#! /bin/sh
# $Id$

if [ $# -ge 2 ];then
	echo >&2 "Syntax: $0 [<diff>]"
	exit 1
fi

prog='
	$wasdiff-- if $wasdiff;
	$wasdiff=3 if /^diff -/ || /^revision /;
	# Do not substitute already existing "./"... or "/dev/null".
	# gdb.spec is using -p1.
	s{^(\Q---\E )gdb-[^/]*/}{$1./} if $wasdiff==2;
	s{^(\Q+++\E )gdb-[^/]*/}{$1./} if $wasdiff==1;
	# binutils.spec is using -p0.
	s{^(\Q---\E )binutils-[^/]*/}{$1} if $wasdiff==2;
	s{^(\Q+++\E )binutils-[^/]*/}{$1} if $wasdiff==1;
	$f=$1 if m{^--- (\S+)\s*$} && $wasdiff==2;
	s{^(\Q+++\E )-\t}{$1$f\t} && wasdiff==1;
	next if /^[?]/;
	next if /^Index:/;
	next if /^index /;
	next if /^={67}$/;
	next if /^RCS file:/;
	next if /^retrieving revision /;
	next if /^diff -/;
	next if /^revision /;
	next if /^new file mode /;
	next if /^deleted file mode /;
	next if m{^/.*,v  -->  standard output$};
	print;
'
if [ $# -eq 1 ];then
	exec perl -ne "$prog" -i "$1"
else
	exec perl -ne "$prog"
fi