mirror of https://github.com/dahall/Vanara.git
116 lines
5.7 KiB
C#
116 lines
5.7 KiB
C#
using System;
|
|
using System.Collections;
|
|
using System.Collections.Generic;
|
|
using Vanara.Extensions;
|
|
using Vanara.InteropServices;
|
|
|
|
namespace Vanara.PInvoke.Collections
|
|
{
|
|
/// <summary>Provides a generic enumerator over native memory.</summary>
|
|
/// <typeparam name="T">The type of the element to extract from memory.</typeparam>
|
|
/// <seealso cref="System.Collections.Generic.IEnumerator{T}"/>
|
|
/// <seealso cref="System.Collections.Generic.IEnumerable{T}"/>
|
|
public class NativeMemoryEnumerator<T> : UntypedNativeMemoryEnumerator, IEnumerator<T>, IEnumerable<T>
|
|
{
|
|
/// <summary>Initializes a new instance of the <see cref="NativeMemoryEnumerator{T}"/> class.</summary>
|
|
/// <param name="ptr">A pointer to the starting address of a specified number of <typeparamref name="T"/> elements in memory.</param>
|
|
/// <param name="length">The number of <typeparamref name="T"/> elements to be included in the enumeration.</param>
|
|
/// <param name="prefixBytes">Bytes to skip before reading the first element.</param>
|
|
/// <param name="allocatedBytes">If known, the total number of bytes allocated to the native memory in <paramref name="ptr"/>.</param>
|
|
/// <exception cref="System.ArgumentOutOfRangeException">count</exception>
|
|
/// <exception cref="System.InsufficientMemoryException"></exception>
|
|
public NativeMemoryEnumerator(IntPtr ptr, int length, int prefixBytes = 0, SizeT allocatedBytes = default) : base(ptr, typeof(T), length, prefixBytes, allocatedBytes) { }
|
|
|
|
/// <summary>Gets the element in the collection at the current position of the enumerator.</summary>
|
|
public new T Current => (T)base.Current;
|
|
|
|
/// <summary>Returns an enumerator that iterates through the collection.</summary>
|
|
/// <returns>A <see cref="T:System.Collections.Generic.IEnumerator`1"/> that can be used to iterate through the collection.</returns>
|
|
public new IEnumerator<T> GetEnumerator() => this;
|
|
}
|
|
|
|
/// <summary>Provides an enumerator over native memory.</summary>
|
|
/// <seealso cref="System.Collections.IEnumerator"/>
|
|
/// <seealso cref="System.Collections.IEnumerable"/>
|
|
public class UntypedNativeMemoryEnumerator : IEnumerator, IEnumerable
|
|
{
|
|
/// <summary>The number of allocated bytes.</summary>
|
|
protected SizeT allocated;
|
|
|
|
/// <summary>The number of elements in the enumeration.</summary>
|
|
protected int count;
|
|
|
|
/// <summary>The index of the current item. (-2) signifies an error. (-1) means MoveNext has not been called..</summary>
|
|
protected int index = -1;
|
|
|
|
/// <summary>The number of bytes to skip before reading the first element.</summary>
|
|
protected int prefix;
|
|
|
|
/// <summary>A pointer to the starting address of a specified number of <see cref="type"/> elements in memory.</summary>
|
|
protected IntPtr ptr;
|
|
|
|
/// <summary>The size of <see cref="type"/>.</summary>
|
|
protected SizeT stSize;
|
|
|
|
/// <summary>The type of the element to extract from memory.</summary>
|
|
protected Type type;
|
|
|
|
/// <summary>Initializes a new instance of the <see cref="NativeMemoryEnumerator{T}"/> class.</summary>
|
|
/// <param name="ptr">A pointer to the starting address of a specified number of <paramref name="type"/> elements in memory.</param>
|
|
/// <param name="type">The type of the element to extract from memory.</param>
|
|
/// <param name="length">The number of <paramref name="type"/> elements to be included in the enumeration.</param>
|
|
/// <param name="prefixBytes">Bytes to skip before reading the first element.</param>
|
|
/// <param name="allocatedBytes">If known, the total number of bytes allocated to the native memory in <paramref name="ptr"/>.</param>
|
|
/// <exception cref="System.ArgumentOutOfRangeException">count</exception>
|
|
/// <exception cref="System.ArgumentNullException">type</exception>
|
|
/// <exception cref="System.InsufficientMemoryException"></exception>
|
|
public UntypedNativeMemoryEnumerator(IntPtr ptr, Type type, int length, int prefixBytes = 0, SizeT allocatedBytes = default)
|
|
{
|
|
if (length < 0 || ptr == IntPtr.Zero && length != 0)
|
|
throw new ArgumentOutOfRangeException(nameof(length));
|
|
if (type is null)
|
|
throw new ArgumentNullException(nameof(type));
|
|
this.type = type;
|
|
this.ptr = ptr;
|
|
count = length;
|
|
prefix = prefixBytes;
|
|
allocated = allocatedBytes == default ? (SizeT)uint.MaxValue : allocatedBytes;
|
|
stSize = InteropExtensions.SizeOf(type);
|
|
if (allocatedBytes > 0 && stSize * length + prefixBytes > allocatedBytes)
|
|
throw new InsufficientMemoryException();
|
|
}
|
|
|
|
/// <summary>Gets the element in the collection at the current position of the enumerator.</summary>
|
|
public virtual object Current
|
|
{
|
|
get
|
|
{
|
|
if (index < 0 || index >= count)
|
|
throw new ArgumentOutOfRangeException(nameof(index));
|
|
var offset = prefix + index * stSize;
|
|
return ptr.Offset(offset).Convert(allocated - (uint)offset - (uint)prefix, type);
|
|
}
|
|
}
|
|
|
|
/// <summary>Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.</summary>
|
|
public virtual void Dispose() { }
|
|
|
|
/// <summary>Returns an enumerator that iterates through a collection.</summary>
|
|
/// <returns>An <see cref="T:System.Collections.IEnumerator"/> object that can be used to iterate through the collection.</returns>
|
|
public IEnumerator GetEnumerator() => this;
|
|
|
|
/// <summary>Advances the enumerator to the next element of the collection.</summary>
|
|
/// <returns>
|
|
/// true if the enumerator was successfully advanced to the next element; false if the enumerator has passed the end of the collection.
|
|
/// </returns>
|
|
public bool MoveNext()
|
|
{
|
|
if (++index >= count)
|
|
index = -2;
|
|
return index >= 0;
|
|
}
|
|
|
|
/// <summary>Sets the enumerator to its initial position, which is before the first element in the collection.</summary>
|
|
public void Reset() => index = -1;
|
|
}
|
|
} |