Function ensure

msgp/write_bytes.go:13–22

ensure 'sz' extra bytes in 'b' btw len(b) and cap(b)

(b []byte, sz int)

// ensure 'sz' extra bytes in 'b' btw len(b) and cap(b)
func ensure(b []byte, sz int) ([]byte, int) {
	l := len(b)
	c := cap(b)
	if c-l < sz {
		o := make([]byte, (2*c)+sz) // exponential growth
		n := copy(o, b)
		return o[:n+sz], n
	}
	return b[:l+sz], l
}

// AppendMapHeader appends a map header with the
// given size to the slice