//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="L4.InternalOp"
// Project: StgSharp
// AuthorGroup: Nitload
// Copyright (c) Nitload. 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.Numerics;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;
using System.Text;
using System.Threading.Tasks;

namespace StgSharp.HighPerformance.Memory
{
    public partial class L4
    {

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private unsafe void AgeAll()
        {
            Vector128<byte> one = Vector128.Create((byte)0x01);
            Vector128<byte> max = Vector128.Create((byte)0x03);
            byte* p = (byte*)_eviction;
            for (int i = 0; i < CacheLineCount; i += 16)
            {
                Vector128<byte> v = Sse2.LoadVector128(p + i);
                v = Sse2.AddSaturate(v, one);
                v = Sse2.Min(v, max);
                Sse2.Store(p + i, v);
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private unsafe void Evict(
                            int count = 1
        )
        {
            int remain = count;
            Vector128<byte> one = Vector128.Create((byte)0x01);
            Vector128<byte> three = Vector128.Create((byte)0x03);
            byte* p = (byte*)_eviction;
            for (int i = 0; i < CacheLineCount && remain > 0; i += 16)
            {
                Vector128<byte> v = Sse2.LoadVector128(p + i);
                Vector128<byte> mask = Sse2.CompareEqual(v, three);
                int evictMask = Sse2.MoveMask(mask);
                while (evictMask != 0 && remain > 0)
                {
                    int bitPos = BitOperations.TrailingZeroCount(evictMask);
                    int index = bitPos + i;
                    CacheLineHead* head = &_head[index];
                    if (Interlocked.CompareExchange(ref head->_refCount, int.MinValue, 0) == 0)
                    {
                        // EvictLine(i + index);
                        _ = _map.TryRemove(head->_origin, out _);
                        RecycleLine(index);
                        remain--;
                    }
                    evictMask &= evictMask - 1;
                }
            }
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private void RecycleLine(
                     int id
        )
        {
            _idMux.Push(id);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        private bool TryGetEmptyLine(
                     out int index
        )
        {
            if (_idMux.TryPop(out index)) {
                return true;
            }
            index = _maxId;
            return Interlocked.Increment(ref _maxId) >= CacheLineCount;
        }

    }
}