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/* This file is part of the KDE project
Copyright (C) 2005 Ivor Hewitt <ivor@kde.org>
Copyright (C) 2008 Maksim Orlovich <maksim@kde.org>
Copyright (C) 2008 Vyacheslav Tokarev <tsjoker@gmail.com>
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public License
along with this library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
#include "khtml_filter_p.h"
#include <QDebug>
// rolling hash parameters
#define HASH_P (1997)
#define HASH_Q (17509)
// HASH_MOD = (HASH_P^7) % HASH_Q
#define HASH_MOD (523)
namespace khtml {
void FilterSet::addFilter(const QString& filterStr)
{
QString filter = filterStr;
if (filter.startsWith(QLatin1Char('!')))
return;
// Strip leading @@
int first = 0;
int last = filter.length() - 1;
if (filter.startsWith(QLatin1String("@@")))
first = 2;
// Strip options, we ignore them for now.
int dollar = filter.lastIndexOf(QLatin1Char('$'));
if (dollar != -1)
last = dollar - 1;
// Perhaps nothing left?
if (first > last)
return;
filter = filter.mid(first, last - first + 1);
// Is it a regexp filter?
if (filter.length()>2 && filter.startsWith(QLatin1Char('/')) && filter.endsWith(QLatin1Char('/')))
{
QString inside = filter.mid(1, filter.length()-2);
QRegExp rx(inside);
reFilters.append(rx);
// qDebug() << "R:" << inside;
}
else
{
// Nope, a wildcard one.
// Note: For these, we also need to handle |.
// Strip wildcards at the ends
first = 0;
last = filter.length() - 1;
while (first < filter.length() && filter[first] == QLatin1Char('*'))
++first;
while (last >= 0 && filter[last] == QLatin1Char('*'))
--last;
if (first > last)
filter = QLatin1String("*"); // erm... Well, they asked for it.
else
filter = filter.mid(first, last - first + 1);
// Now, do we still have any wildcard stuff left?
if (filter.contains("*") || filter.contains("?"))
{
// qDebug() << "W:" << filter;
// check if we can use RK first (and then check full RE for the rest) for better performance
int aPos = filter.indexOf('*');
if (aPos < 0)
aPos = filter.length();
int qPos = filter.indexOf('?');
if (qPos < 0)
qPos = filter.length();
int pos = qMin(aPos, qPos);
if (pos > 7) {
QRegExp rx;
rx.setPatternSyntax(QRegExp::Wildcard);
rx.setPattern(filter.mid(pos));
stringFiltersMatcher.addWildedString(filter.mid(0, pos), rx);
} else {
QRegExp rx;
rx.setPatternSyntax(QRegExp::Wildcard);
rx.setPattern(filter);
reFilters.append(rx);
}
}
else
{
// Fast path
stringFiltersMatcher.addString(filter);
}
}
}
bool FilterSet::isUrlMatched(const QString& url)
{
if (stringFiltersMatcher.isMatched(url))
return true;
for (int c = 0; c < reFilters.size(); ++c)
{
if (url.contains(reFilters[c]))
return true;
}
return false;
}
void FilterSet::clear()
{
reFilters.clear();
stringFiltersMatcher.clear();
}
void StringsMatcher::addString(const QString& pattern)
{
if (pattern.length() < 8) {
// handle short string differently
shortStringFilters.append(pattern);
} else {
// use modified Rabin-Karp's algorithm with 8-length string hash
// i.e. store hash of first 8 chars in the HashMap for fast look-up
stringFilters.append(pattern);
int ind = stringFilters.size() - 1;
int current = 0;
// compute hash using rolling hash
// hash for string: x0,x1,x2...xn-1 will be:
// (p^(n-1)*x0 + p^(n-2)*x1 + ... + p * xn-2 + xn-1) % q
// where p and q some wisely-chosen integers
/*for (int k = 0; k < 8; ++k)*/
int len = pattern.length();
for (int k = len - 8; k < len; ++k)
current = (current * HASH_P + pattern[k].unicode()) % HASH_Q;
// insert computed hash value into HashMap
QHash<int, QVector<int> >::iterator it = stringFiltersHash.find(current + 1);
if (it == stringFiltersHash.end()) {
QVector<int> list;
list.append(ind);
stringFiltersHash.insert(current + 1, list);
fastLookUp.setBit(current);
} else {
it.value().append(ind);
}
}
}
void StringsMatcher::addWildedString(const QString& prefix, const QRegExp& rx)
{
rePrefixes.append(prefix);
reFilters.append(rx);
int index = -rePrefixes.size();
int current = 0;
for (int k = 0; k < 8; ++k)
current = (current * HASH_P + prefix[k].unicode()) % HASH_Q;
// insert computed hash value into HashMap
QHash<int, QVector<int> >::iterator it = stringFiltersHash.find(current + 1);
if (it == stringFiltersHash.end()) {
QVector<int> list;
list.append(index);
stringFiltersHash.insert(current + 1, list);
fastLookUp.setBit(current);
} else {
it.value().append(index);
}
}
bool StringsMatcher::isMatched(const QString& str) const
{
// check short strings first
for (int i = 0; i < shortStringFilters.size(); ++i) {
if (str.contains(shortStringFilters[i]))
return true;
}
int len = str.length();
int k;
int current = 0;
int next = 0;
// compute hash for first 8 characters
for (k = 0; k < 8 && k < len; ++k)
current = (current * HASH_P + str[k].unicode()) % HASH_Q;
QHash<int, QVector<int> >::const_iterator hashEnd = stringFiltersHash.end();
// main Rabin-Karp's algorithm loop
for (k = 7; k < len; ++k, current = next) {
// roll the hash if not at the end
// (calculate hash for the next iteration)
if (k + 1 < len)
next = (HASH_P * ((current + HASH_Q - ((HASH_MOD * str[k - 7].unicode()) % HASH_Q)) % HASH_Q) + str[k + 1].unicode()) % HASH_Q;
if (!fastLookUp.testBit(current))
continue;
// look-up the hash in the HashMap and check all strings
QHash<int, QVector<int> >::const_iterator it = stringFiltersHash.find(current + 1);
// check possible strings
if (it != hashEnd) {
for (int j = 0; j < it.value().size(); ++j) {
int index = it.value()[j];
// check if we got simple string or REs prefix
if (index >= 0) {
int flen = stringFilters[index].length();
if (k - flen + 1 >= 0 && stringFilters[index] == str.midRef(k - flen + 1 , flen))
return true;
} else {
index = -index - 1;
int flen = rePrefixes[index].length();
if (k - 8 + flen < len && rePrefixes[index] == str.midRef(k - 7, flen) &&
str.indexOf(reFilters[index], k - 7 + flen) == k - 7 + flen)
return true;
}
}
}
}
return false;
}
void StringsMatcher::clear()
{
stringFilters.clear();
shortStringFilters.clear();
reFilters.clear();
rePrefixes.clear();
stringFiltersHash.clear();
fastLookUp.resize(HASH_Q);
fastLookUp.fill(0, 0, HASH_Q);
}
}
// kate: indent-width 4; replace-tabs on; tab-width 4; space-indent on;
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