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132 lines
3.6 KiB
132 lines
3.6 KiB
//=============================================================================
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// File: boyermor.cpp
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// Contents: Definitions for DwBoyerMoore
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// Maintainer: Doug Sauder <dwsauder@fwb.gulf.net>
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// WWW: http://www.fwb.gulf.net/~dwsauder/mimepp.html
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//
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// Copyright (c) 1996, 1997 Douglas W. Sauder
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// All rights reserved.
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//
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// IN NO EVENT SHALL DOUGLAS W. SAUDER BE LIABLE TO ANY PARTY FOR DIRECT,
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// INDIRECT, SPECIAL, INCIDENTAL, OR CONSETQUENTIAL DAMAGES ARISING OUT OF
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// THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF DOUGLAS W. SAUDER
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// HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// DOUGLAS W. SAUDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT
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// NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
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// PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS"
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// BASIS, AND DOUGLAS W. SAUDER HAS NO OBLIGATION TO PROVIDE MAINTENANCE,
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// SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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//
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//=============================================================================
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#define DW_IMPLEMENTATION
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#include <mimelib/config.h>
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#include <mimelib/debug.h>
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#include <ctype.h>
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#include <string.h>
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#include <mimelib/boyermor.h>
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DwBoyerMoore::DwBoyerMoore(const char* aCstr)
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: mPat( 0 ), mCiPat( 0 )
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{
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size_t len = strlen(aCstr);
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_Assign(aCstr, len);
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}
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DwBoyerMoore::DwBoyerMoore(const DwString& aStr)
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: mPat( 0 ), mCiPat( 0 )
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{
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_Assign(aStr.data(), aStr.length());
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}
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DwBoyerMoore::DwBoyerMoore(const DwBoyerMoore & other)
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: mPat( 0 ), mCiPat( 0 )
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{
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_Assign(other.mPat, other.mPatLen);
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}
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DwBoyerMoore::~DwBoyerMoore()
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{
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delete[] mPat; mPat = 0;
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delete[] mCiPat; mCiPat = 0;
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}
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const DwBoyerMoore & DwBoyerMoore::operator=( const DwBoyerMoore & other )
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{
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if (this != &other)
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_Assign(other.mPat, other.mPatLen);
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return *this;
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}
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void DwBoyerMoore::Assign(const char* aCstr)
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{
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size_t len = strlen(aCstr);
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_Assign(aCstr, len);
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}
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void DwBoyerMoore::Assign(const DwString& aStr)
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{
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_Assign(aStr.data(), aStr.length());
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}
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void DwBoyerMoore::_Assign(const char* aPat, size_t aPatLen)
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{
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mPatLen = 0;
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delete[] mPat; mPat = 0;
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delete[] mCiPat; mCiPat = 0;
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mPat = new char[aPatLen+1];
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mCiPat = new char[aPatLen+1];
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if (mPat != 0 && aPatLen) {
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mPatLen = aPatLen;
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strncpy(mPat, aPat, mPatLen);
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mCiPat[mPatLen] = mPat[mPatLen] = 0;
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// Initialize the jump table for Boyer-Moore-Horspool algorithm
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size_t i;
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for (i=0; i < 256; ++i)
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mSkipAmt[i] = mCiSkipAmt[i] = (unsigned char) mPatLen;
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for (i=0; i < mPatLen-1; ++i) {
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unsigned char skip = mPatLen - i - 1;
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mCiPat[i] = tolower(mPat[i]);
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mCiSkipAmt[(unsigned char)mCiPat[i]] = skip;
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mCiSkipAmt[(unsigned char)toupper(mCiPat[i])] = skip;
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mSkipAmt[(unsigned char)mPat[i]] = skip;
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}
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mCiPat[i] = tolower(mPat[i]);
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}
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}
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size_t DwBoyerMoore::FindIn(const DwString& aStr, size_t aPos, bool aCs) const
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{
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char *pat = aCs ? mPat : mCiPat;
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const unsigned char *skipAmt = aCs ? mSkipAmt : mCiSkipAmt;
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if (aStr.length() <= aPos) {
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return (size_t) -1;
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}
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if (pat == 0 || mPatLen == 0) {
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return 0;
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}
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size_t bufLen = aStr.length() - aPos;
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const char* buf = aStr.data() + aPos;
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size_t i;
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for (i=mPatLen-1; i < bufLen; i += skipAmt[(unsigned char)buf[i]]) {
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int iBuf = i;
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int iPat = mPatLen - 1;
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while (iPat >= 0 && (aCs ? buf[iBuf] : tolower(buf[iBuf])) == pat[iPat]) {
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--iBuf;
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--iPat;
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}
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if (iPat == -1)
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return aPos + iBuf + 1;
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}
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return (size_t)-1;
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}
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