shellsort.cpp revision 8f913b6793186335504b952aa8add7af3f29b91d
/* $Id$ */
/** @file
* IPRT - RTSortIsSorted.
*/
/*
* Copyright (C) 2010 Sun Microsystems, Inc.
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* you can redistribute it and/or modify it under the terms of the GNU
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 USA or visit http://www.sun.com if you need
* additional information or have any questions.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
#include "internal/iprt.h"
#include <iprt/sort.h>
RTDECL(void) RTSortApvShell(void **papvArray, size_t cElements, PFNRTSORTCMP pfnCmp, void *pvUser)
{
/* Anything worth sorting? */
if (cElements < 2)
return;
size_t cGap = (cElements + 1) / 2;
while (cGap > 0)
{
size_t i;
for (i = cGap; i < cElements; i++)
{
void *pvTmp = papvArray[i];
size_t j = i;
while ( j >= cGap
&& pfnCmp(papvArray[j - cGap], pvTmp, pvUser) > 0)
{
papvArray[j] = papvArray[j - cGap];
j -= cGap;
}
papvArray[j] = pvTmp;
}
/* This does not generate the most optimal gap sequence, but it has the
advantage of being simple and avoid floating point. */
cGap /= 2;
}
}