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re PR libfortran/32812 (random_seed and date_and_time)

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PR libfortran/32812
	* intrinsics/random.c (scramble_seed, unscramble_seed): New
	functions.
	(random_seed_i4): Scramble the seed the user gives us before
	storing it, and unscramble it when we return it back later.

From-SVN: r133104
This commit is contained in:
Francois-Xavier Coudert 2008-03-11 10:49:13 +00:00 committed by François-Xavier Coudert
parent 1ffe34d9f7
commit 2d3ca8b721
2 changed files with 47 additions and 4 deletions
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8
libgfortran/ChangeLog
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@ -1,3 +1,11 @@
2008-03-11 Francois-Xavier Coudert <fxcoudert@gcc.gnu.org>
PR libfortran/32812
* intrinsics/random.c (scramble_seed, unscramble_seed): New
functions.
(random_seed_i4): Scramble the seed the user gives us before
storing it, and unscramble it when we return it back later.
2008-03-05 Hans-Peter Nilsson <hp@axis.com>
PR libfortran/35293

43
libgfortran/intrinsics/random.c
View File

@ -639,6 +639,29 @@ arandom_r16 (gfc_array_r16 *x)
#endif
static void
scramble_seed (unsigned char *dest, unsigned char *src, int size)
{
int i;
for (i = 0; i < size; i++)
dest[(i % 2) * (size / 2) + i / 2] = src[i];
}
static void
unscramble_seed (unsigned char *dest, unsigned char *src, int size)
{
int i;
for (i = 0; i < size; i++)
dest[i] = src[(i % 2) * (size / 2) + i / 2];
}
/* random_seed is used to seed the PRNG with either a default
set of seeds or user specified set of seeds. random_seed
must be called with no argument or exactly one argument. */
@ -647,6 +670,7 @@ void
random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get)
{
int i;
unsigned char seed[4*kiss_size];
__gthread_mutex_lock (&random_lock);
@ -673,9 +697,15 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get)
if (((put->dim[0].ubound + 1 - put->dim[0].lbound)) < kiss_size)
runtime_error ("Array size of PUT is too small.");
/* This code now should do correct strides. */
/* We copy the seed given by the user. */
for (i = 0; i < kiss_size; i++)
kiss_seed[i] = (GFC_UINTEGER_4) put->data[i * put->dim[0].stride];
memcpy (seed + i * sizeof(GFC_UINTEGER_4),
&(put->data[(kiss_size - 1 - i) * put->dim[0].stride]),
sizeof(GFC_UINTEGER_4));
/* We put it after scrambling the bytes, to paper around users who
provide seeds with quality only in the lower or upper part. */
scramble_seed ((unsigned char *) kiss_seed, seed, 4*kiss_size);
}
/* Return the seed to GET data. */
@ -689,9 +719,14 @@ random_seed_i4 (GFC_INTEGER_4 *size, gfc_array_i4 *put, gfc_array_i4 *get)
if (((get->dim[0].ubound + 1 - get->dim[0].lbound)) < kiss_size)
runtime_error ("Array size of GET is too small.");
/* This code now should do correct strides. */
/* Unscramble the seed. */
unscramble_seed (seed, (unsigned char *) kiss_seed, 4*kiss_size);
/* Then copy it back to the user variable. */
for (i = 0; i < kiss_size; i++)
get->data[i * get->dim[0].stride] = (GFC_INTEGER_4) kiss_seed[i];
memcpy (&(get->data[(kiss_size - 1 - i) * get->dim[0].stride]),
seed + i * sizeof(GFC_UINTEGER_4),
sizeof(GFC_UINTEGER_4));
}
__gthread_mutex_unlock (&random_lock);