Pure.HashCodes

Deterministic hash code generation for the Pure ecosystem — stable, byte-enumerable hashes over immutable primitive types.

Overview

Pure.HashCodes provides a single entry point — DeterminedHash — that produces a stable, ordered sequence of bytes for any value implementing a Pure.Primitives.Abstractions interface. Unlike object.GetHashCode(), the output is deterministic across processes and runtimes and can be combined from multiple fields into a single compound hash.

GetHashCode() and ToString() are intentionally unsupported on DeterminedHash and throw NotSupportedException — callers must consume the byte sequence directly.

API

DeterminedHash is a sealed record implementing IDeterminedHash : IEnumerable<byte>.

Constructors

Constructor	Input type
DeterminedHash(IBool)	Boolean value
DeterminedHash(IChar)	Single character
DeterminedHash(IDate)	Date (day / month / year)
DeterminedHash(ITime)	Time (hour / minute / second / …)
DeterminedHash(IDateTime)	Date + time composition
DeterminedHash(IDayOfWeek)	Day of week
DeterminedHash(INumber<double>)	64-bit floating point
DeterminedHash(INumber<float>)	32-bit floating point
DeterminedHash(INumber<int>)	Signed 32-bit integer
DeterminedHash(INumber<uint>)	Unsigned 32-bit integer
DeterminedHash(INumber<ushort>)	Unsigned 16-bit integer
DeterminedHash(IGuid)	GUID value
DeterminedHash(IString)	String value
DeterminedHash(IEnumerable<IDeterminedHash>)	Aggregated compound hash
DeterminedHash(IEnumerable<byte>)	Raw byte sequence

Design Principles

• Deterministic — identical inputs always produce identical byte sequences, regardless of runtime or process lifetime.
• Abstraction-driven — works exclusively with Pure.Primitives.Abstractions interfaces, not concrete types.
• Composable — multiple DeterminedHash values can be aggregated into a single compound hash via IEnumerable<IDeterminedHash>.
• AOT-compatible — the library is fully compatible with Native AOT compilation.

Dependencies

• Pure.HashCodes.Abstractions — defines IDeterminedHash : IEnumerable<byte>, the core hash abstraction
• Pure.Primitives.Abstractions — read-only interfaces for primitive types (IBool, IChar, IDate, ITime, IDateTime, IDayOfWeek, INumber<T>, IGuid, IString)

Target Frameworks

• .NET 7
• .NET 8
• .NET 9
• .NET 10

Installation

dotnet add package Pure.HashCodes

Usage

Hash a single primitive:

using Pure.HashCodes;
using Pure.Primitives.Number;

INumber<int> id = new Int(42);
IEnumerable<byte> hashBytes = new DeterminedHash(id);

Combine multiple fields into a compound hash:

using Pure.HashCodes;
using Pure.HashCodes.Abstractions;

IDeterminedHash nameHash = new DeterminedHash(name);
IDeterminedHash dateHash = new DeterminedHash(birthDate);

IEnumerable<byte> compound = new DeterminedHash(new[] { nameHash, dateHash });