81 lines
2.1 KiB
Java
81 lines
2.1 KiB
Java
/**
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* Container for link between two Osm nodes
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*
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* @author ab
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*/
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package btools.mapaccess;
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import btools.util.ByteDataReader;
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public final class GeometryDecoder
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{
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private ByteDataReader r = new ByteDataReader( null );
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private OsmTransferNode[] cachedNodes;
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private int nCachedNodes = 128;
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// result-cache
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private OsmTransferNode firstTransferNode;
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private boolean lastReverse;
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private byte[] lastGeometry;
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public GeometryDecoder()
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{
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// create some caches
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cachedNodes = new OsmTransferNode[nCachedNodes];
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for( int i=0; i<nCachedNodes; i++ )
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{
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cachedNodes[i] = new OsmTransferNode();
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}
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}
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public OsmTransferNode decodeGeometry( byte[] geometry, OsmNode sourceNode, OsmNode targetNode, boolean reverseLink )
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{
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if ( ( lastGeometry == geometry ) && ( lastReverse == reverseLink ) )
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{
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return firstTransferNode;
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}
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firstTransferNode = null;
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OsmTransferNode lastTransferNode = null;
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OsmNode startnode = reverseLink ? targetNode : sourceNode;
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r.reset( geometry );
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int olon = startnode.ilon;
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int olat = startnode.ilat;
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int oselev = startnode.selev;
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int idx = 0;
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while ( r.hasMoreData() )
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{
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OsmTransferNode trans = idx < nCachedNodes ? cachedNodes[idx++] : new OsmTransferNode();
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trans.ilon = olon + r.readVarLengthSigned();
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trans.ilat = olat + r.readVarLengthSigned();
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trans.selev = (short)(oselev + r.readVarLengthSigned());
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olon = trans.ilon;
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olat = trans.ilat;
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oselev = trans.selev;
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if ( reverseLink ) // reverse chaining
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{
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trans.next = firstTransferNode;
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firstTransferNode = trans;
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}
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else
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{
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trans.next = null;
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if ( lastTransferNode == null )
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{
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firstTransferNode = trans;
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}
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else
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{
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lastTransferNode.next = trans;
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}
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lastTransferNode = trans;
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}
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}
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lastReverse = reverseLink;
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lastGeometry = geometry;
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return firstTransferNode;
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}
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}
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