/// <summary>
/// Reads a number of elements from a memory location into the provided buffer starting at the specified index.
/// </summary>
/// <typeparam name="T">The structure type.</typeparam>
/// <param name="buffer">The destination buffer.</param>
/// <param name="source">The source memory location.</param>
/// <param name="index">The start index within <paramref name="buffer"/>.</param>
/// <param name="count">The number of elements to read.</param>
public static unsafe void ReadArray <T>(T[] buffer, IntPtr source, int index, int count)
where T : struct
{
uint elementSize = (uint)SizeOf <T>();
if (buffer == null)
{
throw new ArgumentNullException(nameof(buffer));
}
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
if (index < 0)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
if (buffer.Length - index < count)
{
throw new ArgumentException(RS.InvalidOffsetIntoArray);
}
void *ptr = source.ToPointer();
byte *p = (byte *)FastStructure.GetPtr <T>(ref buffer[0]);
#if NETFX
UnsafeNativeMethods.CopyMemoryPtr(p + (index * elementSize), ptr, (uint)(elementSize * count));
#else
Buffer.MemoryCopy(ptr, p + (index * elementSize), elementSize * count, elementSize * count);
#endif
}
/// <summary>
/// Writes the structure array buffer to the next available node for writing.
/// </summary>
/// <param name="source">Reference to the buffer to write.</param>
/// <param name="startIndex">The index within the buffer to start writing from.</param>
/// <param name="timeout">The maximum number of milliseconds to wait for a node to become available for writing. Defaults to 1000 (ms).</param>
/// <returns>The number of elements written.</returns>
/// <remarks><![CDATA[
/// The maximum number of elements that can be written can be calculated by the following formula:
/// ```C#
/// Math.Min(source - startIndex, NodeBufferSize) / FastStructure.SizeOf<T>()
/// ```
/// ]]></remarks>
public virtual int Write <T>(T[] source, int startIndex = 0, int timeout = 1000)
where T : struct
{
// Grab a node for writing
Node *node = GetNodeForWriting(timeout);
if (node == null)
{
return(0);
}
// Write the data using the FastStructure class (much faster than the MemoryMappedViewAccessor WriteArray<T> method)
int count = Math.Min(source.Length - startIndex, NodeBufferSize / FastStructure.SizeOf <T>());
base.WriteArray <T>(source, startIndex, count, node->Offset);
node->AmountWritten = count * FastStructure.SizeOf <T>();
// Writing is complete, make node readable
PostNode(node);
return(count);
}
/// <summary>
/// Reads the next available node for reading into the specified structure array.
/// </summary>
/// <typeparam name="T">The structure type to be read.</typeparam>
/// <param name="destination">Reference to the buffer.</param>
/// <param name="startIndex">The index within the destination to start writing to.</param>
/// <param name="timeout">The maximum number of milliseconds to wait for a node to become available for reading. Defaults to 1000 (ms).</param>
/// <returns>The number of elements read into destination.</returns>
/// <remarks><![CDATA[
/// The maximum number of elements that can be read can be determined by the following formula:
///
/// ```C#
/// Math.Min(destination.Length - startIndex, Node.AmountWritten / FastStructure.SizeOf<T>())
/// ```
/// ]]></remarks>
public virtual int Read <T>(T[] destination, int startIndex = 0, int timeout = 1000)
where T : struct
{
Node *node = GetNodeForReading(timeout);
if (node == null)
{
return(0);
}
// Copy the data using the FastStructure class (much faster than the MemoryMappedViewAccessor ReadArray<T> method)
int count = Math.Min(destination.Length - startIndex, node->AmountWritten / FastStructure.SizeOf <T>());
base.ReadArray <T>(destination, startIndex, count, node->Offset);
// Return the node for further writing
ReturnNode(node);
return(count);
}
/// <summary>
/// Writes the generic value type <typeparamref name="T"/> to the location specified by a pointer. This is achieved by emitting a
/// <see cref="DynamicMethod"/> that copies the value from the referenced structure into the specified memory location.
/// </summary>
/// <typeparam name="T">The structure type.</typeparam>
/// <param name="pointer">The pointer position to write.</param>
/// <param name="structure">The structure to write into memory.</param>
/// <remarks>
/// There is no exact equivalent possible in C#, the closest possible (generates the same IL) is the following code:
/// ```C#
/// unsafe void WriteToPointer(ref SharedHeader dest, ref SharedHeader src)
/// {
/// dest = src;
/// }
/// ```
/// </remarks>
public static unsafe void StructureToPtr <T>(ref T structure, IntPtr pointer)
where T : struct
{
FastStructure <T> .StructureToPtr(ref structure, pointer);
}
/// <summary>
/// Loads the generic value type <typeparamref name="T"/> from a pointer. This is achieved by emitting a <see cref="DynamicMethod"/> that
/// returns the value in the memory location as a <typeparamref name="T"/>.
/// </summary>
/// <typeparam name="T">The structure type.</typeparam>
/// <param name="pointer">Unsafe pointer to memory to load the value from.</param>
/// <returns>
/// The value of the structure loaded from memory.
/// </returns>
/// <remarks>
/// The following code demonstrates the equivalent non-generic C# code:
/// ```C#
/// unsafe MyStruct ReadFromPointer(byte* pointer)
/// {
/// return *(MyStruct*)pointer;
/// }
/// ```
/// </remarks>
public static unsafe T PtrToStructure <T>(IntPtr pointer)
where T : struct
{
return(FastStructure <T> .PtrToStructure(pointer));
}
/// <summary>
/// Retrieve a pointer to the passed generic structure type. This is achieved by emitting a <see cref="DynamicMethod"/> to
/// retrieve a pointer to the structure.
/// </summary>
/// <typeparam name="T">The structure type.</typeparam>
/// <param name="structure">The structure to search.</param>
/// <returns>A pointer to the provided structure in memory.</returns>
/// <see cref="FastStructure{T}.GetPtr"/>
public static unsafe void *GetPtr <T>(ref T structure)
where T : struct
{
return(FastStructure <T> .GetPtr(ref structure));
}
/// <summary>
/// Reads a number of elements from a memory location into the provided buffer starting at the specified index.
/// </summary>
/// <typeparam name="T">The structure type.</typeparam>
/// <param name="destination">The destination buffer.</param>
/// <param name="index">The start index within <paramref name="destination"/>.</param>
/// <param name="count">The number of elements to read.</param>
/// <param name="bufferPosition">The source offset within the buffer region of the shared memory.</param>
protected virtual void ReadArray <T>(T[] destination, int index, int count, long bufferPosition)
where T : struct
{
FastStructure.ReadArray <T>(destination, (IntPtr)(BufferStartPtr + bufferPosition), index, count);
}
/// <summary>
/// Reads an array of <typeparamref name="T"/> from the buffer.
/// </summary>
/// <typeparam name="T">A structure type.</typeparam>
/// <param name="destination">Array that will contain the values read from the buffer. The length of this array controls the number of elements to read.</param>
/// <param name="bufferPosition">The offset within the buffer region of the shared memory to read from.</param>
protected virtual void Read <T>(T[] destination, long bufferPosition = 0)
where T : struct
{
FastStructure.ReadArray <T>(destination, (IntPtr)(BufferStartPtr + bufferPosition), 0, destination.Length);
}
/// <summary>
/// Writes an array of <typeparamref name="T"/> into the buffer.
/// </summary>
/// <typeparam name="T">A structure type.</typeparam>
/// <param name="source">The source data to be written to the buffer.</param>
/// <param name="index">The start index within <paramref name="source"/>.</param>
/// <param name="count">The number of elements to write.</param>
/// <param name="bufferPosition">The offset within the buffer region of the shared memory to write to.</param>
protected virtual void WriteArray <T>(T[] source, int index, int count, long bufferPosition = 0)
where T : struct
{
FastStructure.WriteArray <T>((IntPtr)(BufferStartPtr + bufferPosition), source, index, count);
}
