random32.c

linux下的一款播放器

/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: random32.c,v 1.4.32.3 2004/07/09 01:48:16 hubbe Exp $
 * 
 * Portions Copyright (c) 1995-2004 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 (the "RPSL") available at
 * http://www.helixcommunity.org/content/rpsl unless you have licensed
 * the file under the current version of the RealNetworks Community
 * Source License (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.
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL") in which case the provisions of the GPL are applicable
 * instead of those above. If you wish to allow use of your version of
 * this file only under the terms of the GPL, and not to allow others
 * to use your version of this file under the terms of either the RPSL
 * or RCSL, indicate your decision by deleting the provisions above
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 * the GPL. If you do not delete the provisions above, a recipient may
 * use your version of this file under the terms of any one of the
 * RPSL, the RCSL or the GPL.
 * 
 * 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.
 * 
 * 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
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 * ENJOYMENT OR NON-INFRINGEMENT.
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 * Contributor(s):
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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));   
}