Package com.google.common.geometry

Class S2ShapeIndexCoder

java.lang.Object

com.google.common.geometry.S2ShapeIndexCoder

All Implemented Interfaces:

S2Coder<S2ShapeIndex>

@GwtIncompatible("S2LaxPolylineShape and S2LaxPolygonShape")
public class S2ShapeIndexCoder
extends java.lang.Object
implements S2Coder<S2ShapeIndex>

An encoder/decoder of S2ShapeIndexs.

Values from the S2ShapeIndex returned by decode(Bytes, Cursor) are decoded only when they are accessed. This allows for very fast initialization and no additional memory use beyond the encoded data, and a cache of the clipped shapes that have been accessed. When accessing the entire index, this uses slightly more memory than S2ShapeIndex, but uses dramatically less memory when accessing only a few cells of the index.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	S2ShapeIndexCoder.EncodedS2ShapeIndex	Represents an encoded S2ShapeIndex.

Field Summary

Fields

Modifier and Type	Field	Description
static S2ShapeIndexCoder	INSTANCE	An instance of a S2ShapeIndexCoder which can encode an S2ShapeIndex but will throw an IllegalArgumentException if used to decode an S2ShapeIndex.
private java.util.List<S2Shape>	shapes

Constructor Summary

Constructors

Constructor	Description
S2ShapeIndexCoder(java.util.List<S2Shape> shapes)	Constructs a S2ShapeIndexCoder.

Method Summary

Modifier and Type	Method	Description
S2ShapeIndex	decode(PrimitiveArrays.Bytes data, PrimitiveArrays.Cursor cursor)	Decodes a value of type S2Coder from data starting at cursor.position.
private static S2ShapeIndex.S2ClippedShape[]	decodeClippedShapes(java.util.List<S2Shape> shapes, PrimitiveArrays.Bytes data, PrimitiveArrays.Cursor cursor)	Decodes an array of S2ShapeIndex.S2ClippedShape from input from the given shapes.
private static int[]	decodeEdges(int numEdges, PrimitiveArrays.Bytes data, PrimitiveArrays.Cursor cursor)	Decodes numEdges edge IDs of a S2ShapeIndex.S2ClippedShape.
void	encode(S2ShapeIndex value, java.io.OutputStream output)	Encodes value to output.
private static void	encodeCell(S2ShapeIndex.Cell cell, com.google.common.collect.Multimap<S2Shape,java.lang.Integer> shapeIds, java.io.OutputStream output)
private static void	encodeEdges(S2ShapeIndex.S2ClippedShape clipped, java.io.OutputStream output)	Encodes the edge IDs of the given S2ShapeIndex.S2ClippedShape.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final S2ShapeIndexCoder INSTANCE

An instance of a S2ShapeIndexCoder which can encode an S2ShapeIndex but will throw an IllegalArgumentException if used to decode an S2ShapeIndex.

shapes

private final java.util.List<S2Shape> shapes

Constructor Detail

S2ShapeIndexCoder

public S2ShapeIndexCoder(@Nullable
                         java.util.List<S2Shape> shapes)

Constructs a S2ShapeIndexCoder.

Parameters:

shapes - the list of shapes, used only by decode(com.google.common.geometry.PrimitiveArrays.Bytes, com.google.common.geometry.PrimitiveArrays.Cursor), commonly the result of {@link VectorCoder#FAST_SHAPE#decode(Bytes, Cursor)}.

Method Detail

encode

public void encode(S2ShapeIndex value,
                   java.io.OutputStream output)
            throws java.io.IOException

Description copied from interface: S2Coder

Encodes value to output.

Specified by:

encode in interface S2Coder<S2ShapeIndex>

Throws:

java.io.IOException

decode

public S2ShapeIndex decode(PrimitiveArrays.Bytes data,
                           PrimitiveArrays.Cursor cursor)

Description copied from interface: S2Coder

Decodes a value of type S2Coder from data starting at cursor.position. cursor.position is updated to the position of the first byte in data following the encoded value.

Specified by:

decode in interface S2Coder<S2ShapeIndex>

encodeCell

private static void encodeCell(S2ShapeIndex.Cell cell,
                               com.google.common.collect.Multimap<S2Shape,java.lang.Integer> shapeIds,
                               java.io.OutputStream output)
                        throws java.io.IOException

Throws:

java.io.IOException

encodeEdges

private static void encodeEdges(S2ShapeIndex.S2ClippedShape clipped,
                                java.io.OutputStream output)
                         throws java.io.IOException

Encodes the edge IDs of the given S2ShapeIndex.S2ClippedShape.

Throws:

java.io.IOException

decodeEdges

private static int[] decodeEdges(int numEdges,
                                 PrimitiveArrays.Bytes data,
                                 PrimitiveArrays.Cursor cursor)

Decodes numEdges edge IDs of a S2ShapeIndex.S2ClippedShape.

decodeClippedShapes

private static S2ShapeIndex.S2ClippedShape[] decodeClippedShapes(java.util.List<S2Shape> shapes,
                                                                 PrimitiveArrays.Bytes data,
                                                                 PrimitiveArrays.Cursor cursor)

Decodes an array of S2ShapeIndex.S2ClippedShape from input from the given shapes. The S2ShapeIndex.S2ClippedShape at index 0 will store cellId.