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DRY qCompress/qUncompress: introduce CompressedSizeHint_t 

... and use it to remove the associated magic number 4 from the code
base.

As a drive-by, replace a naked qWarning() with the existing
invalidCompressedData() helper function, and a C-style cast with
reinterpret_cast.

Pick-to: 6.4 6.3 6.2
Task-number: QTBUG-106542
Change-Id: I35004757e01bfc0747f7cc65bdf6eb243225caad
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
bb10
Marc Mutz 2022-09-17 10:48:18 +02:00
parent dccca4ab33
commit 3cb00e415d
1 changed files with 23 additions and 11 deletions
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34
src/corelib/text/qbytearray.cpp
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@ -517,7 +517,9 @@ quint16 qChecksum(QByteArrayView data, Qt::ChecksumType standard)
\sa qUncompress(const QByteArray &data)
*/
/*! \relates QByteArray
/*!
\fn QByteArray qCompress(const uchar* data, qsizetype nbytes, int compressionLevel)
\relates QByteArray
\overload
@ -528,10 +530,13 @@ quint16 qChecksum(QByteArrayView data, Qt::ChecksumType standard)
*/
#ifndef QT_NO_COMPRESS
using CompressSizeHint_t = quint32; // 32-bit BE, historically
QByteArray qCompress(const uchar* data, qsizetype nbytes, int compressionLevel)
{
constexpr qsizetype HeaderSize = sizeof(CompressSizeHint_t);
if (nbytes == 0) {
return QByteArray(4, '\0');
return QByteArray(HeaderSize, '\0');
}
if (!data) {
qWarning("qCompress: Data is null");
@ -544,13 +549,15 @@ QByteArray qCompress(const uchar* data, qsizetype nbytes, int compressionLevel)
QByteArray bazip;
int res;
do {
bazip.resize(len + 4);
res = ::compress2((uchar*)bazip.data()+4, &len, data, nbytes, compressionLevel);
bazip.resize(len + HeaderSize);
res = ::compress2(reinterpret_cast<uchar *>(bazip.data()) + HeaderSize, &len,
data, nbytes,
compressionLevel);
switch (res) {
case Z_OK:
bazip.resize(len + 4);
qToBigEndian(quint32(nbytes), bazip.data()); // 4 octets, historically
bazip.resize(len + HeaderSize);
qToBigEndian(CompressSizeHint_t(nbytes), bazip.data());
break;
case Z_MEM_ERROR:
qWarning("qCompress: Z_MEM_ERROR: Not enough memory");
@ -621,12 +628,17 @@ QByteArray qUncompress(const uchar* data, qsizetype nbytes)
qWarning("qUncompress: Data is null");
return QByteArray();
}
if (nbytes <= 4) {
if (nbytes < 4 || (data[0]!=0 || data[1]!=0 || data[2]!=0 || data[3]!=0))
qWarning("qUncompress: Input data is corrupted");
constexpr qsizetype HeaderSize = sizeof(CompressSizeHint_t);
if (nbytes < HeaderSize)
return invalidCompressedData();
const auto expectedSize = qFromBigEndian<CompressSizeHint_t>(data);
if (nbytes == HeaderSize) {
if (expectedSize != 0)
return invalidCompressedData();
return QByteArray();
}
const auto expectedSize = qFromBigEndian<quint32>(data);
uLong len = qMax(expectedSize, 1u);
constexpr size_t MaxZLibSize = (std::numeric_limits<uLong>::max)();
constexpr size_t MaxDecompressedSize = (std::min)(size_t(MaxByteArraySize), MaxZLibSize);
@ -641,7 +653,7 @@ QByteArray qUncompress(const uchar* data, qsizetype nbytes)
forever {
const auto alloc = len;
int res = ::uncompress(reinterpret_cast<uchar *>(d.data()), &len,
data+4, nbytes-4);
data + HeaderSize, nbytes - HeaderSize);
switch (res) {
case Z_OK: {