README #1

From an original README by James Strickland, author of this implementation
of diff.

Files in this directory
-----------------------

	Jamfile			- for building with 'jam'
	README			- this file
	diff.cc			- simple interface for doing diffs
	diff.h			- "
	diffan.cc		- diff analyzer, the hard part
	diffan.h		- "
	diffsp.cc		- diff Sequence, crunches a single file
	diffsp.h		- "
	difftest.cc		- simple test harness for a diff program

External Dependencies
---------------------

	These files rely on the (read) file access routines provided
	by RcsFile, as defined in rcsfio.h.

	These files also use stdhdrs.h, a wrapper for system header files
	that uses #define's to determine what to include.  Mostly all that
	are needed are the very common headers (stdio.h, string.h, stdlib.h)
	and the types header (sys/types.h).

Debugging
---------

	Note that there are a number of

	#if DEBUGLEVEL > n
	 .... debugging output ....
	#endif

	blocks in the code.  If DEBUGLEVEL is not defined, then it is
	#define'd to be zero.  DEBUGLEVEL=1 produces a reasonable amount of
	output (summary information such as #lines).  

What do they do?
----------------

	p4diff (difftest.cc) provides the same style of output as GNU
	diff.  The output is often identical to that of diff(1), although
	sometimes this implementation picks a different edit sequence.