Utilities to read and manipulate patches and CVS

PatchReader is a set of utilities for reading in, transforming, and doing
various other things with a patch. It basically allows you to create a
chain of readers that can read a patch, remove files from a patch, add
CVS context, fix up the patch root according to CVS, and output the patch
as raw unified or through a template processor (used in some places to
output a patch as HTML).