SwiftIPAddress

A small Swift library for parsing and formatting IPv4 and IPv6 addresses. It aims to offer a familiar, idiomatic API with good performance on both Apple and Linux Swift toolchains.

Design goals

Pure Swift

The core types are implemented in pure Swift rather than wrapping inet_ntop / inet_pton. This gives the compiler more room to inline hot paths and keeps the library portable across every platform Swift supports.

Compact representation

Address values are stored in their minimum natural width: IPv4Address holds four bytes and IPv6Address holds sixteen. Both are struct value types with no heap allocation, which keeps per-address overhead predictable in memory-sensitive environments.

Good performance

Parsing and formatting are designed to avoid per-call allocation and to lean on simple bit-twiddling rather than format-string plumbing. In our benchmarks the pure-Swift implementation is competitive with — and often faster than — the libc helpers called from Swift, largely because it skips the Swift/C marshalling that wrapping inet_ntop / inet_pton would require. Your mileage will vary; the benchmark target (IPAddressBenchmarks) is included if you want to measure for yourself.

Installation

Add the package as a Swift Package Manager dependency:

dependencies: [
    .package(url: "https://github.com/Andrew-Dunn/SwiftIPAddress.git",
             from: "1.0.1"),
]

Then import IPAddress wherever you need it:

import IPAddress

let ip = IPv6Address("2b88:b6::14")

API

IPv4Address

An immutable, four-byte value representing an IPv4 address. Supports parsing from a dotted-quad string, construction from octets or a UInt32, and predicates for the common classifications (isLoopback, isPrivate, isLinkLocal, isMulticast, isBroadcast, isDocumentation, isGlobal).

IPv6Address

An immutable, sixteen-byte value representing an IPv6 address. Supports the full RFC 5952 textual forms (including :: compression and the IPv4-mapped ::ffff:X.X.X.X shorthand) and the corresponding classification predicates.

CIDR membership

IPv4CIDR and IPv6CIDR represent a network/prefix pair. Construction pre-computes the masked network and mask, so address.isIncluded(in:) is a single bitwise compare with no string work on the hot path:

let cidr = IPv4CIDR("10.0.0.0/8")!
IPv4Address("10.1.2.3")!.isIncluded(in: cidr)  // true

There is also a convenience overload that takes a CIDR string directly, which is handy for one-shot checks but does the parse on every call.

License

Copyright © Andrew Dunn, 2017

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.