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-rw-r--r--src/corelib/io/qiodevice.cpp167
1 files changed, 73 insertions, 94 deletions
diff --git a/src/corelib/io/qiodevice.cpp b/src/corelib/io/qiodevice.cpp
index 0709a93bad..36f88f2774 100644
--- a/src/corelib/io/qiodevice.cpp
+++ b/src/corelib/io/qiodevice.cpp
@@ -783,27 +783,20 @@ qint64 QIODevice::read(char *data, qint64 maxSize)
CHECK_MAXLEN(read, qint64(-1));
qint64 readSoFar = 0;
- bool moreToRead = true;
- do {
+ bool madeBufferReadsOnly = true;
+ bool deviceAtEof = false;
+ char *readPtr = data;
+ forever {
// Try reading from the buffer.
- qint64 lastReadChunkSize = d->buffer.read(data, maxSize);
- if (lastReadChunkSize > 0) {
- *d->pPos += lastReadChunkSize;
- readSoFar += lastReadChunkSize;
- // fast exit when satisfied by buffer
- if (lastReadChunkSize == maxSize && !(d->openMode & Text)) {
- if (d->buffer.isEmpty()) {
- d->buffer.clear();
- readData(data, 0);
- }
- return readSoFar;
- }
-
- data += lastReadChunkSize;
- maxSize -= lastReadChunkSize;
+ qint64 bufferReadChunkSize = d->buffer.read(data, maxSize);
+ if (bufferReadChunkSize > 0) {
+ *d->pPos += bufferReadChunkSize;
+ readSoFar += bufferReadChunkSize;
+ data += bufferReadChunkSize;
+ maxSize -= bufferReadChunkSize;
#if defined QIODEVICE_DEBUG
- printf("%p \treading %d bytes from buffer into position %d\n", this, lastReadChunkSize,
- int(readSoFar) - lastReadChunkSize);
+ printf("%p \treading %d bytes from buffer into position %d\n", this,
+ bufferReadChunkSize, int(readSoFar) - bufferReadChunkSize);
#endif
} else {
if (d->firstRead) {
@@ -816,100 +809,84 @@ qint64 QIODevice::read(char *data, qint64 maxSize)
d->pDevicePos = &d->seqDumpPos;
}
}
+ }
- if (!maxSize)
- return readSoFar;
-
- if ((d->openMode & Unbuffered) == 0 && maxSize < QIODEVICE_BUFFERSIZE) {
- // In buffered mode, we try to fill up the QIODevice buffer before
- // we do anything else.
- // buffer is empty at this point, try to fill it
- const int bytesToBuffer = QIODEVICE_BUFFERSIZE;
- char *writePointer = d->buffer.reserve(bytesToBuffer);
-
- // Make sure the device is positioned correctly.
- if (d->pos != d->devicePos && !d->isSequential() && !seek(d->pos))
- return readSoFar ? readSoFar : qint64(-1);
- qint64 readFromDevice = readData(writePointer, bytesToBuffer);
- d->buffer.chop(bytesToBuffer - (readFromDevice < 0 ? 0 : int(readFromDevice)));
-
- if (readFromDevice > 0) {
- *d->pDevicePos += readFromDevice;
+ if (maxSize > 0 && !deviceAtEof) {
+ qint64 readFromDevice = 0;
+ // Make sure the device is positioned correctly.
+ if (d->pos == d->devicePos || d->isSequential() || seek(d->pos)) {
+ madeBufferReadsOnly = false; // fix readData attempt
+ if (maxSize >= QIODEVICE_BUFFERSIZE || (d->openMode & Unbuffered)) {
+ // Read big chunk directly to output buffer
+ readFromDevice = readData(data, maxSize);
+ deviceAtEof = (readFromDevice != maxSize);
#if defined QIODEVICE_DEBUG
- printf("%p \treading %d from device into buffer\n", this, int(readFromDevice));
+ printf("%p \treading %d bytes from device (total %d)\n", this,
+ int(readFromDevice), int(readSoFar));
#endif
-
- if (!d->buffer.isEmpty()) {
- lastReadChunkSize = d->buffer.read(data, maxSize);
- readSoFar += lastReadChunkSize;
- data += lastReadChunkSize;
- maxSize -= lastReadChunkSize;
- *d->pPos += lastReadChunkSize;
+ if (readFromDevice > 0) {
+ readSoFar += readFromDevice;
+ data += readFromDevice;
+ maxSize -= readFromDevice;
+ *d->pPos += readFromDevice;
+ *d->pDevicePos += readFromDevice;
+ }
+ } else {
+ const int bytesToBuffer = QIODEVICE_BUFFERSIZE;
+ // Try to fill QIODevice buffer by single read
+ readFromDevice = readData(d->buffer.reserve(bytesToBuffer), bytesToBuffer);
+ deviceAtEof = (readFromDevice != bytesToBuffer);
+ d->buffer.chop(bytesToBuffer - qMax(0, int(readFromDevice)));
+ if (readFromDevice > 0) {
+ *d->pDevicePos += readFromDevice;
#if defined QIODEVICE_DEBUG
- printf("%p \treading %d bytes from buffer at position %d\n", this,
- lastReadChunkSize, int(readSoFar));
+ printf("%p \treading %d from device into buffer\n", this,
+ int(readFromDevice));
#endif
+ continue;
}
}
+ } else {
+ readFromDevice = -1;
}
- }
- // If we need more, try reading from the device.
- if (maxSize > 0) {
- // Make sure the device is positioned correctly.
- if (d->pos != d->devicePos && !d->isSequential() && !seek(d->pos))
- return readSoFar ? readSoFar : qint64(-1);
- qint64 readFromDevice = readData(data, maxSize);
-#if defined QIODEVICE_DEBUG
- printf("%p \treading %d bytes from device (total %d)\n", this, int(readFromDevice), int(readSoFar));
-#endif
- if (readFromDevice == -1 && readSoFar == 0) {
+ if (readFromDevice < 0 && readSoFar == 0) {
// error and we haven't read anything: return immediately
- return -1;
- }
- if (readFromDevice > 0) {
- lastReadChunkSize += int(readFromDevice);
- readSoFar += readFromDevice;
- data += readFromDevice;
- maxSize -= readFromDevice;
- *d->pPos += readFromDevice;
- *d->pDevicePos += readFromDevice;
+ return qint64(-1);
}
}
- // Best attempt has been made to read data, don't try again except for text mode adjustment below
- moreToRead = false;
- if (readSoFar && d->openMode & Text) {
- char *readPtr = data - lastReadChunkSize;
+ if ((d->openMode & Text) && readPtr < data) {
const char *endPtr = data;
- if (readPtr < endPtr) {
- // optimization to avoid initial self-assignment
- while (*readPtr != '\r') {
- if (++readPtr == endPtr)
- return readSoFar;
- }
+ // optimization to avoid initial self-assignment
+ while (*readPtr != '\r') {
+ if (++readPtr == endPtr)
+ break;
+ }
- char *writePtr = readPtr;
+ char *writePtr = readPtr;
- while (readPtr < endPtr) {
- char ch = *readPtr++;
- if (ch != '\r')
- *writePtr++ = ch;
- else {
- --readSoFar;
- --data;
- ++maxSize;
- }
+ while (readPtr < endPtr) {
+ char ch = *readPtr++;
+ if (ch != '\r')
+ *writePtr++ = ch;
+ else {
+ --readSoFar;
+ --data;
+ ++maxSize;
}
-
- // Make sure we get more data if there is room for more. This
- // is very important for when someone seeks to the start of a
- // '\r\n' and reads one character - they should get the '\n'.
- moreToRead = (readPtr != writePtr);
}
+
+ // Make sure we get more data if there is room for more. This
+ // is very important for when someone seeks to the start of a
+ // '\r\n' and reads one character - they should get the '\n'.
+ readPtr = data;
+ continue;
}
- } while (moreToRead);
+
+ break;
+ }
#if defined QIODEVICE_DEBUG
printf("%p \treturning %d, d->pos == %d, d->buffer.size() == %d\n", this,
@@ -917,8 +894,10 @@ qint64 QIODevice::read(char *data, qint64 maxSize)
debugBinaryString(data - readSoFar, readSoFar);
#endif
- if (d->buffer.isEmpty())
+ if (madeBufferReadsOnly && d->buffer.isEmpty()) {
+ d->buffer.clear();
readData(data, 0);
+ }
return readSoFar;
}
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