random32.c

著名的 helix realplayer 基于手机 symbian 系统的 播放器全套源代码

/* ***** BEGIN LICENSE BLOCK ***** 
 * Version: RCSL 1.0/RPSL 1.0 
 *  
 * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved. 
 *      
 * The contents of this file, and the files included with this file, are 
 * subject to the current version of the RealNetworks Public Source License 
 * Version 1.0 (the "RPSL") available at 
 * http://www.helixcommunity.org/content/rpsl unless you have licensed 
 * the file under the RealNetworks Community Source License Version 1.0 
 * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, 
 * in which case the RCSL will apply. You may also obtain the license terms 
 * directly from RealNetworks.  You may not use this file except in 
 * compliance with the RPSL or, if you have a valid RCSL with RealNetworks 
 * applicable to this file, the RCSL.  Please see the applicable RPSL or 
 * RCSL for the rights, obligations and limitations governing use of the 
 * contents of the file.  
 *  
 * This file is part of the Helix DNA Technology. RealNetworks is the 
 * developer of the Original Code and owns the copyrights in the portions 
 * it created. 
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 * This file, and the files included with this file, is distributed and made 
 * available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS 
 * FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * 
 * Technology Compatibility Kit Test Suite(s) Location: 
 *    http://www.helixcommunity.org/content/tck 
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 * ***** END LICENSE BLOCK ***** */ 

#include "hlxclib/stdlib.h"
#include "hxtypes.h"
#include "hxtick.h"
#include "md5.h"    
#include "random32.h"


static ULONG32 md_32(const unsigned char *string, int length)
{
    md5_state_t context;

    union {
	char   c[16]; /* Flawfinder: ignore */
        ULONG32 x[4];
    } digest;
    ULONG32 r;
    int i;
    
    md5_init (&context);
    md5_append (&context, string, length);
    md5_finish ((unsigned char *)&digest, &context);
    r = 0;
    for (i = 0; i < 3; i++) {
       r ^= digest.x[i];
    }
    return r;   
}
   

/*
* Return random unsigned 32-bit quantity. Use 'type' argument if you
* need to generate several different values in close succession.
* Functions used to create "s" is reduced, but that should be fine...
*/
UINT32 random32(int type)
{
   struct {
       int	type;
       UINT32	tick;
       int	rand;
    } s;
    
    s.type  = type;
    s.tick  = HX_GET_TICKCOUNT();
    s.rand  = rand();
    
    return md_32((const unsigned char *)&s, sizeof(s));   
}