random.c

CFL是Unix下的通用抽象库,以简化Unix下的系统软件开发,CFL库中包含几个分组的函数和宏

/* ----------------------------------------------------------------------------
   CFL - A C Foundation Library
   Copyright (C) 1994-2003  Mark A Lindner

   This file is part of CFL.
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.
   
   This library 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
   Library General Public License for more details.
   
   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   ----------------------------------------------------------------------------
   $Log: random.c,v $
   Revision 1.1  2003/03/03 08:20:08  markl
   Initial checkin (clean compile on Solaris & OS X)

   ----------------------------------------------------------------------------
*/

/* Feature test switches */

#include "config.h"

/* System headers */

#ifdef THREADED_LIBRARY
#include <pthread.h>
#endif /* THREADED_LIBRARY */

/* Local headers */

#include "cfl/defs.h"
#include "cfl/system.h"

/* File scope variables */

#ifdef THREADED_LIBRARY

static pthread_once_t __C_random_once = PTHREAD_ONCE_INIT;
static pthread_key_t __C_random_key;

#endif /* THREADED_LIBRARY */

/* File scope functions */

#ifdef THREADED_LIBRARY

static void __C_random_destructor(void *arg)
  {
  C_free(arg);
  }

/*
 */

static void __C_random_init_once(void)
  {
  
  pthread_key_create(&__C_random_key, __C_random_destructor);
  }

#endif /* THREADED_LIBRARY */

/* External functions */

void C_random_seed(void)
  {
#ifdef THREADED_LIBRARY
  // no-op
#else
  srand((uint_t)time(NULL) + (uint_t)getpid());
#endif /* THREADED_LIBRARY */
  }

/*
 */

uint_t C_random(uint_t range)
  {
  uint_t r;
  
#ifdef THREADED_LIBRARY
  uint_t *seed;

  pthread_once(&__C_random_once, __C_random_init_once);

  seed = (uint_t *)pthread_getspecific(__C_random_key);
  if(! seed)
    {
    seed = C_new(uint_t);
    *seed = (time(NULL) + (long)pthread_self());
    pthread_setspecific(__C_random_key, (void *)seed);    
    }
  
  r = (uint_t)rand_r(seed);
#else
  r = (uint_t)rand();
#endif /* THREADED_LIBRARY */

  return((int)((float)range * r / RAND_MAX));
  }

/* end of source file */