geti.myr

use std

use "bio.use"

pkg bio =
	/* unsigned big endian */
	generic getbe8	: (f : file# -> std.option(@a::(numeric,integral)))
	generic getbe16	: (f : file# -> std.option(@a::(numeric,integral)))
	generic getbe32	: (f : file# -> std.option(@a::(numeric,integral)))
	generic getbe64	: (f : file# -> std.option(@a::(numeric,integral)))

	/* signed big endian */
	generic getle8	: (f : file# -> std.option(@a::(numeric,integral)))
	generic getle16	: (f : file# -> std.option(@a::(numeric,integral)))
	generic getle32	: (f : file# -> std.option(@a::(numeric,integral)))
	generic getle64	: (f : file# -> std.option(@a::(numeric,integral)))
;;

/*
  reads a single integer-like value to the output stream, in
  little endian format
*/
generic getle = {f, n -> std.option(@a::(numeric,integral))
	var v, i

	v = 0
	if !ensureread(f, n)
		-> `std.None
	;;
	for i = 0; i < n; i++
		v |= (f.rbuf[f.rstart++] castto(uint64)) << (8*(i castto(uint64)))
	;;
	-> `std.Some v castto(@a::(numeric,integral))
}

/*
  reads a single integer-like value to the output stream, in
  big endian format
*/
generic getbe = {f, n -> std.option(@a::(numeric,integral))
	var v, i

	v = 0
	if !ensureread(f,n)
		-> `std.None
	;;
	for i = 0; i < n; i++
		v <<= 8
		v |= (f.rbuf[f.rstart++] castto(uint64))
	;;
	-> `std.Some v castto(@a::(numeric,integral))
}

generic getbe8  = {f; -> getbe(f, 1)}
generic getbe16 = {f; -> getbe(f, 2)}
generic getbe32 = {f; -> getbe(f, 4)}
generic getbe64 = {f; -> getbe(f, 8)}

generic getle8  = {f; -> getle(f, 1)}
generic getle16 = {f; -> getle(f, 2)}
generic getle32 = {f; -> getle(f, 4)}
generic getle64 = {f; -> getle(f, 8)}