#!/bin/sh

#
# Extract layers from a FIG file
#
# History
#  2002/04/23 : pda : design
#  2013/02/12 : pda : extension to intervals
#

usage ()
{
    echo "usage: $0 layer[-layer] ... < fig-file > fig-file" >&2
    exit 1
}

if [ $# = 0 ]
then
    usage
fi

LAYERS="$*"

for i
do
    if expr "$i" : "^[0-9][0-9]*-[0-9][0-9]*$" > /dev/null
    then
	MIN=`expr "$i" : "\([0-9]*\)-"`
	MAX=`expr "$i" : ".*-\([0-9]*\)"`
	if [ $MIN -gt $MAX ]
	then usage
	fi
	while [ $MIN -le $MAX ]
	do
	    LAYERS="$LAYERS $MIN"
	    MIN=`expr $MIN + 1`
	done
    elif expr "$i" : "^[0-9][0-9]*$" > /dev/null
    then
	LAYERS="$LAYERS $i"
    else
	usage
    fi
done

awk -v "layers_string=$LAYERS" -F" " '
    BEGIN {
	split (layers_string, layers, "[ \t]")
    }
    /^#FIG/ {
	version = $2
	if (version != 3.2)
	{
	    print "Invalid FIG version ($0)" > "/dev/stderr"
	}
	print
	afficher = 1
	next
    }
    /^0 / {
	# color pseudo object
	afficher = 1
	print
	next
    }
    /^1 / {
	# ellipse
	if (layerok($7))
	{
	    afficher = 1
	    print
	}
	else afficher = 0
	next
    }
    /^2 / {
	# polyline
	if (layerok($7))
	{
	    afficher = 1
	    print
	}
	else afficher = 0
	next
    }
    /^3 / {
	# spline
	if (layerok($7))
	{
	    afficher = 1
	    print
	}
	else afficher = 0
	next
    }
    /^4 / {
	# text
	if (layerok($4))
	{
	    afficher = 1
	    print
	}
	else afficher = 0
	next
    }
    /^5 / {
	# arc
	if (layerok($7))
	{
	    afficher = 1
	    print
	}
	else afficher = 0
	next
    }
    /^6 / {
	# compound
	afficher = 1
	print
	next
    }
    /^-6 / {
	# end of compound
	afficher = 1
	print
	next
    }
    /^	/ {
	# ligne de continuation
	if (afficher)
	{
	    print
	}
	next
    }
    {
	afficher = 1
	print
	next
    }

    function layerok (l,           ok, n)
    {
	ok = 0
	for (n in layers)
	{
	    if (l == layers [n])
		ok = 1
	}
	return ok
    }' -