Reduce number of Table A entries.
Previously, Table A entries were unique for each combination of start node,
end node and RoadDef. But no information from the start and end nodes goes
into Table A so we can ignore the start and end nodes and all roads
within a given routing centre that use the same RoadDef can now share a
Table A entry. This reduces the number of entries required which makes
the .img files smaller and, hopefully, also improves the routing because
routing centres can now cover a larger area.
I have tested this with mapsource and on a Nuvi and it appears to work
OK but it really needs more testing before it could be considered for
committing.
So, all feedback is welcome regarding the effect this patch has on
routing performance. With the patch, the routing changed and I thought
it was more sensible but perhaps that's just wishful thinking.
My GB map shrunk from 180 to 174 Mb with this patch.
The Nuvi calculated a route from Lands End to Thurso (800+ miles and quite a
few tiles) in no more than 10 seconds.
Cheers,
Mark
diff --git a/src/uk/me/parabola/imgfmt/app/net/TableA.java b/src/uk/me/parabola/imgfmt/app/net/TableA.java
index a0c87ee..599adf7 100644
--- a/src/uk/me/parabola/imgfmt/app/net/TableA.java
+++ b/src/uk/me/parabola/imgfmt/app/net/TableA.java
@@ -37,7 +37,7 @@ public class TableA {
// This table's start position relative to the start of NOD 1
private int offset;
- private final LinkedHashMap<Arc,Integer> arcs = new LinkedHashMap<Arc,Integer>();
+ private final LinkedHashMap<RoadDef,Integer> arcs = new LinkedHashMap<RoadDef,Integer>();
private static int count;
@@ -47,53 +47,16 @@ public class TableA {
}
/**
- * Internal class tracking all the data a Table A entry needs.
- * Basically a "forward arc".
- */
- private class Arc {
- final RouteNode first; final RouteNode second;
- final RoadDef roadDef;
-
- Arc(RouteArc arc) {
- if (arc.isForward()) {
- first = arc.getSource();
- second = arc.getDest();
- } else {
- first = arc.getDest();
- second = arc.getSource();
- }
- roadDef = arc.getRoadDef();
- }
-
- public boolean equals(Object obj) {
- Arc arc = (Arc) obj;
- return first.equals(arc.first)
- && second.equals(arc.second)
- && roadDef.equals(arc.roadDef);
- }
-
- public int hashCode() {
- return first.hashCode() + 2*second.hashCode() + roadDef.hashCode();
- }
-
- public String toString() {
- return "" + first + "->" + second + " (" + roadDef + ")";
- }
- }
-
- /**
* Add an arc to the table if not present and set its index.
*
* The value may overflow while it isn't certain that
* the table fulfills the size constraint.
*/
public void addArc(RouteArc arc) {
- Arc narc = new Arc(arc);
- int i;
- if (!arcs.containsKey(narc)) {
- i = arcs.size();
- arcs.put(narc, i);
- log.debug("added arc", count, narc, i);
+ if (!arcs.containsKey(arc.getRoadDef())) {
+ int i = arcs.size();
+ arcs.put(arc.getRoadDef(), i);
+ log.debug("added arc", count, arc, i);
}
}
@@ -102,11 +65,10 @@ public class TableA {
*/
public byte getIndex(RouteArc arc) {
log.debug("getting index", arc);
- Arc narc = new Arc(arc);
- assert arcs.containsKey(narc):
- "Trying to read Table A index for non-registered arc: " + count + " " + narc;
- int i = arcs.get(narc);
- assert i < 0x100 : "Table A index too large: " + narc;
+ assert arcs.containsKey(arc.getRoadDef()):
+ "Trying to read Table A index for non-registered arc: " + count + " " + arc;
+ int i = arcs.get(arc.getRoadDef());
+ assert i < 0x100 : "Table A index too large: " + arc;
return (byte) i;
}
@@ -152,18 +114,18 @@ public class TableA {
*/
public void writePost(ImgFileWriter writer) {
writer.position(offset);
- for (Arc arc : arcs.keySet()) {
+ for (RoadDef roadDef : arcs.keySet()) {
// write the table A entries. Consists of a pointer to net
// followed by 2 bytes of class and speed flags and road restrictions.
- log.debug("writing Table A entry", arcs.get(arc));
- int pos = arc.roadDef.getOffsetNet1();
- int access = arc.roadDef.getTabAAccess();
+ log.debug("writing Table A entry", roadDef);
+ int pos = roadDef.getOffsetNet1();
+ int access = roadDef.getTabAAccess();
// top bits of access go into net1 offset
final int ACCESS_TOP_BITS = 0xc000;
pos |= (access & ACCESS_TOP_BITS) << 8;
access &= ~ACCESS_TOP_BITS;
writer.put3(pos);
- writer.put((byte) arc.roadDef.getTabAInfo());
+ writer.put((byte) roadDef.getTabAInfo());
writer.put((byte) access);
}
}
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