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Diffstat (limited to 'src/network/access/http2/bitstreams_p.h')
| -rw-r--r-- | src/network/access/http2/bitstreams_p.h | 185 |
1 files changed, 185 insertions, 0 deletions
diff --git a/src/network/access/http2/bitstreams_p.h b/src/network/access/http2/bitstreams_p.h new file mode 100644 index 0000000000..9eba319dc2 --- /dev/null +++ b/src/network/access/http2/bitstreams_p.h @@ -0,0 +1,185 @@ +/**************************************************************************** +** +** Copyright (C) 2016 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtNetwork 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 The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/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 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef BITSTREAMS_P_H +#define BITSTREAMS_P_H + +// +// W A R N I N G +// ------------- +// +// This file is not part of the Qt API. It exists for the convenience +// of other Qt classes. This header file may change from version to +// version without notice, or even be removed. +// +// We mean it. +// + +#include <QtCore/qglobal.h> +#include <QtCore/qdebug.h> + +#include <type_traits> +#include <algorithm> +#include <vector> + +QT_BEGIN_NAMESPACE + +class QByteArray; + +namespace HPack +{ + +// BitOStream works with an external buffer, +// for example, HEADERS frame. +class Q_AUTOTEST_EXPORT BitOStream +{ +public: + BitOStream(std::vector<uchar> &buffer); + + // Write 'bitLength' bits from the least significant + // bits in 'bits' to bitstream: + void writeBits(uchar bits, quint8 bitLength); + // HPACK data format, we support: + // * 32-bit integers + // * strings + void write(quint32 src); + void write(const QByteArray &src, bool compressed); + + quint64 bitLength() const; + quint64 byteLength() const; + const uchar *begin() const; + const uchar *end() const; + + void clear(); + +private: + Q_DISABLE_COPY(BitOStream); + + std::vector<uchar> &buffer; + quint64 bitsSet; +}; + +class Q_AUTOTEST_EXPORT BitIStream +{ +public: + // Error is set by 'read' functions. + // 'peek' does not set the error, + // since it just peeks some bits + // without the notion of wrong/right. + // 'read' functions only change 'streamOffset' + // on success. + enum class Error + { + NoError, + NotEnoughData, + CompressionError, + InvalidInteger + }; + + BitIStream(); + BitIStream(const uchar *f, const uchar *l); + + quint64 bitLength() const; + bool hasMoreBits() const; + + // peekBits tries to read 'length' bits from the bitstream into + // 'dst' ('length' must be <= sizeof(dst) * 8), packing them + // starting from the most significant bit of the most significant + // byte. It's a template so that we can use it with different + // integer types. Returns the number of bits actually read. + // Does not change stream's offset. + + template<class T> + quint64 peekBits(quint64 from, quint64 length, T *dstPtr) const + { + static_assert(std::is_unsigned<T>::value, "peekBits: unsigned integer type expected"); + + Q_ASSERT(dstPtr); + Q_ASSERT(length <= sizeof(T) * 8); + + if (from >= bitLength() || !length) + return 0; + + T &dst = *dstPtr; + dst = T(); + length = std::min(length, bitLength() - from); + + const uchar *srcByte = first + from / 8; + auto bitsToRead = length + from % 8; + + while (bitsToRead > 8) { + dst = (dst << 8) | *srcByte; + bitsToRead -= 8; + ++srcByte; + } + + dst <<= bitsToRead; + dst |= *srcByte >> (8 - bitsToRead); + dst <<= sizeof(T) * 8 - length; + + return length; + } + + quint64 streamOffset() const + { + return offset; + } + + bool skipBits(quint64 nBits); + bool rewindOffset(quint64 nBits); + + bool read(quint32 *dstPtr); + bool read(QByteArray *dstPtr); + + Error error() const; + +private: + void setError(Error newState); + + const uchar *first; + const uchar *last; + quint64 offset; + Error streamError; +}; + +} // namespace HPack + +QT_END_NAMESPACE + +#endif |