Update BucketTree for 13.0

src/LibHac/Fs/IStorage.cs

@@ -71,7 +71,20 @@ public abstract class IStorage : IDisposable
     }
 
     /// <summary>
-    /// Performs various operations on the file. Used to extend the functionality of the <see cref="IStorage"/> interface.
+    /// Performs various operations on the storage. Used to extend the functionality of the <see cref="IStorage"/> interface.
+    /// </summary>
+    /// <param name="operationId">The operation to be performed.</param>
+    /// <param name="offset">The offset of the range to operate on.</param>
+    /// <param name="size">The size of the range to operate on.</param>
+    /// <returns>The <see cref="Result"/> of the operation.</returns>
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    public Result OperateRange(OperationId operationId, long offset, long size)
+    {
+        return DoOperateRange(Span<byte>.Empty, operationId, offset, size, ReadOnlySpan<byte>.Empty);
+    }
+
+    /// <summary>
+    /// Performs various operations on the storage. Used to extend the functionality of the <see cref="IStorage"/> interface.
     /// </summary>
     /// <param name="outBuffer">A buffer that will contain the response from the operation.</param>
     /// <param name="operationId">The operation to be performed.</param>

src/LibHac/FsSystem/BucketTree.cs

@@ -133,16 +133,10 @@ public partial class BucketTree
         return visitor.Find(virtualAddress);
     }
 
-    public static int QueryHeaderStorageSize() => Unsafe.SizeOf<Header>();
+    public static int QueryHeaderStorageSize() => 16;
 
     public static long QueryNodeStorageSize(long nodeSize, long entrySize, int entryCount)
     {
-        Assert.SdkRequiresLessEqual(sizeof(long), entrySize);
-        Assert.SdkRequiresLessEqual(entrySize + Unsafe.SizeOf<NodeHeader>(), nodeSize);
-        Assert.SdkRequiresWithinMinMax(nodeSize, NodeSizeMin, NodeSizeMax);
-        Assert.SdkRequires(BitUtil.IsPowerOfTwo(nodeSize));
-        Assert.SdkRequiresLessEqual(0, entryCount);
-
         if (entryCount <= 0)
             return 0;
 
@@ -151,12 +145,6 @@ public partial class BucketTree
 
     public static long QueryEntryStorageSize(long nodeSize, long entrySize, int entryCount)
     {
-        Assert.SdkRequiresLessEqual(sizeof(long), entrySize);
-        Assert.SdkRequiresLessEqual(entrySize + Unsafe.SizeOf<NodeHeader>(), nodeSize);
-        Assert.SdkRequiresWithinMinMax(nodeSize, NodeSizeMin, NodeSizeMax);
-        Assert.SdkRequires(BitUtil.IsPowerOfTwo(nodeSize));
-        Assert.SdkRequiresLessEqual(0, entryCount);
-
         if (entryCount <= 0)
             return 0;
 
@@ -165,18 +153,19 @@ public partial class BucketTree
 
     private static int GetEntryCount(long nodeSize, long entrySize)
     {
-        return (int)((nodeSize - Unsafe.SizeOf<NodeHeader>()) / entrySize);
+        return (int)((nodeSize - 16) / entrySize);
     }
 
     private static int GetOffsetCount(long nodeSize)
     {
-        return (int)((nodeSize - Unsafe.SizeOf<NodeHeader>()) / sizeof(long));
+        return (int)((nodeSize - 16) / sizeof(long));
     }
 
     private static int GetEntrySetCount(long nodeSize, long entrySize, int entryCount)
     {
         int entryCountPerNode = GetEntryCount(nodeSize, entrySize);
-        return BitUtil.DivideUp(entryCount, entryCountPerNode);
+        uint divisor = (uint)entryCountPerNode;
+        return (int)(((uint)entryCount + divisor - 1) / divisor);
     }
 
     public static int GetNodeL2Count(long nodeSize, long entrySize, int entryCount)
@@ -187,10 +176,12 @@ public partial class BucketTree
         if (entrySetCount <= offsetCountPerNode)
             return 0;
 
-        int nodeL2Count = BitUtil.DivideUp(entrySetCount, offsetCountPerNode);
-        Abort.DoAbortUnless(nodeL2Count <= offsetCountPerNode);
+        uint divisor1 = (uint)offsetCountPerNode;
+        int nodeL2Count = (int)(((uint)entrySetCount + divisor1 - 1) / divisor1);
+        Assert.SdkLessEqual(nodeL2Count, offsetCountPerNode);
 
-        return BitUtil.DivideUp(entrySetCount - (offsetCountPerNode - (nodeL2Count - 1)), offsetCountPerNode);
+        uint divisor = (uint)offsetCountPerNode;
+        return (int)(((uint)(entrySetCount - (offsetCountPerNode - (nodeL2Count - 1))) + divisor - 1) / divisor);
     }
 
     private static long GetBucketTreeEntryOffset(long entrySetOffset, long entrySize, int entryIndex)
@@ -298,7 +289,7 @@ public partial class BucketTree
 
         public ref NodeHeader GetHeader()
         {
-            Assert.SdkRequiresGreaterEqual(_header.Length / sizeof(long), Unsafe.SizeOf<NodeHeader>());
+            Assert.SdkRequiresGreaterEqual(_header.Length * sizeof(long), Unsafe.SizeOf<NodeHeader>());
 
             return ref Unsafe.As<long, NodeHeader>(ref _header[0]);
         }

src/LibHac/FsSystem/BucketTreeBuilder2.cs

@@ -0,0 +1,314 @@
+using System;
+using System.Buffers.Binary;
+using System.Runtime.CompilerServices;
+using LibHac.Common;
+using LibHac.Diag;
+using LibHac.Fs;
+using LibHac.Util;
+
+namespace LibHac.FsSystem;
+
+public partial class BucketTree2
+{
+    public class Builder
+    {
+        private NodeBuffer _l1Node;
+        private NodeBuffer _l2Node;
+        private NodeBuffer _entrySet;
+
+        private ValueSubStorage _nodeStorage;
+        private ValueSubStorage _entryStorage;
+
+        private int _nodeSize;
+        private int _entrySize;
+        private int _entryCount;
+        private int _entriesPerEntrySet;
+        private int _offsetsPerNode;
+
+        private int _currentL2OffsetIndex;
+        private int _currentEntryIndex;
+        private long _currentOffset;
+
+        public Builder()
+        {
+            _currentOffset = -1;
+        }
+
+        /// <summary>
+        /// Initializes the bucket tree builder.
+        /// </summary>
+        /// <param name="allocator">The <see cref="MemoryResource"/> to use for buffer allocation.</param>
+        /// <param name="headerStorage">The <see cref="ValueSubStorage"/> the tree's header will be written to.Must be at least the size in bytes returned by <see cref="QueryHeaderStorageSize"/>.</param>
+        /// <param name="nodeStorage">The <see cref="ValueSubStorage"/> the tree's nodes will be written to. Must be at least the size in bytes returned by <see cref="QueryNodeStorageSize"/>.</param>
+        /// <param name="entryStorage">The <see cref="ValueSubStorage"/> the tree's entries will be written to. Must be at least the size in bytes returned by <see cref="QueryEntryStorageSize"/>.</param>
+        /// <param name="nodeSize">The size of each node in the bucket tree. Must be a power of 2.</param>
+        /// <param name="entrySize">The size of each entry that will be stored in the bucket tree.</param>
+        /// <param name="entryCount">The exact number of entries that will be added to the bucket tree.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        public Result Initialize(MemoryResource allocator, in ValueSubStorage headerStorage,
+            in ValueSubStorage nodeStorage, in ValueSubStorage entryStorage, int nodeSize, int entrySize,
+            int entryCount)
+        {
+            Assert.NotNull(allocator);
+            Assert.SdkRequiresLessEqual(sizeof(long), entrySize);
+            Assert.SdkRequiresLessEqual(entrySize + Unsafe.SizeOf<NodeHeader>(), nodeSize);
+            Assert.SdkRequiresWithinMinMax(nodeSize, NodeSizeMin, NodeSizeMax);
+            Assert.SdkRequires(BitUtil.IsPowerOfTwo(nodeSize));
+
+            // Set the builder parameters
+            _nodeSize = nodeSize;
+            _entrySize = entrySize;
+            _entryCount = entryCount;
+
+            _entriesPerEntrySet = GetEntryCount(nodeSize, entrySize);
+            _offsetsPerNode = GetOffsetCount(nodeSize);
+            _currentL2OffsetIndex = GetNodeL2Count(nodeSize, entrySize, entryCount);
+
+            // Create and write the header
+            var header = new Header();
+            header.Format(entryCount);
+            Result rc = headerStorage.Write(0, SpanHelpers.AsByteSpan(ref header));
+            if (rc.IsFailure()) return rc;
+
+            // Allocate buffers for the L1 node and entry sets
+            _l1Node.Allocate(allocator, nodeSize);
+            _entrySet.Allocate(allocator, nodeSize);
+
+            int entrySetCount = GetEntrySetCount(nodeSize, entrySize, entryCount);
+
+            // Allocate an L2 node buffer if there are more entry sets than will fit in the L1 node
+            if (_offsetsPerNode < entrySetCount)
+            {
+                _l2Node.Allocate(allocator, nodeSize);
+            }
+
+            _l1Node.FillZero();
+            _l2Node.FillZero();
+            _entrySet.FillZero();
+
+            _nodeStorage.Set(in nodeStorage);
+            _entryStorage.Set(in entryStorage);
+
+            // Set the initial position
+            _currentEntryIndex = 0;
+            _currentOffset = -1;
+
+            return Result.Success;
+        }
+
+        /// <summary>
+        /// Adds a new entry to the bucket tree.
+        /// </summary>
+        /// <typeparam name="T">The type of the entry to add. Added entries should all be the same type.</typeparam>
+        /// <param name="entry">The entry to add.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        public Result Add<T>(in T entry) where T : unmanaged
+        {
+            Assert.SdkRequiresEqual(Unsafe.SizeOf<T>(), _entrySize);
+
+            if (_currentEntryIndex >= _entryCount)
+                return ResultFs.OutOfRange.Log();
+
+            // The entry offset must always be the first 8 bytes of the struct
+            long entryOffset = BinaryPrimitives.ReadInt64LittleEndian(SpanHelpers.AsReadOnlyByteSpan(in entry));
+
+            if (entryOffset <= _currentOffset)
+                return ResultFs.InvalidOffset.Log();
+
+            Result rc = FinalizePreviousEntrySet(entryOffset);
+            if (rc.IsFailure()) return rc;
+
+            AddEntryOffset(entryOffset);
+
+            // Write the new entry
+            int indexInEntrySet = _currentEntryIndex % _entriesPerEntrySet;
+            _entrySet.GetNode<T>().GetWritableArray()[indexInEntrySet] = entry;
+
+            _currentOffset = entryOffset;
+            _currentEntryIndex++;
+
+            return Result.Success;
+        }
+
+        /// <summary>
+        /// Checks if a new entry set is being started. If so, sets the end offset of the previous
+        /// entry set and writes it to the output storage.
+        /// </summary>
+        /// <param name="endOffset">The end offset of the previous entry.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        private Result FinalizePreviousEntrySet(long endOffset)
+        {
+            int prevEntrySetIndex = _currentEntryIndex / _entriesPerEntrySet - 1;
+            int indexInEntrySet = _currentEntryIndex % _entriesPerEntrySet;
+
+            // If the previous Add finished an entry set
+            if (_currentEntryIndex > 0 && indexInEntrySet == 0)
+            {
+                // Set the end offset of that entry set
+                ref NodeHeader entrySetHeader = ref _entrySet.GetHeader();
+
+                entrySetHeader.Index = prevEntrySetIndex;
+                entrySetHeader.EntryCount = _entriesPerEntrySet;
+                entrySetHeader.OffsetEnd = endOffset;
+
+                // Write the entry set to the entry storage
+                long storageOffset = (long)_nodeSize * prevEntrySetIndex;
+                Result rc = _entryStorage.Write(storageOffset, _entrySet.GetBuffer());
+                if (rc.IsFailure()) return rc;
+
+                // Clear the entry set buffer to begin the new entry set
+                _entrySet.FillZero();
+
+                // Check if we're writing in L2 nodes
+                if (_currentL2OffsetIndex > _offsetsPerNode)
+                {
+                    int prevL2NodeIndex = _currentL2OffsetIndex / _offsetsPerNode - 2;
+                    int indexInL2Node = _currentL2OffsetIndex % _offsetsPerNode;
+
+                    // If the previous Add finished an L2 node
+                    if (indexInL2Node == 0)
+                    {
+                        // Set the end offset of that node
+                        ref NodeHeader l2NodeHeader = ref _l2Node.GetHeader();
+
+                        l2NodeHeader.Index = prevL2NodeIndex;
+                        l2NodeHeader.EntryCount = _offsetsPerNode;
+                        l2NodeHeader.OffsetEnd = endOffset;
+
+                        // Write the L2 node to the node storage
+                        long nodeOffset = (long)_nodeSize * (prevL2NodeIndex + 1);
+                        rc = _nodeStorage.Write(nodeOffset, _l2Node.GetBuffer());
+                        if (rc.IsFailure()) return rc;
+
+                        // Clear the L2 node buffer to begin the new node
+                        _l2Node.FillZero();
+                    }
+                }
+            }
+
+            return Result.Success;
+        }
+
+        /// <summary>
+        /// If needed, adds a new entry set's start offset to the L1 or L2 nodes.
+        /// </summary>
+        /// <param name="entryOffset">The start offset of the entry being added.</param>
+        private void AddEntryOffset(long entryOffset)
+        {
+            int entrySetIndex = _currentEntryIndex / _entriesPerEntrySet;
+            int indexInEntrySet = _currentEntryIndex % _entriesPerEntrySet;
+
+            // If we're starting a new entry set we need to add its start offset to the L1/L2 nodes
+            if (indexInEntrySet == 0)
+            {
+                Span<long> l1Data = _l1Node.GetNode<long>().GetWritableArray();
+
+                if (_currentL2OffsetIndex == 0)
+                {
+                    // There are no L2 nodes. Write the entry set end offset directly to L1
+                    l1Data[entrySetIndex] = entryOffset;
+                }
+                else
+                {
+                    if (_currentL2OffsetIndex < _offsetsPerNode)
+                    {
+                        // The current L2 offset is stored in the L1 node
+                        l1Data[_currentL2OffsetIndex] = entryOffset;
+                    }
+                    else
+                    {
+                        // Write the entry set offset to the current L2 node
+                        int l2NodeIndex = _currentL2OffsetIndex / _offsetsPerNode;
+                        int indexInL2Node = _currentL2OffsetIndex % _offsetsPerNode;
+
+                        Span<long> l2Data = _l2Node.GetNode<long>().GetWritableArray();
+                        l2Data[indexInL2Node] = entryOffset;
+
+                        // If we're starting a new L2 node we need to add its start offset to the L1 node
+                        if (indexInL2Node == 0)
+                        {
+                            l1Data[l2NodeIndex - 1] = entryOffset;
+                        }
+                    }
+
+                    _currentL2OffsetIndex++;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Finalizes the bucket tree. Must be called after all entries are added.
+        /// </summary>
+        /// <param name="endOffset">The end offset of the bucket tree.</param>
+        /// <returns>The <see cref="Result"/> of the operation.</returns>
+        public Result Finalize(long endOffset)
+        {
+            // Finalize must only be called after all entries are added
+            if (_entryCount != _currentEntryIndex)
+                return ResultFs.OutOfRange.Log();
+
+            if (endOffset <= _currentOffset)
+                return ResultFs.InvalidOffset.Log();
+
+            if (_currentOffset == -1)
+                return Result.Success;
+
+            Result rc = FinalizePreviousEntrySet(endOffset);
+            if (rc.IsFailure()) return rc;
+
+            int entrySetIndex = _currentEntryIndex / _entriesPerEntrySet;
+            int indexInEntrySet = _currentEntryIndex % _entriesPerEntrySet;
+
+            // Finalize the current entry set if needed
+            if (indexInEntrySet != 0)
+            {
+                ref NodeHeader entrySetHeader = ref _entrySet.GetHeader();
+
+                entrySetHeader.Index = entrySetIndex;
+                entrySetHeader.EntryCount = indexInEntrySet;
+                entrySetHeader.OffsetEnd = endOffset;
+
+                long entryStorageOffset = (long)_nodeSize * entrySetIndex;
+                rc = _entryStorage.Write(entryStorageOffset, _entrySet.GetBuffer());
+                if (rc.IsFailure()) return rc;
+            }
+
+            int l2NodeIndex = BitUtil.DivideUp(_currentL2OffsetIndex, _offsetsPerNode) - 2;
+            int indexInL2Node = _currentL2OffsetIndex % _offsetsPerNode;
+
+            // Finalize the current L2 node if needed
+            if (_currentL2OffsetIndex > _offsetsPerNode && (indexInEntrySet != 0 || indexInL2Node != 0))
+            {
+                ref NodeHeader l2NodeHeader = ref _l2Node.GetHeader();
+                l2NodeHeader.Index = l2NodeIndex;
+                l2NodeHeader.EntryCount = indexInL2Node != 0 ? indexInL2Node : _offsetsPerNode;
+                l2NodeHeader.OffsetEnd = endOffset;
+
+                long l2NodeStorageOffset = _nodeSize * (l2NodeIndex + 1);
+                rc = _nodeStorage.Write(l2NodeStorageOffset, _l2Node.GetBuffer());
+                if (rc.IsFailure()) return rc;
+            }
+
+            // Finalize the L1 node
+            ref NodeHeader l1NodeHeader = ref _l1Node.GetHeader();
+            l1NodeHeader.Index = 0;
+            l1NodeHeader.OffsetEnd = endOffset;
+
+            // L1 count depends on the existence or absence of L2 nodes
+            if (_currentL2OffsetIndex == 0)
+            {
+                l1NodeHeader.EntryCount = BitUtil.DivideUp(_currentEntryIndex, _entriesPerEntrySet);
+            }
+            else
+            {
+                l1NodeHeader.EntryCount = l2NodeIndex + 1;
+            }
+
+            rc = _nodeStorage.Write(0, _l1Node.GetBuffer());
+            if (rc.IsFailure()) return rc;
+
+            _currentOffset = long.MaxValue;
+            return Result.Success;
+        }
+    }
+}

src/LibHac/FsSystem/IndirectStorage.cs

@@ -23,10 +23,10 @@ public class IndirectStorage : IStorage
         public int StorageIndex;
 
         public void SetVirtualOffset(long offset) => VirtualOffset = offset;
-        public long GetVirtualOffset() => VirtualOffset;
+        public readonly long GetVirtualOffset() => VirtualOffset;
 
         public void SetPhysicalOffset(long offset) => PhysicalOffset = offset;
-        public long GetPhysicalOffset() => PhysicalOffset;
+        public readonly long GetPhysicalOffset() => PhysicalOffset;
     }
 
     public static long QueryHeaderStorageSize() => BucketTree.QueryHeaderStorageSize();

src/LibHac/FsSystem/PooledBuffer.cs

@@ -21,26 +21,26 @@ public struct PooledBuffer : IDisposable
     private const int HeapAllocatableSizeMax = HeapBlockSize * (1 << HeapOrderMax);
     private const int HeapAllocatableSizeMaxForLarge = HeapBlockSize * (1 << HeapOrderMaxForLarge);
 
-    private byte[] Array { get; set; }
-    private int Length { get; set; }
+    private byte[] _array;
+    private int _length;
 
     public PooledBuffer(int idealSize, int requiredSize)
     {
-        Array = null;
-        Length = default;
+        _array = null;
+        _length = default;
         Allocate(idealSize, requiredSize);
     }
 
     public Span<byte> GetBuffer()
     {
-        Assert.SdkRequiresNotNull(Array);
-        return Array.AsSpan(0, Length);
+        Assert.SdkRequiresNotNull(_array);
+        return _array.AsSpan(0, _length);
     }
 
     public int GetSize()
     {
-        Assert.SdkRequiresNotNull(Array);
-        return Length;
+        Assert.SdkRequiresNotNull(_array);
+        return _length;
     }
 
     public static int GetAllocatableSizeMax() => GetAllocatableSizeMaxCore(false);
@@ -56,7 +56,7 @@ public struct PooledBuffer : IDisposable
 
     private void AllocateCore(int idealSize, int requiredSize, bool enableLargeCapacity)
     {
-        Assert.SdkRequiresNull(Array);
+        Assert.SdkRequiresNull(_array);
 
         // Check that we can allocate this size.
         Assert.SdkRequiresLessEqual(requiredSize, GetAllocatableSizeMaxCore(enableLargeCapacity));
@@ -66,21 +66,21 @@ public struct PooledBuffer : IDisposable
 
         if (targetSize >= RentThresholdBytes)
         {
-            Array = ArrayPool<byte>.Shared.Rent(targetSize);
+            _array = ArrayPool<byte>.Shared.Rent(targetSize);
         }
         else
         {
-            Array = new byte[targetSize];
+            _array = new byte[targetSize];
         }
 
-        Length = Array.Length;
+        _length = _array.Length;
     }
 
     public void Deallocate()
     {
         // Shrink the buffer to empty.
         Shrink(0);
-        Assert.SdkNull(Array);
+        Assert.SdkNull(_array);
     }
 
     public void Shrink(int idealSize)
@@ -88,23 +88,23 @@ public struct PooledBuffer : IDisposable
         Assert.SdkRequiresLessEqual(idealSize, GetAllocatableSizeMaxCore(true));
 
         // Check if we actually need to shrink.
-        if (Length > idealSize)
+        if (_length > idealSize)
         {
-            Assert.SdkRequiresNotNull(Array);
+            Assert.SdkRequiresNotNull(_array);
 
             // Pretend we shrank the buffer.
-            Length = idealSize;
+            _length = idealSize;
 
             // Shrinking to zero means that we have no buffer.
-            if (Length == 0)
+            if (_length == 0)
             {
                 // Return the array if we rented it.
-                if (Array?.Length >= RentThresholdBytes)
+                if (_array?.Length >= RentThresholdBytes)
                 {
-                    ArrayPool<byte>.Shared.Return(Array);
+                    ArrayPool<byte>.Shared.Return(_array);
                 }
 
-                Array = null;
+                _array = null;
             }
         }
     }

tests/LibHac.Tests/Common/TheoryDataCreator.cs

@@ -0,0 +1,18 @@
+using Xunit;
+
+namespace LibHac.Tests.Common;
+
+public static class TheoryDataCreator
+{
+    public static TheoryData<int> CreateSequence(int start, int count)
+    {
+        var data = new TheoryData<int>();
+
+        for (int i = 0; i < count; i++)
+        {
+            data.Add(start + i);
+        }
+
+        return data;
+    }
+}

tests/LibHac.Tests/FsSystem/BucketTreeBuilderTests.cs

@@ -0,0 +1,164 @@
+using System.Runtime.CompilerServices;
+using LibHac.Fs;
+using LibHac.FsSystem;
+using LibHac.Tests.Common;
+using LibHac.Util;
+using Xunit;
+
+namespace LibHac.Tests.FsSystem;
+
+public class BucketTreeBuilderTests
+{
+    public class BucketTreeBuilderTestConfig
+    {
+        public string ExpectedHeaderDigest { get; init; }
+        public string ExpectedNodeDigest { get; init; }
+        public string ExpectedEntryDigest { get; init; }
+        public ulong RngSeed { get; init; }
+        public SizeRange EntrySizeRange { get; init; }
+        public int NodeSize { get; init; }
+        public int EntryCount { get; init; }
+    }
+
+    // Bucket tree builder parameters and output digests that have been verified manually
+    private static readonly BucketTreeBuilderTestConfig[] BucketTreeBuilderTestData =
+    {
+        // Tiny tree
+        new()
+        {
+            ExpectedHeaderDigest = "34C3355A9C67F91A978FD8CD51A1FB69FB4A6575FA93EEA03FF94E3FDA4FF918",
+            ExpectedNodeDigest = "38B1BAA521BBD24204A2846A184C276DAA46065964910A5FC132BED73187B9F2",
+            ExpectedEntryDigest = "7D61723D0A332128713120961E607188F50A8870360328594F4A5CC1731B10EE",
+            RngSeed = 0,
+            EntrySizeRange = new SizeRange(0x1000, 1, 10),
+            NodeSize = 0x4000,
+            EntryCount = 5
+        },
+        // Slightly larger tree
+        new()
+        {
+            ExpectedHeaderDigest = "B297BF6EE037B9179CA78618D73B1F51F4C980DF18CA79D00BD99EA3CB801491",
+            ExpectedNodeDigest = "DEB446E4EF36937ED253D912D48BCB74C9745E55647E3B900B3730379285580F",
+            ExpectedEntryDigest = "ED8CBA7E42A03D9399562A577E5FE3203DCA6CDAEA44F9EB9D6EFEC174638AE1",
+            RngSeed = 0,
+            EntrySizeRange = new SizeRange(0x1000, 1, 10),
+            NodeSize = 0x4000,
+            EntryCount = 10000
+        },
+        // Very large tree that contains a L2 node
+        new()
+        {
+            ExpectedHeaderDigest = "D36E9BC6C618637F3C615A861826DEE9CA8E0AB37C51D7124D0112E2B2D666C2",
+            ExpectedNodeDigest = "FBB238FFAF8A7585A1413CA9BF12E0C70BCF2B12DA3399F1077C6E3D364886B9",
+            ExpectedEntryDigest = "F3A452EC58B7C937E6AACC31680CAFAEEA63B0BA4D26F7A2EAEAF2FF11ABCF26",
+            RngSeed = 0,
+            EntrySizeRange = new SizeRange(0x1000, 1, 10),
+            NodeSize = 0x4000,
+            EntryCount = 2_000_000
+        },
+        // Tree with node size of 0x400 containing multiple L2 nodes
+        new()
+        {
+            ExpectedHeaderDigest = "B0520728AAD615F48BD45EAD1D8BC953AE0B912C5DB9429DD8DF2BC7B656FBEC",
+            ExpectedNodeDigest = "F785D455960298F7EABAD6E1997CE1FD298BFD802788E84E35FBA4E65FCE90E9",
+            ExpectedEntryDigest = "B467120D77D2ECBD039D9E171F8D604D3F3ED7C60C3551878EF21ED52B02690C",
+            RngSeed = 0,
+            EntrySizeRange = new SizeRange(0x1000, 1, 10),
+            NodeSize = 0x400,
+            EntryCount = 50_000
+        },
+        // Tree with node size of 0x400 containing the maximum number of entries possible with that node size
+        new()
+        {
+            ExpectedHeaderDigest = "33C6DBFDC95C8F5DC75DFE1BD027E9943FAA1B90DEB33039827860BCEC31CAA2",
+            ExpectedNodeDigest = "A732F462E8D545C7409FFB5DE6BDB460A3D466BDBD730173A453FD81C82AA38C",
+            ExpectedEntryDigest = "9EE6FBA4E0D336A7082EF46EC64FD8CEC2BAA5C8CF760C357B9193FE37A04CE3",
+            RngSeed = 0,
+            EntrySizeRange = new SizeRange(0x1000, 1, 10),
+            NodeSize = 0x400,
+            EntryCount = 793_800
+        }
+    };
+
+    public static TheoryData<int> BucketTreeBuilderTestTheoryData =
+        TheoryDataCreator.CreateSequence(0, BucketTreeBuilderTestData.Length);
+
+    [Theory, MemberData(nameof(BucketTreeBuilderTestTheoryData))]
+    public void BuildTree_TreeIsGeneratedCorrectly(int index)
+    {
+        BucketTreeBuilderTestConfig config = BucketTreeBuilderTestData[index];
+
+        BucketTreeTests.BucketTreeData data = BucketTreeCreator.Create(config.RngSeed, config.EntrySizeRange,
+            config.NodeSize, config.EntryCount);
+
+        byte[] headerDigest = new byte[0x20];
+        byte[] nodeDigest = new byte[0x20];
+        byte[] entryDigest = new byte[0x20];
+
+        Crypto.Sha256.GenerateSha256Hash(data.Header, headerDigest);
+        Crypto.Sha256.GenerateSha256Hash(data.Nodes, nodeDigest);
+        Crypto.Sha256.GenerateSha256Hash(data.Entries, entryDigest);
+
+        Assert.Equal(config.ExpectedHeaderDigest, headerDigest.ToHexString());
+        Assert.Equal(config.ExpectedNodeDigest, nodeDigest.ToHexString());
+        Assert.Equal(config.ExpectedEntryDigest, entryDigest.ToHexString());
+    }
+
+    [Fact]
+    public void Initialize_TooManyEntries_ReturnsException()
+    {
+        Assert.Throws<HorizonResultException>(() =>
+            BucketTreeCreator.Create(0, new SizeRange(0x1000, 1, 10), 0x400, 793_801));
+    }
+
+    [Fact]
+    public void Finalize_NotAllEntriesAdded_ReturnsOutOfRange()
+    {
+        const int nodeSize = 0x4000;
+        const int entryCount = 10;
+
+        byte[] headerBuffer = new byte[BucketTree2.QueryHeaderStorageSize()];
+        byte[] nodeBuffer = new byte[(int)BucketTree2.QueryNodeStorageSize(nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount)];
+        byte[] entryBuffer = new byte[(int)BucketTree2.QueryEntryStorageSize(nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount)];
+
+        using var headerStorage = new ValueSubStorage(new MemoryStorage(headerBuffer), 0, headerBuffer.Length);
+        using var nodeStorage = new ValueSubStorage(new MemoryStorage(nodeBuffer), 0, nodeBuffer.Length);
+        using var entryStorage = new ValueSubStorage(new MemoryStorage(entryBuffer), 0, entryBuffer.Length);
+
+        var builder = new BucketTree2.Builder();
+
+        Assert.Success(builder.Initialize(new ArrayPoolMemoryResource(), in headerStorage, in nodeStorage, in entryStorage, nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount));
+
+        var entry = new IndirectStorage.Entry();
+        Assert.Success(builder.Add(in entry));
+
+        Assert.Result(ResultFs.OutOfRange, builder.Finalize(0x1000));
+    }
+
+    [Fact]
+    public void Finalize_InvalidEndOffset_ReturnsInvalidOffset()
+    {
+        const int nodeSize = 0x4000;
+        const int entryCount = 2;
+
+        byte[] headerBuffer = new byte[BucketTree2.QueryHeaderStorageSize()];
+        byte[] nodeBuffer = new byte[(int)BucketTree2.QueryNodeStorageSize(nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount)];
+        byte[] entryBuffer = new byte[(int)BucketTree2.QueryEntryStorageSize(nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount)];
+
+        using var headerStorage = new ValueSubStorage(new MemoryStorage(headerBuffer), 0, headerBuffer.Length);
+        using var nodeStorage = new ValueSubStorage(new MemoryStorage(nodeBuffer), 0, nodeBuffer.Length);
+        using var entryStorage = new ValueSubStorage(new MemoryStorage(entryBuffer), 0, entryBuffer.Length);
+
+        var builder = new BucketTree2.Builder();
+
+        Assert.Success(builder.Initialize(new ArrayPoolMemoryResource(), in headerStorage, in nodeStorage, in entryStorage, nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount));
+
+        var entry = new IndirectStorage.Entry();
+        Assert.Success(builder.Add(in entry));
+
+        entry.SetVirtualOffset(0x10000);
+        Assert.Success(builder.Add(in entry));
+
+        Assert.Result(ResultFs.InvalidOffset, builder.Finalize(0x1000));
+    }
+}

tests/LibHac.Tests/FsSystem/BucketTreeCreator.cs

@@ -0,0 +1,139 @@
+using System.Runtime.CompilerServices;
+using LibHac.Fs;
+using LibHac.FsSystem;
+using Xunit;
+
+namespace LibHac.Tests.FsSystem;
+
+public record struct SizeRange(int BlockSize, int MinBlockCount, int MaxBlockCount);
+
+internal static class BucketTreeCreator
+{
+    public class EntryGenerator
+    {
+        private Random _random;
+
+        private readonly SizeRange _originalEntrySizeRange;
+        private readonly SizeRange _patchEntrySizeRange;
+
+        private IndirectStorage.Entry _currentEntry;
+
+        private long _originalStorageOffset;
+        private long _patchStorageOffset;
+        private long _patchedStorageOffset;
+        private bool _isOriginal;
+
+        public IndirectStorage.Entry CurrentEntry => _currentEntry;
+        public int CurrentEntryIndex { get; private set; }
+        public int CurrentEntrySize { get; private set; }
+
+        public long OriginalStorageSize => _originalStorageOffset;
+        public long PatchStorageSize => _patchStorageOffset;
+        public long PatchedStorageSize => _patchedStorageOffset;
+
+        public EntryGenerator(ulong rngSeed, SizeRange entrySizes)
+        {
+            _random = new Random(rngSeed);
+            _originalEntrySizeRange = entrySizes;
+            _patchEntrySizeRange = entrySizes;
+            _isOriginal = false;
+
+            CurrentEntryIndex = -1;
+        }
+
+        public EntryGenerator(ulong rngSeed, SizeRange originalEntrySizes, SizeRange patchEntrySizes)
+        {
+            _random = new Random(rngSeed);
+            _originalEntrySizeRange = originalEntrySizes;
+            _patchEntrySizeRange = patchEntrySizes;
+            _isOriginal = false;
+
+            CurrentEntryIndex = -1;
+        }
+
+        public void MoveNext()
+        {
+            _isOriginal = !_isOriginal;
+
+            SizeRange range = _isOriginal ? _originalEntrySizeRange : _patchEntrySizeRange;
+
+            int blockCount = _random.Next(range.MinBlockCount, range.MaxBlockCount);
+            int entrySize = blockCount * range.BlockSize;
+
+            CurrentEntryIndex++;
+            CurrentEntrySize = entrySize;
+
+            _currentEntry.SetVirtualOffset(_patchedStorageOffset);
+
+            _patchedStorageOffset += entrySize;
+
+            if (_isOriginal)
+            {
+                _currentEntry.SetPhysicalOffset(_originalStorageOffset);
+                _currentEntry.StorageIndex = 0;
+
+                _originalStorageOffset += entrySize;
+            }
+            else
+            {
+                _currentEntry.SetPhysicalOffset(_patchStorageOffset);
+                _currentEntry.StorageIndex = 1;
+
+                // Advance the original offset too to account for the data that's being replaced in the original storage
+                _originalStorageOffset += entrySize;
+                _patchStorageOffset += entrySize;
+            }
+        }
+    }
+
+    public static BucketTreeTests.BucketTreeData Create(ulong rngSeed, SizeRange entrySizes, int nodeSize, int entryCount)
+    {
+        byte[] headerBuffer = new byte[BucketTree2.QueryHeaderStorageSize()];
+        byte[] nodeBuffer = new byte[(int)BucketTree2.QueryNodeStorageSize(nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount)];
+        byte[] entryBuffer = new byte[(int)BucketTree2.QueryEntryStorageSize(nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount)];
+
+        using var headerStorage = new ValueSubStorage(new MemoryStorage(headerBuffer), 0, headerBuffer.Length);
+        using var nodeStorage = new ValueSubStorage(new MemoryStorage(nodeBuffer), 0, nodeBuffer.Length);
+        using var entryStorage = new ValueSubStorage(new MemoryStorage(entryBuffer), 0, entryBuffer.Length);
+
+        var generator = new EntryGenerator(rngSeed, entrySizes);
+        var builder = new BucketTree2.Builder();
+
+        Assert.Success(builder.Initialize(new ArrayPoolMemoryResource(), in headerStorage, in nodeStorage,
+            in entryStorage, nodeSize, Unsafe.SizeOf<IndirectStorage.Entry>(), entryCount));
+
+        for (int i = 0; i < entryCount; i++)
+        {
+            generator.MoveNext();
+            IndirectStorage.Entry entry = generator.CurrentEntry;
+
+            Assert.Success(builder.Add(in entry));
+        }
+
+        Assert.Success(builder.Finalize(generator.PatchedStorageSize));
+
+        return new BucketTreeTests.BucketTreeData
+        {
+            NodeSize = nodeSize,
+            EntryCount = entryCount,
+            Header = headerBuffer,
+            Nodes = nodeBuffer,
+            Entries = entryBuffer
+        };
+    }
+
+    public static IndirectStorage.Entry[] GenerateEntries(ulong rngSeed, SizeRange entrySizeRange, int entryCount)
+    {
+        var entries = new IndirectStorage.Entry[entryCount];
+
+        var generator = new EntryGenerator(rngSeed, entrySizeRange);
+
+        for (int i = 0; i < entryCount; i++)
+        {
+            generator.MoveNext();
+            entries[i] = generator.CurrentEntry;
+        }
+
+        return entries;
+    }
+}

tests/LibHac.Tests/FsSystem/BucketTreeTests.cs

@@ -0,0 +1,185 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+using LibHac.Fs;
+using LibHac.FsSystem;
+using LibHac.Tests.Common;
+using Xunit;
+
+namespace LibHac.Tests.FsSystem;
+
+public class BucketTreeBuffers
+{
+    public IndirectStorage.Entry[] Entries { get; }
+    public BucketTreeTests.BucketTreeData[] TreeData { get; }
+
+    public BucketTreeBuffers()
+    {
+        (int nodeSize, int entryCount)[] treeConfig = BucketTreeTests.BucketTreeTestParams;
+        TreeData = new BucketTreeTests.BucketTreeData[treeConfig.Length];
+
+        Entries = BucketTreeCreator.GenerateEntries(0, new SizeRange(0x1000, 1, 10), 2_000_001);
+
+        for (int i = 0; i < treeConfig.Length; i++)
+        {
+            (int nodeSize, int entryCount) = treeConfig[i];
+            TreeData[i] = BucketTreeCreator.Create(0, new SizeRange(0x1000, 1, 10), nodeSize, entryCount);
+        }
+    }
+}
+
+public class BucketTreeTests : IClassFixture<BucketTreeBuffers>
+{
+    // Keep the generated data between tests so it only has to be generated once
+    private readonly IndirectStorage.Entry[] _entries;
+    private readonly BucketTreeData[] _treeData;
+
+    public BucketTreeTests(BucketTreeBuffers buffers)
+    {
+        _entries = buffers.Entries;
+        _treeData = buffers.TreeData;
+    }
+
+    public static readonly (int nodeSize, int entryCount)[] BucketTreeTestParams =
+    {
+        (0x4000, 5),
+        (0x4000, 10000),
+        (0x4000, 2_000_000),
+        (0x400, 50_000),
+        (0x400, 793_800)
+    };
+
+    public static TheoryData<int> BucketTreeTestTheoryData =
+        TheoryDataCreator.CreateSequence(0, BucketTreeTestParams.Length);
+
+    public class BucketTreeData
+    {
+        public int NodeSize;
+        public int EntryCount;
+        public byte[] Header;
+        public byte[] Nodes;
+        public byte[] Entries;
+
+        public BucketTree2 CreateBucketTree()
+        {
+            int entrySize = Unsafe.SizeOf<IndirectStorage.Entry>();
+
+            BucketTree.Header header = MemoryMarshal.Cast<byte, BucketTree.Header>(Header.AsSpan())[0];
+            using var nodeStorage = new ValueSubStorage(new MemoryStorage(Nodes), 0, Nodes.Length);
+            using var entryStorage = new ValueSubStorage(new MemoryStorage(Entries), 0, Entries.Length);
+
+            var tree = new BucketTree2();
+            Assert.Success(tree.Initialize(new ArrayPoolMemoryResource(), in nodeStorage, in entryStorage, NodeSize, entrySize, header.EntryCount));
+
+            return tree;
+        }
+    }
+
+    [Theory, MemberData(nameof(BucketTreeTestTheoryData))]
+    private void MoveNext_IterateAllFromStart_ReturnsCorrectEntries(int treeIndex)
+    {
+        ReadOnlySpan<IndirectStorage.Entry> entries = _entries.AsSpan(0, _treeData[treeIndex].EntryCount);
+        BucketTree2 tree = _treeData[treeIndex].CreateBucketTree();
+
+        using var visitor = new BucketTree2.Visitor();
+        Assert.Success(tree.Find(ref visitor.Ref, 0));
+
+        for (int i = 0; i < entries.Length; i++)
+        {
+            if (i != 0)
+            {
+                Result rc = visitor.MoveNext();
+
+                if (!rc.IsSuccess())
+                    Assert.Success(rc);
+            }
+
+            // These tests run about 4x slower if we let Assert.Equal check the values every time
+            if (visitor.CanMovePrevious() != (i != 0))
+                Assert.Equal(i != 0, visitor.CanMovePrevious());
+
+            if (visitor.CanMoveNext() != (i != entries.Length - 1))
+                Assert.Equal(i != entries.Length - 1, visitor.CanMoveNext());
+
+            ref readonly IndirectStorage.Entry entry = ref visitor.Get<IndirectStorage.Entry>();
+
+            if (entries[i].GetVirtualOffset() != entry.GetVirtualOffset())
+                Assert.Equal(entries[i].GetVirtualOffset(), entry.GetVirtualOffset());
+
+            if (entries[i].GetPhysicalOffset() != entry.GetPhysicalOffset())
+                Assert.Equal(entries[i].GetPhysicalOffset(), entry.GetPhysicalOffset());
+
+            if (entries[i].StorageIndex != entry.StorageIndex)
+                Assert.Equal(entries[i].StorageIndex, entry.StorageIndex);
+        }
+    }
+
+    [Theory, MemberData(nameof(BucketTreeTestTheoryData))]
+    private void MovePrevious_IterateAllFromEnd_ReturnsCorrectEntries(int treeIndex)
+    {
+        ReadOnlySpan<IndirectStorage.Entry> entries = _entries.AsSpan(0, _treeData[treeIndex].EntryCount);
+        BucketTree2 tree = _treeData[treeIndex].CreateBucketTree();
+
+        using var visitor = new BucketTree2.Visitor();
+        Assert.Success(tree.Find(ref visitor.Ref, entries[^1].GetVirtualOffset()));
+
+        for (int i = entries.Length - 1; i >= 0; i--)
+        {
+            if (i != entries.Length - 1)
+            {
+                Result rc = visitor.MovePrevious();
+
+                if (!rc.IsSuccess())
+                    Assert.Success(rc);
+            }
+
+            if (visitor.CanMovePrevious() != (i != 0))
+                Assert.Equal(i != 0, visitor.CanMovePrevious());
+
+            if (visitor.CanMoveNext() != (i != entries.Length - 1))
+                Assert.Equal(i != entries.Length - 1, visitor.CanMoveNext());
+
+            ref readonly IndirectStorage.Entry entry = ref visitor.Get<IndirectStorage.Entry>();
+
+            if (entries[i].GetVirtualOffset() != entry.GetVirtualOffset())
+                Assert.Equal(entries[i].GetVirtualOffset(), entry.GetVirtualOffset());
+
+            if (entries[i].GetPhysicalOffset() != entry.GetPhysicalOffset())
+                Assert.Equal(entries[i].GetPhysicalOffset(), entry.GetPhysicalOffset());
+
+            if (entries[i].StorageIndex != entry.StorageIndex)
+                Assert.Equal(entries[i].StorageIndex, entry.StorageIndex);
+        }
+    }
+
+    [Theory, MemberData(nameof(BucketTreeTestTheoryData))]
+    private void Find_RandomAccess_ReturnsCorrectEntries(int treeIndex)
+    {
+        const int findCount = 10000;
+
+        ReadOnlySpan<IndirectStorage.Entry> entries = _entries.AsSpan(0, _treeData[treeIndex].EntryCount);
+        BucketTree2 tree = _treeData[treeIndex].CreateBucketTree();
+
+        var random = new Random(123456);
+
+        for (int i = 0; i < findCount; i++)
+        {
+            int entryIndex = random.Next(0, entries.Length);
+            ref readonly IndirectStorage.Entry expectedEntry = ref entries[entryIndex];
+
+            // Add a random shift amount to test finding offsets in the middle of an entry
+            int offsetShift = random.Next(0, 1) * 0x500;
+
+            using var visitor = new BucketTree2.Visitor();
+            Assert.Success(tree.Find(ref visitor.Ref, expectedEntry.GetVirtualOffset() + offsetShift));
+
+            ref readonly IndirectStorage.Entry actualEntry = ref visitor.Get<IndirectStorage.Entry>();
+
+            Assert.Equal(entryIndex != 0, visitor.CanMovePrevious());
+            Assert.Equal(entryIndex != entries.Length - 1, visitor.CanMoveNext());
+            Assert.Equal(expectedEntry.GetVirtualOffset(), actualEntry.GetVirtualOffset());
+            Assert.Equal(expectedEntry.GetPhysicalOffset(), actualEntry.GetPhysicalOffset());
+            Assert.Equal(expectedEntry.StorageIndex, actualEntry.StorageIndex);
+        }
+    }
+}

tests/LibHac.Tests/FsSystem/BufferedStorageTests.cs

@@ -51,13 +51,12 @@ public class BufferedStorageTests
         public int BufferManagerCacheCount { get; set; }
     }
 
-
     public static AccessTestConfig[] AccessTestConfigs =
     {
         new()
         {
             SizeClassProbs = new[] { 50, 50, 5 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 50, 1 }, // Read, Write, Flush
             AccessTypeProbs = new[] { 10, 10, 5 }, // Random, Sequential, Frequent block
             RngSeed = 35467,
@@ -73,7 +72,7 @@ public class BufferedStorageTests
         new()
         {
             SizeClassProbs = new[] { 50, 50, 5 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 50, 1 }, // Read, Write, Flush
             AccessTypeProbs = new[] { 10, 10, 5 }, // Random, Sequential, Frequent block
             RngSeed = 6548433,
@@ -89,7 +88,7 @@ public class BufferedStorageTests
         new()
         {
             SizeClassProbs = new[] { 50, 50, 0 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 0, 0 },
             AccessTypeProbs = new[] { 10, 10, 5 }, // Random, Sequential, Frequent block
             RngSeed = 756478,
@@ -105,7 +104,7 @@ public class BufferedStorageTests
         new()
         {
             SizeClassProbs = new[] { 50, 50, 0 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 0, 0 },
             AccessTypeProbs = new[] { 0, 0, 5 }, // Random, Sequential, Frequent block
             RngSeed = 38197549,
@@ -121,7 +120,7 @@ public class BufferedStorageTests
         new()
         {
             SizeClassProbs = new[] { 50, 50, 0 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 50, 1 }, // Read, Write, Flush
             AccessTypeProbs = new[] { 10, 10, 5 }, // Random, Sequential, Frequent block
             RngSeed = 567365,
@@ -137,7 +136,7 @@ public class BufferedStorageTests
         new()
         {
             SizeClassProbs = new[] { 50, 50, 0 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 50, 1 }, // Read, Write, Flush
             AccessTypeProbs = new[] { 10, 10, 5 }, // Random, Sequential, Frequent block
             RngSeed = 949365,
@@ -153,7 +152,7 @@ public class BufferedStorageTests
         new()
         {
             SizeClassProbs = new[] { 50, 50, 10 },
-                SizeClassMaxSizes = new[] {0x4000, 0x80000, 0x800000}, // 4 KB, 512 KB, 8 MB
+            SizeClassMaxSizes = new[] { 0x4000, 0x80000, 0x800000 }, // 16 KB, 512 KB, 8 MB
             TaskProbs = new[] { 50, 50, 1 }, // Read, Write, Flush
             AccessTypeProbs = new[] { 10, 10, 5 }, // Random, Sequential, Frequent block
             RngSeed = 670670,