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https://github.com/dadhi/ImTools
Fast and memory-efficient immutable collections and helper data structures
https://github.com/dadhi/ImTools
2-3-tree avl-tree compare-and-swap data-structures dictionary effects functional-programming hashmap hashtable immutable lock-free map memory-efficient open-addressing performance persistent reference-semantics robinhood-hashmap sum-types value-semantics
Last synced: about 1 month ago
JSON representation
Fast and memory-efficient immutable collections and helper data structures
- Host: GitHub
- URL: https://github.com/dadhi/ImTools
- Owner: dadhi
- License: mit
- Created: 2017-01-04T09:50:07.000Z (almost 8 years ago)
- Default Branch: master
- Last Pushed: 2024-11-02T15:11:12.000Z (about 2 months ago)
- Last Synced: 2024-11-03T13:07:53.141Z (about 2 months ago)
- Topics: 2-3-tree, avl-tree, compare-and-swap, data-structures, dictionary, effects, functional-programming, hashmap, hashtable, immutable, lock-free, map, memory-efficient, open-addressing, performance, persistent, reference-semantics, robinhood-hashmap, sum-types, value-semantics
- Language: C#
- Homepage:
- Size: 8.22 MB
- Stars: 225
- Watchers: 7
- Forks: 10
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE.txt
Awesome Lists containing this project
- awesome-dot-net-performance - ImTools - Immutable persistent collections and helpers designed for [performance](https://gist.github.com/mrange/d6e7415113ebfa52ccb660f4ce534dd4) and simplicity of use. (High Performance Libraries / Application Insights)
README
# ImTools
Fast and memory-efficient immutable and mutable collections and helper data structures.
Initially split from the [DryIoc](https://github.com/dadhi/dryioc), and now used in the [FastExpressionCompiler](https://github.com/dadhi/fastexpressioncompiler) too.
[](http://opensource.org/licenses/MIT)
- Windows, Linux, MacOS [](https://ci.appveyor.com/project/MaksimVolkau/imtools/branch/master)
- Lib package [](https://www.nuget.org/packages/ImTools.dll)
- Code package [](https://www.nuget.org/packages/ImTools)
- Latest release [](https://github.com/dadhi/ImTools/releases/tag/v4.0.0)
## Benchmarks
The comparison is done against the previous versions and the variety of BCL C# collections including the experimental `Microsoft.Collections.Extensions.DictionarySlim`.
__Important:__ Keep in mind that immutable collections have a different use-case and a thread-safety guarantees compared to the
`Dictionary`, `DictionarySlim` or even `ConcurrentDictionary`. The closest comparable would be the `ImmutableDictionary`.
The benchmarks do not take the collections "nature" into account and run through the simplest available API path.
### ImHashMap of Type keys and small string values
#### Population
[The benchmark](https://github.com/dadhi/ImTools/blob/master/playground/ImTools.Benchmarks/ImHashMapBenchmarks.cs) inserts from 10 to 1000
items into the `ImHashMap`:
```md
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19043
Intel Core i9-8950HK CPU 2.90GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=6.0.202
[Host] : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
DefaultJob : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
| Method | Count | Mean | Error | StdDev | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
| --------------------------------- | ----- | ------------: | -----------: | -----------: | ----: | ------: | -------: | ------: | ----: | --------: |
| V4_ImHashMap_AddOrUpdate | 1 | 33.32 ns | 0.439 ns | 0.389 ns | 1.00 | 0.00 | 0.0178 | - | - | 112 B |
| V3_ImHashMap_AddOrUpdate | 1 | 35.97 ns | 0.639 ns | 0.567 ns | 1.08 | 0.02 | 0.0178 | - | - | 112 B |
| V4_PartitionedHashMap_AddOrUpdate | 1 | 97.72 ns | 1.294 ns | 1.148 ns | 2.93 | 0.05 | 0.0370 | - | - | 232 B |
| DictSlim_TryAdd | 1 | 59.37 ns | 0.519 ns | 0.434 ns | 1.78 | 0.02 | 0.0229 | - | - | 144 B |
| Dict_TryAdd | 1 | 65.94 ns | 0.631 ns | 0.560 ns | 1.98 | 0.02 | 0.0343 | - | - | 216 B |
| ConcurrentDictionary_TryAdd | 1 | 197.29 ns | 1.883 ns | 1.761 ns | 5.92 | 0.09 | 0.1466 | 0.0007 | - | 920 B |
| ImmutableDict_Builder_Add | 1 | 220.79 ns | 2.648 ns | 2.477 ns | 6.62 | 0.10 | 0.0355 | - | - | 224 B |
| ImmutableDict_Add | 1 | 264.15 ns | 4.786 ns | 3.737 ns | 7.93 | 0.16 | 0.0429 | - | - | 272 B |
| | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 10 | 307.91 ns | 5.281 ns | 4.940 ns | 1.00 | 0.00 | 0.1564 | 0.0005 | - | 984 B |
| V3_ImHashMap_AddOrUpdate | 10 | 389.09 ns | 6.482 ns | 5.746 ns | 1.27 | 0.03 | 0.1593 | 0.0005 | - | 1000 B |
| V4_PartitionedHashMap_AddOrUpdate | 10 | 392.47 ns | 4.296 ns | 5.276 ns | 1.27 | 0.03 | 0.1144 | 0.0005 | - | 720 B |
| DictSlim_TryAdd | 10 | 409.45 ns | 2.216 ns | 1.965 ns | 1.33 | 0.02 | 0.1707 | 0.0005 | - | 1072 B |
| Dict_TryAdd | 10 | 413.38 ns | 5.460 ns | 5.107 ns | 1.34 | 0.03 | 0.1578 | 0.0005 | - | 992 B |
| ConcurrentDictionary_TryAdd | 10 | 1,319.88 ns | 20.332 ns | 19.019 ns | 4.29 | 0.11 | 0.4730 | 0.0076 | - | 2968 B |
| ImmutableDict_Builder_Add | 10 | 1,712.26 ns | 15.264 ns | 26.733 ns | 5.59 | 0.12 | 0.1259 | - | - | 800 B |
| ImmutableDict_Add | 10 | 2,986.38 ns | 17.824 ns | 14.884 ns | 9.70 | 0.18 | 0.4349 | - | - | 2744 B |
| | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 100 | 9,188.79 ns | 116.272 ns | 108.761 ns | 1.00 | 0.00 | 2.8229 | 0.0916 | - | 17792 B |
| V3_ImHashMap_AddOrUpdate | 100 | 10,591.30 ns | 169.894 ns | 141.869 ns | 1.15 | 0.03 | 3.1891 | 0.1068 | - | 20032 B |
| V4_PartitionedHashMap_AddOrUpdate | 100 | 4,491.75 ns | 81.205 ns | 75.959 ns | 0.49 | 0.01 | 1.2360 | 0.0534 | - | 7776 B |
| DictSlim_TryAdd | 100 | 3,201.77 ns | 48.216 ns | 42.743 ns | 0.35 | 0.01 | 1.1902 | 0.0305 | - | 7488 B |
| Dict_TryAdd | 100 | 3,856.61 ns | 70.806 ns | 62.768 ns | 0.42 | 0.01 | 1.6174 | 0.0687 | - | 10192 B |
| ConcurrentDictionary_TryAdd | 100 | 16,035.70 ns | 320.350 ns | 356.068 ns | 1.75 | 0.04 | 4.9133 | 0.5798 | - | 30824 B |
| ImmutableDict_Builder_Add | 100 | 24,427.83 ns | 470.630 ns | 417.201 ns | 2.66 | 0.07 | 1.0376 | 0.0305 | - | 6560 B |
| ImmutableDict_Add | 100 | 48,772.32 ns | 687.894 ns | 574.422 ns | 5.30 | 0.10 | 7.1411 | 0.2441 | - | 44936 B |
| | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 1000 | 277,024.17 ns | 3,349.815 ns | 2,969.524 ns | 1.00 | 0.00 | 45.4102 | 10.7422 | - | 286344 B |
| V3_ImHashMap_AddOrUpdate | 1000 | 234,444.41 ns | 2,324.332 ns | 1,940.923 ns | 0.85 | 0.01 | 51.5137 | 12.2070 | - | 324176 B |
| V4_PartitionedHashMap_AddOrUpdate | 1000 | 146,984.47 ns | 954.053 ns | 845.743 ns | 0.53 | 0.01 | 26.1230 | 7.5684 | - | 164280 B |
| DictSlim_TryAdd | 1000 | 33,447.54 ns | 254.743 ns | 225.823 ns | 0.12 | 0.00 | 9.1553 | 1.7700 | - | 57808 B |
| Dict_TryAdd | 1000 | 40,234.23 ns | 430.048 ns | 381.226 ns | 0.15 | 0.00 | 16.2354 | 5.3711 | - | 102216 B |
| ConcurrentDictionary_TryAdd | 1000 | 165,018.54 ns | 3,075.862 ns | 2,568.484 ns | 0.60 | 0.01 | 41.2598 | 13.6719 | - | 259720 B |
| ImmutableDict_Builder_Add | 1000 | 396,623.48 ns | 4,099.094 ns | 3,834.295 ns | 1.43 | 0.02 | 9.7656 | 2.4414 | - | 64160 B |
| ImmutableDict_Add | 1000 | 813,397.08 ns | 9,203.453 ns | 8,608.916 ns | 2.94 | 0.04 | 105.4688 | 25.3906 | - | 665001 B |
```
### Lookup
[The benchmark](https://github.com/dadhi/ImTools/blob/master/playground/ImTools.Benchmarks/ImHashMapBenchmarks.cs) lookups for the specific key in the
`ImHashMap` containing the specified Count of elements.
```md
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19043
Intel Core i9-8950HK CPU 2.90GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=6.0.202
[Host] : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
DefaultJob : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
| Method | Count | Mean | Error | StdDev | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
| -------------------------------- | ----- | --------: | --------: | --------: | ----: | ------: | ----: | ----: | ----: | --------: |
| V4_ImHashMap_TryFind | 1 | 8.915 ns | 0.1853 ns | 0.1733 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_TryFind | 1 | 7.834 ns | 0.1769 ns | 0.1568 ns | 0.88 | 0.02 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 1 | 8.292 ns | 0.1082 ns | 0.0959 ns | 0.93 | 0.02 | - | - | - | - |
| V3_PartitionedHashMap_TryFind | 1 | 7.681 ns | 0.1245 ns | 0.1039 ns | 0.86 | 0.02 | - | - | - | - |
| DictionarySlim_TryGetValue | 1 | 8.861 ns | 0.1423 ns | 0.1188 ns | 0.99 | 0.02 | - | - | - | - |
| Dictionary_TryGetValue | 1 | 17.914 ns | 0.3447 ns | 0.3055 ns | 2.01 | 0.05 | - | - | - | - |
| ConcurrentDictionary_TryGetValue | 1 | 13.381 ns | 0.2709 ns | 0.2401 ns | 1.50 | 0.04 | - | - | - | - |
| ImmutableDict_TryGet | 1 | 19.040 ns | 0.3068 ns | 0.2870 ns | 2.14 | 0.06 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 10 | 9.462 ns | 0.2690 ns | 0.2246 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_TryFind | 10 | 9.038 ns | 0.1650 ns | 0.1463 ns | 0.96 | 0.02 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 10 | 8.575 ns | 0.2031 ns | 0.1900 ns | 0.91 | 0.03 | - | - | - | - |
| V3_PartitionedHashMap_TryFind | 10 | 5.869 ns | 0.1026 ns | 0.1743 ns | 0.63 | 0.02 | - | - | - | - |
| DictionarySlim_TryGetValue | 10 | 7.384 ns | 0.1882 ns | 0.1668 ns | 0.78 | 0.03 | - | - | - | - |
| Dictionary_TryGetValue | 10 | 14.082 ns | 0.2168 ns | 0.1921 ns | 1.49 | 0.04 | - | - | - | - |
| ConcurrentDictionary_TryGetValue | 10 | 11.436 ns | 0.1398 ns | 0.1239 ns | 1.21 | 0.03 | - | - | - | - |
| ImmutableDict_TryGet | 10 | 17.927 ns | 0.4467 ns | 0.4780 ns | 1.90 | 0.09 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 100 | 12.147 ns | 0.1475 ns | 0.1308 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_TryFind | 100 | 11.357 ns | 0.1695 ns | 0.1323 ns | 0.94 | 0.01 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 100 | 8.520 ns | 0.2142 ns | 0.1899 ns | 0.70 | 0.02 | - | - | - | - |
| V3_PartitionedHashMap_TryFind | 100 | 7.785 ns | 0.1374 ns | 0.1147 ns | 0.64 | 0.01 | - | - | - | - |
| DictionarySlim_TryGetValue | 100 | 6.918 ns | 0.1544 ns | 0.1289 ns | 0.57 | 0.01 | - | - | - | - |
| Dictionary_TryGetValue | 100 | 13.804 ns | 0.3474 ns | 0.3717 ns | 1.14 | 0.04 | - | - | - | - |
| ConcurrentDictionary_TryGetValue | 100 | 11.432 ns | 0.2194 ns | 0.2052 ns | 0.94 | 0.02 | - | - | - | - |
| ImmutableDict_TryGet | 100 | 21.593 ns | 0.4048 ns | 0.3786 ns | 1.78 | 0.03 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 1000 | 15.492 ns | 0.3859 ns | 0.4881 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_TryFind | 1000 | 14.339 ns | 0.2612 ns | 0.2444 ns | 0.92 | 0.03 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 1000 | 11.508 ns | 0.1839 ns | 0.1630 ns | 0.74 | 0.03 | - | - | - | - |
| V3_PartitionedHashMap_TryFind | 1000 | 9.508 ns | 0.2340 ns | 0.2074 ns | 0.61 | 0.02 | - | - | - | - |
| DictionarySlim_TryGetValue | 1000 | 7.099 ns | 0.1984 ns | 0.2037 ns | 0.46 | 0.01 | - | - | - | - |
| Dictionary_TryGetValue | 1000 | 13.696 ns | 0.1341 ns | 0.1120 ns | 0.88 | 0.03 | - | - | - | - |
| ConcurrentDictionary_TryGetValue | 1000 | 11.358 ns | 0.1464 ns | 0.1222 ns | 0.73 | 0.03 | - | - | - | - |
| ImmutableDict_TryGet | 1000 | 25.875 ns | 0.3752 ns | 0.3510 ns | 1.67 | 0.06 | - | - | - | - |
```
### Enumeration
[The benchmark source](https://github.com/dadhi/ImTools/blob/master/playground/ImTools.Benchmarks/ImHashMapBenchmarks.cs)
```md
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19043
Intel Core i9-8950HK CPU 2.90GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=6.0.202
[Host] : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
DefaultJob : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
| Method | Count | Mean | Error | StdDev | Median | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
| ------------------------------- | ----- | -----------: | ---------: | ---------: | -----------: | ----: | ------: | -----: | ----: | ----: | --------: |
| V4_ImHashMap_Enumerate | 1 | 39.51 ns | 0.865 ns | 0.996 ns | 39.43 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_Enumerate | 1 | 44.11 ns | 0.879 ns | 0.822 ns | 44.28 ns | 1.12 | 0.04 | 0.0255 | - | - | 160 B |
| V4_PartitionedHashMap_Enumerate | 1 | 118.94 ns | 1.644 ns | 1.538 ns | 118.91 ns | 3.01 | 0.09 | - | - | - | - |
| V3_PartitionedHashMap_Enumerate | 1 | 180.82 ns | 3.462 ns | 3.238 ns | 181.09 ns | 4.57 | 0.14 | 0.0522 | - | - | 328 B |
| DictionarySlim_Enumerate | 1 | 12.77 ns | 0.254 ns | 0.238 ns | 12.76 ns | 0.32 | 0.01 | - | - | - | - |
| Dictionary_Enumerate | 1 | 15.24 ns | 0.652 ns | 1.817 ns | 14.36 ns | 0.46 | 0.05 | - | - | - | - |
| ConcurrentDictionary_foreach | 1 | 177.04 ns | 2.073 ns | 1.939 ns | 176.68 ns | 4.47 | 0.12 | 0.0100 | - | - | 64 B |
| ImmutableDict_Enumerate | 1 | 161.96 ns | 0.760 ns | 0.635 ns | 161.98 ns | 4.08 | 0.12 | - | - | - | - |
| | | | | | | | | | | | |
| V4_ImHashMap_Enumerate | 10 | 191.91 ns | 3.010 ns | 2.668 ns | 192.57 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_Enumerate | 10 | 223.10 ns | 1.885 ns | 1.574 ns | 223.12 ns | 1.16 | 0.02 | 0.0381 | - | - | 240 B |
| V4_PartitionedHashMap_Enumerate | 10 | 379.75 ns | 4.543 ns | 4.027 ns | 379.74 ns | 1.98 | 0.03 | - | - | - | - |
| V3_PartitionedHashMap_Enumerate | 10 | 604.47 ns | 4.257 ns | 3.774 ns | 603.87 ns | 3.15 | 0.05 | 0.1793 | - | - | 1128 B |
| DictionarySlim_Enumerate | 10 | 73.15 ns | 1.438 ns | 1.345 ns | 72.82 ns | 0.38 | 0.01 | - | - | - | - |
| Dictionary_Enumerate | 10 | 57.95 ns | 0.749 ns | 0.701 ns | 57.86 ns | 0.30 | 0.01 | - | - | - | - |
| ConcurrentDictionary_foreach | 10 | 505.36 ns | 7.959 ns | 7.445 ns | 504.00 ns | 2.64 | 0.05 | 0.0095 | - | - | 64 B |
| ImmutableDict_Enumerate | 10 | 556.35 ns | 10.730 ns | 9.512 ns | 558.53 ns | 2.90 | 0.06 | - | - | - | - |
| | | | | | | | | | | | |
| V4_ImHashMap_Enumerate | 100 | 2,023.65 ns | 33.506 ns | 29.702 ns | 2,031.78 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_Enumerate | 100 | 1,992.46 ns | 23.400 ns | 20.744 ns | 1,992.05 ns | 0.98 | 0.02 | 0.0381 | - | - | 240 B |
| V4_PartitionedHashMap_Enumerate | 100 | 2,626.85 ns | 42.089 ns | 37.311 ns | 2,616.34 ns | 1.30 | 0.02 | - | - | - | - |
| V3_PartitionedHashMap_Enumerate | 100 | 3,469.16 ns | 30.415 ns | 26.962 ns | 3,469.32 ns | 1.71 | 0.03 | 0.4349 | - | - | 2728 B |
| DictionarySlim_Enumerate | 100 | 615.29 ns | 10.217 ns | 9.057 ns | 617.89 ns | 0.30 | 0.01 | - | - | - | - |
| Dictionary_Enumerate | 100 | 578.30 ns | 3.310 ns | 2.764 ns | 578.14 ns | 0.29 | 0.00 | - | - | - | - |
| ConcurrentDictionary_foreach | 100 | 3,444.60 ns | 55.779 ns | 52.176 ns | 3,425.75 ns | 1.70 | 0.03 | 0.0076 | - | - | 64 B |
| ImmutableDict_Enumerate | 100 | 4,557.81 ns | 71.187 ns | 63.105 ns | 4,552.69 ns | 2.25 | 0.03 | - | - | - | - |
| | | | | | | | | | | | |
| V4_ImHashMap_Enumerate | 1000 | 22,259.46 ns | 204.173 ns | 180.994 ns | 22,241.67 ns | 1.00 | 0.00 | - | - | - | - |
| V3_ImHashMap_Enumerate | 1000 | 21,710.99 ns | 288.512 ns | 240.921 ns | 21,770.78 ns | 0.98 | 0.02 | 0.0610 | - | - | 480 B |
| V4_PartitionedHashMap_Enumerate | 1000 | 28,097.70 ns | 392.513 ns | 306.449 ns | 28,134.91 ns | 1.26 | 0.02 | - | - | - | - |
| V3_PartitionedHashMap_Enumerate | 1000 | 31,132.68 ns | 473.705 ns | 443.104 ns | 31,208.71 ns | 1.40 | 0.01 | 0.4272 | - | - | 2728 B |
| DictionarySlim_Enumerate | 1000 | 6,472.19 ns | 53.546 ns | 47.467 ns | 6,482.73 ns | 0.29 | 0.00 | - | - | - | - |
| Dictionary_Enumerate | 1000 | 5,700.68 ns | 65.696 ns | 61.452 ns | 5,698.15 ns | 0.26 | 0.00 | - | - | - | - |
| ConcurrentDictionary_foreach | 1000 | 43,550.74 ns | 848.746 ns | 752.391 ns | 43,765.79 ns | 1.96 | 0.04 | - | - | - | 64 B |
| ImmutableDict_Enumerate | 1000 | 46,089.57 ns | 524.157 ns | 464.651 ns | 46,183.41 ns | 2.07 | 0.03 | - | - | - | - |
```
### ImHashMap with int keys and small string values
`ImHashMap` stores the `int` keys and `string` values.
#### Population
[The benchmark](https://github.com/dadhi/ImTools/blob/master/playground/ImTools.Benchmarks/ImMapBenchmarks.cs) inserts from 1 to 10 000 of items into the `ImHashMap`:
```md
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19043
Intel Core i9-8950HK CPU 2.90GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=6.0.202
[Host] : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
DefaultJob : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
| Method | Count | Mean | Error | StdDev | Median | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
| ------------------------------- | ----- | ---------------: | -------------: | -------------: | ---------------: | ----: | ------: | --------: | -------: | -------: | --------: |
| V4_ImHashMap_AddOrUpdate | 1 | 13.30 ns | 0.296 ns | 0.277 ns | 13.30 ns | 1.00 | 0.00 | 0.0051 | - | - | 32 B |
| V2_ImMap_AddOrUpdate | 1 | 17.09 ns | 0.207 ns | 0.184 ns | 17.08 ns | 1.28 | 0.03 | 0.0076 | - | - | 48 B |
| V4_PartitionedImMap_AddOrUpdate | 1 | 79.98 ns | 1.023 ns | 1.467 ns | 79.66 ns | 6.04 | 0.16 | 0.0293 | - | - | 184 B |
| DictSlim_GetOrAddValueRef | 1 | 41.18 ns | 0.416 ns | 0.369 ns | 41.28 ns | 3.10 | 0.08 | 0.0204 | - | - | 128 B |
| Dict_TryAdd | 1 | 37.06 ns | 0.418 ns | 0.370 ns | 37.08 ns | 2.79 | 0.06 | 0.0344 | - | - | 216 B |
| ConcurrentDict_TryAdd | 1 | 146.05 ns | 2.124 ns | 1.773 ns | 145.64 ns | 10.95 | 0.27 | 0.1376 | 0.0007 | - | 864 B |
| ImmutableDict_Builder_Add | 1 | 120.60 ns | 0.788 ns | 0.658 ns | 120.43 ns | 9.05 | 0.20 | 0.0253 | - | - | 160 B |
| ImmutableDict_Add | 1 | 107.37 ns | 1.833 ns | 2.384 ns | 106.71 ns | 8.11 | 0.25 | 0.0166 | - | - | 104 B |
| | | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 10 | 229.89 ns | 1.484 ns | 1.239 ns | 230.08 ns | 1.00 | 0.00 | 0.1173 | - | - | 736 B |
| V2_ImMap_AddOrUpdate | 10 | 551.17 ns | 4.425 ns | 3.695 ns | 550.33 ns | 2.40 | 0.02 | 0.2823 | - | - | 1776 B |
| V4_PartitionedImMap_AddOrUpdate | 10 | 242.93 ns | 4.599 ns | 3.840 ns | 242.93 ns | 1.06 | 0.02 | 0.0749 | - | - | 472 B |
| DictSlim_GetOrAddValueRef | 10 | 281.33 ns | 5.547 ns | 5.935 ns | 280.41 ns | 1.22 | 0.03 | 0.1326 | - | - | 832 B |
| Dict_TryAdd | 10 | 258.89 ns | 3.412 ns | 3.025 ns | 258.85 ns | 1.13 | 0.01 | 0.1578 | 0.0005 | - | 992 B |
| ConcurrentDict_TryAdd | 10 | 540.34 ns | 3.092 ns | 2.741 ns | 539.06 ns | 2.35 | 0.01 | 0.1945 | 0.0010 | - | 1224 B |
| ImmutableDict_Builder_Add | 10 | 1,514.60 ns | 8.675 ns | 7.244 ns | 1,513.34 ns | 6.59 | 0.05 | 0.1163 | - | - | 736 B |
| ImmutableDict_Add | 10 | 2,632.30 ns | 51.955 ns | 48.599 ns | 2,639.68 ns | 11.45 | 0.22 | 0.4196 | - | - | 2640 B |
| | | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 100 | 8,221.37 ns | 125.831 ns | 117.703 ns | 8,192.32 ns | 1.00 | 0.00 | 2.9602 | 0.1221 | - | 18640 B |
| V2_ImMap_AddOrUpdate | 100 | 12,184.44 ns | 179.889 ns | 168.268 ns | 12,140.26 ns | 1.48 | 0.02 | 5.9357 | 0.2441 | - | 37296 B |
| V4_PartitionedImMap_AddOrUpdate | 100 | 3,370.45 ns | 23.906 ns | 18.664 ns | 3,363.21 ns | 0.41 | 0.01 | 1.4801 | 0.0839 | - | 9304 B |
| DictSlim_GetOrAddValueRef | 100 | 2,652.96 ns | 37.693 ns | 35.258 ns | 2,649.32 ns | 0.32 | 0.00 | 1.3275 | 0.0534 | - | 8336 B |
| Dict_TryAdd | 100 | 2,828.22 ns | 21.898 ns | 19.412 ns | 2,826.77 ns | 0.34 | 0.01 | 2.0828 | 0.1297 | - | 13072 B |
| ConcurrentDict_TryAdd | 100 | 10,866.25 ns | 111.428 ns | 104.229 ns | 10,909.92 ns | 1.32 | 0.02 | 3.6316 | 0.3510 | - | 22784 B |
| ImmutableDict_Builder_Add | 100 | 25,598.91 ns | 273.166 ns | 255.520 ns | 25,525.67 ns | 3.11 | 0.06 | 1.4648 | 0.0916 | - | 9376 B |
| ImmutableDict_Add | 100 | 46,542.15 ns | 412.627 ns | 344.562 ns | 46,612.94 ns | 5.68 | 0.09 | 7.9346 | 0.3662 | - | 49952 B |
| | | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 1000 | 152,860.18 ns | 1,517.703 ns | 1,345.404 ns | 152,745.43 ns | 1.00 | 0.00 | 46.6309 | 0.4883 | - | 293656 B |
| V2_ImMap_AddOrUpdate | 1000 | 198,915.64 ns | 2,889.932 ns | 2,561.850 ns | 198,557.64 ns | 1.30 | 0.02 | 84.9609 | 0.2441 | - | 534144 B |
| V4_PartitionedImMap_AddOrUpdate | 1000 | 83,983.62 ns | 1,391.788 ns | 1,301.880 ns | 83,699.54 ns | 0.55 | 0.01 | 27.0996 | 9.0332 | - | 170456 B |
| DictSlim_GetOrAddValueRef | 1000 | 26,659.61 ns | 349.284 ns | 326.721 ns | 26,615.57 ns | 0.17 | 0.00 | 11.6272 | 2.8992 | - | 73120 B |
| Dict_TryAdd | 1000 | 31,317.33 ns | 475.471 ns | 444.756 ns | 31,251.40 ns | 0.21 | 0.00 | 21.2402 | 0.0610 | - | 133896 B |
| ConcurrentDict_TryAdd | 1000 | 112,582.19 ns | 1,221.657 ns | 1,082.967 ns | 112,203.70 ns | 0.74 | 0.01 | 32.7148 | 0.1221 | - | 205368 B |
| ImmutableDict_Builder_Add | 1000 | 350,888.85 ns | 3,757.786 ns | 3,515.035 ns | 352,417.77 ns | 2.30 | 0.03 | 15.1367 | 4.8828 | - | 95776 B |
| ImmutableDict_Add | 1000 | 692,782.78 ns | 5,756.492 ns | 5,102.980 ns | 694,477.10 ns | 4.53 | 0.05 | 112.3047 | 0.9766 | - | 710209 B |
| | | | | | | | | | | | |
| V4_ImHashMap_AddOrUpdate | 10000 | 3,879,586.59 ns | 64,823.212 ns | 60,635.673 ns | 3,882,537.11 ns | 1.00 | 0.00 | 632.8125 | 312.5000 | 46.8750 | 3993786 B |
| V2_ImMap_AddOrUpdate | 10000 | 4,485,663.73 ns | 54,179.233 ns | 45,242.113 ns | 4,483,992.58 ns | 1.16 | 0.02 | 1109.3750 | 226.5625 | 101.5625 | 6972711 B |
| V4_PartitionedImMap_AddOrUpdate | 10000 | 2,822,478.66 ns | 49,570.016 ns | 85,505.842 ns | 2,806,964.45 ns | 0.73 | 0.04 | 433.5938 | 214.8438 | - | 2720602 B |
| DictSlim_GetOrAddValueRef | 10000 | 424,813.34 ns | 2,027.361 ns | 1,797.203 ns | 424,378.52 ns | 0.11 | 0.00 | 124.5117 | 124.5117 | 124.5117 | 975754 B |
| Dict_TryAdd | 10000 | 526,320.80 ns | 9,338.940 ns | 8,278.727 ns | 523,071.63 ns | 0.14 | 0.00 | 221.6797 | 221.6797 | 221.6797 | 1261763 B |
| ConcurrentDict_TryAdd | 10000 | 2,721,195.59 ns | 62,415.534 ns | 182,069.041 ns | 2,805,224.80 ns | 0.72 | 0.04 | 273.4375 | 121.0938 | 42.9688 | 1645328 B |
| ImmutableDict_Builder_Add | 10000 | 4,653,773.55 ns | 48,265.920 ns | 42,786.481 ns | 4,645,701.95 ns | 1.20 | 0.02 | 148.4375 | 70.3125 | - | 959781 B |
| ImmutableDict_Add | 10000 | 10,911,107.09 ns | 101,847.861 ns | 85,047.577 ns | 10,956,526.56 ns | 2.81 | 0.04 | 1468.7500 | 265.6250 | 125.0000 | 9271220 B |
```
#### Lookup
[The benchmark](https://github.com/dadhi/ImTools/blob/master/playground/ImTools.Benchmarks/ImMapBenchmarks.cs) lookups for the last added index in the `ImHashMap`
containing the specified Count of elements.
```md
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19043
Intel Core i9-8950HK CPU 2.90GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=6.0.202
[Host] : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
DefaultJob : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
| Method | Count | Mean | Error | StdDev | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
| ----------------------------- | ----- | ---------: | --------: | --------: | ----: | ------: | ----: | ----: | ----: | --------: |
| V4_ImHashMap_TryFind | 1 | 2.5662 ns | 0.0840 ns | 0.0701 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 1 | 2.9264 ns | 0.0775 ns | 0.0687 ns | 1.14 | 0.03 | - | - | - | - |
| V2_ImMap_TryFind | 1 | 0.8574 ns | 0.0826 ns | 0.0772 ns | 0.33 | 0.02 | - | - | - | - |
| DictSlim_TryGetValue | 1 | 3.7989 ns | 0.1118 ns | 0.1046 ns | 1.48 | 0.05 | - | - | - | - |
| Dict_TryGetValue | 1 | 7.5973 ns | 0.2095 ns | 0.1857 ns | 2.95 | 0.08 | - | - | - | - |
| ConcurrentDict_TryGetValue | 1 | 8.1365 ns | 0.1859 ns | 0.1552 ns | 3.17 | 0.08 | - | - | - | - |
| ImmutableDict_TryGetValue | 1 | 15.7728 ns | 0.3912 ns | 0.4348 ns | 6.16 | 0.25 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 10 | 3.0618 ns | 0.0535 ns | 0.0474 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 10 | 2.5114 ns | 0.1019 ns | 0.0851 ns | 0.82 | 0.02 | - | - | - | - |
| V2_ImMap_TryFind | 10 | 3.5793 ns | 0.1092 ns | 0.1022 ns | 1.17 | 0.04 | - | - | - | - |
| DictSlim_TryGetValue | 10 | 4.0213 ns | 0.0329 ns | 0.0275 ns | 1.31 | 0.02 | - | - | - | - |
| Dict_TryGetValue | 10 | 6.9583 ns | 0.0809 ns | 0.0717 ns | 2.27 | 0.03 | - | - | - | - |
| ConcurrentDict_TryGetValue | 10 | 7.9926 ns | 0.0997 ns | 0.0884 ns | 2.61 | 0.05 | - | - | - | - |
| ImmutableDict_TryGetValue | 10 | 17.5147 ns | 0.3430 ns | 0.3209 ns | 5.72 | 0.15 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 100 | 6.9090 ns | 0.1161 ns | 0.1030 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 100 | 2.6762 ns | 0.0542 ns | 0.1045 ns | 0.39 | 0.02 | - | - | - | - |
| V2_ImMap_TryFind | 100 | 7.1365 ns | 0.1727 ns | 0.1442 ns | 1.03 | 0.03 | - | - | - | - |
| DictSlim_TryGetValue | 100 | 4.4196 ns | 0.0861 ns | 0.0719 ns | 0.64 | 0.01 | - | - | - | - |
| Dict_TryGetValue | 100 | 7.6746 ns | 0.0770 ns | 0.0643 ns | 1.11 | 0.02 | - | - | - | - |
| ConcurrentDict_TryGetValue | 100 | 8.0521 ns | 0.1363 ns | 0.1138 ns | 1.17 | 0.03 | - | - | - | - |
| ImmutableDict_TryGetValue | 100 | 19.5683 ns | 0.1622 ns | 0.1355 ns | 2.83 | 0.04 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 1000 | 12.7430 ns | 0.2270 ns | 0.2123 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 1000 | 7.0856 ns | 0.0987 ns | 0.0824 ns | 0.55 | 0.01 | - | - | - | - |
| V2_ImMap_TryFind | 1000 | 10.9892 ns | 0.2986 ns | 0.3067 ns | 0.86 | 0.02 | - | - | - | - |
| DictSlim_TryGetValue | 1000 | 4.3216 ns | 0.1560 ns | 0.1459 ns | 0.34 | 0.01 | - | - | - | - |
| Dict_TryGetValue | 1000 | 7.9061 ns | 0.1667 ns | 0.1478 ns | 0.62 | 0.02 | - | - | - | - |
| ConcurrentDict_TryGetValue | 1000 | 8.1644 ns | 0.1095 ns | 0.0914 ns | 0.64 | 0.02 | - | - | - | - |
| ImmutableDict_TryGetValue | 1000 | 22.1566 ns | 0.2936 ns | 0.2603 ns | 1.74 | 0.03 | - | - | - | - |
| | | | | | | | | | | |
| V4_ImHashMap_TryFind | 10000 | 17.4170 ns | 0.2906 ns | 0.2576 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_TryFind | 10000 | 11.0928 ns | 0.1834 ns | 0.1626 ns | 0.64 | 0.01 | - | - | - | - |
| V2_ImMap_TryFind | 10000 | 15.6074 ns | 0.2325 ns | 0.2175 ns | 0.90 | 0.02 | - | - | - | - |
| DictSlim_TryGetValue | 10000 | 4.4326 ns | 0.1312 ns | 0.1228 ns | 0.25 | 0.01 | - | - | - | - |
| Dict_TryGetValue | 10000 | 7.5615 ns | 0.0669 ns | 0.0559 ns | 0.43 | 0.01 | - | - | - | - |
| ConcurrentDict_TryGetValue | 10000 | 7.5147 ns | 0.1537 ns | 0.1437 ns | 0.43 | 0.01 | - | - | - | - |
| ImmutableDict_TryGetValue | 10000 | 37.8435 ns | 0.4362 ns | 0.4080 ns | 2.17 | 0.04 | - | - | - | - |
```
**Interpreting results:** `ImHashMap` holds very good against `ImmutableDictionary` sibling and even against `Dictionary`(s)
(especially if we are talking about PartitionedImHashMap) up to certain count, indicating that immutable collection could be
quite fast for lookups.
#### Enumeration
[The benchmark source code](https://github.com/dadhi/ImTools/blob/master/playground/ImTools.Benchmarks/ImMapBenchmarks.cs)
```md
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19043
Intel Core i9-8950HK CPU 2.90GHz (Coffee Lake), 1 CPU, 12 logical and 6 physical cores
.NET Core SDK=6.0.202
[Host] : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
DefaultJob : .NET Core 6.0.4 (CoreCLR 6.0.422.16404, CoreFX 6.0.422.16404), X64 RyuJIT
| Method | Count | Mean | Error | StdDev | Ratio | RatioSD | Gen 0 | Gen 1 | Gen 2 | Allocated |
| ----------------------------- | ----- | ------------: | -----------: | ------------: | ----: | ------: | -----: | ----: | ----: | --------: |
| V4_HashMap_foreach | 1 | 39.92 ns | 0.820 ns | 0.767 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_foreach | 1 | 116.81 ns | 1.450 ns | 1.286 ns | 2.93 | 0.06 | - | - | - | - |
| V2_ImMap_Enumerate | 1 | 23.93 ns | 0.346 ns | 0.306 ns | 0.60 | 0.01 | 0.0114 | - | - | 72 B |
| DictSlim_foreach | 1 | 12.08 ns | 0.160 ns | 0.133 ns | 0.30 | 0.01 | - | - | - | - |
| Dict_foreach | 1 | 13.23 ns | 0.221 ns | 0.185 ns | 0.33 | 0.01 | - | - | - | - |
| ConcurrentDict_foreach | 1 | 160.56 ns | 1.083 ns | 0.960 ns | 4.02 | 0.07 | 0.0100 | - | - | 64 B |
| ImmutableDict_foreach | 1 | 162.69 ns | 2.671 ns | 2.367 ns | 4.08 | 0.09 | - | - | - | - |
| | | | | | | | | | | |
| V4_HashMap_foreach | 10 | 153.45 ns | 0.997 ns | 0.884 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_foreach | 10 | 404.07 ns | 3.534 ns | 3.133 ns | 2.63 | 0.02 | - | - | - | - |
| V2_ImMap_Enumerate | 10 | 122.57 ns | 2.177 ns | 1.700 ns | 0.80 | 0.01 | 0.0176 | - | - | 112 B |
| DictSlim_foreach | 10 | 53.15 ns | 0.771 ns | 0.721 ns | 0.35 | 0.01 | - | - | - | - |
| Dict_foreach | 10 | 51.03 ns | 0.977 ns | 0.816 ns | 0.33 | 0.01 | - | - | - | - |
| ConcurrentDict_foreach | 10 | 282.17 ns | 4.126 ns | 3.860 ns | 1.84 | 0.03 | 0.0100 | - | - | 64 B |
| ImmutableDict_foreach | 10 | 554.93 ns | 7.623 ns | 6.758 ns | 3.62 | 0.05 | - | - | - | - |
| | | | | | | | | | | |
| V4_HashMap_foreach | 100 | 1,620.36 ns | 15.329 ns | 12.801 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_foreach | 100 | 1,966.77 ns | 26.880 ns | 25.144 ns | 1.21 | 0.02 | - | - | - | - |
| V2_ImMap_Enumerate | 100 | 1,148.46 ns | 12.437 ns | 11.025 ns | 0.71 | 0.01 | 0.0210 | - | - | 136 B |
| DictSlim_foreach | 100 | 529.39 ns | 5.573 ns | 4.940 ns | 0.33 | 0.00 | - | - | - | - |
| Dict_foreach | 100 | 494.13 ns | 9.209 ns | 8.614 ns | 0.31 | 0.01 | - | - | - | - |
| ConcurrentDict_foreach | 100 | 2,370.15 ns | 33.237 ns | 31.090 ns | 1.46 | 0.02 | 0.0076 | - | - | 64 B |
| ImmutableDict_foreach | 100 | 4,524.35 ns | 40.547 ns | 33.858 ns | 2.79 | 0.03 | - | - | - | - |
| | | | | | | | | | | |
| V4_HashMap_foreach | 1000 | 17,206.01 ns | 152.714 ns | 135.377 ns | 1.00 | 0.00 | - | - | - | - |
| V4_PartitionedHashMap_foreach | 1000 | 21,030.80 ns | 325.220 ns | 288.299 ns | 1.22 | 0.02 | - | - | - | - |
| V2_ImMap_Enumerate | 1000 | 12,200.97 ns | 173.829 ns | 162.600 ns | 0.71 | 0.01 | 0.0153 | - | - | 160 B |
| DictSlim_foreach | 1000 | 4,913.65 ns | 76.788 ns | 71.827 ns | 0.29 | 0.00 | - | - | - | - |
| Dict_foreach | 1000 | 4,963.77 ns | 69.813 ns | 65.303 ns | 0.29 | 0.00 | - | - | - | - |
| ConcurrentDict_foreach | 1000 | 21,569.87 ns | 162.467 ns | 144.023 ns | 1.25 | 0.01 | - | - | - | 64 B |
| ImmutableDict_foreach | 1000 | 47,263.06 ns | 907.028 ns | 804.057 ns | 2.75 | 0.05 | - | - | - | - |
| | | | | | | | | | | |
| V4_HashMap_foreach | 10000 | 182,837.99 ns | 2,052.717 ns | 1,819.680 ns | 1.00 | 0.00 | - | - | - | 176 B |
| V4_PartitionedHashMap_foreach | 10000 | 232,269.89 ns | 2,514.057 ns | 2,099.352 ns | 1.27 | 0.02 | - | - | - | - |
| V2_ImMap_Enumerate | 10000 | 138,194.71 ns | 1,605.065 ns | 1,340.302 ns | 0.76 | 0.01 | - | - | - | 192 B |
| DictSlim_foreach | 10000 | 49,479.00 ns | 937.417 ns | 1,003.025 ns | 0.27 | 0.00 | - | - | - | - |
| Dict_foreach | 10000 | 46,780.99 ns | 380.189 ns | 355.629 ns | 0.26 | 0.00 | - | - | - | - |
| ConcurrentDict_foreach | 10000 | 194,166.07 ns | 919.960 ns | 860.531 ns | 1.06 | 0.01 | - | - | - | 64 B |
| ImmutableDict_foreach | 10000 | 507,513.23 ns | 9,995.314 ns | 12,640.872 ns | 2.80 | 0.07 | - | - | - | 1 B |
```
## End-to-end Example
Let's assume you are implementing yet another DI container because why not :-)
Container should contain registry of `Type` to `Factory` mappings.
On resolution `Factory` is compiled to the delegate which you would like to cache, because compilation is costly.
The cache will store the mappings from `Type` to `Func`.
__The requirements:__
- The container may be used in parallel from different threads including registrations and resolutions.
- The container state should not be corrupted and the cache should correspond to the current state of registrations.
Let's design the basic container structure to support the requirements and __without locking__:
```cs
public class Container
{
private readonly Ref _registry = Ref.Of(new Registry());
public void Register() where TImpl : TService, new()
{
_registry.Swap(reg => reg.With(typeof(TService), new Factory(typeof(TImpl))));
}
public object Resolve()
{
return (TService)(_registry.Value.Resolve(typeof(TService)) ?? ThrowUnableToResolve(typeof(TService)));
}
public object ThrowUnableToResolve(Type t) { throw new InvalidOperationException("Unable to resolve: " + t); }
class Registry
{
ImHashMap _registrations = ImHashMap.Empty;
Ref>> _resolutionCache = Ref.Of(ImHashMap>.Empty);
// Creating a new registry with +1 registration and new reference to cache value
public Registry With(Type serviceType, Factory implFactory)
{
return new Registry()
{
_registrations = _registrations.AddOrUpdate(serviceType, implFactory),
// Here is most interesting part:
// We are creating new independent reference pointing to cache value,
// isolating it from possible parallel resolutions,
// which will swap older version/ref of cache and won't touch the new one.
_resolutionCache = Ref.Of(_resolutionCache.Value)
};
}
public object Resolve(Type serviceType)
{
var func = _resolutionCache.Value.GetValueOrDefault(serviceType);
if (func != null)
return func();
var reg = _registrations.GetValueOrDefault(serviceType);
if (reg == null)
return null;
func = reg.CompileDelegate();
_resolutionCache.Swap(cache => cache.AddOrUpdate(serviceType, func));
return func.Invoke();
}
}
class Factory
{
public readonly Type ImplType;
public Factory(Type implType) { ImplType = implType; }
public Func CompileDelegate() { return () => Activator.CreateInstance(ImplType); }
}
}
```