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/***************************************************************************
* *
* Copyright (C) 2005 Piotr Wawrzyniak (piti@piti.vsv.pl *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
***************************************************************************/
/*
W tym pliku zawarta jest procedura odpowiedzialna za przeszukiwanie
stringu. Procedure przepisana wprost z ksi±¿ki z algorytmami.
In this file there is procedure that looks for any patern in given
string. Procedure taken directry from book.
*/
#include<iostream>
#include<string.h>
#include<ctype.h>
#include"prz_string.h"
using namespace std;
//const int K=26*2+2*2+1+1+1;// znaki ASCII+polskie litery+spacja+dwukropek+srednik
const int K=256;
int shift[K];
//-------------------------------------------------------
int indeks(char c)
{
switch(c)
{
case ' ':return 0; // spacja=0
case '.':return 46;
case 'ê':return 53;
case 'Ê':return 54; // polskie litery
case '³':return 55;
case '£':return 56; // itd. dla pozosta³ych polskich liter
case '?':return 63;
case ':':return 58;
case ';':return 59;
case '{':return 123;
case '}':return 125;
default:
if(islower(c))
return c-'a'+1;
else return c-'A'+27;
}
}
//-------------------------------------------------------
int init_shifts(char *w)
{
int M=strlen(w);
for(int i=0;i<K;i++) shift[i]=M;
for(int i=0;i<M;i++)
shift[indeks(w[i])]=M-i-1;
return 0;
}
//-------------------------------------------------------
int bm(char *w,char *t)
{
init_shifts(w);
int i, j,N=strlen(t),M=strlen(w);
for(i=M-1,j=M-1;j>0;i--,j--)
while(t[i]!=w[j])
{
int x=shift[indeks(t[i])];
if(M-j>x) i+=M-j;else
i+=x;
if (i>=N) return -1;
j=M-1;
}
return i;
}
//-------------------------------------------------------
/*void main()
{
char *t,*w;
cout<<"Napisz tekst do przeszukania ";
cin>>t;
cout<<"Napisz wzorzec do znalezienia ";
cin>>w;
cout << "Wynik poszukiwañ="<<bm(w,t)<<endl;
}
*/
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