+ # Peeks up to `n` bytes in the buffer
+ #
+ # The operation does not consume the buffer
+ #
+ # ~~~nitish
+ # var x = new FileReader.open("File.txt")
+ # assert x.peek(5) == x.read(5)
+ # ~~~
+ fun peek(i: Int): Bytes do
+ if eof then return new Bytes.empty
+ var remsp = _buffer_length - _buffer_pos
+ if i <= remsp then
+ var bf = new Bytes.with_capacity(i)
+ bf.append_ns_from(_buffer, i, _buffer_pos)
+ return bf
+ end
+ var bf = new Bytes.with_capacity(i)
+ bf.append_ns_from(_buffer, remsp, _buffer_pos)
+ _buffer_pos = _buffer_length
+ read_intern(i - bf.length, bf)
+ remsp = _buffer_length - _buffer_pos
+ var full_len = bf.length + remsp
+ if full_len > _buffer_capacity then
+ var c = _buffer_capacity
+ while c < full_len do c = c * 2 + 2
+ _buffer_capacity = c
+ end
+ var nns = new NativeString(_buffer_capacity)
+ bf.items.copy_to(nns, bf.length, 0, 0)
+ _buffer.copy_to(nns, remsp, _buffer_pos, bf.length)
+ _buffer = nns
+ _buffer_pos = 0
+ _buffer_length = full_len
+ return bf
+ end
+
+ redef fun read_bytes(i)
+ do
+ if last_error != null then return new Bytes.empty
+ var buf = new Bytes.with_capacity(i)
+ read_intern(i, buf)
+ return buf
+ end
+
+ # Fills `buf` with at most `i` bytes read from `self`
+ private fun read_intern(i: Int, buf: Bytes): Int do
+ if eof then return 0
+ var p = _buffer_pos
+ var bufsp = _buffer_length - p
+ if bufsp >= i then
+ _buffer_pos += i
+ buf.append_ns_from(_buffer, i, p)
+ return i
+ end
+ _buffer_pos = _buffer_length
+ var readln = _buffer_length - p
+ buf.append_ns_from(_buffer, readln, p)
+ var rd = read_intern(i - readln, buf)
+ return rd + readln
+ end
+
+ redef fun read_all_bytes