--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/xmlpatterns/acceltree/qcompressedwhitespace_p.h Mon Jan 11 14:00:40 2010 +0000
@@ -0,0 +1,186 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtXmlPatterns 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+//
+// W A R N I N G
+// -------------
+//
+// This file is not part of the Qt API. It exists purely as an
+// implementation detail. This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+
+#ifndef Patternist_CompressedWhitespace_H
+#define Patternist_CompressedWhitespace_H
+
+#include <QtGlobal>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+class QChar;
+class QString;
+class QStringRef;
+
+namespace QPatternist
+{
+ /**
+ * @short A compression facility for whitespace nodes.
+ *
+ * CompressedWhitespace compresses and decompresses strings that consists of
+ * whitespace only, and do so with a scheme that is designed to do this
+ * specialized task in an efficient way. The approach is simple: each
+ * sequence of equal whitespace in the input gets coded into one byte,
+ * where the first two bits signals the type, CharIdentifier, and the
+ * remininding six bits is the count.
+ *
+ * For instance, this scheme manages to compress a sequence of spaces
+ * followed by a new line into 16 bits(one QChar), and QString stores
+ * strings of one QChar quite efficiently, by avoiding a heap allocation.
+ *
+ * There is no way to tell whether a QString is compressed or not.
+ *
+ * The compression scheme originates from Saxon, by Michael Kay.
+ *
+ * @author Frans Englich <frans.englich@nokia.com>
+ */
+ class CompressedWhitespace
+ {
+ public:
+ /**
+ * @short Compresses @p input into a compressed format, returned
+ * as a QString.
+ *
+ * The caller guarantees that input is not empty
+ * and consists only of whitespace.
+ *
+ * The returned format is opaque. There is no way to find out
+ * whether a QString contains compressed data or not.
+ *
+ * @see decompress()
+ */
+ static QString compress(const QStringRef &input);
+
+ /**
+ * @short Decompresses @p input into a usual QString.
+ *
+ * @p input must be a QString as per returned from compress().
+ *
+ * @see compress()
+ */
+ static QString decompress(const QString &input);
+
+ private:
+ /**
+ * We use the two upper bits for communicating what space it is.
+ */
+ enum CharIdentifier
+ {
+ Space = 0x0,
+
+ /**
+ * 0xA, \\r
+ *
+ * Binary: 10000000
+ */
+ CR = 0x80,
+
+ /**
+ * 0xD, \\n
+ *
+ * Binary: 01000000
+ */
+ LF = 0x40,
+
+ /**
+ * Binary: 11000000
+ */
+ Tab = 0xC0
+ };
+
+ enum Constants
+ {
+ /* We can at maximum store this many consecutive characters
+ * of one type. We use 6 bits for the count. */
+ MaxCharCount = (1 << 6) - 1,
+
+ /**
+ * Binary: 11111111
+ */
+ Lower8Bits = (1 << 8) - 1,
+
+ /**
+ * Binary: 111111
+ */
+ Lower6Bits = (1 << 6) - 1,
+
+ /*
+ * Binary: 11000000
+ */
+ UpperTwoBits = 3 << 6
+ };
+
+ static inline CharIdentifier toIdentifier(const QChar ch);
+
+ static inline quint8 toCompressedChar(const QChar ch, const int len);
+ static inline QChar toChar(const CharIdentifier id);
+
+ /**
+ * @short Returns @c true if @p number is an even number, otherwise
+ * @c false.
+ */
+ static inline bool isEven(const int number);
+
+ /**
+ * @short This class can only be used via its static members.
+ */
+ inline CompressedWhitespace();
+ Q_DISABLE_COPY(CompressedWhitespace)
+ };
+}
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif