# Buffer user defined functions Reference

Below is a complete list of the user defined functions available in AutoIt. Click on a user defined function name for a detailed description.

When using them you need to add a #include <WinAPISys.au3>.

User Defined Function | Description
--- | ---
_WinAPI_CompressBuffer | Compresses a buffer with specified compression format and engine type
_WinAPI_ComputeCrc32 | Calculates the CRC32 checksum of a block of memory
_WinAPI_DecompressBuffer | Decompresses an entire compressed buffer