mapnik/plugins/input/osm/osmparser.cpp

// much of this is based on osm2pgsql

#include "osmparser.h"
#include "osm.h"
#include <string>
#include <cassert>

using std::cerr;
using std::endl;


 osm_item* osmparser::cur_item=NULL;
 long osmparser::curID=0;
 bool osmparser::in_node=false, osmparser::in_way=false;
 osm_dataset* osmparser::components=NULL;
 std::string osmparser::error="";
 std::map<long,osm_node*> osmparser::tmp_node_store=std::map<long,osm_node*>();

void osmparser::processNode(xmlTextReaderPtr reader)
{
  xmlChar *name = xmlTextReaderName(reader);
  if(name==NULL)
    name=xmlStrdup(BAD_CAST "--");

  switch(xmlTextReaderNodeType(reader))
  {
    case XML_READER_TYPE_ELEMENT:
      startElement(reader,name);
      break;

    case XML_READER_TYPE_END_ELEMENT:
      endElement(name);
  }
  xmlFree(name);
}

void osmparser::startElement(xmlTextReaderPtr reader, const xmlChar *name)
{
  std::string tags; 
  xmlChar *xid, *xlat, *xlon, *xk, *xv;

    if(xmlStrEqual(name,BAD_CAST "node"))
    {
      curID = 0;
      in_node = true;
      osm_node *node=new osm_node;
      xlat=xmlTextReaderGetAttribute(reader,BAD_CAST "lat");
      xlon=xmlTextReaderGetAttribute(reader,BAD_CAST "lon");
      xid=xmlTextReaderGetAttribute(reader,BAD_CAST "id");
      assert(xlat);
      assert(xlon);
      assert(xid);
      node->lat=atof((char*)xlat);  
      node->lon=atof((char*)xlon);  
      node->id = atol((char*)xid);
      cur_item = node;  
      tmp_node_store[node->id] = node;
      xmlFree(xid);
      xmlFree(xlon);
      xmlFree(xlat);
    }
    else if (xmlStrEqual(name,BAD_CAST "way")) 
    {
      curID=0;
      in_way = true;
      osm_way *way=new osm_way;
      xid=xmlTextReaderGetAttribute(reader,BAD_CAST "id");
      assert(xid);
      way->id = atol((char*)xid); 
      cur_item  =  way; 
      // Prevent ways with no name being assigned a name of "0"
      cur_item->keyvals["name"] = ""; 

      // HACK: allows comparison with "" in the XML file. Otherwise it
      // doesn't work. Only do for the most crucial tags for Freemap's
      // purposes.  TODO investigate why this is
      cur_item->keyvals["width"] = "";  
      cur_item->keyvals["horse"] = "";  
      cur_item->keyvals["foot"] = "";  
      cur_item->keyvals["bicycle"] = "";  
      xmlFree(xid);
    }
    else if (xmlStrEqual(name,BAD_CAST "nd"))
    {
      xid=xmlTextReaderGetAttribute(reader,BAD_CAST "ref");
      assert(xid);
      long ndid = atol((char*)xid); 
      if(tmp_node_store.find(ndid)!=tmp_node_store.end())
      {
        (static_cast<osm_way*>(cur_item))->nodes.push_back
            (tmp_node_store[ndid]);
      }
      xmlFree(xid);
    }
    else if (xmlStrEqual(name,BAD_CAST "tag"))
    {
      std::string key="", value="";
      xk = xmlTextReaderGetAttribute(reader,BAD_CAST "k");
      xv = xmlTextReaderGetAttribute(reader,BAD_CAST "v");
      assert(xk);
      assert(xv);
      cur_item->keyvals[(char*)xk] = (char*)xv; 
      xmlFree(xk);
      xmlFree(xv);
    }
}

void osmparser::endElement(const xmlChar* name)
{
  if(xmlStrEqual(name,BAD_CAST "node"))
  {
    in_node = false;
    components->add_node(static_cast<osm_node*>(cur_item));
  }
  else if(xmlStrEqual(name,BAD_CAST "way"))
  {
    in_way = false;
    components->add_way(static_cast<osm_way*>(cur_item));
  }
}

bool osmparser::parse(osm_dataset *ds, const char* filename)
{
  components=ds;
  xmlTextReaderPtr reader = xmlNewTextReaderFilename(filename);
  int ret=do_parse(reader);
  xmlFreeTextReader(reader);
  return (ret==0) ?  true:false;
}

bool osmparser::parse(osm_dataset *ds,char* data, int nbytes)
{
  // from cocoasamurai.blogspot.com/2008/10/getting-some-xml-love-with-
  // libxml2.html, converted from Objective-C to straight C

  components=ds;
  xmlTextReaderPtr reader = xmlReaderForMemory(data,nbytes,NULL,NULL,0);
  int ret=do_parse(reader);
  xmlFreeTextReader(reader);
  return (ret==0) ? true:false;
}

  
int osmparser::do_parse(xmlTextReaderPtr reader)
{
  int ret=-1;
  if(reader!=NULL)
  {
    ret = xmlTextReaderRead(reader);
    while(ret==1)
    {
      processNode(reader);
      ret=xmlTextReaderRead(reader);
    }
  }
  return ret;
}