Method readValue

json/json.go:392–447

readValue reads one JSON value from the buffer and returns its raw bytes. It is optimized for the "one JSON value per line" case.

()

// readValue reads one JSON value from the buffer and returns its raw bytes. It
// is optimized for the "one JSON value per line" case.
func (dec *Decoder) readValue() (v []byte, err error) {
	var n int
	var r []byte
	d := decoder{flags: dec.flags}

	for {
		if len(dec.remain) != 0 {
			v, r, _, err = d.parseValue(dec.remain)
			if err == nil {
				dec.remain, n = skipSpacesN(r)
				dec.inputOffset += int64(len(v) + n)
				return
			}
			if len(r) != 0 {
				// Parsing of the next JSON value stopped at a position other
				// than the end of the input buffer, which indicaates that a
				// syntax error was encountered.
				return
			}
		}

		if err = dec.err; err != nil {
			if len(dec.remain) != 0 && err == io.EOF {
				err = io.ErrUnexpectedEOF
			}
			return
		}

		if dec.buffer == nil {
			dec.buffer = make([]byte, 0, minBufferSize)
		} else {
			dec.buffer = dec.buffer[:copy(dec.buffer[:cap(dec.buffer)], dec.remain)]
			dec.remain = nil
		}

		if (cap(dec.buffer) - len(dec.buffer)) < minReadSize {
			buf := make([]byte, len(dec.buffer), 2*cap(dec.buffer))
			copy(buf, dec.buffer)
			dec.buffer = buf
		}

		n, err = io.ReadFull(dec.reader, dec.buffer[len(dec.buffer):cap(dec.buffer)])
		if n > 0 {
			dec.buffer = dec.buffer[:len(dec.buffer)+n]
			if err != nil {
				err = nil
			}
		} else if err == io.ErrUnexpectedEOF {
			err = io.EOF
		}
		dec.remain, n = skipSpacesN(dec.buffer)
		d.flags = dec.flags | internalParseFlags(dec.remain)
		dec.inputOffset += int64(n)
		dec.err = err
	}
}

// DisallowUnknownFields is documented at https://golang.org/pkg/encoding/json/#Decoder.DisallowUnknownFields