/**************************************************************************** ** ** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the QLALR module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** No Commercial Usage ** This file contains pre-release code and may not be distributed. ** You may use this file in accordance with the terms and conditions ** contained in the Technology Preview License Agreement accompanying ** this package. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 2.1 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 2.1 requirements ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. ** ** In addition, as a special exception, Nokia gives you certain additional ** rights. These rights are described in the Nokia Qt LGPL Exception ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. ** ** If you have questions regarding the use of this file, please contact ** Nokia at qt-info@nokia.com. ** ** ** ** ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #ifndef QPARSER_H #define QPARSER_H #include <QtCore/QSharedDataPointer> #include <QtCore/QVarLengthArray> template <typename _Parser, typename _Table, typename _Value = int> class QParser: protected _Table { public: QParser(); ~QParser(); bool parse(); inline _Value &sym(int index); private: inline int nextToken() { return static_cast<_Parser*> (this)->nextToken(); } inline void consumeRule(int rule) { static_cast<_Parser*> (this)->consumeRule(rule); } enum { DefaultStackSize = 128 }; struct Data: public QSharedData { Data(): stackSize (DefaultStackSize), tos (0) {} QVarLengthArray<int, DefaultStackSize> stateStack; QVarLengthArray<_Value, DefaultStackSize> parseStack; int stackSize; int tos; void reallocateStack() { stackSize <<= 1; stateStack.resize(stackSize); parseStack.resize(stackSize); } }; QSharedDataPointer<Data> d; }; template <typename _Parser, typename _Table, typename _Value> inline _Value &QParser<_Parser, _Table, _Value>::sym(int n) { return d->parseStack [d->tos + n - 1]; } template <typename _Parser, typename _Table, typename _Value> QParser<_Parser, _Table, _Value>::QParser(): d(new Data()) { } template <typename _Parser, typename _Table, typename _Value> QParser<_Parser, _Table, _Value>::~QParser() { } template <typename _Parser, typename _Table, typename _Value> bool QParser<_Parser, _Table, _Value>::parse() { const int INITIAL_STATE = 0; d->tos = 0; d->reallocateStack(); int act = d->stateStack[++d->tos] = INITIAL_STATE; int token = -1; forever { if (token == -1 && - _Table::TERMINAL_COUNT != _Table::action_index[act]) token = nextToken(); act = _Table::t_action(act, token); if (d->stateStack[d->tos] == _Table::ACCEPT_STATE) return true; else if (act > 0) { if (++d->tos == d->stackSize) d->reallocateStack(); d->parseStack[d->tos] = d->parseStack[d->tos - 1]; d->stateStack[d->tos] = act; token = -1; } else if (act < 0) { int r = - act - 1; d->tos -= _Table::rhs[r]; act = d->stateStack[d->tos++]; consumeRule(r); act = d->stateStack[d->tos] = _Table::nt_action(act, _Table::lhs[r] - _Table::TERMINAL_COUNT); } else break; } return false; } #endif // QPARSER_H