如何在不知道未压缩数据大小的情况下使用RtlDecompressBuffer？

I would like to use the WINAPI RtlDecompressBuffer in User Mode to decompress a buffer previously compressed using RtlCompressBuffer. I have the code for compression but it seems that in order to decompress I need to know the size of the uncompressed data as the function needs it as a parameter. I would like to use the WINAPI RtlDecompressBuf