/// <summary>
/// Writes a number of elements to a memory location from the provided buffer starting at the specified index.
/// </summary>
/// <typeparam name="T">The structure type</typeparam>
/// <param name="destination">The destination memory location.</param>
/// <param name="buffer">The source buffer.</param>
/// <param name="index">The start index within <paramref name="buffer"/>.</param>
/// <param name="count">The number of elements to write.</param>
public static unsafe void WriteArray <T>(IntPtr destination, T[] buffer, int index, int count)
where T : struct
{
uint elementSize = (uint)SizeOf <T>();
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (count < 0)
{
throw new ArgumentOutOfRangeException("count");
}
if (index < 0)
{
throw new ArgumentOutOfRangeException("index");
}
if (buffer.Length - index < count)
{
throw new ArgumentException("Invalid offset into array specified by index and count");
}
void *ptr = destination.ToPointer();
byte *p = (byte *)FastStructure.GetPtr <T>(ref buffer[0]);
UnsafeNativeMethods.CopyMemoryPtr(ptr, p + (index * elementSize), (uint)(elementSize * count));
}
/// <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 (default 1000ms)</param>
/// <returns>The number of elements written</returns>
/// <remarks>The maximum number of elements that can be written is the minimum of the length of <paramref name="source"/> subtracted by <paramref name="startIndex"/> and <see cref="NodeBufferSize"/> divided by <code>FastStructure.SizeOf>T<()</code>.</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 (default 1000ms)</param>
/// <returns>The number of elements read into destination</returns>
/// <remarks>The maximum number of elements that can be read is the minimum of the length of <paramref name="destination"/> subtracted by <paramref name="startIndex"/> and <see cref="Node.AmountWritten"/> divided by <code>FastStructure.SizeOf>T<()</code>.</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>
/// 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);
}
/// <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.
/// <para>There is no exact equivalent possible in C#, the closest possible (generates the same IL) is the following code:</para>
/// <code>
/// unsafe void WriteToPointer(ref SharedHeader dest, ref SharedHeader src)
/// {
/// dest = src;
/// }
/// </code>
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="pointer"></param>
/// <param name="structure"></param>
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"/>.
/// <para>The equivalent non-generic C# code:</para>
/// <code>
/// unsafe MyStruct ReadFromPointer(byte* pointer)
/// {
/// return *(MyStruct*)pointer;
/// }
/// </code>
/// </summary>
/// <typeparam name="T">Any value/structure type</typeparam>
/// <param name="pointer">Unsafe pointer to memory to load the value from</param>
/// <returns>The newly loaded value</returns>
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"></typeparam>
/// <param name="structure"></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));
}
