# Read from `bytes` in memory
#
# ~~~
# var reader = new BytesReader(b"a…b")
# assert reader.read_char == 'a'
# assert reader.read_byte == 0xE2 # 1st byte of '…'
# assert reader.read_byte == 0x80 # 2nd byte of '…'
# assert reader.read_char == '�' # Reads the last byte as an invalid char
# assert reader.read_all_bytes == b"b"
# ~~~
class BytesReader
	super Reader

	# Source data to read
	var bytes: Bytes

	# The current position in `bytes`
	private var cursor = 0

	redef fun raw_read_byte
	do
		if cursor >= bytes.length then return -1

		var c = bytes[cursor]
		cursor += 1
		return c.to_i
	end

	redef fun close do bytes = new Bytes.empty

	redef fun read_all_bytes
	do
		var res = bytes.slice_from(cursor)
		cursor = bytes.length
		return res
	end

	redef fun raw_read_bytes(ns, max) do
		if cursor >= bytes.length then return 0

		var copy = max.min(bytes.length - cursor)
		bytes.items.copy_to(ns, copy, cursor, 0)
		cursor += copy
		return copy
	end

	redef fun eof do return cursor >= bytes.length
end