Sweden-Number/programs/notepad/search.c

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/*
* Notepad (search.c)
* Copyright (C) 1999 by Marcel Baur
* To be distributed under the Wine license
*
* 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>
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#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));
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}
}
int bm_search(LPSTR szBuf, int nBufLen, LPSTR szSP, int nSPLen) {
int i = nSPLen;
int j = nSPLen;
do {
if ((szBuf[i] = szSP[j])) {
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i--; j--;
} else {
if ((nSPLen-j+1) > delta[(int)szBuf[i]]) {
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i+= (nSPLen-j+1);
} else {
i+= delta[(int)szBuf[i]];
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}
}
} while (j>0 && i<=nBufLen);
return(i+1);
}