Use internal read buffer of QIODevice

It is reasonable to use the internal read buffer of QIODevice instead of
additional QRingBuffer which currently are used. It will allow to reduce
an overhead when copying data as now there is not an excess chain with
QRingBuffer. Besides, the majority of I/O classes from QtCore (except
QProcess) also use the internal QIODevice buffer which are optimized for
this purpoze.

Tested on Windows 8 and Linux with the virtual com0com and on-board
serial ports.

Change-Id: I6c3d4b84593940ccfef8c15c9fbef16bddcd002f
Reviewed-by: Sergey Belyashov <Sergey.Belyashov@gmail.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/src/serialport/qserialport_wince.cpp b/src/serialport/qserialport_wince.cpp
index 47c11ee6..a53aff7a 100644
--- a/src/serialport/qserialport_wince.cpp
+++ b/src/serialport/qserialport_wince.cpp
@@ -331,12 +331,12 @@ bool QSerialPortPrivate::setBreakEnabled(bool set)
 
 qint64 QSerialPortPrivate::readData(char *data, qint64 maxSize)
 {
-    return readBuffer.read(data, maxSize);
+    return buffer.read(data, maxSize);
 }
 
 bool QSerialPortPrivate::waitForReadyRead(int msec)
 {
-    if (!readBuffer.isEmpty())
+    if (!buffer.isEmpty())
         return true;
 
     QElapsedTimer stopWatch;
@@ -499,8 +499,8 @@ bool QSerialPortPrivate::notifyRead()
 
     DWORD bytesToRead = (policy == QSerialPort::IgnorePolicy) ? ReadChunkSize : 1;
 
-    if (readBufferMaxSize && bytesToRead > (readBufferMaxSize - readBuffer.size())) {
-        bytesToRead = readBufferMaxSize - readBuffer.size();
+    if (readBufferMaxSize && bytesToRead > (readBufferMaxSize - buffer.size())) {
+        bytesToRead = readBufferMaxSize - buffer.size();
         if (bytesToRead == 0) {
             // Buffer is full. User must read data from the buffer
             // before we can read more from the port.
@@ -508,18 +508,18 @@ bool QSerialPortPrivate::notifyRead()
         }
     }
 
-    char *ptr = readBuffer.reserve(bytesToRead);
+    char *ptr = buffer.reserve(bytesToRead);
 
     DWORD readBytes = 0;
     BOOL sucessResult = ::ReadFile(handle, ptr, bytesToRead, &readBytes, NULL);
 
     if (!sucessResult) {
-        readBuffer.truncate(bytesToRead);
+        buffer.chop(bytesToRead);
         q->setError(QSerialPort::ReadError);
         return false;
     }
 
-    readBuffer.truncate(readBytes);
+    buffer.chop(readBytes);
 
     // Process emulate policy.
     if ((policy != QSerialPort::IgnorePolicy) && parityErrorOccurred) {
@@ -528,11 +528,11 @@ bool QSerialPortPrivate::notifyRead()
 
         switch (policy) {
         case QSerialPort::SkipPolicy:
-            readBuffer.getChar();
+            buffer.getChar();
             return true;
         case QSerialPort::PassZeroPolicy:
-            readBuffer.getChar();
-            readBuffer.putChar('\0');
+            buffer.getChar();
+            buffer.ungetChar('\0');
             break;
         case QSerialPort::StopReceivingPolicy:
             // FIXME: Maybe need disable read notifier?