/*
* Copyright (c) 2008-2012 Zmanda, Inc. All Rights Reserved.
* Copyright (c) 2013-2016 Carbonite, Inc. All Rights Reserved.
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Contact information: Carbonite Inc., 756 N Pastoria Ave
* Sunnyvale, CA 94086, USA, or: http://www.zmanda.com
*/
#include "amanda.h"
#include "simpleprng.h"
/* A *very* basic linear congruential generator; values are as cited in
* http://en.wikipedia.org/wiki/Linear_congruential_generator for Numerical Recipes */
#define A 1664525
#define C 1013904223
void
simpleprng_seed(
simpleprng_state_t *state,
guint32 seed)
{
g_assert(seed != 0);
state->val = seed;
state->count = 0;
}
guint32
simpleprng_get_seed(
simpleprng_state_t *state)
{
return state->val;
}
guint32 simpleprng_rand(
simpleprng_state_t *state)
{
state->count++;
return (state->val = (A * state->val) + C);
}
void simpleprng_fill_buffer(
simpleprng_state_t *state,
gpointer buf,
size_t len)
{
guint8 *p = buf;
while (len--) {
*(p++) = simpleprng_rand_byte(state);
}
}
static char *
hexstr(guint8 *p, int len)
{
char *tmpbuf;
char *result = NULL;
int i;
for (i = 0; i < len; i++) {
if (result) {
tmpbuf = g_strdup_printf("%s %02x", result, (guint)(*(p++)));
g_free(result);
result = tmpbuf;
}
else
result = g_strdup_printf("[%02x", (guint)(*(p++)));
}
tmpbuf = g_strdup_printf("%s]", result);
g_free(result);
result = tmpbuf;
return result;
}
gboolean simpleprng_verify_buffer(
simpleprng_state_t *state,
gpointer buf,
size_t len)
{
guint8 *p = buf;
while (len--) {
guint64 count = state->count;
guint8 expected = simpleprng_rand_byte(state);
guint8 got = *p;
if (expected != got) {
int remaining = MIN(len, 16);
guint8 expbytes[16] = { expected };
char *gotstr = hexstr(p, remaining);
char *expstr;
int i;
for (i = 1; i < remaining; i++)
expbytes[i] = simpleprng_rand_byte(state);
expstr = hexstr(expbytes, remaining);
g_fprintf(stderr,
"random value mismatch at offset %ju: got %s, expected %s\n",
(uintmax_t)count, gotstr, expstr);
g_free(gotstr);
g_free(expstr);
return FALSE;
}
p++;
}
return TRUE;
}