#include "tile.hpp"
#include "vector_tile.pb.h"

#include <google/protobuf/io/zero_copy_stream_impl.h>

namespace avecado {

tile::tile(unsigned int z_, unsigned int x_, unsigned int y_)
  : z(z_), x(x_), y(y_), m_mapnik_tile(new mapnik::vector::tile) {
}

tile::~tile() {
}

std::string tile::get_data() const {
  std::ostringstream buffer;
  buffer << *this;
  return buffer.str();
}

mapnik::vector::tile const &tile::mapnik_tile() const {
  return *m_mapnik_tile;
}

mapnik::vector::tile &tile::mapnik_tile() {
  return *m_mapnik_tile;
}

std::ostream &operator<<(std::ostream &out, const tile &t) {
  google::protobuf::io::OstreamOutputStream stream(&out);
  bool write_ok = t.mapnik_tile().SerializeToZeroCopyStream(&stream);

  if (!write_ok) {
    throw std::runtime_error("Unable to write tile to output stream.");
  }

  return out;
}

} // namespace avecado

#include "tile.hpp"
#include "vector_tile.pb.h"

#include <google/protobuf/io/zero_copy_stream_impl.h>

namespace avecado {

tile::tile(unsigned int z_, unsigned int x_, unsigned int y_)
  : z(z_), x(x_), y(y_), m_mapnik_tile(new mapnik::vector::tile) {
}

tile::~tile() {
}

std::string tile::get_data() const {
  std::string buffer;

  if (m_mapnik_tile->SerializeToString(&buffer)) {
    return buffer;

  } else {
    throw std::runtime_error("Error while serializing protocol buffer tile.");
  }
}

mapnik::vector::tile const &tile::mapnik_tile() const {
  return *m_mapnik_tile;
}

mapnik::vector::tile &tile::mapnik_tile() {
  return *m_mapnik_tile;
}

std::ostream &operator<<(std::ostream &out, const tile &t) {
  google::protobuf::io::OstreamOutputStream stream(&out);
  bool write_ok = t.mapnik_tile().SerializeToZeroCopyStream(&stream);

  if (!write_ok) {
    throw std::runtime_error("Unable to write tile to output stream.");
  }

  return out;
}

} // namespace avecado

--- 
+++ 
@@ -13,14 +13,9 @@
 }
 
 std::string tile::get_data() const {
-  std::string buffer;
-
-  if (m_mapnik_tile->SerializeToString(&buffer)) {
-    return buffer;
-
-  } else {
-    throw std::runtime_error("Error while serializing protocol buffer tile.");
-  }
+  std::ostringstream buffer;
+  buffer << *this;
+  return buffer.str();
 }
 
 mapnik::vector::tile const &tile::mapnik_tile() const {
Make it so that serialisation to PBF happens in only one place.
