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use io;
use fmt;
export type packet = []u8;
def PCKSZ: size = 8;
export type packet_reader = struct {
buf: [256]u8,
good: []u8,
};
export fn new() packet_reader = {
let pr = packet_reader {
buf = [0...],
...
};
pr.good = pr.buf[0..0];
return pr;
};
// call when input is ready. could block otherwise
export fn read(pr: *packet_reader, sock: io::handle) (void | io::error | io::EOF) = {
const remaining_amt = len(pr.good);
const read_pos = if (remaining_amt > 0) {
// still some unconsumed content in the buffer
// move unconsumed stuff to start of buffer
fmt::printfln("moving {} remaining bytes",remaining_amt)!;
pr.buf[0..remaining_amt] = pr.good;
yield remaining_amt;
} else 0z;
const nread = match(io::read(sock, pr.buf[read_pos..])?) {
case io::EOF => return io::EOF;
case let n: size => yield n;
};
fmt::printfln("read {} bytes",nread)!;
const total_amt = read_pos + nread;
pr.good = pr.buf[0..total_amt];
fmt::printfln("now {} bytes in buffer",total_amt)!;
};
export fn next(pr: *packet_reader) (packet | done) = {
// either parse a full packet out of the front of good,
// move good along that many bytes,
// and return the packet,
// or, ascertain there is no full packet, and return done
if (len(pr.good) < PCKSZ) return done;
const packet_bytes = pr.good[..PCKSZ];
pr.good = pr.good[PCKSZ..];
return packet_bytes;
};
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