89 lines
1.7 KiB
Go
89 lines
1.7 KiB
Go
package pbf
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import (
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"bytes"
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"code.google.com/p/goprotobuf/proto"
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"compress/zlib"
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structs "encoding/binary"
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"goposm/parser/pbf/osmpbf"
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"io"
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"log"
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"os"
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)
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func ReadPrimitiveBlock(pos BlockPosition) *osmpbf.PrimitiveBlock {
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file, err := os.Open(pos.Filename)
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if err != nil {
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log.Panic(err)
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}
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defer file.Close()
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var block = &osmpbf.PrimitiveBlock{}
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var blob = &osmpbf.Blob{}
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blobData := make([]byte, pos.Size)
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file.Seek(pos.Offset, 0)
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io.ReadFull(file, blobData)
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err = proto.Unmarshal(blobData, blob)
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if err != nil {
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log.Panic("unmarshaling error blob: ", err)
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}
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buf := bytes.NewBuffer(blob.GetZlibData())
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r, err := zlib.NewReader(buf)
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if err != nil {
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log.Panic("zlib error: ", err)
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}
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raw := make([]byte, blob.GetRawSize())
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io.ReadFull(r, raw)
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err = proto.Unmarshal(raw, block)
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if err != nil {
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log.Panic("unmarshaling error: ", err)
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}
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return block
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}
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func (pbf *PBF) BlockPositions() (positions chan BlockPosition) {
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positions = make(chan BlockPosition, 8)
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go func() {
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for {
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offset, size := pbf.NextDataPosition()
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if size == 0 {
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close(positions)
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pbf.Close()
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return
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}
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positions <- BlockPosition{pbf.filename, offset, size}
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}
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}()
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return
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}
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func (pbf *PBF) nextBlobHeaderSize() (size int32) {
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pbf.offset += 4
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structs.Read(pbf.file, structs.BigEndian, &size)
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return
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}
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func (pbf *PBF) nextBlobHeader() *osmpbf.BlobHeader {
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var blobHeader = &osmpbf.BlobHeader{}
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size := pbf.nextBlobHeaderSize()
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if size == 0 {
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return blobHeader
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}
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data := make([]byte, size)
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io.ReadFull(pbf.file, data)
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err := proto.Unmarshal(data, blobHeader)
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if err != nil {
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log.Fatal("unmarshaling error (header): ", err)
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}
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pbf.offset += int64(size)
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return blobHeader
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}
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