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mirror of https://github.com/moparisthebest/wget synced 2024-07-03 16:38:41 -04:00

[svn] Use *rand48 where available.

This commit is contained in:
hniksic 2005-06-28 15:22:10 -07:00
parent e289d2ecc4
commit b8456c0fb4
4 changed files with 53 additions and 38 deletions

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@ -1,3 +1,7 @@
2005-06-29 Hrvoje Niksic <hniksic@xemacs.org>
* configure.in: Check for drand48.
2005-06-26 Hrvoje Niksic <hniksic@xemacs.org>
* m4/wget.m4: Use proper GPL header.

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@ -204,7 +204,7 @@ dnl
AC_FUNC_ALLOCA
AC_FUNC_MMAP
AC_FUNC_FSEEKO
AC_CHECK_FUNCS(strptime timegm snprintf vsnprintf)
AC_CHECK_FUNCS(strptime timegm snprintf vsnprintf drand48)
AC_CHECK_FUNCS(usleep ftello sigblock sigsetjmp symlink)
dnl We expect to have these functions on Unix-like systems configure

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@ -1,3 +1,8 @@
2005-06-29 Hrvoje Niksic <hniksic@xemacs.org>
* utils.c (random_number): Use lrand48 if available.
(random_float): Use drand48 if available.
2005-06-29 Hrvoje Niksic <hniksic@xemacs.org>
* main.c (secs_to_human_time): Use print_decimal when printing

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@ -1571,68 +1571,74 @@ determine_screen_width (void)
return 0;
#endif /* neither TIOCGWINSZ nor WINDOWS */
}
/* Whether the rnd system (either rand or [dl]rand48) has been
seeded. */
static int rnd_seeded;
/* Return a random number between 0 and MAX-1, inclusive.
If MAX is greater than the value of RAND_MAX+1 on the system, the
returned value will be in the range [0, RAND_MAX]. This may be
fixed in a future release.
If the system does not support lrand48 and MAX is greater than the
value of RAND_MAX+1 on the system, the returned value will be in
the range [0, RAND_MAX]. This may be fixed in a future release.
The random number generator is seeded automatically the first time
it is called.
This uses rand() for portability. It has been suggested that
random() offers better randomness, but this is not required for
Wget, so I chose to go for simplicity and use rand
unconditionally.
DO NOT use this for cryptographic purposes. It is only meant to be
used in situations where quality of the random numbers returned
doesn't really matter. */
This uses lrand48 where available, rand elsewhere. DO NOT use it
for cryptography. It is only meant to be used in situations where
quality of the random numbers returned doesn't really matter. */
int
random_number (int max)
{
static int seeded;
#ifdef HAVE_DRAND48
if (!rnd_seeded)
{
srand48 ((long) time (NULL) ^ (long) getpid ());
rnd_seeded = 1;
}
return lrand48 () % max;
#else /* not HAVE_DRAND48 */
double bounded;
int rnd;
if (!seeded)
if (!rnd_seeded)
{
srand (time (NULL));
seeded = 1;
srand ((unsigned) time (NULL) ^ (unsigned) getpid ());
rnd_seeded = 1;
}
rnd = rand ();
/* On systems that don't define RAND_MAX, assume it to be 2**15 - 1,
and enforce that assumption by masking other bits. */
#ifndef RAND_MAX
# define RAND_MAX 32767
rnd &= RAND_MAX;
#endif
/* Like rand() % max, but uses the high-order bits for better
randomness on architectures where rand() is implemented using a
simple congruential generator. */
/* This is equivalent to rand() % max, but uses the high-order bits
for better randomness on architecture where rand() is implemented
using a simple congruential generator. */
bounded = (double) max * rnd / (RAND_MAX + 1.0);
return (int) bounded;
bounded = (double)max * rnd / (RAND_MAX + 1.0);
return (int)bounded;
#endif /* not HAVE_DRAND48 */
}
/* Return a random uniformly distributed floating point number in the
[0, 1) range. The precision of returned numbers is 9 digits.
Modify this to use drand48() where available! */
[0, 1) range. Uses drand48 where available, and a really lame
kludge elsewhere. */
double
random_float (void)
{
/* We can't rely on any specific value of RAND_MAX, but it must
always be greater than 1000. */
int rnd1 = random_number (1000);
int rnd2 = random_number (1000);
int rnd3 = random_number (1000);
return rnd1 / 1000.0 + rnd2 / 1000000.0 + rnd3 / 1000000000.0;
#ifdef HAVE_DRAND48
if (!rnd_seeded)
{
srand48 ((long) time (NULL) ^ (long) getpid ());
rnd_seeded = 1;
}
return drand48 ();
#else /* not HAVE_DRAND48 */
return ( random_number (10000) / 10000.0
+ random_number (10000) / (10000.0 * 10000.0)
+ random_number (10000) / (10000.0 * 10000.0 * 10000.0)
+ random_number (10000) / (10000.0 * 10000.0 * 10000.0 * 10000.0));
#endif /* not HAVE_DRAND48 */
}
/* Implementation of run_with_timeout, a generic timeout-forcing