Function EncodeUntaggedDecimalValue

postgres/parser/encoding/encoding.go:872–885

EncodeUntaggedDecimalValue encodes an apd.Decimal value, appends it to the supplied buffer, and returns the final buffer.

(appendTo []byte, d *apd.Decimal)

// EncodeUntaggedDecimalValue encodes an apd.Decimal value, appends it to the supplied
// buffer, and returns the final buffer.
func EncodeUntaggedDecimalValue(appendTo []byte, d *apd.Decimal) []byte {
	// To avoid the allocation, leave space for the varint, encode the decimal,
	// encode the varint, and shift the encoded decimal to the end of the
	// varint.
	varintPos := len(appendTo)
	// Manually append 10 (binary.MaxVarintLen64) 0s to avoid the allocation.
	appendTo = append(appendTo, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
	decOffset := len(appendTo)
	appendTo = EncodeNonsortingDecimal(appendTo, d)
	decLen := len(appendTo) - decOffset
	varintLen := binary.PutUvarint(appendTo[varintPos:decOffset], uint64(decLen))
	copy(appendTo[varintPos+varintLen:varintPos+varintLen+decLen], appendTo[decOffset:decOffset+decLen])
	return appendTo[:varintPos+varintLen+decLen]
}

// DecodeValueTag decodes a value encoded by EncodeValueTag, used as a prefix in
// each of the other EncodeFooValue methods.