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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:critical reason:data-parser
#ifndef QBYTEDATABUFFER_P_H
#define QBYTEDATABUFFER_P_H
//
// 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.
//
#include <QtNetwork/private/qtnetworkglobal_p.h>
#include <QtCore/qbytearray.h>
#include <QtCore/qlist.h>
#include <climits>
QT_BEGIN_NAMESPACE
// this class handles a list of QByteArrays. It is a variant of QRingBuffer
// that avoid malloc/realloc/memcpy.
class QByteDataBuffer
{
private:
QList<QByteArray> buffers;
qint64 bufferCompleteSize = 0;
qint64 firstPos = 0;
public:
static inline void popFront(QByteArray &ba, qint64 n)
{
ba = QByteArray(ba.constData() + n, ba.size() - n);
}
inline void squeezeFirst()
{
if (!buffers.isEmpty() && firstPos > 0) {
popFront(buffers.first(), firstPos);
firstPos = 0;
}
}
inline void append(const QByteDataBuffer& other)
{
if (other.isEmpty())
return;
buffers.append(other.buffers);
bufferCompleteSize += other.byteAmount();
if (other.firstPos > 0)
popFront(buffers[bufferCount() - other.bufferCount()], other.firstPos);
}
inline void append(QByteDataBuffer &&other)
{
if (other.isEmpty())
return;
auto otherBufferCount = other.bufferCount();
auto otherByteAmount = other.byteAmount();
buffers.append(std::move(other.buffers));
bufferCompleteSize += otherByteAmount;
if (other.firstPos > 0)
popFront(buffers[bufferCount() - otherBufferCount], other.firstPos);
}
inline void append(const QByteArray& bd)
{
append(QByteArray(bd));
}
inline void append(QByteArray &&bd)
{
if (bd.isEmpty())
return;
bufferCompleteSize += bd.size();
buffers.append(std::move(bd));
}
inline void prepend(const QByteArray& bd)
{
prepend(QByteArray(bd));
}
inline void prepend(QByteArray &&bd)
{
if (bd.isEmpty())
return;
squeezeFirst();
bufferCompleteSize += bd.size();
buffers.prepend(std::move(bd));
}
// return the first QByteData. User of this function has to free() its .data!
// preferably use this function to read data.
inline QByteArray read()
{
Q_ASSERT(!isEmpty());
squeezeFirst();
bufferCompleteSize -= buffers.first().size();
return buffers.takeFirst();
}
// return everything. User of this function has to free() its .data!
// avoid to use this, it might malloc and memcpy.
inline QByteArray readAll()
{
return read(byteAmount());
}
// return amount. User of this function has to free() its .data!
// avoid to use this, it might malloc and memcpy.
inline QByteArray read(qint64 amount)
{
amount = qMin(byteAmount(), amount);
if constexpr (sizeof(qsizetype) == sizeof(int)) { // 32-bit
// While we cannot overall have more than INT_MAX memory allocated,
// the QByteArrays we hold may be shared copies of each other,
// causing byteAmount() to exceed INT_MAX.
if (amount > INT_MAX)
qBadAlloc(); // what resize() would do if it saw past the truncation
}
QByteArray byteData;
byteData.resize(qsizetype(amount));
read(byteData.data(), byteData.size());
return byteData;
}
// return amount bytes. User of this function has to free() its .data!
// avoid to use this, it will memcpy.
qint64 read(char* dst, qint64 amount)
{
amount = qMin(amount, byteAmount());
qint64 originalAmount = amount;
char *writeDst = dst;
while (amount > 0) {
const QByteArray &first = buffers.first();
qint64 firstSize = first.size() - firstPos;
if (amount >= firstSize) {
// take it completely
bufferCompleteSize -= firstSize;
amount -= firstSize;
memcpy(writeDst, first.constData() + firstPos, firstSize);
writeDst += firstSize;
firstPos = 0;
buffers.takeFirst();
} else {
// take a part of it & it is the last one to take
bufferCompleteSize -= amount;
memcpy(writeDst, first.constData() + firstPos, amount);
firstPos += amount;
amount = 0;
}
}
return originalAmount;
}
/*!
\internal
Returns a view into the first QByteArray contained inside,
ignoring any already read data. Call advanceReadPointer()
to advance the view forward. When a QByteArray is exhausted
the view returned by this function will view into another
QByteArray if any. Returns a default constructed view if
no data is available.
\sa advanceReadPointer
*/
QByteArrayView readPointer() const
{
if (isEmpty())
return {};
return { buffers.first().constData() + qsizetype(firstPos),
buffers.first().size() - qsizetype(firstPos) };
}
/*!
\internal
Advances the read pointer by \a distance.
\sa readPointer
*/
void advanceReadPointer(qint64 distance)
{
qint64 newPos = firstPos + distance;
if (isEmpty()) {
newPos = 0;
} else if (auto size = buffers.first().size(); newPos >= size) {
while (newPos >= size) {
bufferCompleteSize -= (size - firstPos);
newPos -= size;
buffers.pop_front();
if (isEmpty()) {
size = 0;
newPos = 0;
break;
}
size = buffers.front().size();
}
bufferCompleteSize -= newPos;
} else {
bufferCompleteSize -= newPos - firstPos;
}
firstPos = newPos;
}
inline char getChar()
{
Q_ASSERT_X(!isEmpty(), "QByteDataBuffer::getChar",
"Cannot read a char from an empty buffer!");
char c;
read(&c, 1);
return c;
}
inline void clear()
{
buffers.clear();
bufferCompleteSize = 0;
firstPos = 0;
}
// The byte count of all QByteArrays
inline qint64 byteAmount() const
{
return bufferCompleteSize;
}
// the number of QByteArrays
qsizetype bufferCount() const
{
return buffers.size();
}
inline bool isEmpty() const
{
return byteAmount() == 0;
}
inline qint64 sizeNextBlock() const
{
if (buffers.isEmpty())
return 0;
else
return buffers.first().size() - firstPos;
}
QByteArray &operator[](qsizetype i)
{
if (i == 0)
squeezeFirst();
return buffers[i];
}
inline bool canReadLine() const {
qsizetype i = 0;
if (i < buffers.size()) {
if (buffers.at(i).indexOf('\n', firstPos) != -1)
return true;
++i;
for (; i < buffers.size(); i++)
if (buffers.at(i).contains('\n'))
return true;
}
return false;
}
const QByteArray &last() const { return buffers.last(); }
};
QT_END_NAMESPACE
#endif // QBYTEDATABUFFER_P_H