type eofReader struct {
	buf []byte
}

func (r *eofReader) Read(p []byte) (int, error) {
	read := copy(p, r.buf)
	r.buf = r.buf[read:]

	switch read {
	case 0, len(r.buf):
		// As allowed in the documentation, this will return io.EOF
		// in the same call that consumes the last of the data.
		// https://godoc.org/io#Reader

		if tok == '#' {
			// A leftover wisp of a #include/#define/etc,
			// to let us know that p.sawCode should be true now.
			// Otherwise ignored.
			continue
		}
		return tok
	}
}

// line consumes a single assembly line from p.lex of the form
//
//	{label:} WORD[.cond] [ arg {, arg} ] (';' | '\n')
//
// It adds any labels to p.pendingLabels and returns the word, cond,

			}
			if n > 0 {
				s.empties = 0
				break
			}
			loop++
			if loop > maxConsecutiveEmptyReads {
				s.setErr(io.ErrNoProgress)
				break
			}
		}
	}
}

// advance consumes n bytes of the buffer. It reports whether the advance was legal.
func (s *Scanner) advance(n int) bool {
	if n < 0 {
		s.setErr(ErrNegativeAdvance)
		return false
	}
	if n > s.end-s.start {

}

// ReadRune reads and returns the next UTF-8-encoded
// Unicode code point from the buffer.
// If no bytes are available, the error returned is io.EOF.
// If the bytes are an erroneous UTF-8 encoding, it
// consumes one byte and returns U+FFFD, 1.
func (b *Buffer) ReadRune() (r rune, size int, err error) {
	if b.empty() {
		// Buffer is empty, reset to recover space.
		b.Reset()
		return 0, 0, io.EOF
	}
	c := b.buf[b.off]

		}
		if hdr.Name != v.wantName {
			t.Errorf("test %d, Header.Name = %s, want %s", i, hdr.Name, v.wantName)
		}
		if v.wantErr == nil && r.Len() == 0 {
			t.Errorf("test %d, canary byte unexpectedly consumed", i)
		}
	}
}

// testNonEmptyReader wraps an io.Reader and ensures that
// Read is never called with an empty buffer.
type testNonEmptyReader struct{ io.Reader }

	b.lastByte = -1
	b.lastRuneSize = -1
	return nil
}

// ReadRune reads a single UTF-8 encoded Unicode character and returns the
// rune and its size in bytes. If the encoded rune is invalid, it consumes one byte
// and returns unicode.ReplacementChar (U+FFFD) with a size of 1.
func (b *Reader) ReadRune() (r rune, size int, err error) {