On Thu, 14 Oct 2010 16:47:13 -0400, Steven Schveighoffer
<schvei...@yahoo.com> wrote:
On Thu, 14 Oct 2010 14:43:56 -0400, Andrei Alexandrescu
How? Denis' implementation has two copies in the mix. (I'm not counting
.dup etc.) Anyhow, let's do this - write down your interfaces so I can
comment on them. We talk "oh that's a buffering interface" and "that
requires buffering" and "that's an extra copy" and so on but we have
little concrete contenders. I put my cards on the table, you put yours.
I'll see if I can put something together.
Here's a rough outline:
enum Anchor
{
Begin,
Current,
End
}
interface Seek
{
ulong seek(long delta, Anchor whence);
final ulong tell() { return seek(0, Anchor.Current); }
bool seekable(); // define as false if seeking is not supported, true
if it
// is supported (this doesn't necessarily mean a seek
will
// succeed).
}
interface InputTransport : Seek
{
size_t read(ubyte[] data); // returns 0 on EOF.
}
// defined to implement either a D buffered object or wrap a FILE *.
//
interface BufferedInputTransport : Seek
{
size_t read(ubyte[] data); // returns 0 on EOF.
//
// read data into the buffer until the delegate returns other than ~0
//
// The delegate is passed the entire buffer so far, with the start of
the
// new data just read. It returns other than ~0 when it determines
the end
// of the data in question.
//
ubyte[] readUntil(uint delegate(ubyte[] data, uint start) process);
//
// same as readUntil except append to the given arr, Any excess
// data will be pushed into the internal buffer.
//
size_t appendUntil(uint delegate(ubyte[] data, uint start) process,
ref ubyte[] arr)
// various buffer functions.
@property size_t bufsize();
@property size_t readable();
// etc.
}
The way I see it working is, there are two implementations for
BufferedInputTransport: FILEInputTransport and DBufferInputTransport.
There are numerous implementations of InputTransport, each of which can be
passed to the DBufferInputTransport, which uses its own buffer
implementation. For example, a network socket, file, inter-thread stream,
an array, etc.
This way, you can play nice with C's stdio when necessary (i.e. for
stdin/stdout/stderr) and avoid the FILE limitations and performance issues
otherwise.
-Steve
