| Operation |
Meaning |
| create/write |
Initialize state of transformation for writing into channel.
The buffer is irrelevant, and empty. A return value is
ignored. First call for writing part.
|
| delete/write |
Cleanup state of transformation for writing into channel.
The buffer is irrelevant, and empty. A return value is
ignored. Last call for writing part.
|
| write |
Execute write transformation on the given buffer. The return
value is interpreted as transformation result.
|
| flush/write |
Flush out all buffers internal to the transformation. The
given buffer is empty. The return value is interpreted as
transformation result.
|
| clear/write |
Cleanup state of transformation for writing into channel.
The buffer is irrelevant, and empty. A return value is
ignored.
|
| create/read |
Initialize state of transformation for read from channel.
The buffer is irrelevant, and empty. A return value is
ignored. First call for reading part.
|
| delete/read |
Cleanup state of transformation for read from channel. The
buffer is irrelevant, and empty. A return value is ignored.
Last call for reading part.
|
| read |
Execute read transformation on the given buffer. The return
value is interpreted as transformation result. Normally the
inverse of the write transformation.
|
| flush/read |
Flush out all buffers internal to the transformation. The
given buffer is empty. The return value is interpreted as
transformation result. Required to get buffered partial
results at EOF of the underlying channel.
|
| clear/read |
Cleanup state of transformation for read from channel. The
buffer is irrelevant, and empty. A return value is ignored.
Called during seeks on the channel.
|
| query/maxRead |
The transformation is queried for the maximum number of
bytes to read. This call is done just before reading more
data from the underlying. The return value has to be an
integer number. A negative value signal acceptance of
whatever number of characters the trf layer decides to
read.
|
| query/ratio |
The transformation is queried for its natural seek ratio.
Called once after the creation of the transformation (and
its attachment to a channel). The return value has to be
a list containing at least 2 elements. The first two
elements of the list are interpreted as the natural ratio
of the transformation.
|
