From 4f2a3b53a0520f3f53ade1da3056b32417b61fcd Mon Sep 17 00:00:00 2001
From: Oliver Tonnhofer <olt@bogosoft.com>
Date: Wed, 26 Dec 2012 17:30:07 +0100
Subject: [PATCH] refactored pbf counter

---
 parser.go | 140 ++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 89 insertions(+), 51 deletions(-)

diff --git a/parser.go b/parser.go
index a27edd5..3ee57bf 100644
--- a/parser.go
+++ b/parser.go
@@ -7,78 +7,116 @@ import (
 	// "goposm/osmpbf/fileformat"
 	"bytes"
 	"compress/zlib"
-	"io/ioutil"
+	"io"
 	"log"
 	"os"
 	"osmpbf"
 )
 
-func nextBlobHeader(file *os.File, offset int64) (position int64, size int32) {
-	newOffset, err := file.Seek(offset, 0)
-	if offset != newOffset {
-		log.Fatal(err)
-		return
+type PBF struct {
+	file     *os.File
+	filename string
+	offset   int64
+}
+
+func Open(filename string) (f *PBF, err error) {
+	f = new(PBF)
+	f.filename = filename
+	file, err := os.Open(filename)
+	f.file = file
+	if err != nil {
+		return nil, err
+	}
+	return f, nil
+}
+
+func (pbf *PBF) NextDataPosition() (offset int64, size int32) {
+	header := pbf.nextBlobHeader()
+	size = header.GetDatasize()
+	offset = pbf.offset
+
+	pbf.offset += int64(size)
+	pbf.file.Seek(pbf.offset, 0)
+
+	if header.GetType() == "OSMHeader" {
+		return pbf.NextDataPosition()
 	}
-	position = offset + 4
-	binary.Read(file, binary.BigEndian, &size)
 	return
 }
 
+func (pbf *PBF) nextBlobHeaderSize() (size int32) {
+	pbf.offset += 4
+	binary.Read(pbf.file, binary.BigEndian, &size)
+	return
+}
+
+func (pbf *PBF) nextBlobHeader() *osmpbf.BlobHeader {
+	var blobHeader = &osmpbf.BlobHeader{}
+
+	size := pbf.nextBlobHeaderSize()
+	if size == 0 {
+		return blobHeader
+	}
+
+	data := make([]byte, size)
+	io.ReadFull(pbf.file, data)
+
+	err := proto.Unmarshal(data, blobHeader)
+	if err != nil {
+		log.Fatal("unmarshaling error (header): ", err)
+	}
+
+	pbf.offset += int64(size)
+	return blobHeader
+}
+
+func ReadPrimitiveBlock(file *os.File, offset int64, size int32) *osmpbf.PrimitiveBlock {
+	var block = &osmpbf.PrimitiveBlock{}
+	var blob = &osmpbf.Blob{}
+
+	blobData := make([]byte, size)
+	file.Seek(offset, 0)
+	io.ReadFull(file, blobData)
+	err := proto.Unmarshal(blobData, blob)
+	if err != nil {
+		log.Fatal("unmarshaling error blob: ", err)
+	}
+
+	buf := bytes.NewBuffer(blob.GetZlibData())
+	r, err := zlib.NewReader(buf)
+	if err != nil {
+		log.Fatal("zlib error: ", err)
+	}
+	raw := make([]byte, blob.GetRawSize())
+	io.ReadFull(r, raw)
+
+	if err != nil {
+		log.Fatal("zlib read error: ", err)
+	}
+	err = proto.Unmarshal(raw, block)
+	if err != nil {
+		log.Fatal("unmarshaling error: ", err)
+	}
+
+	return block
+}
+
 func blockPositions(filename string) {
+	pbf, err := Open(filename)
+
 	file, err := os.Open(filename)
 	if err != nil {
 		log.Fatal(err)
 	}
-	var offset int64
-	var blobHeader = &osmpbf.BlobHeader{}
-	var blob = &osmpbf.Blob{}
-	var block = &osmpbf.PrimitiveBlock{}
 
 	var nodesCounter, relationsCounter, waysCounter int
 
 	for {
-		position, size := nextBlobHeader(file, offset)
+		offset, size := pbf.NextDataPosition()
 		if size == 0 {
 			break
 		}
-		data := make([]byte, size)
-
-		file.Read(data)
-		err = proto.Unmarshal(data, blobHeader)
-		if err != nil {
-			log.Fatal("unmarshaling error: ", err)
-		}
-
-		offset = position + int64(size) + int64(blobHeader.GetDatasize())
-
-		if blobHeader.GetType() == "OSMHeader" {
-			fmt.Println("Skip header", blobHeader.GetType())
-			continue
-		}
-
-		blobData := make([]byte, blobHeader.GetDatasize())
-		file.Read(blobData)
-		err = proto.Unmarshal(blobData, blob)
-		if err != nil {
-			log.Fatal("unmarshaling error: ", err)
-		}
-
-		buf := bytes.NewBuffer(blob.GetZlibData())
-		r, err := zlib.NewReader(buf)
-		if err != nil {
-			log.Fatal("zlib error: ", err)
-		}
-		// raw := make([]byte, blob.GetRawSize())
-		raw, err := ioutil.ReadAll(r)
-
-		// bytes, err := r.Read(raw)
-		if err != nil {
-			log.Fatal("zlib read error: ", err)
-		}
-		err = proto.Unmarshal(raw, block)
-		if err != nil {
-			log.Fatal("unmarshaling error: ", err)
-		}
+		block := ReadPrimitiveBlock(file, offset, size)
 
 		for _, group := range block.Primitivegroup {
 			dense := group.GetDense()