9cd42417a8
Append strict collision/topology payloads to the existing prepared package so later physics cutover can drop parsed DAT graphs without adding a second mapping or changing traversal behavior. The full 2,232,170-key catalog is deterministic across worker counts, exact-byte aliased, corruption-isolated, and cancellation-safe.
50 lines
1.5 KiB
C#
50 lines
1.5 KiB
C#
using System.Security.Cryptography;
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namespace AcDream.Bake;
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/// <summary>
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/// Offline-only exact-byte deduplication catalog. SHA-256 narrows candidates;
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/// a complete byte comparison is still mandatory before any alias is emitted.
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/// </summary>
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internal sealed class ExactPayloadAliasCatalog
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{
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private readonly Dictionary<string, List<Entry>> _entriesByDigest =
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new(StringComparer.Ordinal);
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public bool TryFind(ReadOnlySpan<byte> payload, out ulong primaryKey)
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{
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string digest = Digest(payload);
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if (_entriesByDigest.TryGetValue(digest, out List<Entry>? candidates))
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{
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foreach (Entry candidate in candidates)
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{
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if (payload.SequenceEqual(candidate.Payload))
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{
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primaryKey = candidate.PrimaryKey;
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return true;
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}
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}
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}
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primaryKey = 0;
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return false;
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}
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public void Add(ulong primaryKey, byte[] payload)
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{
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ArgumentNullException.ThrowIfNull(payload);
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string digest = Digest(payload);
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if (!_entriesByDigest.TryGetValue(digest, out List<Entry>? entries))
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{
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entries = [];
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_entriesByDigest.Add(digest, entries);
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}
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entries.Add(new Entry(primaryKey, payload));
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}
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private static string Digest(ReadOnlySpan<byte> payload) =>
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Convert.ToHexString(SHA256.HashData(payload));
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private sealed record Entry(ulong PrimaryKey, byte[] Payload);
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}
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