diff options
| -rw-r--r-- | src/corelib/io/qiodevice.cpp | 83 | ||||
| -rw-r--r-- | src/corelib/io/qiodevice_p.h | 2 | ||||
| -rw-r--r-- | tests/benchmarks/corelib/io/qiodevice/main.cpp | 32 |
3 files changed, 72 insertions, 45 deletions
diff --git a/src/corelib/io/qiodevice.cpp b/src/corelib/io/qiodevice.cpp index 8cef993cf4..41a4d7a1ba 100644 --- a/src/corelib/io/qiodevice.cpp +++ b/src/corelib/io/qiodevice.cpp @@ -1047,26 +1047,29 @@ qint64 QIODevice::read(char *data, qint64 maxSize) /*! \internal */ -qint64 QIODevicePrivate::read(char *data, qint64 maxSize) +qint64 QIODevicePrivate::read(char *data, qint64 maxSize, bool peeking) { Q_Q(QIODevice); const bool buffered = (openMode & QIODevice::Unbuffered) == 0; const bool sequential = isSequential(); - const bool keepDataInBuffer = sequential && transactionStarted; + const bool keepDataInBuffer = sequential + ? peeking || transactionStarted + : peeking && buffered; + const qint64 savedPos = pos; qint64 readSoFar = 0; bool madeBufferReadsOnly = true; bool deviceAtEof = false; char *readPtr = data; + qint64 bufferPos = (sequential && transactionStarted) ? transactionPos : Q_INT64_C(0); forever { // Try reading from the buffer. qint64 bufferReadChunkSize = keepDataInBuffer - ? buffer.peek(data, maxSize, transactionPos) + ? buffer.peek(data, maxSize, bufferPos) : buffer.read(data, maxSize); if (bufferReadChunkSize > 0) { - if (keepDataInBuffer) - transactionPos += bufferReadChunkSize; - else if (!sequential) + bufferPos += bufferReadChunkSize; + if (!sequential) pos += bufferReadChunkSize; #if defined QIODEVICE_DEBUG printf("%p \treading %lld bytes from buffer into position %lld\n", q, @@ -1160,6 +1163,16 @@ qint64 QIODevicePrivate::read(char *data, qint64 maxSize) break; } + // Restore positions after reading + if (keepDataInBuffer) { + if (peeking) + pos = savedPos; // does nothing on sequential devices + else + transactionPos = bufferPos; + } else if (peeking) { + seekBuffer(savedPos); // unbuffered random-access device + } + if (madeBufferReadsOnly && isBufferEmpty()) q->readData(data, 0); @@ -1773,27 +1786,7 @@ bool QIODevicePrivate::putCharHelper(char c) */ qint64 QIODevicePrivate::peek(char *data, qint64 maxSize) { - Q_Q(QIODevice); - - if (transactionStarted) { - const qint64 savedTransactionPos = transactionPos; - const qint64 savedPos = pos; - - qint64 readBytes = q->read(data, maxSize); - - // Restore initial position - if (isSequential()) - transactionPos = savedTransactionPos; - else - seekBuffer(savedPos); - return readBytes; - } - - q->startTransaction(); - qint64 readBytes = q->read(data, maxSize); - q->rollbackTransaction(); - - return readBytes; + return read(data, maxSize, true); } /*! @@ -1801,26 +1794,17 @@ qint64 QIODevicePrivate::peek(char *data, qint64 maxSize) */ QByteArray QIODevicePrivate::peek(qint64 maxSize) { - Q_Q(QIODevice); + QByteArray result(maxSize, Qt::Uninitialized); - if (transactionStarted) { - const qint64 savedTransactionPos = transactionPos; - const qint64 savedPos = pos; + const qint64 readBytes = read(result.data(), maxSize, true); - QByteArray result = q->read(maxSize); - - // Restore initial position - if (isSequential()) - transactionPos = savedTransactionPos; + if (readBytes < maxSize) { + if (readBytes <= 0) + result.clear(); else - seekBuffer(savedPos); - return result; + result.resize(readBytes); } - q->startTransaction(); - QByteArray result = q->read(maxSize); - q->rollbackTransaction(); - return result; } @@ -1858,7 +1842,12 @@ bool QIODevice::getChar(char *c) */ qint64 QIODevice::peek(char *data, qint64 maxSize) { - return d_func()->peek(data, maxSize); + Q_D(QIODevice); + + CHECK_MAXLEN(peek, qint64(-1)); + CHECK_READABLE(peek, qint64(-1)); + + return d->peek(data, maxSize); } /*! @@ -1880,7 +1869,13 @@ qint64 QIODevice::peek(char *data, qint64 maxSize) */ QByteArray QIODevice::peek(qint64 maxSize) { - return d_func()->peek(maxSize); + Q_D(QIODevice); + + CHECK_MAXLEN(peek, QByteArray()); + CHECK_MAXBYTEARRAYSIZE(peek); + CHECK_READABLE(peek, QByteArray()); + + return d->peek(maxSize); } /*! diff --git a/src/corelib/io/qiodevice_p.h b/src/corelib/io/qiodevice_p.h index 0e424b6831..71a326dd53 100644 --- a/src/corelib/io/qiodevice_p.h +++ b/src/corelib/io/qiodevice_p.h @@ -171,7 +171,7 @@ public: void setReadChannelCount(int count); void setWriteChannelCount(int count); - qint64 read(char *data, qint64 maxSize); + qint64 read(char *data, qint64 maxSize, bool peeking = false); virtual qint64 peek(char *data, qint64 maxSize); virtual QByteArray peek(qint64 maxSize); diff --git a/tests/benchmarks/corelib/io/qiodevice/main.cpp b/tests/benchmarks/corelib/io/qiodevice/main.cpp index b106a9fd3d..de4660a253 100644 --- a/tests/benchmarks/corelib/io/qiodevice/main.cpp +++ b/tests/benchmarks/corelib/io/qiodevice/main.cpp @@ -39,6 +39,8 @@ class tst_qiodevice : public QObject private slots: void read_old(); void read_old_data() { read_data(); } + void peekAndRead(); + void peekAndRead_data() { read_data(); } //void read_new(); //void read_new_data() { read_data(); } private: @@ -86,6 +88,36 @@ void tst_qiodevice::read_old() } } +void tst_qiodevice::peekAndRead() +{ + QFETCH(qint64, size); + + QString name = "tmp" + QString::number(size); + + { + QFile file(name); + file.open(QIODevice::WriteOnly); + file.seek(size); + file.write("x", 1); + file.close(); + } + + QBENCHMARK { + QFile file(name); + file.open(QIODevice::ReadOnly); + + QByteArray ba(size / 1024, Qt::Uninitialized); + while (!file.atEnd()) { + file.peek(ba.data(), ba.size()); + file.read(ba.data(), ba.size()); + } + } + + { + QFile file(name); + file.remove(); + } +} QTEST_MAIN(tst_qiodevice) |