Function EncodeTSVectorPGBinary

pkg/util/tsearch/encoding.go:106–124

EncodeTSVectorPGBinary encodes a tsvector into a serialized representation that's identical to Postgres's wire protocol representation. The below comment explains the wire protocol representation. It is taken from this page: https://www.npgsql.org/dev/types.html tsvector: UInt32 number of lexeme

(appendTo []byte, vector TSVector)

//	    for each position:
//	        UInt16 WordEntryPos, where the most significant 2 bits is weight, and the 14 least significant bits is pos (can't be 0). Weights 3,2,1,0 represent A,B,C,D
func EncodeTSVectorPGBinary(appendTo []byte, vector TSVector) ([]byte, error) {
	appendTo = encoding.EncodeUint32Ascending(appendTo, uint32(len(vector)))
	for _, term := range vector {
		l := term.lexeme
		appendTo = append(appendTo, []byte(l)...)
		appendTo = append(appendTo, byte(0))
		i := len(term.positions)
		appendTo = encoding.EncodeUint16Ascending(appendTo, uint16(i))
		for _, pos := range term.positions {
			weight, err := pos.weight.TSVectorPGEncoding()
			if err != nil {
				return nil, err
			}
			out := pos.position | (uint16(weight) << 14)
			appendTo = encoding.EncodeUint16Ascending(appendTo, out)
		}
	}
	return appendTo, nil
}

// DecodeTSVectorPGBinary decodes a tsvector from the input byte slice which is
// formatted in Postgres binary protocol.