Update number of last range possible streams.

Author: akasarto

perf/MicroBenchmarks/ComparisonBenchmarks.cs

@@ -0,0 +1,43 @@
+using ApacheOrcDotNet.OptimizedReader.Infrastructure;
+using BenchmarkDotNet.Attributes;
+using System;
+using System.Collections.Generic;
+
+/*
+|                              Method |      Mean |     Error |    StdDev | Rank | Allocated |
+|------------------------------------ |----------:|----------:|----------:|-----:|----------:|
+|                       ArrayEquality |  7.720 ns | 0.0755 ns | 0.0706 ns |    1 |         - |
+|    DictionaryContainsKeyAndEquality | 12.429 ns | 0.0690 ns | 0.0645 ns |    2 |         - |
+|               DictionaryTryGetValue | 13.052 ns | 0.0677 ns | 0.0633 ns |    3 |         - |
+ */
+
+namespace MicroBenchmarks
+{
+    [RankColumn]
+    [MemoryDiagnoser]
+    public class ComparisonBenchmarks
+    {
+        private const int size = 255;
+        private readonly StreamRange[] _buffer = new StreamRange[size];
+        private readonly Dictionary<int, StreamRange> _buffer2 = new();
+        private readonly StreamRange _testRange = new StreamRange(255, 255, 255);
+
+        public ComparisonBenchmarks()
+        {
+            for (int i = 0; i < size; i++)
+            {
+                _buffer[i] = new StreamRange(i, i, i);
+                _buffer2.Add(i, new StreamRange(i, i, i));
+            }
+        }
+
+        [Benchmark]
+        public bool ArrayEquality() => _buffer[128] == _testRange;
+
+        [Benchmark]
+        public bool DictionaryContainsKeyAndEquality() => _buffer2.ContainsKey(128) && _buffer[128] == _testRange;
+
+        [Benchmark]
+        public bool DictionaryTryGetValue() => _buffer2.TryGetValue(128, out var range) && range == _testRange;
+    }
+}

src/ApacheOrcDotNet.OptimizedReader/_Constants.cs

@@ -1,5 +1,4 @@
-using ApacheOrcDotNet.Protocol;
-using System;
+using System;
 
 namespace ApacheOrcDotNet.OptimizedReader
 {
@@ -9,7 +8,7 @@ public static class Constants
         public static DateTime UnixEpochUtc = new(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
         public static DateTime UnixEpochUnspecified = new(1970, 1, 1, 0, 0, 0, DateTimeKind.Unspecified);
 
-        public static int NumPossibleStreams = Enum.GetValues<StreamKind>().Length;
+        public static int NumPossibleStreams = byte.MaxValue;
 
         public const int RleBufferMaxLength = ushort.MaxValue + 1;
         public const int NumCompressedBlocksToPreLoad = 2;