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125 lines
2.7 KiB
125 lines
2.7 KiB
/*
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* Re-entrant mergesort.
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* Copyright (c) 1998 New Generation Software (NGS) Oy
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*
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* Author: Markku Rossi <mtr@ngs.fi>
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*/
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/*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free
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* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
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* MA 02111-1307, USA
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*/
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/*
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* $Source: /tmp/cvsroot-15-2-2007/clamav-devel/libclamav/js/mrgsort.c,v $
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* $Id: mrgsort.c,v 1.2 2006/10/28 11:27:44 njh Exp $
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*/
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#if HAVE_CONFIG_H
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#include "clamav-config.h"
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#endif
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#ifdef CL_EXPERIMENTAL
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#include <stdio.h>
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#include <stdlib.h>
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#include <assert.h>
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#include "mrgsort.h"
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/*
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* Types and definitions.
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*/
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#define COPY(buf1, idx1, buf2, idx2) \
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memcpy ((buf1) + (idx1) * size, (buf2) + (idx2) * size, size);
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/*
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* Static functions.
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*/
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static void
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do_mergesort (unsigned char *base, unsigned int size, unsigned char *tmp,
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unsigned int l, unsigned int r,
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MergesortCompFunc func, void *func_ctx)
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{
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unsigned int i, j, k, m;
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if (r <= l)
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return;
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m = (r + l) / 2;
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do_mergesort (base, size, tmp, l, m, func, func_ctx);
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do_mergesort (base, size, tmp, m + 1, r, func, func_ctx);
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memcpy (tmp + l * size, base + l * size, (r - l + 1) * size);
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i = l;
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j = m + 1;
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k = l;
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/* Merge em. */
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while (i <= m && j <= r)
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{
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if ((*func) (tmp + i * size, tmp + j * size, func_ctx) <= 0)
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{
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COPY (base, k, tmp, i);
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i++;
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}
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else
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{
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COPY (base, k, tmp, j);
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j++;
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}
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k++;
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}
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/* Copy left-overs. Only one of the following will be executed. */
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for (; i <= m; i++)
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{
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COPY (base, k, tmp, i);
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k++;
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}
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for (; j <= r; j++)
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{
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COPY (base, k, tmp, j);
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k++;
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}
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}
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/*
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* Global functions.
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*/
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void
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mergesort_r (void *base, unsigned int number_of_elements,
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unsigned int size, MergesortCompFunc comparison_func,
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void *comparison_func_context)
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{
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void *tmp;
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if (number_of_elements == 0)
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return;
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/* Allocate tmp buffer. */
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tmp = malloc (number_of_elements * size);
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assert (tmp != NULL);
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do_mergesort (base, size, tmp, 0, number_of_elements - 1, comparison_func,
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comparison_func_context);
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free (tmp);
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}
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#endif /*CL_EXPERIMENTAL*/
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