On 9/26/10 23:34 PDT, Shin Fujishiro wrote:
Thus I think we need a buffering layer that exposes a randomly
accessible array to upper layers. ByLine() can be easily and
efficiently implemented with the following primitives defined:
Buffer
{
// The entire buffer.
ubyte[] buffer();
// Slice of buffer() where data is available.
ubyte[] available();
// Moves the beginning of available() by n in buffer().
void bump(sizediff_t n);
// Reads next blob from a source.
bool fetch();
}
Yes, cstdio-esque rawRead() is no good for high-level ByLine. What
high-level I/O entities want is: A randomly accessible buffer. Device
handles may expose block-oriented streaming primitives, but they
must be made "partially random accessible" by the buffering layer.
But that's too big an interface. When would one ever need buffer[], when
the beginning and the end of the buffer may be used for different
portions of the input?
A better stream interface, which actually extends the standard input
range interface:
struct Stream(T)
{
@property T[] front();
void munchFront(size_t bytes) in { assert(bytes <= front.length; }
bool empty();
void popFront();
}
This still doesn't allow filling the buffer with a new line, but it does
offer the ability to a client to copy lines into its own buffer.
Andrei
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