mirror of https://github.com/dahall/Vanara.git
313 lines
16 KiB
C#
313 lines
16 KiB
C#
using System;
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using System.Linq;
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using System.Reflection;
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using System.Runtime.InteropServices;
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using Vanara.Extensions;
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using Vanara.PInvoke;
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namespace Vanara.InteropServices
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{
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/// <summary>
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/// For structures with a single array as the last field that are intended to be variable length, this class manages the structure and
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/// automatically marshals the correct structure to memory.
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/// </summary>
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/// <typeparam name="T">The type of the structure.</typeparam>
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public class SafeAnysizeStruct<T> : SafeAnysizeStructBase<T>
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{
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private FieldInfo fiCount;
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/// <summary>Initializes a new instance of the <see cref="SafeAnysizeStruct{T}"/> class.</summary>
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/// <param name="value">The initial value of the structure, if provided.</param>
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/// <param name="sizeFieldName">
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/// The name of the field in <typeparamref name="T"/> that holds the length of the array. If <see langword="null"/>, the first
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/// public field will be selected. If "*", then the array size will be determined by the amount of allocated memory.
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/// </param>
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/// <exception cref="InvalidOperationException">This class can only manange sequential layout structures.</exception>
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public SafeAnysizeStruct(in T value, string sizeFieldName = null) : base(baseSz)
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{
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InitCountField(sizeFieldName);
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ToNative(value);
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}
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/// <summary>Initializes a new instance of the <see cref="SafeAnysizeStruct{T}"/> class from a pointer.</summary>
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/// <param name="allocatedMemory">A pointer to memory that holds the value of an instance of <typeparamref name="T"/>.</param>
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/// <param name="size">The size of the allocated memory in <paramref name="allocatedMemory"/> in bytes.</param>
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/// <param name="sizeFieldName">
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/// The name of the field in <typeparamref name="T"/> that holds the length of the array. If <see langword="null"/>, the first
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/// public field will be selected. If "*", then the array size will be determined by the amount of allocated memory.
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/// </param>
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public SafeAnysizeStruct(IntPtr allocatedMemory, SizeT size, string sizeFieldName = null) : base(allocatedMemory, size, false)
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{
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if (allocatedMemory == IntPtr.Zero) throw new ArgumentNullException(nameof(allocatedMemory));
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if (baseSz > size) throw new OutOfMemoryException();
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InitCountField(sizeFieldName);
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}
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/// <summary>Initializes a new instance of the <see cref="SafeAnysizeStruct{T}"/> class with an initial empty memory allocation.</summary>
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/// <param name="size">The size of the reserved memory in bytes.</param>
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/// <param name="sizeFieldName">
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/// The name of the field in <typeparamref name="T"/> that holds the length of the array. If <see langword="null"/>, the first
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/// public field will be selected.
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/// </param>
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public SafeAnysizeStruct(SizeT size, string sizeFieldName = null) : base(size) => InitCountField(sizeFieldName);
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/// <summary>Performs an implicit conversion from <typeparamref name="T"/> to <see cref="SafeAnysizeStructBase{T}"/>.</summary>
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/// <param name="s">The <typeparamref name="T"/> instance.</param>
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/// <returns>The result of the conversion.</returns>
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[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
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public static implicit operator SafeAnysizeStruct<T>(in T s) => new(s);
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/// <summary>Gets the length of the array from the structure.</summary>
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/// <param name="local">The local, system marshaled, structure instance extracted from the pointer.</param>
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/// <returns>The element length of the 'anysize' array.</returns>
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[System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining)]
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protected override int GetArrayLength(in T local) => fiCount is null ? GetArrLenFromSz() : (fiCount.FieldType == typeof(IntPtr) ? ((IntPtr)fiCount.GetValue(local)).ToInt32() : Convert.ToInt32(fiCount.GetValue(local)));
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private int GetArrLenFromSz() => 1 + (Size - baseSz) / Marshal.SizeOf(elemType);
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private void InitCountField(string sizeFieldName)
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{
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fiCount = string.IsNullOrEmpty(sizeFieldName) ? structType.GetOrderedFields(binds).First() : structType.GetField(sizeFieldName, binds);
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if (fiCount is null && sizeFieldName != "*") throw new ArgumentException("Invalid size field name.", nameof(sizeFieldName));
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}
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}
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/// <summary>
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/// For structures with a single array as the last field that are intended to be variable length, this class manages the structure and
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/// automatically marshals the correct structure to memory.
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/// </summary>
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/// <typeparam name="T">The type of the structure.</typeparam>
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public abstract class SafeAnysizeStructBase<T> : SafeMemoryHandle<CoTaskMemoryMethods>
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{
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internal const BindingFlags binds = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
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/// <summary>The base, unextended size of T.</summary>
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protected static readonly int baseSz;
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/// <summary>The type of the structure and type of the anysize array's elements.</summary>
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protected static readonly Type elemType, structType;
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/// <summary>The reflected field of the array.</summary>
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protected static readonly FieldInfo fiArray;
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static SafeAnysizeStructBase()
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{
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structType = typeof(T);
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if (!structType.IsLayoutSequential)
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throw new InvalidOperationException("This class can only manange sequential layout structures.");
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baseSz = Marshal.SizeOf(structType);
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fiArray = structType.GetOrderedFields(binds).Last();
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if (!fiArray.FieldType.IsArray)
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throw new ArgumentException("The field information must be for an array.", nameof(fiArray));
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elemType = fiArray.FieldType.FindElementType();
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}
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/// <summary>Initializes a new instance of the <see cref="SafeAnysizeStructBase{T}"/> class.</summary>
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/// <param name="size">The size of memory to allocate, in bytes.</param>
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protected SafeAnysizeStructBase(SizeT size) : base(size) { }
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/// <summary>Initializes a new instance of the <see cref="SafeAnysizeStructBase{T}"/> class.</summary>
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/// <param name="allocatedMemory">The allocated memory.</param>
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/// <param name="size">The size.</param>
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/// <param name="ownsHandle">if set to <see langword="true"/> [owns handle].</param>
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protected SafeAnysizeStructBase(IntPtr allocatedMemory, SizeT size, bool ownsHandle) : base(allocatedMemory, size, ownsHandle) { }
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/// <summary>Gets or sets the structure value.</summary>
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public T Value { get => FromNative(handle, Size); set => ToNative(value); }
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/// <summary>
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/// Performs an explicit conversion from <see cref="SafeAnysizeStructBase{T}"/> to <see cref="IntPtr"/>. The <c>IntPtr</c> is the
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/// memory location of the fully marshaled structure with the full final field array.
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/// </summary>
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/// <param name="s">The <see cref="SafeAnysizeStructBase{T}"/> instance.</param>
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/// <returns>The result of the conversion.</returns>
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public static implicit operator IntPtr(SafeAnysizeStructBase<T> s) => s?.handle ?? IntPtr.Zero;
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/// <summary>Performs an explicit conversion from <see cref="SafeAnysizeStructBase{T}"/> to <typeparamref name="T"/>.</summary>
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/// <param name="s">The <see cref="SafeAnysizeStructBase{T}"/> instance.</param>
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/// <returns>The result of the conversion.</returns>
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public static implicit operator T(SafeAnysizeStructBase<T> s) => s is null ? default : s.Value;
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/// <summary>Converts the native memory to <typeparamref name="T"/>.</summary>
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/// <param name="allocatedMemory">The allocated memory.</param>
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/// <param name="size">The size.</param>
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/// <returns></returns>
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protected virtual T FromNative(IntPtr allocatedMemory, int size)
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{
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var local = (T)Marshal.PtrToStructure(allocatedMemory, structType); // Can't use Convert or get circular ref.
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var cnt = GetArrayLength(local);
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var arrOffset = Marshal.OffsetOf(structType, fiArray.Name).ToInt32();
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fiArray.SetValueDirect(__makeref(local), allocatedMemory.ToArray(elemType, cnt, arrOffset, size));
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return local;
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}
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/// <summary>Gets the length of the array from the structure.</summary>
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/// <param name="local">The local, system marshaled, structure instance extracted from the pointer.</param>
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/// <returns>The element length of the 'anysize' array.</returns>
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protected abstract int GetArrayLength(in T local);
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/// <summary>Converts the managed instance to native.</summary>
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/// <param name="value">The managed value.</param>
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protected virtual void ToNative(T value)
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{
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// Get the current array for the last field (or create one if needed)
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var arrVal = fiArray.GetValue(value);
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if (arrVal is null || ((Array)arrVal).Length == 0)
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{
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arrVal = Array.CreateInstance(elemType, 1);
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((Array)arrVal).SetValue(Activator.CreateInstance(elemType), 0);
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fiArray.SetValueDirect(__makeref(value), arrVal);
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}
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// Determine mem required for current struct and last field value
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var arrElemSz = Marshal.SizeOf(elemType);
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var arrLen = ((Array)arrVal).Length;
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var memSz = baseSz + arrElemSz * (arrLen - 1);
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// Set memory size
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Size = memSz;
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// Marshal base structure - don't use Write to prevent loops
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Marshal.StructureToPtr(value, handle, false);
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// Push each element of the array into memory, starting with second item in array since first was pushed by StructureToPtr
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for (var i = 1; i < arrLen; i++)
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handle.Write(((Array)arrVal).GetValue(i), baseSz + arrElemSz * (i - 1), memSz);
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}
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}
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/// <summary>
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/// A marshaler implementation of <see cref="IVanaraMarshaler"/> to set the marshaler as an attribute using <see
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/// cref="SafeAnysizeStruct{T}"/>. Use the cookie paramter of <see
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/// cref="SafeAnysizeStructMarshaler{T}.SafeAnysizeStructMarshaler(string)"/> to specify the name of the field in <typeparamref
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/// name="T"/> that specifies the number of elements in the last field of <typeparamref name="T"/>.
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/// </summary>
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/// <typeparam name="T">The structure type to be marshaled.</typeparam>
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/// <seealso cref="Vanara.InteropServices.IVanaraMarshaler"/>
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public class SafeAnysizeStructMarshaler<T> : IVanaraMarshaler
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{
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private readonly string sizeFieldName;
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/// <summary>Initializes a new instance of the <see cref="SafeAnysizeStructMarshaler{T}"/> class.</summary>
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/// <param name="cookie">
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/// The name of the field in <typeparamref name="T"/> that specifies the number of elements in the last field of <typeparamref name="T"/>.
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/// </param>
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public SafeAnysizeStructMarshaler(string cookie) => sizeFieldName = cookie;
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SizeT IVanaraMarshaler.GetNativeSize() => Marshal.SizeOf(typeof(T));
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SafeAllocatedMemoryHandle IVanaraMarshaler.MarshalManagedToNative(object managedObject) =>
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managedObject is null ? SafeCoTaskMemHandle.Null : new SafeAnysizeStruct<T>((T)managedObject, sizeFieldName);
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object IVanaraMarshaler.MarshalNativeToManaged(IntPtr pNativeData, SizeT allocatedBytes)
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{
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if (pNativeData == IntPtr.Zero) return null;
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using var s = new SafeAnysizeStruct<T>(pNativeData, allocatedBytes, sizeFieldName);
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return s.Value;
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}
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}
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/// <summary>
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/// A marshaler implementation of <see cref="IVanaraMarshaler"/> to marshal structures whose last field is a character array of length
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/// (1) and that uses a field to determine the length of the full string.
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/// <para>
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/// Use the cookie paramter of <see cref="AnySizeStringMarshaler{T}"/> to specify the name of the field in <typeparamref name="T"/> that
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/// specifies the length of the string in the last field of <typeparamref name="T"/> along with use indicators.
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/// </para>
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/// <para>
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/// If the field specifies byte, rather than character length, follow the field name with a colon (:) followed by 'b' (for bytes) or 'c'
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/// (for characters).
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/// </para>
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/// <para>
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/// If the field specifies a length that does NOT include the NULL terminator, follow the field name, colon (:), and type specifier by
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/// 'r' (for raw) or 'n' (for null-terminated).
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/// </para>
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/// <para>If the field name is "*", then the string length will be determined by the amount of allocated memory.</para>
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/// </summary>
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/// <typeparam name="T">The structure type to be marshaled.</typeparam>
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public class AnySizeStringMarshaler<T> : IVanaraMarshaler
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{
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private static readonly int charSz;
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private static readonly int baseSz;
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private readonly FieldInfo fiCount;
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private static readonly FieldInfo fiArray;
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private static readonly int strOffset;
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private readonly bool cntIsBytes = false;
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private readonly bool cntInclNull = true;
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private readonly bool allMem = false;
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static AnySizeStringMarshaler()
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{
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var structType = typeof(T);
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if (!structType.IsLayoutSequential)
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throw new InvalidOperationException("This class can only manange sequential layout structures.");
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baseSz = Marshal.SizeOf(structType);
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fiArray = structType.GetOrderedFields(SafeAnysizeStructBase<T>.binds).Last();
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if (fiArray.FieldType != typeof(string))
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throw new ArgumentException("The field information must be for a string.", nameof(fiArray));
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charSz = StringHelper.GetCharSize(typeof(T).StructLayoutAttribute.CharSet);
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strOffset = Marshal.OffsetOf(structType, fiArray.Name).ToInt32();// unchecked((uint)Marshal.ReadInt32(fiArray.FieldHandle.Value.Offset(4 + IntPtr.Size))) & 0x7FFFFFF;
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}
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/// <summary>Initializes a new instance of the <see cref="AnySizeStringMarshaler{T}"/> class.</summary>
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/// <param name="cookie">
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/// The name of the field in <typeparamref name="T"/> that specifies the number of elements in the last field of <typeparamref name="T"/>.
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/// <para>
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/// If the field specifies byte, rather than character length, follow the field name with a colon (:) followed by 'b' (for bytes) or
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/// 'c' (for characters).
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/// </para>
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/// <para>
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/// If the field specifies a length that does NOT include the NULL terminator, follow the field name, colon (:), and type specifier
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/// by 'r' (for raw) or 'n' (for null-terminated).
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/// </para>
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/// </param>
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public AnySizeStringMarshaler(string cookie)
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{
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if (string.IsNullOrEmpty(cookie))
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fiCount = typeof(T).GetOrderedFields(SafeAnysizeStructBase<T>.binds).First();
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else if (cookie == "*")
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allMem = true;
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else
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{
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var parts = cookie.Split(':');
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if (parts.Length == 2 && parts[1].Length >= 2)
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{
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cntIsBytes = parts[1][0] == 'b';
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cntInclNull = parts[1].Length > 1 && parts[1][1] == 'n';
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}
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fiCount = typeof(T).GetField(parts[0], SafeAnysizeStructBase<T>.binds);
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}
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if (fiCount is null && !allMem) throw new ArgumentException("Invalid string length field name.", nameof(cookie));
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}
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SizeT IVanaraMarshaler.GetNativeSize() => baseSz;
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SafeAllocatedMemoryHandle IVanaraMarshaler.MarshalManagedToNative(object managedObject)
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{
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var h = managedObject is null ? SafeCoTaskMemHandle.Null : new SafeCoTaskMemHandle(baseSz);
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var str = fiArray.GetValue(managedObject) as string;
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var len = allMem ? StringHelper.GetByteCount(str, true, typeof(T).StructLayoutAttribute.CharSet) : Convert.ToInt32(fiCount.GetValue(managedObject));
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var clen = cntIsBytes ? len / charSz : len;
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if (cntInclNull && !allMem) --clen;
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if (str is not null && str.Length > clen)
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str = str.Substring(0, clen);
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h.Size += StringHelper.GetByteCount(str, cntInclNull, typeof(T).StructLayoutAttribute.CharSet) - charSz;
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Marshal.StructureToPtr(managedObject, h, false);
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StringHelper.Write(str, ((IntPtr)h).Offset(strOffset), out _, cntInclNull, typeof(T).StructLayoutAttribute.CharSet);
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return h;
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}
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object IVanaraMarshaler.MarshalNativeToManaged(IntPtr pNativeData, SizeT allocatedBytes)
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{
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if (pNativeData == IntPtr.Zero) return null;
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var o = Marshal.PtrToStructure(pNativeData, typeof(T));
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int len;
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if (allMem)
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len = (allocatedBytes - strOffset) / charSz;
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else
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{
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len = Convert.ToInt32(fiCount.GetValue(o));
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if (cntIsBytes) len /= charSz;
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if (cntInclNull) --len;
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}
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fiArray.SetValue(o, StringHelper.GetString(pNativeData.Offset(strOffset), len, typeof(T).StructLayoutAttribute.CharSet));
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return o;
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}
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}
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} |