Method Prev

pkg/sql/sem/tree/datum.go:1627–1645

Prev implements the Datum interface.

(_ *EvalContext)

// Prev implements the Datum interface.
func (d *DIPAddr) Prev(_ *EvalContext) (Datum, bool) {
	// We will do one of the following to get the Prev IPAddr:
	//	- Decrement IP address if we won't underflow the IP.
	//	- Decrement mask and set the IP to max in family if we will underflow.
	//	- Jump down from IPv6 to IPv4 if we will underflow both IP and mask.
	if d.Family == ipaddr.IPv6family && d.Addr.Equal(dIPv6min) {
		if d.Mask == 0 {
			// Jump down IP family.
			return dMaxIPv4Addr, true
		}
		// Decrease mask size, wrap IPv6 IP address.
		return NewDIPAddr(DIPAddr{ipaddr.IPAddr{Family: ipaddr.IPv6family, Addr: dIPv6max, Mask: d.Mask - 1}}), true
	} else if d.Family == ipaddr.IPv4family && d.Addr.Equal(dIPv4min) {
		// Decrease mask size, wrap IPv4 IP address.
		return NewDIPAddr(DIPAddr{ipaddr.IPAddr{Family: ipaddr.IPv4family, Addr: dIPv4max, Mask: d.Mask - 1}}), true
	}
	// Decrement IP address.
	return NewDIPAddr(DIPAddr{ipaddr.IPAddr{Family: d.Family, Addr: d.Addr.Sub(1), Mask: d.Mask}}), true
}

// Next implements the Datum interface.
func (d *DIPAddr) Next(_ *EvalContext) (Datum, bool) {