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Merged
CoreyKaylor merged 3 commits into from
Dec 12, 2025
Merged

New options for built-in Comparers #190

CoreyKaylor merged 3 commits into from
Dec 12, 2025

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@CoreyKaylor CoreyKaylor commented Dec 12, 2025

Adds 12 built-in, allocation-free IComparer implementations for custom key sorting and duplicate comparison.

New comparers in LightningDB.Comparers namespace:

Comparer Description
BitwiseComparer Lexicographic byte comparison (memcmp-style)
ReverseBitwiseComparer Lexicographic descending
SignedIntegerComparer int/long with proper negative ordering
ReverseSignedIntegerComparer Signed integer descending
UnsignedIntegerComparer uint/ulong (matches MDB_INTEGERKEY)
ReverseUnsignedIntegerComparer Unsigned integer descending
Utf8StringComparer Ordinal UTF-8 comparison
ReverseUtf8StringComparer UTF-8 descending
LengthComparer Length first, then content
ReverseLengthComparer Reverse length, then content
LengthOnlyComparer Size only, ignores content
HashCodeComparer Hash-based for fast large value comparison

Usage:
var config = new DatabaseConfiguration { Flags = DatabaseOpenFlags.Create };
config.CompareWith(SignedIntegerComparer.Instance);

Design:

  • Singleton pattern via Instance property
  • Zero allocations in comparison hot path using Span and MemoryMarshal
  • Works with existing CompareWith() / FindDuplicatesWith() API
  • No new dependencies

@CoreyKaylor CoreyKaylor merged commit 8ebf7f8 into main Dec 12, 2025
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@CoreyKaylor CoreyKaylor deleted the sorting branch December 12, 2025 18:19
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@CoreyKaylor