osmselect.go

package main


import "context"
import "github.com/paulmach/osm"
import "github.com/paulmach/osm/osmpbf"
import "github.com/paulmach/osm/osmxml"

import "encoding/xml"
import "fmt"
import "os"
import "flag"
import "io"

var all,nodes,ways,rels bool

var in_stdin, in_pbf bool
var limit,offset uint64

var in_file string

var out_ind bool

func init(){
	flag.BoolVar(&all,"all",false,"select *")
	flag.BoolVar(&nodes,"nodes",false,"select OSM Nodes")
	flag.BoolVar(&ways,"ways",false,"select OSM Ways")
	flag.BoolVar(&rels,"rels",false,"select OSM Relations")
	flag.BoolVar(&in_stdin,"stdin",false,"use stdin as input")
	flag.BoolVar(&in_pbf,"pbf",false,".pbf-format")
	flag.BoolVar(&out_ind,"indent",false,"pretty-print XML")
	
	flag.Uint64Var(&limit,"limit",0,"Max. number of elements, 0==infinity")
	flag.Uint64Var(&offset,"offset",0,"Number of elements to skip")
	
	flag.StringVar(&in_file,"file","","use file as input")
}

var pre = xml.StartElement{xml.Name{"","osm"},[]xml.Attr{
	{xml.Name{"","version"},"0.6"},
	{xml.Name{"","generator"},"osmselect 0.1"},
}}
var post = xml.EndElement{xml.Name{"","osm"}}


func main() {
	flag.Parse()
	fmt.Print(xml.Header)
	enc := xml.NewEncoder(os.Stdout)
	if out_ind { enc.Indent(""," ") }
	enc.EncodeToken(pre)
	
	var src io.Reader
	
	if in_stdin {
		src = os.Stdin
	} else if in_file!="" {
		f,err := os.Open(in_file)
		if err==nil { src = f } else { fmt.Fprintf(os.Stderr,"Opening input-file %q: %v\n",in_file,err) }
	}
	
	if src==nil{
		enc.EncodeToken(post)
		enc.Flush()
		fmt.Println()
		return
	}
	
	var s osm.Scanner
	if in_pbf {
		s = osmpbf.New(context.Background(),src,4)
	} else {
		s = osmxml.New(context.Background(),src)
	}
	defer s.Close()
	
	nolimit := limit==0
	
	for s.Scan() {
		o := s.Object()
		if all { goto skipped }
		switch o.ObjectID().Type() {
		case osm.TypeNode: if !nodes { continue }
		case osm.TypeWay: if !ways { continue }
		case osm.TypeRelation: if !rels { continue }
		}
		skipped:
		if offset>0 {
			offset--
			continue
		}
		if nolimit {} else if limit==0  { break }
		limit--
		enc.Encode(o)
	}
	
	err := s.Err()
	if err!=nil { fmt.Fprintf(os.Stderr,"premature end: %v\n",err) }
	
	enc.EncodeToken(post)
	enc.Flush()
	fmt.Println()
}