|The asio library expects a const_iterator (the const-ness refers to the fact that the underlying avro of buffers will not be modified, even though the data in those buffers is being modified). |
Public Member Functions
|OutputBuffer (size_type reserveSize=0)|
|Default constructor. |
|void||reserve (size_type reserveSize)|
|Reserve enough space for a wroteTo() operation. |
|size_type||writeTo (const data_type *data, size_type size)|
|Write a block of data to the buffer. |
|template<typename T >|
|void||writeTo (T val)|
|Write a single value to the buffer. |
|size_type||wroteTo (size_type size)|
|Update the state of the buffer after writing through the iterator interface. |
|bool||empty () const|
|Does the buffer have any data? |
|size_type||size () const|
|Returns the size of the buffer, in bytes. |
|size_type||freeSpace () const|
|Returns the current free space that is available to write to in the buffer, in bytes. |
|template<class BufferType >|
|void||append (const BufferType &buf)|
|Appends the data in the argument to the end of this buffer. |
|const_iterator||begin () const|
|Return an iterator pointing to the first data chunk of this buffer that may be written to. |
|const_iterator||end () const|
|Return the end iterator for writing. |
|Discard any data in this buffer. |
|void||discardData (size_t bytes)|
|Discard the specified number of bytes from this data, starting at the beginning. |
|InputBuffer||extractData (size_type bytes)|
|Remove bytes from this buffer, starting from the beginning, and place them into a new buffer. |
|Remove all bytes from this buffer, returning them in a new buffer. |
|OutputBuffer||clone () const|
|Clone this buffer, creating a copy that contains the same data. |
|void||appendForeignData (const data_type *data, size_type size, const detail::free_func &func)|
|Add unmanaged data to the buffer. |
|int||numChunks () const|
|Returns the number of chunks that contain free space. |
|int||numDataChunks () const|
|Returns the number of chunks that contain data. |
The OutputBuffer (write-only buffer).
Use cases for OutputBuffer
OutputBuffer is assignable and copy-constructable. On copy or assignment, only a pointer is copied, so the two resulting copies are identical, so modifying one will modify both.
The asio library expects a const_iterator (the const-ness refers to the fact that the underlying avro of buffers will not be modified, even though the data in those buffers is being modified).
The iterator provides the list of addresses an operation can write to.
|avro::OutputBuffer::OutputBuffer||(||size_type|| reserveSize =
Will pre-allocate at least the requested size, but can grow larger on demand.
Destructor uses the default, which resets a shared pointer, deleting the underlying data if no other copies of exist.
Copy and assignment operators are not explicitly provided because the default ones work fine. The default makes only a shallow copy, so the copies will refer to the same memory. This is required by asio functions, which will implicitly make copies for asynchronous operations. Therefore, the user must be careful that if they create multiple copies of the same OutputBuffer, only one is being modified otherwise undefined behavior may occur.
Referenced by clone().
|void avro::OutputBuffer::append||(||const BufferType &||buf||)||
|void avro::OutputBuffer::appendForeignData||(||const data_type *||data,|
|const detail::free_func &||func|
Add unmanaged data to the buffer.
The buffer will not automatically free the data, but it will call the supplied function when the data is no longer referenced by the buffer (or copies of the buffer).
Discard the specified number of bytes from this data, starting at the beginning.
Throws if the size is greater than the number of bytes.
Remove all bytes from this buffer, returning them in a new buffer.
After removing data, some freeSpace may remain in this buffer.
Remove bytes from this buffer, starting from the beginning, and place them into a new buffer.
Throws if the number of requested bytes exceeds the size of the buffer. Data and freeSpace in the buffer after bytes remains in this buffer.
|size_type avro::OutputBuffer::freeSpace||(||)|| const
Reserve enough space for a wroteTo() operation.
When using writeTo(), the buffer will grow dynamically as needed. But when using the iterator to write (followed by wroteTo()), data may only be written to the space available, so this ensures there is enough room in the buffer before the write operation.
Referenced by OutputBuffer().
Write a single value to the buffer.
The buffer size will automatically grow if there is not room for the byte. The value must be a "fundamental" type, e.g. int, float, etc. (otherwise use the other writeTo tests).
|size_type avro::OutputBuffer::writeTo||(||const data_type *||data,|
Update the state of the buffer after writing through the iterator interface.
This function exists primarily for the boost:asio which writes directly to the buffer using its iterator. In this case, the internal state of the buffer does not reflect that the data was written This informs the buffer how much data was written.
The buffer does not automatically resize in this case, the bytes written cannot exceed the amount of free space. Attempting to write more will throw a std::length_error exception.