| ost::Buffer(3) | Library Functions Manual | ost::Buffer(3) |
NAME¶
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.
SYNOPSIS¶
#include <buffer.h>
Inherits ost::Conditional.
Inherited by ost::FixedBuffer.
Public Member Functions¶
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 Public Attributes¶
static const size_t timeout
value to return when a timed operation returned with a timeout.
Protected Member Functions¶
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.
Related Functions¶
(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)
Detailed Description¶
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
Producer/Consumer buffer for use between threads.
Constructor & Destructor Documentation¶
ost::Buffer::Buffer (size_t capacity)¶
Create a buffer object of known capacity.
Parameters
virtual ost::Buffer::~Buffer () [virtual]¶
In derived functions, may be used to free the actual memory used to hold buffered data.
Member Function Documentation¶
size_t ost::Buffer::getSize (void) [inline]¶
Return the capacity of the buffer as specified at creation.
Returns
size_t ost::Buffer::getUsed (void) [inline]¶
Return the current capacity in use for the buffer. Free space is technically getSize() - getUsed().
Returns
See also
virtual bool ost::Buffer::isValid (void) [virtual]¶
New virtual to test if buffer is a valid object.
Returns
Reimplemented in ost::FixedBuffer.
virtual size_t ost::Buffer::onPeek (void * buf) [protected], [pure virtual]¶
Invoke derived class buffer peeking method.
Returns
Parameters
Implemented in ost::FixedBuffer.
virtual size_t ost::Buffer::onPost (void * buf) [protected], [pure virtual]¶
Invoke derived class posting of object to buffer.
Returns
Parameters
Implemented in ost::FixedBuffer.
virtual size_t ost::Buffer::onWait (void * buf) [protected], [pure virtual]¶
Invoke derived class object request from buffer.
Returns
Parameters
Implemented in ost::FixedBuffer.
size_t ost::Buffer::peek (void * buf)¶
Peek at the current content (first object) in the buffer.
Returns
Parameters
Referenced by peek().
size_t ost::Buffer::post (void * buf, timeout_t timeout = 0)¶
Post an object into the buffer and enable a waiting thread to receive it.
Returns
Parameters
timeout time to wait.
Referenced by put().
size_t ost::Buffer::wait (void * buf, timeout_t timeout = 0)¶
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
timeout time to wait.
Referenced by get().
Friends And Related Function Documentation¶
size_t get (Buffer & b, void * o, timeout_t t = 0) [related]¶
References wait().
size_t peek (Buffer & b, void * o) [related]¶
Examples
SampleSocketPort.cpp.
References peek().
size_t put (Buffer & b, void * o, timeout_t t = 0) [related]¶
References post().
Member Data Documentation¶
const size_t ost::Buffer::timeout [static]¶
value to return when a timed operation returned with a timeout.
Author¶
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| Sun Dec 27 2020 | GNU CommonC++ |