2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
2018-05-29 21:21:26 +02:00
|
|
|
* libs/libc/stdlib/lib_srand.c
|
2012-11-10 17:06:01 +01:00
|
|
|
*
|
2016-07-17 15:11:09 +02:00
|
|
|
* Copyright (C) 2007, 2011, 2016 Gregory Nutt. All rights reserved.
|
2012-11-10 17:06:01 +01:00
|
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
|
|
*
|
|
|
|
* Redistribution and use in source and binary forms, with or without
|
|
|
|
* modification, are permitted provided that the following conditions
|
|
|
|
* are met:
|
|
|
|
*
|
|
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
|
|
* notice, this list of conditions and the following disclaimer.
|
|
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
|
|
* notice, this list of conditions and the following disclaimer in
|
|
|
|
* the documentation and/or other materials provided with the
|
|
|
|
* distribution.
|
|
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
|
|
* used to endorse or promote products derived from this software
|
|
|
|
* without specific prior written permission.
|
|
|
|
*
|
|
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
|
|
*
|
2012-12-01 17:32:03 +01:00
|
|
|
****************************************************************************/
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
2012-11-10 17:06:01 +01:00
|
|
|
* Included Files
|
2012-12-01 17:32:03 +01:00
|
|
|
****************************************************************************/
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2016-07-17 15:56:25 +02:00
|
|
|
#include <nuttx/config.h>
|
|
|
|
|
2012-11-10 17:06:01 +01:00
|
|
|
#include <sys/types.h>
|
|
|
|
#include <stdlib.h>
|
|
|
|
|
2016-07-21 22:05:44 +02:00
|
|
|
#include <nuttx/lib/lib.h>
|
2016-07-17 15:56:25 +02:00
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
|
|
|
* Pre-processor Definitions
|
|
|
|
****************************************************************************/
|
2016-07-17 15:56:25 +02:00
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
/* First, second, and thired order congruential generators are supported */
|
2012-11-10 17:06:01 +01:00
|
|
|
|
|
|
|
#ifndef CONFIG_LIB_RAND_ORDER
|
2012-12-01 17:32:03 +01:00
|
|
|
# define CONFIG_LIB_RAND_ORDER 1
|
2012-11-10 17:06:01 +01:00
|
|
|
#endif
|
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
#if CONFIG_LIB_RAND_ORDER > 3
|
|
|
|
# undef CONFIG_LIB_RAND_ORDER
|
|
|
|
# define CONFIG_LIB_RAND_ORDER 3
|
|
|
|
#endif
|
|
|
|
|
2012-11-10 17:06:01 +01:00
|
|
|
/* Values needed by the random number generator */
|
|
|
|
|
|
|
|
#define RND1_CONSTK 470001
|
|
|
|
#define RND1_CONSTP 999563
|
|
|
|
#define RND2_CONSTK1 366528
|
|
|
|
#define RND2_CONSTK2 508531
|
|
|
|
#define RND2_CONSTP 998917
|
|
|
|
#define RND3_CONSTK1 360137
|
|
|
|
#define RND3_CONSTK2 519815
|
|
|
|
#define RND3_CONSTK3 616087
|
|
|
|
#define RND3_CONSTP 997783
|
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
2012-11-10 17:06:01 +01:00
|
|
|
* Private Function Prototypes
|
2012-12-01 17:32:03 +01:00
|
|
|
****************************************************************************/
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
/* First order congruential generators */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
static inline unsigned long fgenerate1(void);
|
2012-12-01 19:04:10 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER == 1)
|
2012-11-10 17:06:01 +01:00
|
|
|
static double_t frand1(void);
|
2012-12-01 19:04:10 +01:00
|
|
|
#endif
|
|
|
|
|
|
|
|
/* Second order congruential generators */
|
|
|
|
|
2012-11-10 17:06:01 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 1)
|
2012-12-07 17:00:56 +01:00
|
|
|
static inline unsigned long fgenerate2(void);
|
2012-12-01 19:04:10 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER == 2)
|
2012-11-10 17:06:01 +01:00
|
|
|
static double_t frand2(void);
|
2012-12-01 19:04:10 +01:00
|
|
|
#endif
|
|
|
|
|
|
|
|
/* Third order congruential generators */
|
|
|
|
|
2012-11-10 17:06:01 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 2)
|
2012-12-07 17:00:56 +01:00
|
|
|
static inline unsigned long fgenerate3(void);
|
2012-11-10 17:06:01 +01:00
|
|
|
static double_t frand3(void);
|
|
|
|
#endif
|
|
|
|
#endif
|
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
|
|
|
* Private Data
|
|
|
|
****************************************************************************/
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
static unsigned long g_randint1;
|
2012-11-10 17:06:01 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 1)
|
2012-12-01 17:32:03 +01:00
|
|
|
static unsigned long g_randint2;
|
2012-11-10 17:06:01 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 2)
|
2012-12-01 17:32:03 +01:00
|
|
|
static unsigned long g_randint3;
|
2012-11-10 17:06:01 +01:00
|
|
|
#endif
|
|
|
|
#endif
|
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
2012-11-10 17:06:01 +01:00
|
|
|
* Private Functions
|
2012-12-01 17:32:03 +01:00
|
|
|
****************************************************************************/
|
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
/* First order congruential generators */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
static inline unsigned long fgenerate1(void)
|
2012-11-10 17:06:01 +01:00
|
|
|
{
|
2012-12-01 17:32:03 +01:00
|
|
|
unsigned long randint;
|
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
/* First order congruential generator. One may be added to the result of the
|
|
|
|
* generated value to avoid the value zero. This would be fatal for the
|
|
|
|
* first order random number generator.
|
2012-12-01 17:32:03 +01:00
|
|
|
*/
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
randint = (RND1_CONSTK * g_randint1) % RND1_CONSTP;
|
|
|
|
g_randint1 = (randint == 0 ? 1 : randint);
|
2012-12-07 17:00:56 +01:00
|
|
|
return randint;
|
2012-12-01 19:04:10 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
#if (CONFIG_LIB_RAND_ORDER == 1)
|
|
|
|
static double_t frand1(void)
|
|
|
|
{
|
|
|
|
/* First order congruential generator. */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
unsigned long randint = fgenerate1();
|
2012-11-10 17:06:01 +01:00
|
|
|
|
|
|
|
/* Construct an floating point value in the range from 0.0 up to 1.0 */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
return ((double_t)randint) / ((double_t)RND1_CONSTP);
|
2012-12-01 17:32:03 +01:00
|
|
|
}
|
2012-12-01 19:04:10 +01:00
|
|
|
#endif
|
|
|
|
|
|
|
|
/* Second order congruential generators */
|
2012-11-10 17:06:01 +01:00
|
|
|
|
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 1)
|
2012-12-07 17:00:56 +01:00
|
|
|
static inline unsigned long fgenerate2(void)
|
2012-11-10 17:06:01 +01:00
|
|
|
{
|
2012-12-01 17:32:03 +01:00
|
|
|
unsigned long randint;
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-02 18:34:08 +01:00
|
|
|
/* Second order congruential generator. */
|
2012-12-01 17:32:03 +01:00
|
|
|
|
|
|
|
randint = (RND2_CONSTK1 * g_randint1 +
|
2012-12-01 19:44:57 +01:00
|
|
|
RND2_CONSTK2 * g_randint2) % RND2_CONSTP;
|
2012-12-01 17:32:03 +01:00
|
|
|
|
|
|
|
g_randint2 = g_randint1;
|
2012-12-02 18:34:08 +01:00
|
|
|
g_randint1 = randint;
|
|
|
|
|
|
|
|
/* We cannot permit both values to become zero. That would be fatal for the
|
|
|
|
* second order random number generator.
|
|
|
|
*/
|
|
|
|
|
|
|
|
if (g_randint2 == 0 && g_randint1 == 0)
|
|
|
|
{
|
|
|
|
g_randint2 = 1;
|
|
|
|
}
|
2012-12-07 17:00:56 +01:00
|
|
|
|
|
|
|
return randint;
|
2012-12-01 19:04:10 +01:00
|
|
|
}
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER == 2)
|
|
|
|
static double_t frand2(void)
|
|
|
|
{
|
|
|
|
/* Second order congruential generator */
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
unsigned long randint = fgenerate2();
|
2012-12-01 17:32:03 +01:00
|
|
|
|
2012-12-01 19:04:10 +01:00
|
|
|
/* Construct an floating point value in the range from 0.0 up to 1.0 */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
return ((double_t)randint) / ((double_t)RND2_CONSTP);
|
2012-12-01 17:32:03 +01:00
|
|
|
}
|
2012-12-01 19:04:10 +01:00
|
|
|
#endif
|
|
|
|
|
|
|
|
/* Third order congruential generators */
|
2012-11-10 17:06:01 +01:00
|
|
|
|
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 2)
|
2012-12-07 17:00:56 +01:00
|
|
|
static inline unsigned long fgenerate3(void)
|
2012-11-10 17:06:01 +01:00
|
|
|
{
|
2012-12-01 17:32:03 +01:00
|
|
|
unsigned long randint;
|
|
|
|
|
2012-12-02 18:34:08 +01:00
|
|
|
/* Third order congruential generator. */
|
2012-12-01 17:32:03 +01:00
|
|
|
|
|
|
|
randint = (RND3_CONSTK1 * g_randint1 +
|
|
|
|
RND3_CONSTK2 * g_randint2 +
|
2012-12-01 19:44:57 +01:00
|
|
|
RND3_CONSTK2 * g_randint3) % RND3_CONSTP;
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
g_randint3 = g_randint2;
|
|
|
|
g_randint2 = g_randint1;
|
2012-12-02 18:34:08 +01:00
|
|
|
g_randint1 = randint;
|
|
|
|
|
|
|
|
/* We cannot permit all three values to become zero. That would be fatal for the
|
|
|
|
* third order random number generator.
|
|
|
|
*/
|
|
|
|
|
|
|
|
if (g_randint3 == 0 && g_randint2 == 0 && g_randint1 == 0)
|
|
|
|
{
|
|
|
|
g_randint3 = 1;
|
|
|
|
}
|
2012-12-07 17:00:56 +01:00
|
|
|
|
|
|
|
return randint;
|
2012-12-01 19:04:10 +01:00
|
|
|
}
|
|
|
|
|
|
|
|
static double_t frand3(void)
|
|
|
|
{
|
|
|
|
/* Third order congruential generator */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
unsigned long randint = fgenerate3();
|
2012-11-10 17:06:01 +01:00
|
|
|
|
|
|
|
/* Construct an floating point value in the range from 0.0 up to 1.0 */
|
|
|
|
|
2012-12-07 17:00:56 +01:00
|
|
|
return ((double_t)randint) / ((double_t)RND3_CONSTP);
|
2012-12-01 17:32:03 +01:00
|
|
|
}
|
2012-11-10 17:06:01 +01:00
|
|
|
#endif
|
|
|
|
#endif
|
|
|
|
|
2012-12-01 17:32:03 +01:00
|
|
|
/****************************************************************************
|
2012-11-10 17:06:01 +01:00
|
|
|
* Public Functions
|
2012-12-01 17:32:03 +01:00
|
|
|
****************************************************************************/
|
|
|
|
|
|
|
|
/****************************************************************************
|
2016-07-17 15:56:25 +02:00
|
|
|
* Name: srand
|
|
|
|
*
|
|
|
|
* Description:
|
2016-07-17 16:31:02 +02:00
|
|
|
* Seed the congruential random number generator.
|
2016-07-17 15:56:25 +02:00
|
|
|
*
|
2012-12-01 17:32:03 +01:00
|
|
|
****************************************************************************/
|
2012-11-10 17:06:01 +01:00
|
|
|
|
|
|
|
void srand(unsigned int seed)
|
|
|
|
{
|
2012-12-01 17:32:03 +01:00
|
|
|
g_randint1 = seed;
|
2012-11-10 17:06:01 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 1)
|
2012-12-01 17:32:03 +01:00
|
|
|
g_randint2 = seed;
|
2012-12-07 17:00:56 +01:00
|
|
|
(void)fgenerate1();
|
2012-11-10 17:06:01 +01:00
|
|
|
#if (CONFIG_LIB_RAND_ORDER > 2)
|
2012-12-01 17:32:03 +01:00
|
|
|
g_randint3 = seed;
|
2012-12-07 17:00:56 +01:00
|
|
|
(void)fgenerate2();
|
2012-11-10 17:06:01 +01:00
|
|
|
#endif
|
|
|
|
#endif
|
2012-12-01 17:32:03 +01:00
|
|
|
}
|
2012-11-10 17:06:01 +01:00
|
|
|
|
2016-07-17 15:56:25 +02:00
|
|
|
/****************************************************************************
|
|
|
|
* Name: nrand
|
|
|
|
*
|
|
|
|
* Description:
|
2016-07-17 16:31:02 +02:00
|
|
|
* Return a random, unsigned long value in the range of 0 to (limit - 1)
|
2016-07-17 15:56:25 +02:00
|
|
|
*
|
|
|
|
****************************************************************************/
|
|
|
|
|
|
|
|
unsigned long nrand(unsigned long limit)
|
2012-11-10 17:06:01 +01:00
|
|
|
{
|
2016-07-17 15:56:25 +02:00
|
|
|
unsigned long result;
|
|
|
|
double_t ratio;
|
|
|
|
|
|
|
|
/* Loop to be sure a legal random number is generated */
|
|
|
|
|
|
|
|
do
|
|
|
|
{
|
2016-07-17 16:31:02 +02:00
|
|
|
/* Get a random integer in the range 0.0 - 1.0 */
|
2016-07-17 15:56:25 +02:00
|
|
|
|
|
|
|
#if (CONFIG_LIB_RAND_ORDER == 1)
|
|
|
|
ratio = frand1();
|
|
|
|
#elif (CONFIG_LIB_RAND_ORDER == 2)
|
|
|
|
ratio = frand2();
|
|
|
|
#else /* if (CONFIG_LIB_RAND_ORDER > 2) */
|
|
|
|
ratio = frand3();
|
|
|
|
#endif
|
|
|
|
|
2016-07-17 16:31:02 +02:00
|
|
|
/* Then, produce the return-able value in the requested range */
|
2016-07-17 15:56:25 +02:00
|
|
|
|
|
|
|
result = (unsigned long)(((double_t)limit) * ratio);
|
2016-07-17 16:31:02 +02:00
|
|
|
|
2018-07-19 23:19:17 +02:00
|
|
|
/* Loop because there is an (unlikely) possibility that rounding
|
|
|
|
* could increase the result at the limit value about the limit.
|
2016-07-17 16:31:02 +02:00
|
|
|
*/
|
2016-07-17 15:56:25 +02:00
|
|
|
}
|
|
|
|
while (result >= limit);
|
|
|
|
|
|
|
|
return result;
|
2012-12-01 17:32:03 +01:00
|
|
|
}
|