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61 lines
1.4 KiB
C
61 lines
1.4 KiB
C
/*
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* Copyright (C) 2007
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* pancake <pancake@youterm.com>
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*
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* radare is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* radare 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
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with radare; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#if 0
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From Wikipedia, the free encyclopedia
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In information theory, the Hamming distance between two strings of equal
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length is the number of positions for which the corresponding symbols
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are different. Put another way, it measures the minimum number of
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substitutions required to change one into the other, or the number of
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errors that transformed one string into the other.
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#endif
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#include "r_types.h"
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static int hamdist(int x, ut64 y)
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{
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int dist = 0, val = x^y;
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while(val) {
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++dist;
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val &= val - 1;
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}
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return dist;
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}
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ut8 r_hash_hamdist(const ut8 *buf, ut64 len)
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{
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int x = 0;
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int y = 0;
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int i;
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for(i=0;i<len;i++) {
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y = buf[i];
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x = hamdist(x, y);
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}
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return x;
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}
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