package patricia
import (
"encoding/binary"
"net"
)
const _leftmost32Bit = uint32(1 << 31)
// IPv4Address is a representation of an IPv4 address and CIDR
type IPv4Address struct {
Address uint32
Length uint
}
// NewIPv4Address creates an address from the input IPv4 address
func NewIPv4Address(address uint32, length uint) IPv4Address {
return IPv4Address{
Address: address,
Length: length,
}
}
// NewIPv4AddressFromBytes creates an address from the input IPv4 address bytes
// - address must be 4 or 16 bytes
func NewIPv4AddressFromBytes(address []byte, length uint) IPv4Address {
byteCount := len(address)
if byteCount != 4 && byteCount != 16 {
return IPv4Address{Address: 0, Length: 0}
}
return IPv4Address{
Address: binary.BigEndian.Uint32(net.IP(address).To4()),
Length: length,
}
}
// ShiftLeft shifts the address to the left
func (i *IPv4Address) ShiftLeft(shiftCount uint) {
i.Address <<= shiftCount
i.Length -= shiftCount
}
// IsLeftBitSet returns whether the leftmost bit is set
func (i *IPv4Address) IsLeftBitSet() bool {
return i.Address >= _leftmost32Bit
}
// String returns a string version of this IP address.
// - not optimized for performance, alloates a byte slice
func (i IPv4Address) String() string {
data := make([]byte, 4)
binary.BigEndian.PutUint32(data, i.Address)
ipNet := net.IPNet{
IP: data,
Mask: net.CIDRMask(int(i.Length), 32),
}
return ipNet.String()
}