1/* 2 PIM for Quagga 3 Copyright (C) 2008 Everton da Silva Marques 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 2 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, but 11 WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program; see the file COPYING; if not, write to the 17 Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, 18 MA 02110-1301 USA 19 20 $QuaggaId: $Format:%an, %ai, %h$ $ 21*/ 22 23#include "pim_rand.h" 24#include "pim_time.h" 25 26/* Quick and dirty random number generator from NUMERICAL RECIPES IN C: 27 THE ART OF SCIENTIFIC COMPUTING (ISBN 0-521-43108-5). */ 28/* BEWARE: '_qseed_' is assigned! */ 29#define QRANDOM(_qseed_) ((_qseed_) = (((_qseed_) * 1664525L) + 1013904223L)) 30 31static long qpim_rand_seed; 32 33void pim_rand_init() 34{ 35 qpim_rand_seed = pim_time_monotonic_sec() ^ getpid(); 36} 37 38long pim_rand() 39{ 40 return QRANDOM(qpim_rand_seed); 41} 42 43int pim_rand_next(int min, int max) 44{ 45 long rand; 46 47 assert(min <= max); 48 49 /* FIXME better random generator ? */ 50 51 rand = QRANDOM(qpim_rand_seed); 52 if (rand < 0) 53 rand = -rand; 54 rand = rand % (1 + max - min) + min; 55 56 assert(rand >= min); 57 assert(rand <= max); 58 59 return rand; 60} 61