Cidr<A extends IpAddress> final

final class Cidr<A extends IpAddress>

A CIDR (Classless Inter-Domain Routing) block — an IpAddress combined with a prefix length that defines a subnet.

The address need not be the network address; use normalized or CidrStrict to obtain a block whose address is the network prefix. The prefix bits are clamped to the valid range for the address type (0–32 for IPv4, 0–128 for IPv6).

Example: 192.168.1.100/24 describes the subnet 192.168.1.0/24.

Implementers

• CidrStrict<A extends IpAddress>

Properties

address final

final A address

The IP address component of this CIDR block.

Implementation

final A address;

hashCode no setter override

int get hashCode

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

Implementation

@override
int get hashCode => Object.hashAll([address, prefixBits]);

prefixBits final

final int prefixBits

The number of leading bits that define the network prefix.

Implementation

final int prefixBits;

runtimeType no setter inherited

Type get runtimeType

A representation of the runtime type of the object.

Inherited from Object.

Implementation

external Type get runtimeType;

Methods

contains()

bool contains<AA extends IpAddress>(AA a)

Returns true if a falls within this CIDR block (i.e. between prefix and last inclusive).

Implementation

bool contains<AA extends IpAddress>(AA a) {
  final start = prefix();
  final end = last();

  return start <= a && a <= end;
}

last()

A last()

Returns the last (broadcast/highest) address of this CIDR block.

Implementation

A last() => _transform(
  (v4) => v4.maskedLast(Ipv4Address.mask(prefixBits)),
  (v6) => v6.maskedLast(Ipv6Address.mask(prefixBits)),
);

mask()

A mask()

Returns the subnet mask address corresponding to prefixBits.

Implementation

A mask() => _transform(
  (_) => Ipv4Address.mask(prefixBits),
  (_) => Ipv6Address.mask(prefixBits),
);

normalized()

CidrStrict<A> normalized()

Returns this block normalized to a CidrStrict, where the address is the network prefix (all host bits zeroed).

Implementation

CidrStrict<A> normalized() => CidrStrict.from(this);

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Object.

Implementation

@pragma("vm:entry-point")
@pragma("wasm:entry-point")
external dynamic noSuchMethod(Invocation invocation);

prefix()

A prefix()

Returns the first (network) address of this CIDR block.

Implementation

A prefix() => _transform(
  (v4) => v4.masked(Ipv4Address.mask(prefixBits)),
  (v6) => v6.masked(Ipv6Address.mask(prefixBits)),
);

toString() override

String toString()

Returns the CIDR notation string, e.g. "192.168.1.0/24".

Implementation

@override
String toString() => '$address/$prefixBits';

Operators

operator ==() override

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

• Total: It must return a boolean for all arguments. It should never throw.

• Reflexive: For all objects o, o == o must be true.

• Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.

• Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Implementation

@override
bool operator ==(Object other) => switch (other) {
  final Cidr that => address == that.address && prefixBits == that.prefixBits,
  _ => false,
};

Static Methods

fromIpAndMask()

Cidr<A> fromIpAndMask<A extends IpAddress>(A address, A mask)

Creates a Cidr from an address and a subnet mask address. The prefix bits are derived from mask via IpAddress.prefixBits.

Implementation

static Cidr<A> fromIpAndMask<A extends IpAddress>(A address, A mask) =>
    address &#47; mask.prefixBits() as Cidr<A>;

fromString()

Option<Cidr<IpAddress>> fromString(String value)

Parses a CIDR string (e.g. "192.168.0.0/24" or "::1/128") into a Cidr<IpAddress>, returning None if parsing fails.

Implementation

static Option<Cidr<IpAddress>> fromString(String value) =>
    _fromStringGeneral(value, IpAddress.fromString);

fromStringV4()

Option<Cidr<Ipv4Address>> fromStringV4(String value)

Parses an IPv4 CIDR string (e.g. "10.0.0.0/8"), returning None if parsing fails or the address is not IPv4.

Implementation

static Option<Cidr<Ipv4Address>> fromStringV4(String value) =>
    _fromStringGeneral(value, Ipv4Address.fromString);

fromStringV6()

Option<Cidr<Ipv6Address>> fromStringV6(String value)

Parses an IPv6 CIDR string (e.g. "2001:db8::/32"), returning None if parsing fails or the address is not IPv6.

Implementation

static Option<Cidr<Ipv6Address>> fromStringV6(String value) =>
    _fromStringGeneral(value, Ipv6Address.fromString);

of()

Cidr<A> of<A extends IpAddress>(A address, int prefixBits)

Creates a Cidr from address and prefixBits, clamping prefixBits to the valid range for the address family.

Implementation

static Cidr<A> of<A extends IpAddress>(A address, int prefixBits) {
  final b = prefixBits.clamp(0, address.bitSize);
  return Cidr._(address, b);
}