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Diffstat (limited to 'util/qlalr/examples/qparser/qparser.h')
| -rw-r--r-- | util/qlalr/examples/qparser/qparser.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/util/qlalr/examples/qparser/qparser.h b/util/qlalr/examples/qparser/qparser.h new file mode 100644 index 0000000000..a5678d0c33 --- /dev/null +++ b/util/qlalr/examples/qparser/qparser.h @@ -0,0 +1,152 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the QLALR module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and Digia. For licensing terms and +** conditions see http://qt.digia.com/licensing. For further information +** use the contact form at http://qt.digia.com/contact-us. +** +** 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, Digia gives you certain additional +** rights. These rights are described in the Digia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#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 |