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Bayonne2 / Common C++ 2 Framework
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Bayonne2 / Common C++ 2 Framework
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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. More...
#include <buffer.h>
Public Member Functions | |
| Buffer (size_t capacity) | |
| Create a buffer object of known capacity. More... | |
| virtual | ~Buffer () |
| In derived functions, may be used to free the actual memory used to hold buffered data. More... | |
| size_t | getSize (void) |
| Return the capacity of the buffer as specified at creation. More... | |
| size_t | getUsed (void) |
| Return the current capacity in use for the buffer. More... | |
| size_t | wait (void *buf, timeout_t timeout=0) |
| Let one or more threads wait for an object to become available in the buffer. More... | |
| size_t | post (void *buf, timeout_t timeout=0) |
| Post an object into the buffer and enable a waiting thread to receive it. More... | |
| size_t | peek (void *buf) |
| Peek at the current content (first object) in the buffer. More... | |
| virtual bool | isValid (void) |
| New virtual to test if buffer is a valid object. More... | |
| void | signal (bool broadcast) |
| Signal a conditional object and a waiting threads. More... | |
| bool | wait (timeout_t timer=0, bool locked=false) |
| Wait to be signaled from another thread. More... | |
| void | enterMutex (void) |
| Locks the conditional's mutex for this thread. More... | |
| void | lock (void) |
| In the future we will use lock in place of enterMutex since the conditional composite is not a recursive mutex, and hence using enterMutex may cause confusion in expectation with the behavior of the Mutex class. More... | |
| bool | tryEnterMutex (void) |
| Tries to lock the conditional for the current thread. More... | |
| bool | test (void) |
| void | leaveMutex (void) |
| Leaving a mutex frees that mutex for use by another thread. More... | |
| void | unlock (void) |
Static Public Attributes | |
| static const size_t | timeout |
| value to return when a timed operation returned with a timeout. More... | |
Protected Member Functions | |
| virtual size_t | onPeek (void *buf)=0 |
| Invoke derived class buffer peeking method. More... | |
| virtual size_t | onWait (void *buf)=0 |
| Invoke derived class object request from buffer. More... | |
| virtual size_t | onPost (void *buf)=0 |
| Invoke derived class posting of object to buffer. More... | |
Private Attributes | |
| size_t | _size |
| size_t | _used |
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) |
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.
| Buffer::Buffer | ( | size_t | capacity | ) |
Create a buffer object of known capacity.
| capacity | is the integer capacity of the buffer. |
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virtual |
In derived functions, may be used to free the actual memory used to hold buffered data.
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inherited |
Locks the conditional's mutex for this thread.
Remember that Conditional's mutex is NOT a recursive mutex!
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inline |
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inline |
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virtual |
New virtual to test if buffer is a valid object.
Reimplemented in FixedBuffer.
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inherited |
Leaving a mutex frees that mutex for use by another thread.
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inlineinherited |
In the future we will use lock in place of enterMutex since the conditional composite is not a recursive mutex, and hence using enterMutex may cause confusion in expectation with the behavior of the Mutex class.
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protectedpure virtual |
Invoke derived class buffer peeking method.
| buf | pointer to copy contents of head of buffer to. |
Implemented in ost::BayonneMsgport, and FixedBuffer.
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protectedpure virtual |
Invoke derived class posting of object to buffer.
| buf | pointer to object being posted to the buffer. |
Implemented in ost::BayonneMsgport, and FixedBuffer.
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protectedpure virtual |
Invoke derived class object request from buffer.
| buf | pointer to hold object returned from the buffer. |
Implemented in ost::BayonneMsgport, and FixedBuffer.
| size_t Buffer::peek | ( | void * | buf | ) |
Peek at the current content (first object) in the buffer.
| buf | pointer to store object found in the buffer. |
| size_t Buffer::post | ( | void * | buf, |
| timeout_t | timeout = 0 |
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| ) |
Post an object into the buffer and enable a waiting thread to receive it.
| buf | pointer to object to store in the buffer. |
| timeout | time to wait. |
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inherited |
Signal a conditional object and a waiting threads.
| broadcast | this signal to all waiting threads if true. |
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inherited |
Tries to lock the conditional for the current thread.
Behaves like enterMutex , except that it doesn't block the calling thread.
| size_t Buffer::wait | ( | void * | buf, |
| timeout_t | timeout = 0 |
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| ) |
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.
| buf | pointer to store object retrieved from the buffer. |
| timeout | time to wait. |
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inherited |
Wait to be signaled from another thread.
| timer | time period to wait. |
| locked | flag if already locked the mutex. |
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static |
1.8.6