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Diffstat (limited to 'nx-X11/extras/drm/libdrm/xf86drmRandom.c')
| -rw-r--r-- | nx-X11/extras/drm/libdrm/xf86drmRandom.c | 224 |
1 files changed, 0 insertions, 224 deletions
diff --git a/nx-X11/extras/drm/libdrm/xf86drmRandom.c b/nx-X11/extras/drm/libdrm/xf86drmRandom.c deleted file mode 100644 index 301aaf4c2..000000000 --- a/nx-X11/extras/drm/libdrm/xf86drmRandom.c +++ /dev/null @@ -1,224 +0,0 @@ -/* xf86drmRandom.c -- "Minimal Standard" PRNG Implementation - * Created: Mon Apr 19 08:28:13 1999 by faith@precisioninsight.com - * - * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. - * All Rights Reserved. - * - * Permission is hereby granted, free of charge, to any person obtaining a - * copy of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, copy, modify, merge, publish, distribute, sublicense, - * and/or sell copies of the Software, and to permit persons to whom the - * Software is furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice (including the next - * paragraph) shall be included in all copies or substantial portions of the - * Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR - * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, - * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER - * DEALINGS IN THE SOFTWARE. - * - * Authors: Rickard E. (Rik) Faith <faith@valinux.com> - * - * $XFree86: xc/programs/Xserver/hw/xfree86/os-support/linux/drm/xf86drmRandom.c,v 1.4 2000/06/17 00:03:34 martin Exp $ - * - * DESCRIPTION - * - * This file contains a simple, straightforward implementation of the Park - * & Miller "Minimal Standard" PRNG [PM88, PMS93], which is a Lehmer - * multiplicative linear congruential generator (MLCG) with a period of - * 2^31-1. - * - * This implementation is intended to provide a reliable, portable PRNG - * that is suitable for testing a hash table implementation and for - * implementing skip lists. - * - * FUTURE ENHANCEMENTS - * - * If initial seeds are not selected randomly, two instances of the PRNG - * can be correlated. [Knuth81, pp. 32-33] describes a shuffling technique - * that can eliminate this problem. - * - * If PRNGs are used for simulation, the period of the current - * implementation may be too short. [LE88] discusses methods of combining - * MLCGs to produce much longer periods, and suggests some alternative - * values for A and M. [LE90 and Sch92] also provide information on - * long-period PRNGs. - * - * REFERENCES - * - * [Knuth81] Donald E. Knuth. The Art of Computer Programming. Volume 2: - * Seminumerical Algorithms. Reading, Massachusetts: Addison-Wesley, 1981. - * - * [LE88] Pierre L'Ecuyer. "Efficient and Portable Combined Random Number - * Generators". CACM 31(6), June 1988, pp. 742-774. - * - * [LE90] Pierre L'Ecuyer. "Random Numbers for Simulation". CACM 33(10, - * October 1990, pp. 85-97. - * - * [PM88] Stephen K. Park and Keith W. Miller. "Random Number Generators: - * Good Ones are Hard to Find". CACM 31(10), October 1988, pp. 1192-1201. - * - * [Sch92] Bruce Schneier. "Pseudo-Ransom Sequence Generator for 32-Bit - * CPUs". Dr. Dobb's Journal 17(2), February 1992, pp. 34, 37-38, 40. - * - * [PMS93] Stephen K. Park, Keith W. Miller, and Paul K. Stockmeyer. In - * "Technical Correspondence: Remarks on Choosing and Implementing Random - * Number Generators". CACM 36(7), July 1993, pp. 105-110. - * - */ - -#ifdef HAVE_XORG_CONFIG_H -#include <xorg-config.h> -#endif - -#define RANDOM_MAIN 0 - -#if RANDOM_MAIN -# include <stdio.h> -# include <stdlib.h> -#else -# include "drm.h" -# include "xf86drm.h" -# ifdef XFree86LOADER -# include "xf86.h" -# include "xf86_ansic.h" -# else -# include <stdio.h> -# include <stdlib.h> -# endif -#endif - -#define N(x) drm##x - -#define RANDOM_MAGIC 0xfeedbeef -#define RANDOM_DEBUG 0 - -#if RANDOM_MAIN -#define RANDOM_ALLOC malloc -#define RANDOM_FREE free -#else -#define RANDOM_ALLOC drmMalloc -#define RANDOM_FREE drmFree -#endif - -typedef struct RandomState { - unsigned long magic; - unsigned long a; - unsigned long m; - unsigned long q; /* m div a */ - unsigned long r; /* m mod a */ - unsigned long check; - long seed; -} RandomState; - -#if RANDOM_MAIN -extern void *N(RandomCreate)(unsigned long seed); -extern int N(RandomDestroy)(void *state); -extern unsigned long N(Random)(void *state); -extern double N(RandomDouble)(void *state); -#endif - -void *N(RandomCreate)(unsigned long seed) -{ - RandomState *state; - - state = RANDOM_ALLOC(sizeof(*state)); - if (!state) return NULL; - state->magic = RANDOM_MAGIC; -#if 0 - /* Park & Miller, October 1988 */ - state->a = 16807; - state->m = 2147483647; - state->check = 1043618065; /* After 10000 iterations */ -#else - /* Park, Miller, and Stockmeyer, July 1993 */ - state->a = 48271; - state->m = 2147483647; - state->check = 399268537; /* After 10000 iterations */ -#endif - state->q = state->m / state->a; - state->r = state->m % state->a; - - state->seed = seed; - /* Check for illegal boundary conditions, - and choose closest legal value. */ - if (state->seed <= 0) state->seed = 1; - if (state->seed >= state->m) state->seed = state->m - 1; - - return state; -} - -int N(RandomDestroy)(void *state) -{ - RANDOM_FREE(state); - return 0; -} - -unsigned long N(Random)(void *state) -{ - RandomState *s = (RandomState *)state; - long hi; - long lo; - - hi = s->seed / s->q; - lo = s->seed % s->q; - s->seed = s->a * lo - s->r * hi; - if (s->seed <= 0) s->seed += s->m; - - return s->seed; -} - -double N(RandomDouble)(void *state) -{ - RandomState *s = (RandomState *)state; - - return (double)N(Random)(state)/(double)s->m; -} - -#if RANDOM_MAIN -static void check_period(long seed) -{ - unsigned long count = 0; - unsigned long initial; - void *state; - - state = N(RandomCreate)(seed); - initial = N(Random)(state); - ++count; - while (initial != N(Random)(state)) { - if (!++count) break; - } - printf("With seed of %10ld, period = %10lu (0x%08lx)\n", - seed, count, count); - N(RandomDestroy)(state); -} - -int main(void) -{ - RandomState *state; - int i; - unsigned long rand; - - state = N(RandomCreate)(1); - for (i = 0; i < 10000; i++) { - rand = N(Random)(state); - } - printf("After 10000 iterations: %lu (%lu expected): %s\n", - rand, state->check, - rand - state->check ? "*INCORRECT*" : "CORRECT"); - N(RandomDestroy)(state); - - printf("Checking periods...\n"); - check_period(1); - check_period(2); - check_period(31415926); - - return 0; -} -#endif |