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FixedArrayPtr<T> and MarshalledFixedArrayPtr<T>

Abstraction for a pointer to a value of type T with a known length.

Zero overhead but not 1:1 codegen in all scenarios. e.g. Multiplying an element in place via Setter can be slower (.NET 7).

A helper to allow you to manage a collection of items in unmanaged, static memory; for example, find an item.

Properties

  • Pointer: A Ptr representing the memory address of the first element in the fixed-size array.
  • Count: The number of elements in the fixed-size array.
  • ArraySize: The total size in bytes of the fixed-size array.

Examples

Initialization

var ptr = new FixedArrayPtr<int>(address, count);
  • Address: The memory address of the first element in the fixed-size array.
  • Count: The number of elements in the fixed-size array.

Element Access

The following methods should be used with in memory/RAM addresses. See Memory Read/Write for APIs that work with ICanReadWriteMemory implementations.

ref T AsRef(int index);
T Get(int index);
void Get(int index, out T value);
void Set(int index, in T value);

These methods provide access to individual elements in the fixed-size array. The AsRef() method returns a reference to an element, allowing for direct modification of the element's value. The Get() and Set() methods retrieve and update the values of elements at specified indices.

Memory Read/Write

T Get<TSource>(TSource source, int index);
void Get<TSource>(TSource source, int index, out T value);
void Set<TSource>(TSource source, int index, in T value);
These methods provide access to individual elements in the fixed-size array, allowing read and write operations to be performed on an implementation of ICanReadWriteMemory. This can be useful when working with external processes or other memory sources.

Copying

void CopyFrom(Span<T> sourceArray, int length);
void CopyFrom(Span<T> sourceArray, int length, int sourceIndex, int destinationIndex);
void CopyTo(Span<T> destinationArray, int length);
void CopyTo(Span<T> destinationArray, int length, int sourceIndex, int destinationIndex);

These methods provide copying functionality between the fixed-size array and managed arrays. CopyFrom() copies elements from a managed array to the fixed-size array, and CopyTo() copies elements from the fixed-size array to a managed array.

Both methods support copying a specified number of elements, as well as specifying source and destination indices for the copy operation.

bool Contains(in T item);
bool Contains<TSource>(TSource source, in T item);
int IndexOf(in T item);
int IndexOf<TSource>(TSource source, in T item);

These methods provide search functionality for the fixed-size array, allowing you to check for the existence of an element or find its index. The Contains() methods return true if the specified item is found in the array, and the IndexOf() methods return the index of the first occurrence of the specified item or -1 if the item is not found.

SourcedFixedArrayPtr<T>

This is a tuple of FixedArrayPtr<T> and TSource.

API surface is the same, all methods are delegated to underlying FixedArrayPtr<T>.

Notably however, this API enables the use of LINQ; i.e. the following are now valid:

foreach (int value in sourcedFixedArrayPtr)
{
    // ...
}

sourcedFixedArrayPtr.Max(x => x);

etc.