//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="HLSFAllocator.Level.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.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.HighPerformance.Memory
{
    public unsafe partial class HybridLayerSegregatedFitAllocator
    {

        private const int MaxLevel = 9;

        private static readonly int[] levelSize = [
            64, 256, 1024, 4096, 16384, 65536, 262144, 1048576, 4194304, 16777216
            ];

        public int AlignOfLevel(int bucketLevel)
        {
            int blockSize = levelSize[bucketLevel];
            return int.Min(blockSize, _align);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private int GetLevelFromSize(uint size)
        {
            // Ensure minimum size
            if (size <= 64)
            {
                return 0;
            }

            // Use binary operations to find the appropriate level
            // Level sizes are powers of 2: 64(2^6), 256(2^8), 1024(2^10), etc.
            // We can use bit operations to efficiently determine the level


            // Find the position of the highest set bit (equivalent to log2)
            int msb = 31 - System.Numerics.BitOperations.LeadingZeroCount(size);


            // Map bit position to level index
            // Level 0: 64 (2^6)   -> msb = 6
            // Level 1: 256 (2^8)  -> msb = 8  
            // Level 2: 1024 (2^10) -> msb = 10
            // Pattern: level = (msb - 6) / 2, but we need to handle boundaries

            if (msb <= 6)
            {
                return 0;      // size <= 64
            }

            if (msb <= 7)
            {
                return 0;      // size <= 128, still fits in level 0 (64-256)
            }

            if (msb <= 8)
            {
                return 1;      // size <= 256
            }

            if (msb <= 9)
            {
                return 1;      // size <= 512, still fits in level 1 (256-1024)
            }

            if (msb <= 10)
            {
                return 2;     // size <= 1024
            }

            if (msb <= 11)
            {
                return 2;     // size <= 2048, still fits in level 2 (1024-4096)
            }

            if (msb <= 12)
            {
                return 3;     // size <= 4096
            }

            if (msb <= 13)
            {
                return 3;     // size <= 8192, still fits in level 3 (4096-16384)
            }

            if (msb <= 14)
            {
                return 4;     // size <= 16384
            }

            if (msb <= 15)
            {
                return 4;     // size <= 32768, still fits in level 4 (16384-65536)
            }

            if (msb <= 16)
            {
                return 5;     // size <= 65536
            }

            if (msb <= 17)
            {
                return 5;     // size <= 131072, still fits in level 5 (65536-262144)
            }

            if (msb <= 18)
            {
                return 6;     // size <= 262144
            }

            if (msb <= 19)
            {
                return 6;     // size <= 524288, still fits in level 6 (262144-1048576)
            }

            if (msb <= 20)
            {
                return 7;     // size <= 1048576
            }

            if (msb <= 21)
            {
                return 7;     // size <= 2097152, still fits in level 7 (1048576-4194304)
            }

            if (msb <= 22)
            {
                return 8;     // size <= 4194304
            }

            if (msb <= 23)
            {
                return 8;     // size <= 8388608, still fits in level 8 (4194304-16777216)
            }

            // If size is larger than all predefined levels, use the last level
            return levelSize.Length - 1;
        }

    }

    public enum CommonMemoryAlign : int
    {

        XMMLevel = 16,
        YMMLevel = 32,
        ZMMLevel = 64,

        ArmNEONLevel = 16,

    }
}