Category Archives: .NET

Fast shared Array, Buffer and Circular Buffer / Ring Buffer for .NET IPC with Memory Mapped Files

About the SharedMemory library

The SharedMemory class library provides a set of C# classes that utilise a non-persisted memory-mapped file for very fast low-level inter-process communication (IPC) to share data using the following data structures: buffer, array and circular buffer (also known as a ring buffer).

SharedMemory uses the MemoryMappedFile class introduced in .NET 4, and provides a partial P/Invoke wrapper around the Windows API for versions prior to this. The library was originally inspired by the following CodeProject article: “Fast IPC Communication Using Shared Memory and InterlockedCompareExchange“.

The library abstracts the use of the memory mapped file, adding a header that includes information about the size of the shared memory region so that readers are able to open the shared memory without knowing the size before hand. A helper class to support the fast copying of C# fixed-size structures in a generic fashion is also included.

The project source can be found on GitHub and Codeplex, with binaries available via Nuget and Codeplex.

What is a memory mapped file?

A memory-mapped file is an area of virtual memory that may have been mapped to a physical file and can be read from and written to by multiple processes on the same system. The file or portions thereof are accessed via views to one or more processes as a contiguous block of memory. Each view can then be read/written to using a memory location.

A memory-mapped file can be created as one of two types:

  • persisted: mapped to a physical file, and
  • non-persisted: in-memory only,  commonly used for inter-process communication (IPC).

A memory-mapped file is referenced using a unique name, unlike named pipes however a memory-mapped file cannot be accessed directly over a network.

Continue reading Fast shared Array, Buffer and Circular Buffer / Ring Buffer for .NET IPC with Memory Mapped Files

x86/x86-64 Disassembler for .NET – SharpDisasm

About the disassembler

SharpDisasm is a full C# port of the libudis86 x86/x86-64 disassembler. Disassembly of 16-bit, 32-bit and 64-bit instructions can be output to both Intel and AT&T syntax.

The library supports decoding each instruction to an object that provides access to low-level information for further analysis (e.g. instruction size, operand number and types etc).

SharpDisasm is a full C# port of the libudis86 C-library disassembler.

Disassembler features

  • a full C# port of the libudis86 C library
  • a set of simple C# classes wrapping the udis86 C API
  • support for x86 16-bit, 32-bit and 64-bit instruction set architectures
  • support for outputting in Intel and AT&T syntax
  • support for all x86 and x86-64 (AMD64) General purpose and System instructions.
  • support for the following ISA extensions:
    • MMX, FPU (x87), AMD 3DNow
    • SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AES
    • AMD-V, INTEL-VMX, SMX

The disassembler is exposed through the SharpDisam.Disassembler class.

Output from the provided example console app:

Downloads

Download source from GitHub or download binaries on Codeplex or NuGet.