On 1/6/14, 1:58 PM, Josef Bacik wrote:
> I was trying to reproduce something with fsx and I noticed that no matter what
> seed I set I was getting the same file. Come to find out we are overloading
> random() with our own custom horribleness for some unknown reason. So nuke the
> damn thing from orbit and rely on glibc's random(). With this fix the -S option
> actually does something with fsx. Thanks,
Hm, old comments seem to indicate that this was done <handwave> to make random
behave the same on different architectures (i.e. same result from same seed,
I guess?) I . . . don't know if that is true of glibc's random(), is it?
I'd like to dig into the history just a bit before we yank this, just to
be sure.
-Eric
> Signed-off-by: Josef Bacik <jbacik@xxxxxx>
> ---
> lib/Makefile | 3 +-
> lib/random.c | 240 -----------------------------------------------------------
> 2 files changed, 1 insertion(+), 242 deletions(-)
> delete mode 100644 lib/random.c
>
> diff --git a/lib/Makefile b/lib/Makefile
> index c7348ce..a9e32bc 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -16,8 +16,7 @@ LT_AGE = 0
> #
> CFILES = dataascii.c databin.c datapid.c file_lock.c forker.c \
> pattern.c open_flags.c random_range.c string_to_tokens.c \
> - str_to_bytes.c tlibio.c write_log.c \
> - random.c
> + str_to_bytes.c tlibio.c write_log.c
>
> default: depend $(LTLIBRARY)
>
> diff --git a/lib/random.c b/lib/random.c
> deleted file mode 100644
> index eb23cd9..0000000
> --- a/lib/random.c
> +++ /dev/null
> @@ -1,240 +0,0 @@
> -/**************************************************************************
> - *
> - * random.c -- pseudo random number generator
> - * Copyright (C) 1994 Chris Wallace (csw@xxxxxxxxxxxxxxxxxxxxxx)
> - *
> - * This program is free software; you can redistribute it and/or modify
> - * it under the terms of the GNU General Public License as published by
> - * the Free Software Foundation; either version 2 of the License, or
> - * (at your option) any later version.
> - *
> - * This program is distributed in the hope that it will be useful,
> - * but WITHOUT ANY WARRANTY; without even the implied warranty of
> - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> - * GNU General Public License for more details.
> - *
> - * You should have received a copy of the GNU General Public License
> - * along with this program; if not, write to the Free Software
> - * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> - *
> - *
> - **************************************************************************/
> -
> -#include <sys/types.h>
> -
> -/*
> - * modified by dxm@xxxxxxx so that this file acts as a drop in replacement
> - * for srandom and random.
> - */
> -
> -/*
> - * A random number generator called as a function by
> - * random (iseed) or irandm (iseed)
> - * The parameter should be a pointer to a 2-element int32_t vector.
> - * The first function returns a double uniform in 0 .. 1.
> - * The second returns a int32_t integer uniform in 0 .. 2**31-1
> - * Both update iseed[] in exactly the same way.
> - * iseed[] must be a 2-element integer vector.
> - * The initial value of the second element may be anything.
> - *
> - * The period of the random sequence is 2**32 * (2**32-1)
> - * The table mt[0:127] is defined by mt[i] = 69069 ** (128-i)
> - */
> -
> -#define MASK ((int32_t) 593970775)
> -/* or in hex, 23674657 */
> -
> -#define SCALE ((double) 1.0 / (1024.0 * 1024.0 * 1024.0 * 2.0))
> -/* i.e. 2 to power -31 */
> -
> -static int32_t mt [128] = {
> - 902906369,
> - 2030498053,
> - -473499623,
> - 1640834941,
> - 723406961,
> - 1993558325,
> - -257162999,
> - -1627724755,
> - 913952737,
> - 278845029,
> - 1327502073,
> - -1261253155,
> - 981676113,
> - -1785280363,
> - 1700077033,
> - 366908557,
> - -1514479167,
> - -682799163,
> - 141955545,
> - -830150595,
> - 317871153,
> - 1542036469,
> - -946413879,
> - -1950779155,
> - 985397153,
> - 626515237,
> - 530871481,
> - 783087261,
> - -1512358895,
> - 1031357269,
> - -2007710807,
> - -1652747955,
> - -1867214463,
> - 928251525,
> - 1243003801,
> - -2132510467,
> - 1874683889,
> - -717013323,
> - 218254473,
> - -1628774995,
> - -2064896159,
> - 69678053,
> - 281568889,
> - -2104168611,
> - -165128239,
> - 1536495125,
> - -39650967,
> - 546594317,
> - -725987007,
> - 1392966981,
> - 1044706649,
> - 687331773,
> - -2051306575,
> - 1544302965,
> - -758494647,
> - -1243934099,
> - -75073759,
> - 293132965,
> - -1935153095,
> - 118929437,
> - 807830417,
> - -1416222507,
> - -1550074071,
> - -84903219,
> - 1355292929,
> - -380482555,
> - -1818444007,
> - -204797315,
> - 170442609,
> - -1636797387,
> - 868931593,
> - -623503571,
> - 1711722209,
> - 381210981,
> - -161547783,
> - -272740131,
> - -1450066095,
> - 2116588437,
> - 1100682473,
> - 358442893,
> - -1529216831,
> - 2116152005,
> - -776333095,
> - 1265240893,
> - -482278607,
> - 1067190005,
> - 333444553,
> - 86502381,
> - 753481377,
> - 39000101,
> - 1779014585,
> - 219658653,
> - -920253679,
> - 2029538901,
> - 1207761577,
> - -1515772851,
> - -236195711,
> - 442620293,
> - 423166617,
> - -1763648515,
> - -398436623,
> - -1749358155,
> - -538598519,
> - -652439379,
> - 430550625,
> - -1481396507,
> - 2093206905,
> - -1934691747,
> - -962631983,
> - 1454463253,
> - -1877118871,
> - -291917555,
> - -1711673279,
> - 201201733,
> - -474645415,
> - -96764739,
> - -1587365199,
> - 1945705589,
> - 1303896393,
> - 1744831853,
> - 381957665,
> - 2135332261,
> - -55996615,
> - -1190135011,
> - 1790562961,
> - -1493191723,
> - 475559465,
> - 69069
> - };
> -
> -double
> -_random (int32_t is [2])
> -{
> - int32_t it, leh, nit;
> -
> - it = is [0];
> - leh = is [1];
> - if (it <= 0)
> - it = (it + it) ^ MASK;
> - else
> - it = it + it;
> - nit = it - 1;
> -/* to ensure all-ones pattern omitted */
> - leh = leh * mt[nit & 127] + nit;
> - is [0] = it; is [1] = leh;
> - if (leh < 0) leh = ~leh;
> - return (SCALE * ((int32_t) (leh | 1)));
> -}
> -
> -
> -
> -int32_t
> -_irandm (int32_t is [2])
> -{
> - int32_t it, leh, nit;
> -
> - it = is [0];
> - leh = is [1];
> - if (it <= 0)
> - it = (it + it) ^ MASK;
> - else
> - it = it + it;
> - nit = it - 1;
> -/* to ensure all-ones pattern omitted */
> - leh = leh * mt[nit & 127] + nit;
> - is [0] = it; is [1] = leh;
> - if (leh < 0) leh = ~leh;
> - return (leh);
> -}
> -
> -/*
> - * make this a drop in replacement for random and srandom
> - *
> - * XXX not thread safe I guess.
> - */
> -
> -static int32_t saved_seed[2];
> -
> -long random(void)
> -{
> - return _irandm(saved_seed);
> -}
> -
> -void srandom(unsigned seed)
> -{
> - saved_seed[0]=seed;
> - saved_seed[1]=0;
> - _irandm(saved_seed);
> -}
> -
>
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