| ost::Buffer(3) | Library Functions Manual | ost::Buffer(3) |
ost::Buffer - The buffer class represents an IPC service that is built upon a buffer of fixed capacity that can be used to transfer objects between one or more producer and consumer threads.
#include <buffer.h>
Inherits ost::Conditional.
Inherited by ost::FixedBuffer.
Buffer (size_t capacity)
Create a buffer object of known capacity. virtual ~Buffer ()
In derived functions, may be used to free the actual memory used to hold
buffered data. size_t getSize (void)
Return the capacity of the buffer as specified at creation. size_t
getUsed (void)
Return the current capacity in use for the buffer. size_t wait (void
*buf, timeout_t timeout=0)
Let one or more threads wait for an object to become available in the buffer.
size_t post (void *buf, timeout_t timeout=0)
Post an object into the buffer and enable a waiting thread to receive it.
size_t peek (void *buf)
Peek at the current content (first object) in the buffer. virtual bool
isValid (void)
New virtual to test if buffer is a valid object.
static const size_t timeout
value to return when a timed operation returned with a timeout.
virtual size_t onPeek (void *buf)=0
Invoke derived class buffer peeking method. virtual size_t onWait (void
*buf)=0
Invoke derived class object request from buffer. virtual size_t onPost
(void *buf)=0
Invoke derived class posting of object to buffer.
(Note that these are not member functions.)
size_t get (Buffer &b, void *o, timeout_t t=0)
size_t put (Buffer &b, void *o, timeout_t t=0)
size_t peek (Buffer &b, void *o)
The buffer class represents an IPC service that is built upon a buffer of fixed capacity that can be used to transfer objects between one or more producer and consumer threads.
Producer threads post objects into the buffer, and consumer threads wait for and receive objects from the buffer. Semaphores are used to to block the buffer from overflowing and indicate when there is data available, and mutexes are used to protect multiple consumers and producer threads from stepping over each other.
The buffer class is an abstract class in that the actual data being buffered is not directly specified within the buffer class itself. The buffer class should be used as a base class for a class that actually impliments buffering and which may be aware of the data types actually are being buffered. A template class could be created based on buffer for this purpose. Another possibility is to create a class derived from both Thread and Buffer which can be used to implement message passing threads.
Author:
Create a buffer object of known capacity.
Parameters:
In derived functions, may be used to free the actual memory used to hold buffered data.
Return the capacity of the buffer as specified at creation.
Returns:
Return the current capacity in use for the buffer. Free space is technically getSize() - getUsed().
Returns:
See also:
References ost::wait().
New virtual to test if buffer is a valid object.
Returns:
Reimplemented in ost::FixedBuffer.
Invoke derived class buffer peeking method.
Returns:
Parameters:
Implemented in ost::FixedBuffer.
Invoke derived class posting of object to buffer.
Returns:
Parameters:
Implemented in ost::FixedBuffer.
Invoke derived class object request from buffer.
Returns:
Parameters:
Implemented in ost::FixedBuffer.
Peek at the current content (first object) in the buffer.
Returns:
Parameters:
Referenced by peek().
Post an object into the buffer and enable a waiting thread to receive it.
Returns:
Parameters:
Referenced by put().
Let one or more threads wait for an object to become available in the buffer. The waiting thread(s) will wait forever if no object is ever placed into the buffer.
Returns:
Parameters:
Examples:
SampleSocketPort.cpp.
References peek().
References post().
value to return when a timed operation returned with a timeout.
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| Wed Oct 31 2018 | GNU CommonC++ |