KBufferedIO Class Reference
This abstract class implements basic functionality for buffered input/output. Buffered I/O. More...
#include <kbufferedio.h>
Inheritance diagram for KBufferedIO:

Public Types | |
enum | closeModes { availRead = 0x01, dirtyWrite = 0x02, involuntary = 0x10, delayed = 0x20, closedNow = 0x40 } |
Signals | |
void | bytesWritten (int nbytes) |
void | closed (int state) |
Public Member Functions | |
virtual | ~KBufferedIO () |
virtual void | closeNow ()=0 |
virtual bool | setBufferSize (int rsize, int wsize=-2) |
virtual int | bytesAvailable () const |
virtual int | waitForMore (int msec)=0 |
virtual int | bytesToWrite () const |
virtual bool | canReadLine () const |
virtual int | peekBlock (char *data, uint maxlen)=0 |
virtual int | unreadBlock (const char *data, uint len) |
Protected Member Functions | |
virtual unsigned | consumeReadBuffer (unsigned nbytes, char *destbuffer, bool discard=true) |
virtual void | consumeWriteBuffer (unsigned nbytes) |
virtual unsigned | feedReadBuffer (unsigned nbytes, const char *buffer, bool atBeginning=false) |
virtual unsigned | feedWriteBuffer (unsigned nbytes, const char *buffer) |
virtual unsigned | readBufferSize () const |
virtual unsigned | writeBufferSize () const |
virtual void | virtual_hook (int id, void *data) |
Protected Attributes | |
QPtrList< QByteArray > | inBuf |
QPtrList< QByteArray > | outBuf |
unsigned | inBufIndex |
unsigned | outBufIndex |
Detailed Description
This abstract class implements basic functionality for buffered input/output. Buffered I/O.Through the available methods, you can find out how many bytes are available for reading, how many are still unsent and you can peek at the buffered data.
This class was intentionally written to resemble QSocket, because KExtendedSocket is a subclass of this one. This is so that applications written using QSocket's buffering characteristics will be more easily ported to the more powerful KExtendedSocket class.
KBufferedIO already provides a powerful internal buffering algorithm. However, this does not include the I/O itself, which must be implemented in derived classes. Thus, to implement a class that does some I/O, you must override, in addition to the pure virtual QIODevice methods, these two:
If your derived class reimplements the buffering algorithm, you must then decide which buffering functions to override. For instance, you may want to change the protected functions like feedReadBuffer() and consumeReadBuffer().
- Author:
- Thiago Macieira <thiagom@mail.com>
Definition at line 56 of file kbufferedio.h.
Member Enumeration Documentation
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The modes for closed() signal.
Definition at line 68 of file kbufferedio.h. |
Constructor & Destructor Documentation
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Destroys this class. The flushing of the buffers is implementation dependant. The default implementation discards the contents Definition at line 95 of file kbufferedio.cpp. |
Member Function Documentation
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Closes the stream now, discarding the contents of the write buffer. That is, we won't try to flush that buffer before closing. If you want that buffer to be flushed, you can call QIODevice::flush(), which is blocking, and then closeNow, or you can call QIODevice::close() for a delayed close. |
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Sets the internal buffer size to value. Not all implementations support this. The parameters may be 0 to make the class unbuffered or -1 to let the class choose the size (which may be unlimited) or -2 to leave the buffer size untouched. Note that setting the write buffer size to any value smaller than the current size of the buffer will force it to flush first, which can make this call blocking. The default implementation does not support setting the buffer sizes. You can only call this function with values -1 for "don't care" or -2 for "unchanged"
Definition at line 102 of file kbufferedio.cpp. |
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Returns the number of bytes available for reading in the read buffer.
Definition at line 112 of file kbufferedio.cpp. References readBufferSize(). Referenced by canReadLine(). |
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Waits for more data to be available and returns the amount of available data then.
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Returns the number of bytes yet to write, still in the write buffer.
Definition at line 117 of file kbufferedio.cpp. References writeBufferSize(). |
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Checks whether there is enough data in the buffer to read a line. The default implementation reads directly from inBuf, so if your implementation changes the meaning of that member, then you must override this function.
Definition at line 123 of file kbufferedio.cpp. References bytesAvailable(). |
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Reads into the user buffer at most maxlen bytes, but does not consume that data from the read buffer. This is useful to check whether we already have the needed data to process something. This function may want to try and read more data from the system provided it won't block.
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Unreads some data. That is, write the data to the beginning of the read buffer, so that next calls to readBlock or peekBlock will see this data instead. Note not all devices implement this since this could mean a semantic problem. For instance, sockets are sequential devices, so they won't accept unreading.
Definition at line 153 of file kbufferedio.cpp. References feedReadBuffer(). |
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This signal gets sent whenever bytes are written from the buffer.
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This signal gets sent when the stream is closed.
The
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Consumes data from the input buffer.
That is, this will copy the data stored in the input (read) buffer into the given
Definition at line 162 of file kbufferedio.cpp. References inBuf, and readBufferSize(). |
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Consumes data from the output buffer. Since this is called whenever we managed to send data out the wire, we can only discard this amount from the buffer. There is no copying and no "peeking" for the output buffer. Note this function should be called AFTER the data was sent. After it is called, the data is no longer available in the buffer. And don't pass wrong nbytes values.
Definition at line 212 of file kbufferedio.cpp. References outBuf. |
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Feeds data into the input buffer. This happens when we detected available data in the device and read it.
The data will be appended to the buffer or inserted at the beginning, depending on whether
Definition at line 241 of file kbufferedio.cpp. References inBuf. Referenced by unreadBlock(). |
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Feeds data into the output buffer. This happens when the user told us to write some data. The data will be appended to the buffer.
Definition at line 257 of file kbufferedio.cpp. References outBuf. |
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Returns the number of bytes in the read buffer.
Definition at line 268 of file kbufferedio.cpp. Referenced by bytesAvailable(), and consumeReadBuffer(). |
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Returns the number of bytes in the write buffer.
Definition at line 281 of file kbufferedio.cpp. Referenced by bytesToWrite(). |
Member Data Documentation
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For an explanation on how this buffer work, please refer to the comments at the top of kbufferedio.cpp.
Definition at line 212 of file kbufferedio.h. Referenced by consumeReadBuffer(), and feedReadBuffer(). |
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For an explanation on how this buffer work, please refer to the comments at the top of kbufferedio.cpp.
Definition at line 218 of file kbufferedio.h. Referenced by consumeWriteBuffer(), and feedWriteBuffer(). |
The documentation for this class was generated from the following files: