bmpattern.cpp

来自「IBM的解析xml的工具Xerces的源代码」· C++ 代码 · 共 230 行

/*
 * Copyright 2001,2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * $Log: BMPattern.cpp,v $
 * Revision 1.5  2004/09/08 13:56:47  peiyongz
 * Apache License Version 2.0
 *
 * Revision 1.4  2003/10/01 16:32:40  neilg
 * improve handling of out of memory conditions, bug #23415.  Thanks to David Cargill.
 *
 * Revision 1.3  2003/05/15 18:42:54  knoaman
 * Partial implementation of the configurable memory manager.
 *
 * Revision 1.2  2002/11/04 15:17:00  tng
 * C++ Namespace Support.
 *
 * Revision 1.1.1.1  2002/02/01 22:22:28  peiyongz
 * sane_include
 *
 * Revision 1.2  2001/05/11 13:26:40  tng
 * Copyright update.
 *
 * Revision 1.1  2001/03/02 19:22:31  knoaman
 * Schema: Regular expression handling part I
 *
 */

// ---------------------------------------------------------------------------
//  Includes
// ---------------------------------------------------------------------------
#include <xercesc/util/regx/BMPattern.hpp>
#include <xercesc/util/XMLString.hpp>
#include <xercesc/util/Janitor.hpp>
#include <xercesc/framework/MemoryManager.hpp>
#include <xercesc/util/OutOfMemoryException.hpp>

XERCES_CPP_NAMESPACE_BEGIN

// ---------------------------------------------------------------------------
//  BMPattern: Constructors
// ---------------------------------------------------------------------------
BMPattern::BMPattern( const XMLCh*         const pattern
                    ,       bool                 ignoreCase
                    ,       MemoryManager* const manager) :

    fIgnoreCase(ignoreCase)
    , fShiftTableLen(256)
    , fShiftTable(0)
    , fPattern(0)
    , fUppercasePattern(0)
    , fMemoryManager(manager)
{
	try {
        fPattern = XMLString::replicate(pattern, fMemoryManager);
		initialize();
	}
    catch(const OutOfMemoryException&)
    {
        throw;
    }
    catch(...) {

		cleanUp();
		throw;
	}
}

BMPattern::BMPattern( const XMLCh*         const pattern
                    ,       int                  tableSize
                    ,       bool                 ignoreCase
                    ,       MemoryManager* const manager) :

    fIgnoreCase(ignoreCase)
    , fShiftTableLen(tableSize)
    , fShiftTable(0)
    , fPattern(0)
    , fUppercasePattern(0)
    , fMemoryManager(manager)
{
	try {
        fPattern = XMLString::replicate(pattern, fMemoryManager);
		initialize();
	}
    catch(const OutOfMemoryException&)
    {
        throw;
    }
    catch(...) {

		cleanUp();
		throw;
	}
}

BMPattern::~BMPattern() {

	cleanUp();
}

// ---------------------------------------------------------------------------
//  BMPattern: matches methods
// ---------------------------------------------------------------------------
int BMPattern::matches(const XMLCh* const content, int start, int limit) {

	const unsigned int	patternLen = XMLString::stringLen(fPattern);
	// Uppercase Content
	XMLCh* ucContent = 0;

	if (patternLen == 0)
		return start;

	if (fIgnoreCase) {
		
		ucContent = XMLString::replicate(content, fMemoryManager);
		XMLString::upperCase(ucContent);
	}

	ArrayJanitor<XMLCh> janUCContent(ucContent, fMemoryManager);

	int index = start + patternLen;

	while (index <= limit) {

		int patternIndex = patternLen;
		int nIndex = index + 1;
		XMLCh ch;

		while (patternIndex > 0) {

			ch = content[--index];

			if (ch != fPattern[--patternIndex]) {

				// No match, so we will break. But first we have
				// to check the ignore case flag. If it is set, then
				// we try to match with the case ignored
				if (!fIgnoreCase ||
					(fUppercasePattern[patternIndex] != ucContent[index]))
					break;
			}

			if (patternIndex == 0)
				return index;
		}

		index += fShiftTable[ch % fShiftTableLen] + 1;

		if (index < nIndex)
			index = nIndex;
	}

	return -1;
}

// ---------------------------------------------------------------------------
//  BMPattern: private helpers methods
// ---------------------------------------------------------------------------
void BMPattern::initialize() {

	const unsigned int	patternLen = XMLString::stringLen(fPattern);
	XMLCh* lowercasePattern = 0;

	fShiftTable = (int*) fMemoryManager->allocate(fShiftTableLen*sizeof(int)); //new int[fShiftTableLen];

	if (fIgnoreCase) {

		fUppercasePattern = XMLString::replicate(fPattern, fMemoryManager);
		lowercasePattern = XMLString::replicate(fPattern, fMemoryManager);
		XMLString::upperCase(fUppercasePattern);
		XMLString::lowerCase(lowercasePattern);
	}

	ArrayJanitor<XMLCh> janLowercase(lowercasePattern, fMemoryManager);

	for (unsigned int i=0; i< fShiftTableLen; i++)
		fShiftTable[i] = patternLen;

	for (unsigned int k=0; k< patternLen; k++) {

		XMLCh	ch = fPattern[k];
		int		diff = patternLen - k - 1;
		int		index = ch % fShiftTableLen;

		if (diff < fShiftTable[index])
			fShiftTable[index] = diff;

		if (fIgnoreCase) {

			for (int j=0; j< 2; j++) {

				ch = (j == 0) ? fUppercasePattern[k] : lowercasePattern[k];
				index = ch % fShiftTableLen;

				if (diff < fShiftTable[index])
					fShiftTable[index] = diff;
			}
		}
	}
}

// ---------------------------------------------------------------------------
//  BMPattern: Cleanup
// ---------------------------------------------------------------------------
void BMPattern::cleanUp() {

    fMemoryManager->deallocate(fPattern);//delete [] fPattern;
    fMemoryManager->deallocate(fUppercasePattern);//delete [] fUppercasePattern;
    fMemoryManager->deallocate(fShiftTable);
}

XERCES_CPP_NAMESPACE_END

/**
  *	End of file BMPattern.cpp
  */