Sweden-Number/programs/notepad/search.c

70 lines
1.9 KiB
C

/*
* Notepad (search.c)
* Copyright (C) 1999 by Marcel Baur
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* This file features Heuristic Boyer-Moore Text Search
*
* Always: - Buf is the Buffer containing the whole text
* ======= - SP is the Search Pattern, which has to be found in Buf.
*
*/
#include <windows.h>
#define CHARSETSIZE 255
int delta[CHARSETSIZE];
/* rightmostpos: return rightmost position of ch in szSP (or -1) */
int rightmostpos(char ch, LPSTR szSP, int nSPLen) {
int i = nSPLen;
while ((i>0) & (szSP[i]!=ch)) i--;
return(i);
}
/* setup_delta: setup delta1 cache */
void setup_delta(LPSTR szSP, int nSPLen) {
int i;
for (i=0; i<CHARSETSIZE; i++) {
delta[i] = nSPLen;
}
for (i=0; i<nSPLen; i++) {
delta[(int)szSP[i]] = (nSPLen - rightmostpos(szSP[i], szSP, nSPLen));
}
}
int bm_search(LPSTR szBuf, int nBufLen, LPSTR szSP, int nSPLen) {
int i = nSPLen;
int j = nSPLen;
do {
if ((szBuf[i] = szSP[j])) {
i--; j--;
} else {
if ((nSPLen-j+1) > delta[(int)szBuf[i]]) {
i+= (nSPLen-j+1);
} else {
i+= delta[(int)szBuf[i]];
}
}
} while (j>0 && i<=nBufLen);
return(i+1);
}