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Make RomFsDictionary hash table resizable

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This commit is contained in:
Alex Barney 2019-02-01 15:31:13 -06:00
parent eeb6ebf0a7
commit b99bb84e9c
2 changed files with 86 additions and 6 deletions
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86
src/LibHac/IO/RomFs/RomFsDictionary.cs
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@ -1,4 +1,5 @@
using System;
using System.Collections.Generic;
using System.IO;
using System.Runtime.InteropServices;
@ -6,6 +7,7 @@ namespace LibHac.IO.RomFs
{
internal class RomFsDictionary<T> where T : unmanaged
{
private int _count;
private int _length;
private int _capacity;
@ -22,6 +24,8 @@ namespace LibHac.IO.RomFs
_length = Entries.Length;
_capacity = Entries.Length;
_count = CountEntries();
}
public RomFsDictionary(int capacity)
@ -30,7 +34,7 @@ namespace LibHac.IO.RomFs
Buckets = new int[size];
Buckets.AsSpan().Fill(-1);
Entries = new byte[(_sizeOfEntry + 0x10) * size]; // Estimate 0x10 bytes per name
Entries = new byte[EstimateEntryTableSize(size)];
_capacity = Entries.Length;
}
@ -104,6 +108,7 @@ namespace LibHac.IO.RomFs
SetEntryInternal(newOffset, ref entry, ref key.Name);
Buckets[bucket] = newOffset;
_count++;
return newOffset;
}
@ -113,7 +118,7 @@ namespace LibHac.IO.RomFs
if (_length + bytesNeeded > _capacity)
{
EnsureEntryTableCapacity(_length + bytesNeeded);
EnsureCapacityBytes(_length + bytesNeeded);
}
int offset = _length;
@ -172,7 +177,7 @@ namespace LibHac.IO.RomFs
entryName.CopyTo(Entries.AsSpan(offset + _sizeOfEntry, entry.KeyLength));
}
private void EnsureEntryTableCapacity(int value)
private void EnsureCapacityBytes(int value)
{
if (value < 0) throw new ArgumentOutOfRangeException(nameof(value));
if (value <= _capacity) return;
@ -197,5 +202,80 @@ namespace LibHac.IO.RomFs
_capacity = value;
}
}
public int CountEntries()
{
int count = 0;
int nextStructOffset = (sizeof(int) + Marshal.SizeOf<T>()) / 4;
Span<int> data = MemoryMarshal.Cast<byte, int>(Entries.AsSpan());
for (int i = 0; i < Buckets.Length; i++)
{
int next = Buckets[i];
while (next != -1)
{
next = data[next / 4 + nextStructOffset];
count++;
}
}
return count;
}
public void Resize(int newSize)
{
var newBuckets = new int[newSize];
newBuckets.AsSpan().Fill(-1);
List<int> offsets = GetEntryOffsets();
var key = new RomEntryKey();
for (int i = 0; i < offsets.Count; i++)
{
ref RomFsEntry<T> entry = ref GetEntryReference(offsets[i], out key.Name);
key.Parent = entry.Parent;
uint hashCode = key.GetRomHashCode();
int bucket = (int)(hashCode % newSize);
entry.Next = newBuckets[bucket];
newBuckets[bucket] = offsets[i];
}
Buckets = newBuckets;
}
private ref RomFsEntry<T> GetEntryReference(int offset, out ReadOnlySpan<byte> name)
{
ref RomFsEntry<T> entry = ref MemoryMarshal.Cast<byte, RomFsEntry<T>>(Entries.AsSpan(offset))[0];
name = Entries.AsSpan(offset + _sizeOfEntry, entry.KeyLength);
return ref entry;
}
private List<int> GetEntryOffsets()
{
var offsets = new List<int>(_count);
int nextStructOffset = (sizeof(int) + Marshal.SizeOf<T>()) / 4;
Span<int> data = MemoryMarshal.Cast<byte, int>(Entries.AsSpan());
for (int i = 0; i < Buckets.Length; i++)
{
int next = Buckets[i];
while (next != -1)
{
offsets.Add(next);
next = data[next / 4 + nextStructOffset];
}
}
offsets.Sort();
return offsets;
}
private int EstimateEntryTableSize(int count) => (_sizeOfEntry + 0x10) * count; // Estimate 0x10 bytes per name
}
}

6
src/LibHac/IO/RomFs/RomFsEntries.cs
View file

@ -34,7 +34,7 @@ namespace LibHac.IO.RomFs
public T Value;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct RomFsEntry<T> where T : unmanaged
{
public int Parent;
@ -43,7 +43,7 @@ namespace LibHac.IO.RomFs
public int KeyLength;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct FileRomEntry
{
public int NextSibling;
@ -57,7 +57,7 @@ namespace LibHac.IO.RomFs
public long Length;
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
[StructLayout(LayoutKind.Sequential, Pack = 4)]
public struct DirectoryRomEntry
{
public int NextSibling;