[−][src]Crate circular
Circular, a stream abstraction designed for use with nom
Circular provides a Buffer
type that wraps a Vec<u8>
with a position
and end. Compared to a stream abstraction that would use std::io::Read
,
it separates the reading and consuming phases. Read
is designed to write
the data in a mutable slice and consume it from the stream as it does that.
When used in streaming mode, nom will try to parse a slice, then tell you
how much it consumed. So you don't know how much data was actually used
until the parser returns. Circular::Buffer
exposes a data()
method
that gives an immutable slice of all the currently readable data,
and a consume()
method to advance the position in the stream.
The space()
and fill()
methods are the write counterparts to those methods.
extern crate circular; use circular::Buffer; use std::io::Write; fn main() { // allocate a new Buffer let mut b = Buffer::with_capacity(10); assert_eq!(b.available_data(), 0); assert_eq!(b.available_space(), 10); let res = b.write(&b"abcd"[..]); assert_eq!(res.ok(), Some(4)); assert_eq!(b.available_data(), 4); assert_eq!(b.available_space(), 6); //the 4 bytes we wrote are immediately available and usable for parsing assert_eq!(b.data(), &b"abcd"[..]); // this will advance the position from 0 to 2. it does not modify the underlying Vec b.consume(2); assert_eq!(b.available_data(), 2); assert_eq!(b.available_space(), 6); assert_eq!(b.data(), &b"cd"[..]); // shift moves the available data at the beginning of the buffer. // the position is now 0 b.shift(); assert_eq!(b.available_data(), 2); assert_eq!(b.available_space(), 8); assert_eq!(b.data(), &b"cd"[..]); }
Structs
Buffer | the Buffer contains the underlying memory and data positions |