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;
}