Method decodeSlice

json/decode.go:570–645

(b []byte, p unsafe.Pointer, size uintptr, t reflect.Type, decode decodeFunc)

var empty struct{}

func (d decoder) decodeSlice(b []byte, p unsafe.Pointer, size uintptr, t reflect.Type, decode decodeFunc) ([]byte, error) {
	if hasNullPrefix(b) {
		*(*slice)(p) = slice{}
		return b[4:], nil
	}

	if len(b) < 2 {
		return d.inputError(b, t)
	}

	if b[0] != '[' {
		// Go 1.7- behavior: fallback to decoding as a []byte if the element
		// type is byte; allow conversions from JSON strings even tho the
		// underlying type implemented unmarshaler interfaces.
		if t.Elem().Kind() == reflect.Uint8 {
			return d.decodeBytes(b, p)
		}
		return d.inputError(b, t)
	}

	input := b
	b = b[1:]

	s := (*slice)(p)
	s.len = 0

	var err error
	for {
		b = skipSpaces(b)

		if len(b) != 0 && b[0] == ']' {
			if s.data == nil {
				s.data = unsafe.Pointer(&empty)
			}
			return b[1:], nil
		}

		if s.len != 0 {
			if len(b) == 0 {
				return b, syntaxError(b, "unexpected EOF after array element")
			}
			if b[0] != ',' {
				return b, syntaxError(b, "expected ',' after array element but found '%c'", b[0])
			}
			b = skipSpaces(b[1:])
		}

		if s.len == s.cap {
			c := s.cap

			if c == 0 {
				c = 10
			} else {
				c *= 2
			}

			*s = extendSlice(t, s, c)
		}