| // Licensed to the Apache Software Foundation (ASF) under one or more |
| // contributor license agreements. See the NOTICE file distributed with |
| // this work for additional information regarding copyright ownership. |
| // The ASF licenses this file to You under the Apache License, Version 2.0 |
| // (the "License"); you may not use this file except in compliance with |
| // the License. You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| using System; |
| using System.Buffers; |
| using System.Diagnostics; |
| using System.Runtime.CompilerServices; |
| using System.Runtime.InteropServices; |
| using System.Threading; |
| |
| namespace Apache.Arrow.Memory |
| { |
| public class NativeMemoryManager: MemoryManager<byte> |
| { |
| private IntPtr _ptr; |
| private readonly int _offset; |
| private readonly int _length; |
| |
| public NativeMemoryManager(IntPtr ptr, int offset, int length) |
| { |
| _ptr = ptr; |
| _offset = offset; |
| _length = length; |
| } |
| |
| ~NativeMemoryManager() |
| { |
| Dispose(false); |
| } |
| |
| public override unsafe Span<byte> GetSpan() |
| { |
| void* ptr = CalculatePointer(0); |
| return new Span<byte>(ptr, _length); |
| } |
| |
| public override unsafe MemoryHandle Pin(int elementIndex = 0) |
| { |
| // NOTE: Unmanaged memory doesn't require GC pinning because by definition it's not |
| // managed by the garbage collector. |
| |
| void* ptr = CalculatePointer(elementIndex); |
| return new MemoryHandle(ptr, default, this); |
| } |
| |
| public override void Unpin() |
| { |
| // SEE: Pin implementation |
| return; |
| } |
| |
| protected override void Dispose(bool disposing) |
| { |
| // Only free once. |
| |
| lock (this) |
| { |
| if (_ptr != IntPtr.Zero) |
| { |
| Marshal.FreeHGlobal(_ptr); |
| Interlocked.Exchange(ref _ptr, IntPtr.Zero); |
| GC.RemoveMemoryPressure(_length); |
| } |
| } |
| } |
| |
| [MethodImpl(MethodImplOptions.AggressiveInlining)] |
| private unsafe void* CalculatePointer(int index) => |
| (_ptr + _offset + index).ToPointer(); |
| } |
| } |