bigz/uint128 provides a high-performance Uint128 type that supports standard arithmetic operations. Unlike math/big, operations on Uint128 always produce new values instead of modifying a pointer receiver. A Uint128 value is therefore immutable, just like uint64 and friends.

bigz/uint256 provides similar Uint256 type.

Released under the MIT License.

go get github.com/Pilatuz/bigz

The name uint128.Uint128 and uint256.Uint256 stutter, so it is recommended either using a "facade" package:

import (
    "github.com/Pilatuz/bigz"
)

// then use bigz.Uint128 type
// then use bigz.Uint256 type

or type aliasing to give it a project-specific name:

import (
    "github.com/Pilatuz/bigz/uint128"
    "github.com/Pilatuz/bigz/uint256"
)

type U128 = uint128.Uint128
type U256 = uint256.Uint256

The key differences from original package:

• No panics! All methods have wrap-around semantic!
• Zero and Max are functions to prevent modification of global variables.
• New was removed to encourage explicit Uint128{Lo: ..., Hi: ...} initialization. Just not to confuse what is going first, i.e. New(lo, hi) or New(hi, lo).
• Trivial (via big.Int) implementation of fmt.Formatter interface to support for example hex output as fmt.Sprintf("%X", u).
• Trivial (via big.Int) implementation of TextMarshaller and TextUnmarshaler interfaces to support JSON encoding.
• Store/Load methods support little-endian and big-endian byte order.
• New Not and AndNot methods.
• New uint256.Uint256 type.

The 128-bit or 256-bit integer can be initialized in the following ways:

The following arithmetic operations are supported:

The following logical and comparison operations are supported:

The following bit operations are supported:

The following miscellaneous operations are supported:

See the documentation for a complete API specification.