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Better seed support for (random).

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* doc/lispref/numbers.texi (Random Numbers): Document new behavior of
the calls (random) and (random STRING).
* etc/NEWS: Document new behavior of (random), (random "string").
* lisp/play/5x5.el, lisp/play/animate.el, lisp/play/cookie1.el:
* lisp/play/dissociate.el, lisp/play/doctor.el, lisp/play/dunnet.el:
* lisp/play/gomoku.el, lisp/play/landmark.el, lisp/play/mpuz.el:
* lisp/play/tetris.el, lisp/play/zone.el:
* lisp/calc/calc-comb.el (math-init-random-base):
* lisp/play/blackbox.el (bb-init-board):
* lisp/play/life.el (life):
* lisp/server.el (server-use-tcp):
* lisp/type-break.el (type-break):
Remove unnecessary call to (random t).
* lisp/net/sasl.el (sasl-unique-id-function):
Change (random t) to (random), now that the latter is more random.
* lisp/play/life.el (life-initialized): Remove no-longer-needed var.
* lisp/gnus/gnus-sync.el (gnus-sync-lesync-setup):
* lisp/gnus/message.el (message-canlock-generate, message-unique-id):
Change (random t) to (random), now that the latter is more random.
* lisp/org/org-id.el (org-id-uuid):
Change (random t) to (random), now that the latter is more random.
* src/emacs.c (main): Call init_random.
* src/fns.c (Frandom): Set the seed from a string argument, if given.
Remove long-obsolete Gentzel cruft.
* src/lisp.h, src/sysdep.c (seed_random): Now takes address and size, not long.
(init_random): New function.
This commit is contained in:
Paul Eggert 2012-08-31 18:04:26 -07:00
parent 5bf647499a
commit 0e23ef9dde
33 changed files with 112 additions and 88 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
doc/lispref/ChangeLog
View file

@ -1,3 +1,9 @@
2012-09-01 Paul Eggert <eggert@cs.ucla.edu>
Better seed support for (random).
* numbers.texi (Random Numbers): Document new behavior of
the calls (random) and (random STRING).
2012-08-21 Martin Rudalics <rudalics@gmx.at>
* windows.texi (Window Point): Document recent changes in

30
doc/lispref/numbers.texi
View file

@ -1199,30 +1199,32 @@ numbers are not truly random, but they have certain properties that
mimic a random series. For example, all possible values occur equally
often in a pseudo-random series.
In Emacs, pseudo-random numbers are generated from a ``seed'' number.
In Emacs, pseudo-random numbers are generated from a ``seed''.
Starting from any given seed, the @code{random} function always
generates the same sequence of numbers. Emacs always starts with the
same seed value, so the sequence of values of @code{random} is actually
the same in each Emacs run! For example, in one operating system, the
first call to @code{(random)} after you start Emacs always returns
@minus{}1457731, and the second one always returns @minus{}7692030. This
repeatability is helpful for debugging.
generates the same sequence of numbers. Emacs typically starts with a
different seed each time, so the sequence of values of @code{random}
typically differs in each Emacs run.
If you want random numbers that don't always come out the same, execute
@code{(random t)}. This chooses a new seed based on the current time of
day and on Emacs's process @acronym{ID} number.
Sometimes you want the random number sequence to be repeatable. For
example, when debugging a program whose behavior depends on the random
number sequence, it is helpful to get the same behavior in each
program run. To make the sequence repeat, execute @code{(random "")}.
This sets the seed to a constant value for your particular Emacs
executable (though it may differ for other Emacs builds). You can use
other strings to choose various seed values.
@defun random &optional limit
This function returns a pseudo-random integer. Repeated calls return a
series of pseudo-random integers.
If @var{limit} is a positive integer, the value is chosen to be
nonnegative and less than @var{limit}.
nonnegative and less than @var{limit}. Otherwise, the value
might be any integer representable in Lisp.
If @var{limit} is @code{t}, it means to choose a new seed based on the
current time of day and on Emacs's process @acronym{ID} number.
On some machines, any integer representable in Lisp may be the result
of @code{random}. On other machines, the result can never be larger
than a certain maximum or less than a certain (negative) minimum.
If @var{limit} is a string, it means to choose a new seed based on the
string's contents.
@end defun

5
etc/ChangeLog
View file

@ -1,3 +1,8 @@
2012-09-01 Paul Eggert <eggert@cs.ucla.edu>
Better seeds for (random).
* NEWS: Document new behavior of (random), (random "string").
2012-08-28 Andreas Schwab <schwab@linux-m68k.org>
* charsets/MULE-ethiopic.map: Fix typo in comment.

5
etc/NEWS
View file

@ -527,6 +527,11 @@ inefficiency, and not namespace-clean.
* Incompatible Lisp Changes in Emacs 24.3
** (random) by default now returns a different random sequence in
every Emacs run. Use (random S), where S is a string, to set the
random seed to a value based on S, in order to get a repeatable
sequence in later calls.
** The function `x-select-font' can return a font spec, instead of a
font name as a string. Whether it returns a font spec or a font name
depends on the graphical library.

16
lisp/ChangeLog
View file

@ -1,3 +1,19 @@
2012-09-01 Paul Eggert <eggert@cs.ucla.edu>
Better seed support for (random).
* play/5x5.el, play/animate.el, play/cookie1.el, play/dissociate.el:
* play/doctor.el, play/dunnet.el, play/gomoku.el, play/landmark.el:
* play/mpuz.el, play/tetris.el, play/zone.el:
* calc/calc-comb.el (math-init-random-base):
* play/blackbox.el (bb-init-board):
* play/life.el (life):
* server.el (server-use-tcp):
* type-break.el (type-break):
Remove unnecessary call to (random t).
* net/sasl.el (sasl-unique-id-function):
Change (random t) to (random), now that the latter is more random.
* play/life.el (life-initialized): Remove no-longer-needed var.
2012-08-31 Alp Aker <alp.tekin.aker@gmail.com>
* window.el (switch-to-prev-buffer, switch-to-next-buffer):

1
lisp/allout-widgets.el
View file

@ -1374,7 +1374,6 @@ FROM and TO must be in increasing order, as must be the pairs in RANGES."
;; (time-trial
;; '(let ((size 10000)
;; doing)
;; (random t)
;; (dotimes (count size)
;; (setq doing (random size))
;; (funcall try doing (+ doing (random 5)))

15
lisp/calc/calc-comb.el
View file

@ -77,7 +77,7 @@
4877 4889 4903 4909 4919 4931 4933 4937 4943 4951 4957 4967 4969 4973
4987 4993 4999 5003])
;; The variable math-prime-factors-finished is set by calcFunc-prfac to
;; The variable math-prime-factors-finished is set by calcFunc-prfac to
;; indicate whether factoring is complete, and used by calcFunc-factors,
;; calcFunc-totient and calcFunc-moebius.
(defvar math-prime-factors-finished)
@ -510,8 +510,8 @@
(while (<= (length math-stirling-local-cache) n)
(let ((i (1- (length math-stirling-local-cache)))
row)
(setq math-stirling-local-cache
(vconcat math-stirling-local-cache
(setq math-stirling-local-cache
(vconcat math-stirling-local-cache
(make-vector (length math-stirling-local-cache) nil)))
(aset math-stirling-cache k math-stirling-local-cache)
(while (< (setq i (1+ i)) (length math-stirling-local-cache))
@ -572,7 +572,6 @@
(let ((i 200))
(while (> (setq i (1- i)) 0)
(math-random-base))))
(random t)
(setq var-RandSeed nil
math-random-cache nil
math-random-shift -4) ; assume RAND_MAX >= 16383
@ -629,7 +628,7 @@
(i (/ (+ n slop) 3))
(rnum 0))
(while (> i 0)
(setq rnum
(setq rnum
(math-add
(math-random-three-digit-number)
(math-mul rnum 1000)))
@ -823,11 +822,11 @@
(setq sum (%
(+
sum
(calcFunc-mod
(calcFunc-mod
q 1000000))
111111))
(setq q
(math-quotient
(setq q
(math-quotient
q 1000000)))
(cond ((= (% sum 3) 0) '(nil 3))
((= (% sum 7) 0) '(nil 7))

7
lisp/gnus/ChangeLog
View file

@ -1,3 +1,10 @@
2012-09-01 Paul Eggert <eggert@cs.ucla.edu>
Better seeds for (random).
* gnus-sync.el (gnus-sync-lesync-setup):
* message.el (message-canlock-generate, message-unique-id):
Change (random t) to (random), now that the latter is more random.
2012-08-31 Dave Abrahams <dave@boostpro.com>
* auth-source.el (auth-sources): Fix macos keychain access.

2
lisp/gnus/gnus-sync.el
View file

@ -225,7 +225,7 @@ When SALT is nil, a random one will be generated using `random'."
(security-object (concat url "/_security"))
(user-record `((names . [,user]) (roles . [])))
(couch-user-name (format "org.couchdb.user:%s" user))
(salt (or salt (sha1 (format "%s" (random t)))))
(salt (or salt (sha1 (format "%s" (random)))))
(couch-user-record
`((_id . ,couch-user-name)
(type . user)

5
lisp/gnus/message.el
View file

@ -4820,9 +4820,7 @@ Do not use this for anything important, it is cryptographically weak."
(require 'sha1)
(let (sha1-maximum-internal-length)
(sha1 (concat (message-unique-id)
(format "%x%x%x" (random)
(progn (random t) (random))
(random))
(format "%x%x%x" (random) (random) (random))
(prin1-to-string (recent-keys))
(prin1-to-string (garbage-collect))))))
@ -5525,7 +5523,6 @@ In posting styles use `(\"Expires\" (make-expires-date 30))'."
;; You might for example insert a "." somewhere (not next to another dot
;; or string boundary), or modify the "fsf" string.
(defun message-unique-id ()
(random t)
;; Don't use microseconds from (current-time), they may be unsupported.
;; Instead we use this randomly inited counter.
(setq message-unique-id-char

2
lisp/net/sasl.el
View file

@ -183,7 +183,7 @@ It contain at least 64 bits of entropy."
;; Don't use microseconds from (current-time), they may be unsupported.
;; Instead we use this randomly inited counter.
(setq sasl-unique-id-char
(% (1+ (or sasl-unique-id-char (logand (random t) (1- (lsh 1 20)))))
(% (1+ (or sasl-unique-id-char (logand (random) (1- (lsh 1 20)))))
;; (current-time) returns 16-bit ints,
;; and 2^16*25 just fits into 4 digits i base 36.
(* 25 25)))

6
lisp/org/ChangeLog
View file

@ -1,3 +1,9 @@
2012-09-01 Paul Eggert <eggert@cs.ucla.edu>
Better seed support for (random).
* org-id.el (org-id-uuid):
Change (random t) to (random), now that the latter is more random.
2012-07-29 Paul Eggert <eggert@cs.ucla.edu>
Don't use the abbreviation "win" to refer to Windows (Bug#10421).

2
lisp/org/org-id.el
View file

@ -318,7 +318,7 @@ So a typical ID could look like \"Org:4nd91V40HI\"."
(defun org-id-uuid ()
"Return string with random (version 4) UUID."
(let ((rnd (md5 (format "%s%s%s%s%s%s%s"
(random t)
(random)
(current-time)
(user-uid)
(emacs-pid)

2
lisp/play/5x5.el
View file

@ -953,8 +953,6 @@ lest."
(y-or-n-p prompt)
t))
(random t)
(provide '5x5)
;;; 5x5.el ends here

2
lisp/play/animate.el
View file

@ -201,8 +201,6 @@ the buffer *Birthday-Present-for-Name*."
(animate-string "my sunshine" 18 34)
(animate-string "to stay!" 19 34))
(random t)
(provide 'animate)
;;; animate.el ends here

3
lisp/play/blackbox.el
View file

@ -93,7 +93,7 @@
(define-key map (vector 'remap oldfun) newfun))
(defvar blackbox-mode-map
(defvar blackbox-mode-map
(let ((map (make-keymap)))
(suppress-keymap map t)
(blackbox-redefine-key map 'backward-char 'bb-left)
@ -257,7 +257,6 @@ a reflection."
(bb-goto (cons bb-x bb-y)))
(defun bb-init-board (num-balls)
(random t)
(let (board pos)
(while (>= (setq num-balls (1- num-balls)) 0)
(while

3
lisp/play/cookie1.el
View file

@ -53,9 +53,6 @@
;;; Code:
; Randomize the seed in the random number generator.
(random t)
(defconst cookie-delimiter "\n%%\n\\|\n%\n\\|\0"
"Delimiter used to separate cookie file entries.")

2
lisp/play/dissociate.el
View file

@ -94,8 +94,6 @@ Default is 2."
(funcall search-function overlap opoint t))))))
(sit-for 0))))
(random t)
(provide 'dissociate)
;;; dissociate.el ends here

2
lisp/play/doctor.el
View file

@ -1620,8 +1620,6 @@ Hack on previous word, setting global variable DOCTOR-OWNER to correct result."
(defun doctor-chat () (doctor-type (doc$ doctor--chatlst)))
(random t)
(provide 'doctor)
;;; doctor.el ends here

1
lisp/play/dunnet.el
View file

@ -3010,7 +3010,6 @@ drwxr-xr-x 3 root staff 2048 Jan 1 1970 ..")
(dun-uexit nil)))
(random t)
(setq tloc (+ 60 (random 18)))
(dun-replace dun-room-objects tloc
(append (nth tloc dun-room-objects) (list 18)))

2
lisp/play/gomoku.el
View file

@ -1197,8 +1197,6 @@ If the game is finished, this command requests for another game."
(move-to-column (+ gomoku-x-offset
(* gomoku-square-width (1- gomoku-board-width)))))
(random t)
(provide 'gomoku)
;;; gomoku.el ends here

2
lisp/play/landmark.el
View file

@ -1683,8 +1683,6 @@ Use \\[describe-mode] for more info."
;;;allout-layout: (0 : -1 -1 0)
;;;End:
(random t)
(provide 'landmark)
;;; landmark.el ends here

6
lisp/play/life.el
View file

@ -111,9 +111,6 @@
;; Sadly, mode-line-format won't display numbers.
(defvar life-generation-string nil)
(defvar life-initialized nil
"Non-nil if `life' has been run at least once.")
;;;###autoload
(defun life (&optional sleeptime)
"Run Conway's Life simulation.
@ -121,9 +118,6 @@ The starting pattern is randomly selected. Prefix arg (optional first
arg non-nil from a program) is the number of seconds to sleep between
generations (this defaults to 1)."
(interactive "p")
(or life-initialized
(random t))
(setq life-initialized t)
(or sleeptime (setq sleeptime 1))
(life-setup)
(catch 'life-exit

2
lisp/play/mpuz.el
View file

@ -35,8 +35,6 @@
:prefix "mpuz-"
:group 'games)
(random t) ; randomize
(defcustom mpuz-silent 'error
"Set this to nil if you want dings on inputs.
The value t means never ding, and `error' means only ding on wrong input."

2
lisp/play/tetris.el
View file

@ -635,8 +635,6 @@ tetris-mode keybindings:
(tetris-mode)
(tetris-start-game))
(random t)
(provide 'tetris)
;;; tetris.el ends here

2
lisp/play/zone.el
View file

@ -675,8 +675,6 @@ If nil, `zone-pgm-random-life' chooses a value from 0-3 (inclusive).")
(kill-buffer nil))))
(random t)
;;;;;;;;;;;;;;;
(provide 'zone)

1
lisp/server.el
View file

@ -94,7 +94,6 @@
(setq val t)
(unless load-in-progress
(message "Local sockets unsupported, using TCP sockets")))
(when val (random t))
(set-default sym val))
:group 'server
:type 'boolean

1
lisp/type-break.el
View file

@ -577,7 +577,6 @@ as per the function `type-break-schedule'."
(unless type-break-terse-messages
(message "Press any key to resume from typing break."))
(random t)
(let* ((len (length type-break-demo-functions))
(idx (random len))
(fn (nth idx type-break-demo-functions)))

9
src/ChangeLog
View file

@ -1,3 +1,12 @@
2012-09-01 Paul Eggert <eggert@cs.ucla.edu>
Better seed support for (random).
* emacs.c (main): Call init_random.
* fns.c (Frandom): Set the seed from a string argument, if given.
Remove long-obsolete Gentzel cruft.
* lisp.h, sysdep.c (seed_random): Now takes address and size, not long.
(init_random): New function.
2012-08-31 Dmitry Antipov <dmantipov@yandex.ru>
Remove mark_ttys function and fix tty_display_info initialization.

1
src/emacs.c
View file

@ -1281,6 +1281,7 @@ Using an Emacs configured with --with-x-toolkit=lucid does not have this problem
init_data ();
init_atimer ();
running_asynch_code = 0;
init_random ();
no_loadup
= argmatch (argv, argc, "-nl", "--no-loadup", 6, NULL, &skip_args);

28
src/fns.c
View file

@ -74,32 +74,16 @@ Other values of LIMIT are ignored. */)
(Lisp_Object limit)
{
EMACS_INT val;
Lisp_Object lispy_val;
if (EQ (limit, Qt))
{
EMACS_TIME t = current_emacs_time ();
seed_random (getpid () ^ EMACS_SECS (t) ^ EMACS_NSECS (t));
}
init_random ();
else if (STRINGP (limit))
seed_random (SSDATA (limit), SBYTES (limit));
val = get_random ();
if (NATNUMP (limit) && XFASTINT (limit) != 0)
{
/* Try to take our random number from the higher bits of VAL,
not the lower, since (says Gentzel) the low bits of `random'
are less random than the higher ones. We do this by using the
quotient rather than the remainder. At the high end of the RNG
it's possible to get a quotient larger than n; discarding
these values eliminates the bias that would otherwise appear
when using a large n. */
EMACS_INT denominator = (INTMASK + 1) / XFASTINT (limit);
do
val = get_random () / denominator;
while (val >= XFASTINT (limit));
}
else
val = get_random ();
XSETINT (lispy_val, val);
return lispy_val;
val %= XFASTINT (limit);
return make_number (val);
}
/* Heuristic on how many iterations of a tight loop can be safely done

3
src/lisp.h
View file

@ -3405,7 +3405,8 @@ extern void child_setup_tty (int);
extern void setup_pty (int);
extern int set_window_size (int, int, int);
extern EMACS_INT get_random (void);
extern void seed_random (long);
extern void seed_random (void *, ptrdiff_t);
extern void init_random (void);
extern int emacs_open (const char *, int, int);
extern int emacs_close (int);
extern ptrdiff_t emacs_read (int, char *, ptrdiff_t);

24
src/sysdep.c
View file

@ -1765,19 +1765,37 @@ init_signals (void)
#endif /* !RAND_BITS */
void
seed_random (long int arg)
seed_random (void *seed, ptrdiff_t seed_size)
{
#if defined HAVE_RANDOM || ! defined HAV_LRAND48
unsigned int arg = 0;
#else
long int arg = 0;
#endif
unsigned char *argp = (unsigned char *) &arg;
unsigned char *seedp = seed;
ptrdiff_t i;
for (i = 0; i < seed_size; i++)
argp[i % sizeof arg] ^= seedp[i];
#ifdef HAVE_RANDOM
srandom ((unsigned int)arg);
srandom (arg);
#else
# ifdef HAVE_LRAND48
srand48 (arg);
# else
srand ((unsigned int)arg);
srand (arg);
# endif
#endif
}
void
init_random (void)
{
EMACS_TIME t = current_emacs_time ();
uintmax_t v = getpid () ^ EMACS_SECS (t) ^ EMACS_NSECS (t);
seed_random (&v, sizeof v);
}
/*
* Return a nonnegative random integer out of whatever we've got.
* It contains enough bits to make a random (signed) Emacs fixnum.