Implement SegmentedDictionary<TKey, TValue> #50156
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These files are based on dotnet/runtime@cf258a14 (v5.0.0-rtm.20519.4).
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The APIs providing the scenario are not public, and not easily ported.
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| @@ -13,13 +13,57 @@ internal static class SegmentedArray | |||
| /// <seealso cref="Array.Clear(Array, int, int)"/> | |||
| internal static void Clear<T>(SegmentedArray<T> buckets, int index, int length) | |||
| { | |||
| throw new NotImplementedException(); | |||
| if (index < 0 || length < 0 || (uint)(index + length) > (uint)buckets.Length) | |||
| ThrowHelper.ThrowArgumentOutOfRangeException(); | |||
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Consider breaking this up and including the argument that was out of range.
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This is the same check used for Array.Clear:
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With that said, this class is weird - the instinct is to keep all the original coding approach from Array but it's both ugly and difficult to port directly. So I could really go either way on it.
333fred
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333fred
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333fred
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|
Done review pass (commit 15) |
This code normally runs in a 64-bit process, so favor the faster implementation for that case.
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@jaredpar Can you review this? |
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This collection is derived from
Dictionary<TKey, TValue>(dotnet/runtime@cb5f173b, which is .NET 5.0.2), with the backing arrays replaced bySegmentedArray<T>to avoid all Large Object Heap allocations. In most cases, the performance of this collection is indistinguishable fromDictionary<TKey, TValue>, with the exception of not using the Large Object Heap.Aside from the changes to segment the storage arrays, the following changes are made relative to the original implementation:
SegmentedDictionary<TKey, TValue>does not support binary serializationSegmentedDictionary<TKey, TValue>always uses default string comparers by default, and does not attempt to force the use of non-randomized comparers for performance in low-collision scenariosSegmentedDictionary<TKey, TValue>always uses HashHelpers.FastMod, which optimizes AnyCPU performance for 64-bit runtimes💡 If necessary, updates from dotnet/runtime can be incorporated back into roslyn by branching off of
276a8a6 (which is a verbatim copy of the original files updated to include a link to the original source), and then merging the resulting minimized changes back into master. Commit 276a8a6 shows the update from dotnet/runtime@cf258a14 to dotnet/runtime@cb5f173b.