#!/bin/sh
#
# Make a diff file for patch, using CVS
# Syntax: make_patch old_version new_version outfile
# (prompted for if omitted)
#
# We will attempt to construct a Prereq: PREREQ from a string of the form
#	static char version[] = ... version PREREQ ...
# in the old AA_Version.h (if it's present in the patch file)
#
if [ "$1" = "" ]; then
	echo -n "Old version? " ; read old
else
	old=$1
fi
if [ "$2" = "" ]; then
	echo -n "New version? " ; read new
else
	new=$2
fi
echo 'Remember to update the patch level (both "cvs tags" and AA_Version.h)'
if [ "$3" = "" ]; then
	echo "Diff file to produce?" ; read file
else
	file=$3
fi
if [ -w $file ]; then
	echo -n "patch file already exists -- continue? [n/y] "
	read cont
	if [ "$cont" != "y" ]; then exit 1; fi
fi
#
# Now use cvs to build a patch file
#
cvs patch -fq -r $old -r $new sm > $file
#
# Now move the AA_version.h entry to the top, and create a Prereq: entry
#
trap 'for rm -f _head _body' 0 1 2 3 9
#
#
if sed -e "/^diff -c .*AA_Version.h/{
:lab1
w _head
s/.*//
n
/diff -c/!b lab1
b
}" $file > _body ; then
	prereq=`sed -n "/! static char version_string\[\] = \"/{
s/.*SM, version \([^ ]*\).*/\1/
p
q
}" _head`
	if [ "$prereq" = "" ]; then
		echo "No Prereq found: enter one (or nothing if none is desired)"
		read prereq
	else
		echo Prerequisite = $prereq
	fi
	if [ "$prereq" != "" ]; then
		echo Prereq: $prereq > $file
	else
		cp /dev/null $file
	fi
#
	cat _head _body >> $file
else
	echo "There is no AA_Version.h file in the patch, and thus no Prereq:"
	mv _body $file
	exit 1
fi