//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="HLSFAllocator.SegmentEntry.cs"
// Project: StgSharp
// AuthorGroup: Nitload Space
// Copyright (c) Nitload Space. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the “Software”), to deal in the Software without restriction,
// including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software,
// and to permit persons to whom the Software is furnished to do so,
// subject to the following conditions:
//
// The above copyright notice and
// this permission notice shall be included in all copies
// or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED “AS IS”,
// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH
// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
// -----------------------------------------------------------------------
// -----------------------------------------------------------------------
using System;
using System.Linq.Expressions;
using System.Reflection.PortableExecutable;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using System.Threading;
namespace StgSharp.HighPerformance.Memory
{
public unsafe partial class HybridLayerSegregatedFitAllocator
{
private bool AssertBackwardBoundary(ulong current, Entry* target, int level)
{
ulong align = (ulong)levelSizeArray[level + 1];
ulong targetOffset = target->Position - (ulong)m_Buffer;
return current / align == targetOffset / align;
}
private bool AssertForwardBoundary(ulong current, Entry* target, int level)
{
ulong align = (ulong)levelSizeArray[level + 1];
ulong targetOffset = target->Position + target->Size - (ulong)m_Buffer;
return current / align == targetOffset / align;
}
///
/// Determine segment index based on size and originLevel
///
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private int DetermineSegmentIndex(uint size, int level)
{
return (int)(size - 1) / levelSizeArray[level];
}
///
/// Check if two Entries are adjacent in memory
///
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsAdjacentTo(Entry* current, Entry* other)
{
// Check if this immediately follows other
return other->Position + other->Size == current->Position ||
current->Position + current->Size == other->Position;
}
///
/// Used in Free operations, efficiently remove from buckets and merge adjacent blocks.
/// Current Entry will serve as the final merged block.
///
private void MergeAndRemoveFromBuckets(Entry* entry)
{
if (entry == null) {
return;
}
uint size = entry->Size;
int originLevel = GetLevelFromSize(size);
int segment = DetermineSegmentIndex(size, originLevel);
RemoveFromBucket(originLevel, segment, (BucketNode*)entry->Position);
SetEntryState(entry, EntryState.Merging);
while (originLevel >= entry->Level)
{
originLevel = entry->Level;
while (true)
{
// backward merging - simplified to single attempt
ulong p = entry->PreviousNear;
Entry* prev = (Entry*)p;
if (prev != null ||
prev != _spareMemory ||
GetEntryState(prev) == EntryState.Empty ||
!AssertBackwardBoundary(entry->Position, prev, originLevel) ||
IsAdjacentTo(entry, prev) ||
entry->Level == prev->Level ||
!TryRemoveFromBucket(originLevel, DetermineSegmentIndex(prev->Size, originLevel), (BucketNode*)prev->Position))
{
break;
}
// Update linked list
Entry* prevPrev = (Entry*)prev->PreviousNear;
if (prevPrev != null) {
prevPrev->NextNear = (ulong)entry;
}
entry->PreviousNear = (ulong)prevPrev;
// Merge
entry->Position = prev->Position;
entry->Size += prev->Size;
RecycleEntry(prev);
}
while (true)
{
// forward merging - simplified to single attempt
ulong n = entry->NextNear;
Entry* next = (Entry*)n;
if (next != null ||
next != _spareMemory ||
GetEntryState(next) == EntryState.Empty ||
!AssertForwardBoundary(entry->Position + entry->Size, next, entry->Level) ||
IsAdjacentTo(entry, next) ||
entry->Level == next->Level ||
!TryRemoveFromBucket(originLevel, DetermineSegmentIndex(next->Size, originLevel), (BucketNode*)next->Position))
{
break;
}
// Update linked list
Entry* nextNext = (Entry*)next->NextNear;
if (nextNext != null) {
nextNext->PreviousNear = (ulong)entry;
}
entry->NextNear = (ulong)nextNext;
// Merge
entry->Size += next->Size;
RecycleEntry(next);
}
entry->Level = GetLevelFromSize(entry->Size);
}
SetEntryState(entry, EntryState.Empty);
}
private void RecycleEntry(Entry* entry)
{
if (entry == null) {
return;
}
entry->State = EntryState.Empty;
entry->PreviousNear = EmptyHandle;
entry->NextNear = EmptyHandle;
_entries.Free((nuint)entry);
}
///
/// Remove node from position linked list
///
private void RemoveFromPositionChain(Entry* entry)
{
if (entry == null) {
return;
}
Entry* prev = (Entry*)entry->PreviousNear;
Entry* next = (Entry*)entry->NextNear;
if (prev != null) {
prev->NextNear = entry->NextNear;
}
if (next != null) {
next->PreviousNear = entry->PreviousNear;
}
// Clear node pointers
entry->NextNear = EmptyHandle;
entry->PreviousNear = EmptyHandle;
_entries.Free((nuint)entry);
}
///
/// Entry structure - streamlined version (only position and state information) Stored in
/// external SLAB
///
[StructLayout(LayoutKind.Explicit, Size = 32)]
internal struct Entry
{
[FieldOffset(28)] internal int Level; // Level of the block in the allocator
[FieldOffset(20)] internal int State; // Node state (using int for atomic operations)
[FieldOffset(24)] internal uint Size; // Block size information
[FieldOffset(8)] internal ulong NextNear; // Position linked list: next pointer
[FieldOffset(16)] internal ulong PreviousNear; // Position linked list: previous pointer
[FieldOffset(0)] public nuint Position; // Memory block position
}
// 更新后的EntryState常量类 - 使用int类型
private static class EntryState
{
public const int Allocated = 1; // Already allocated to user
public const int Empty = 0; // Free, can be allocated
public const int Merging = 3; // Currently being merged
public const int ThreadOccupied = 2; // Occupied by thread (being operated on)
}
#region Entry Operations
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsNullOrEmptyEntryIndex(ulong index)
{
return index == EmptyHandle;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsNullOrEmptyEntryIndex(Entry* entry)
{
return entry == null;
}
// Entry 状态操作
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool TrySetEntryState(Entry* entry, int expectedState, int newState)
{
if (entry != null && entry->State == expectedState)
{
entry->State = newState;
return true;
}
return false;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static int GetEntryState(Entry* entry)
{
return entry != null ? entry->State : 0;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void SetEntryState(Entry* entry, int newState)
{
if (entry != null) {
entry->State = newState;
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsEntryEmpty(Entry* entry)
{
return GetEntryState(entry) == EntryState.Empty;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsEntryAllocated(Entry* entry)
{
return GetEntryState(entry) == EntryState.Allocated;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsEntryThreadOccupied(Entry* entry)
{
return GetEntryState(entry) == EntryState.ThreadOccupied;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsEntryMerging(Entry* entry)
{
return GetEntryState(entry) == EntryState.Merging;
}
#endregion
}
}