using System.Runtime.InteropServices;

namespace UnmanagedMMU.Allocators
{
    /// <summary>
    /// Wrapper class around <see cref="NativeMemory.AlignedAlloc(nuint, nuint)"/> and <see cref="NativeMemory.AlignedFree(void*)"/>.
    /// </summary>
    internal sealed unsafe class DefaultUnmanagedAllocator : IUnmanagedAllocator
    {
        /// <inheritdoc/>
        public void* Alloc(nuint size)
        {
            return NativeMemory.AlignedAlloc(size, 16);
        }

        /// <inheritdoc/>
        public void* AllocAligned(nuint size, nuint alignment)
        {
            if (!((alignment & (alignment - 1)) == 0 && alignment > 0))
            {
                throw new ArgumentException("Alignment must be a power of 2.", nameof(alignment));
            }
            return NativeMemory.AlignedAlloc(size, alignment);
        }

        /// <inheritdoc/>
        public void Free(void* ptr)
        {
            NativeMemory.Free(ptr);
        }

        /// <inheritdoc/>
        public void FreeAligned(void* ptr, nuint alignment = 0)
        {
            NativeMemory.AlignedFree(ptr);
        }
    }
}