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types.go
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types.go
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package goip
import (
"math"
"math/big"
"strconv"
)
const (
maxBitCountInternal = math.MaxUint8
minBitCountInternal = 0
maxPortNumInternal = math.MaxUint16
minPortNumInternal = 0
)
var (
p PrefixLen
>
zero = bigZero()
minusOne = big.NewInt(-1)
falseVal = false
trueVal = true
cachedPrefixBitCounts, cachedPrefixLens = initPrefLens()
)
type PortInt = int // using signed integers allows for easier arithmetic
// Port represents the port of a UDP or TCP address.
// A nil value indicates no port.
type Port = *PortNum
type boolSetting struct {
isSet bool
val bool
}
// BitCount is a bit count of an address, section, grouping, segment or division.
// Using signed integers simplifies arithmetic by avoiding errors.
// However, all methods adjust the number of bits according to the address size,
// so negative numbers of bits or numbers of bits greater than the address size are meaningless.
// Using signed integers allows you to simplify arithmetic.
type BitCount = int
// PrefixBitCount is the number of bits in a non-zero PrefixLen.
// For arithmetic you can use the signed integer type BitCount,
// which you can get from PrefixLen using the Len method.
type PrefixBitCount uint8
// PrefixLen indicates the prefix length for an address, section, division group, segment or division.
// A value of zero, i.e. nil, indicates that there is no prefix length.
type PrefixLen = *PrefixBitCount
// Len returns the length of the prefix. If the receiver is nil, representing the absence of a prefix length, returns 0.
// It will also return 0 if the receiver is a prefix with length of 0. To distinguish the two, compare the receiver with nil.
func (prefixBitCount *PrefixBitCount) Len() BitCount {
if prefixBitCount == nil {
return 0
}
return prefixBitCount.bitCount()
}
// IsNil returns true if this is nil, meaning it represents having no prefix length, or the absence of a prefix length
func (prefixBitCount *PrefixBitCount) IsNil() bool {
return prefixBitCount == nil
}
// Matches compares a PrefixLen value with a bit count
func (prefixBitCount *PrefixBitCount) Matches(other BitCount) bool {
return prefixBitCount != nil && prefixBitCount.bitCount() == other
}
// Equal compares two PrefixLen values for equality. This method is intended for the PrefixLen type. BitCount values should be compared with the == operator.
func (prefixBitCount *PrefixBitCount) Equal(other PrefixLen) bool {
if prefixBitCount == nil {
return other == nil
}
return other != nil && prefixBitCount.bitCount() == other.bitCount()
}
// String returns the bit count as a base-10 positive integer string, or "<nil>" if the receiver is a nil pointer.
func (prefixBitCount *PrefixBitCount) String() string {
if prefixBitCount == nil {
return nilString()
}
return strconv.Itoa(prefixBitCount.bitCount())
}
// Compare compares PrefixLen values, returning -1, 0, or 1 if this prefix length is less than, equal to, or greater than the given prefix length.
// This method is intended for the PrefixLen type.
// BitCount values should be compared with ==, >, <, >= and <= operators.
func (prefixBitCount *PrefixBitCount) Compare(other PrefixLen) int {
if prefixBitCount == nil {
if other == nil {
return 0
}
return 1
} else if other == nil {
return -1
}
return prefixBitCount.bitCount() - other.bitCount()
}
func (prefixBitCount *PrefixBitCount) bitCount() BitCount {
return BitCount(*prefixBitCount)
}
func (prefixBitCount *PrefixBitCount) copy() PrefixLen {
if prefixBitCount == nil {
return nil
}
return prefixBitCount
}
// PortNum is the port number for a non-nil Port.
// For arithmetic, you might wish to use the signed integer type PortInt instead.
type PortNum uint16
func (portNum *PortNum) portNum() PortInt {
return PortInt(*portNum)
}
// Num converts to a PortPortIntNum, returning 0 if the receiver is nil.
func (portNum *PortNum) Num() PortInt {
if portNum == nil {
return 0
}
return PortInt(*portNum)
}
// Port dereferences this PortNum, while returning 0 if the receiver is nil.
func (portNum *PortNum) Port() PortNum {
if portNum == nil {
return 0
}
return *portNum
}
// Matches compares a Port value with a port number.
func (portNum *PortNum) Matches(other PortInt) bool {
return portNum != nil && portNum.portNum() == other
}
// String returns the bit count as a base-10 positive integer string,
// or "<nil>" if the receiver is a nil pointer.
func (portNum *PortNum) String() string {
if portNum == nil {
return nilString()
}
return strconv.Itoa(portNum.portNum())
}
func (portNum *PortNum) copy() Port {
if portNum == nil {
return nil
}
return portNum
}
// Equal compares two Port values for equality.
func (portNum *PortNum) Equal(other Port) bool {
if portNum == nil {
return other == nil
}
return other != nil && portNum.portNum() == other.portNum()
}
// Compare compares PrefixLen values,
// returning -1, 0, or 1 if the receiver is less than,
// equal to, or greater than the argument.
func (portNum *PortNum) Compare(other Port) int {
if portNum == nil {
if other == nil {
return 0
}
return -1
} else if other == nil {
return 1
}
return portNum.portNum() - other.portNum()
}
// wrapperIterator notifies the iterator to the right when wrapperIterator reaches its final value.
type wrappedIterator struct {
iterator Iterator[*IPAddressSegment]
finalValue []bool
indexi int
}
func (wrapped *wrappedIterator) HasNext() bool {
return wrapped.iterator.HasNext()
}
func (wrapped *wrappedIterator) Next() *IPAddressSegment {
iter := wrapped.iterator
next := iter.Next()
if !iter.HasNext() {
wrapped.finalValue[wrapped.indexi+1] = true
}
return next
}
// HostBitCount is the count of bits in a host.
// For arithmetic, you may wish to use the signed integer type BitCount instead,
// which you can get from a HostBitCount using the Len method.
type HostBitCount uint8
// BlockSize is the reverse of BitsForCount, giving the total number of values when ranging across the number of host bits.
// The nil *HostBitCount returns 0.
func (hostBitCount *HostBitCount) BlockSize() *big.Int {
if hostBitCount == nil {
return bigZero()
}
return new(big.Int).Lsh(bigOneConst(), uint(*hostBitCount))
}
// Len returns the length of the host.
// If the receiver is nil, representing the absence of a host length, returns 0.
// It will also return 0 if the receiver has a host length of 0.
// To distinguish the two, compare the receiver with nil.
func (hostBitCount *HostBitCount) Len() BitCount {
if hostBitCount == nil {
return 0
}
return BitCount(*hostBitCount)
}
// String returns the bit count as a base-10 positive integer string, or "<nil>" if the receiver is a nil pointer.
func (hostBitCount *HostBitCount) String() string {
if hostBitCount == nil {
return nilString()
}
return strconv.Itoa(hostBitCount.Len())
}
// IsNil returns true if this is nil, meaning it represents having no identified host length.
func (hostBitCount *HostBitCount) IsNil() bool {
return hostBitCount == nil
}
func bigIsZero(val *BigDivInt) bool {
return len(val.Bits()) == 0 // slightly faster than div.value.BitLen() == 0
}
func bigOne() *big.Int {
return big.NewInt(1)
}
func bigOneConst() *big.Int {
return one
}
func bigZero() *big.Int {
return new(big.Int)
}
func bigZeroConst() *big.Int {
return zero
}
func bigMinusOneConst() *big.Int {
return minusOne
}
func bigSixteen() *big.Int {
return big.NewInt(16)
}
// ToPrefixLen converts the given int to a prefix length
func ToPrefixLen(i int) PrefixLen {
res := PrefixBitCount(i)
return &res
}
func checkSubnet(item BitItem, prefixLength BitCount) BitCount {
return checkBitCount(prefixLength, item.GetBitCount())
}
func checkDiv(div DivisionType, prefixLength BitCount) BitCount {
return checkBitCount(prefixLength, div.GetBitCount())
}
func checkBitCount(prefixLength, max BitCount) BitCount {
if prefixLength > max {
return max
} else if prefixLength < 0 {
return 0
}
return prefixLength
}
func initPrefLens() ([]PrefixBitCount, []PrefixLen) {
cachedPrefBitcounts := make([]PrefixBitCount, maxBitCountInternal)
cachedPrefLens := make([]PrefixLen, maxBitCountInternal)
for i := 0; i <= IPv6BitCount; i++ {
cachedPrefBitcounts[i] = PrefixBitCount(i)
cachedPrefLens[i] = &cachedPrefBitcounts[i]
}
return cachedPrefBitcounts, cachedPrefLens
}
func cacheBitCount(i BitCount) PrefixLen {
if i < minBitCountInternal {
i = minBitCountInternal
}
if i < len(cachedPrefixBitCounts) {
return &cachedPrefixBitCounts[i]
}
if i > maxBitCountInternal {
i = maxBitCountInternal
}
res := PrefixBitCount(i)
return &res
}
func checkPrefLen(prefixLength PrefixLen, max BitCount) PrefixLen {
if prefixLength != nil {
prefLen := prefixLength.bitCount()
if prefLen > max {
return cacheBitCount(max)
} else if prefLen < 0 {
return cacheBitCount(0)
}
}
return prefixLength
}
func bigAbsIsOne(val *BigDivInt) bool {
bits := val.Bits()
return len(bits) == 1 && bits[0] == 1
}
func bigIsOne(val *BigDivInt) bool {
return bigAbsIsOne(val) && val.Sign() > 0
}
func cachePrefixLen(external PrefixLen) PrefixLen {
if external == nil {
return nil
}
return cacheBitCount(external.bitCount())
}
func cachePorts(i PortInt) Port {
if i < minPortNumInternal {
i = minPortNumInternal
} else if i > maxPortNumInternal {
i = maxPortNumInternal
}
res := PortNum(i)
return &res
}
func cachePrefix(i BitCount) *PrefixLen {
if i < minBitCountInternal {
i = minBitCountInternal
}
if i < len(cachedPrefixLens) {
return &cachedPrefixLens[i]
}
if i > maxBitCountInternal {
i = maxBitCountInternal
}
val := PrefixBitCount(i)
res := &val
return &res
}
// BitsForCount returns the number of bits required outside the prefix length
// for a single prefix block to span at least as many addresses as the given count.
// Mathematically, it is the ceiling of the base 2 logarithm of the given count.
// A count of zero returns nil.
func BitsForCount(count uint64) (result *HostBitCount) {
if count != 0 {
var res HostBitCount
countMinusOne := count - 1
if (countMinusOne & (0xfff0000000000000)) != 0 { // conversion to float64 will fail
count = (countMinusOne >> 53) + 1
res = 53
}
res += HostBitCount(math.Ilogb(float64((count << 1) - 1)))
return &res
}
return nil
}
func cacheNilPrefix() *PrefixLen {
return &p
}