c config: update size information 2018-12-28 03:20:17 +01:00
dos2unix.c config: update size information 2018-12-28 03:20:17 +01:00
du.c du: support -b "apparent size" 2021-06-16 17:45:28 +02:00
echo.c *: --help tweaks 2021-06-14 20:47:20 +02:00
env.c env: implement -0 2021-06-17 13:39:46 +02:00
expand.c libbb: introduce and use fputs_stdout 2021-02-03 20:52:40 +01:00
expr.c *: --help tweaks 2021-06-13 01:08:48 +02:00
factor.c factor: fix comment 2020-12-23 02:03:04 +01:00
false.c config: deindent all help texts 2017-07-21 09:50:55 +02:00
fold.c *: --help text tweaks 2021-04-14 15:15:45 +02:00
head.c head,tail: trim --help text 2021-06-02 04:01:10 +02:00
hostid.c config: update size information 2018-12-28 03:20:17 +01:00
id_test.sh
id.c *: --help tweaks 2021-06-14 20:47:20 +02:00
install.c libbb: reduce the overhead of single parameter bb_error_msg() calls 2019-07-02 11:35:03 +02:00
Kbuild.src shells: make hush test optional, rename ASH_BUILTIN_foo -> ASH_foo 2017-01-10 15:13:30 +01:00
link.c config: update size information 2018-12-28 03:20:17 +01:00
ln.c help text: replace [OPTIONS] with actual options (if not too long) 2020-12-13 22:34:05 +01:00
logname.c libbb: reduce the overhead of single parameter bb_error_msg() calls 2019-07-02 11:35:03 +02:00
ls.c ls: revert last change (short name must be allocated) 2021-06-25 19:48:34 +02:00
md5_sha1_sum.c sha3sum: fix --help: -a does not depend on FEATURE_MD5_SHA1_SUM_CHECK 2020-11-27 15:55:46 +01:00
mkdir.c help text tweaks 2020-12-13 19:04:19 +01:00
mkfifo.c config: update size information 2018-12-28 03:20:17 +01:00
mknod.c Fix mknod compilation on the FreeBSD 2021-01-04 13:28:28 +01:00
mktemp.c config: update size information 2018-12-28 03:20:17 +01:00
mv.c cp,mv: fix -t DIR option 2021-06-25 00:23:29 +02:00
nice.c config: update size information 2018-12-28 03:20:17 +01:00
nl.c nl: ensure '-b n' option displays file content 2021-02-02 17:37:41 +01:00
nohup.c whitespace and comment format fixes, no code changes 2017-10-05 15:19:25 +02:00
nproc.c nproc: code shrink 2021-06-24 13:47:49 +02:00
od_bloaty.c libbb: introduce and use fputs_stdout 2021-02-03 20:52:40 +01:00
od.c do not use `a' quoting style in comments 2017-08-02 14:26:33 +02:00
paste.c libbb: introduce and use fputs_stdout 2021-02-03 20:52:40 +01:00
printenv.c config: update size information 2018-12-28 03:20:17 +01:00
printf.c timeout,top,watch,ping: parse NN.N fractional duration in locales with other separators 2021-03-23 13:50:02 +01:00
pwd.c config: update size information 2018-12-28 03:20:17 +01:00
readlink.c config: update size information 2018-12-28 03:20:17 +01:00
realpath.c *: --help text tweaks 2021-04-14 15:15:45 +02:00
rm.c libbb: reduce the overhead of single parameter bb_error_msg() calls 2019-07-02 11:35:03 +02:00
rmdir.c help text tweaks 2020-12-13 19:04:19 +01:00
seq.c config: update size information 2018-12-28 03:20:17 +01:00
shred.c shred: with -u, unlink file even if it is zero length 2021-06-20 13:48:21 +02:00
shuf.c shuf: speed-up when limited output is requested 2021-08-22 15:40:21 +02:00
sleep.c timeout,top,watch,ping: parse NN.N fractional duration in locales with other separators 2021-03-23 13:50:02 +01:00
sort.c uniq: support -z 2021-06-17 00:36:13 +02:00
split.c decrease paddign: gcc-9.3.1 slaps 32-byte alignment on arrays willy-nilly 2020-11-30 13:03:03 +01:00
stat.c libbb: introduce and use fputs_stdout 2021-02-03 20:52:40 +01:00
stty.c libbb: introduce and use fputs_stdout 2021-02-03 20:52:40 +01:00
sum.c config: update size information 2018-12-28 03:20:17 +01:00
sync.c fsync,sync: merge into one source module 2019-04-02 14:55:29 +02:00
tac.c config: update size information 2018-12-28 03:20:17 +01:00
tail.c tail: do not lose the tail of old file if new file (-F) is detected 2021-06-02 05:17:44 +02:00
tee.c tee: do not intercept SIGPIPE 2019-10-07 14:25:45 +02:00
test_ptr_hack.c *: make GNU licensing statement forms more regular 2010-08-16 20:14:46 +02:00
test.c decrease paddign: gcc-9.3.1 slaps 32-byte alignment on arrays willy-nilly 2020-11-30 13:03:03 +01:00
timeout.c help text tweaks 2020-12-18 04:12:51 +01:00
touch.c touch: fix SEGV if !ENABLE_FEATURE_TOUCH_SUSV3 2021-08-15 20:23:40 +02:00
tr.c libbb: reduce the overhead of single parameter bb_error_msg() calls 2019-07-02 11:35:03 +02:00
true.c config: deindent all help texts 2017-07-21 09:50:55 +02:00
truncate.c *: --help text tweaks 2021-04-14 15:15:45 +02:00
tty.c *: more --help tweaks, mostly expanding ts --help 2021-06-13 03:12:09 +02:00
uname.c *: more --help tweaks, mostly expanding ts --help 2021-06-13 03:12:09 +02:00
uniq.c uniq: really support -z 2021-06-24 23:37:06 +02:00
unlink.c config: update size information 2018-12-28 03:20:17 +01:00
usleep.c config: update size information 2018-12-28 03:20:17 +01:00
uudecode.c base32/64: accept -i "skip bad chars" option (currently in effect unconditionally) 2021-06-13 23:58:17 +02:00
uuencode.c libbb: reduce the overhead of single parameter bb_error_msg() calls 2019-07-02 11:35:03 +02:00
wc.c *: --help text tweaks 2021-04-14 15:15:45 +02:00
who.c *: more --help tweaks 2021-06-15 10:00:18 +02:00
whoami.c config: update size information 2018-12-28 03:20:17 +01:00
yes.c *: more --help tweaks, mostly expanding ts --help 2021-06-13 03:12:09 +02:00