text: #include <rbdl/rbdl.h>
  
  #include "urdfreader.h"
  
  #include <assert.h>
  #include <iostream>
  #include <fstream>
  #include <map>
  #include <stack>
  
  #ifdef RBDL_USE_ROS_URDF_LIBRARY
  #include <urdf_model/model.h>
  #include <urdf_parser/urdf_parser.h>
  
  typedef boost::shared_ptr<urdf::Link> LinkPtr;
  typedef const boost::shared_ptr<const urdf::Link> ConstLinkPtr;
  typedef boost::shared_ptr<urdf::Joint> JointPtr;
  typedef boost::shared_ptr<urdf::ModelInterface> ModelPtr;
  
  #else
  #include <urdf/urdfdom_headers/urdf_model/include/urdf_model/model.h>
  #include <urdf/urdfdom/urdf_parser/include/urdf_parser/urdf_parser.h>
  
  typedef my_shared_ptr<urdf::Link> LinkPtr;
  typedef const my_shared_ptr<const urdf::Link> ConstLinkPtr;
  typedef my_shared_ptr<urdf::Joint> JointPtr;
  typedef my_shared_ptr<urdf::ModelInterface> ModelPtr;
  
  #endif
  
  using namespace std;
  
  namespace RigidBodyDynamics {
  
  namespace Addons {
  
  using namespace Math;
  
  typedef vector<LinkPtr> URDFLinkVector;
  typedef vector<JointPtr> URDFJointVector;
  typedef map<string, LinkPtr > URDFLinkMap;
  typedef map<string, JointPtr > URDFJointMap;
  
  bool construct_model (Model* rbdl_model, ModelPtr urdf_model, bool floating_base, bool verbose) {
    LinkPtr urdf_root_link;
  
    URDFLinkMap link_map;
    link_map = urdf_model->links_;
  
    URDFJointMap joint_map;
    joint_map = urdf_model->joints_;
  
    vector<string> joint_names;
  
    // Holds the links that we are processing in our depth first traversal with the top element being the current link.
    stack<LinkPtr > link_stack;
    // Holds the child joint index of the current link
    stack<int> joint_index_stack;
  
    // add the bodies in a depth-first order of the model tree
    link_stack.push (link_map[(urdf_model->getRoot()->name)]);
  
    // add the root body
    ConstLinkPtr& root = urdf_model->getRoot ();
    Vector3d root_inertial_rpy;
    Vector3d root_inertial_position;
    Matrix3d root_inertial_inertia;
    double root_inertial_mass;
  
    if (root->inertial) {
      root_inertial_mass = root->inertial->mass;
  
      root_inertial_position.set (
          root->inertial->origin.position.x,
          root->inertial->origin.position.y,
          root->inertial->origin.position.z);
  
      root_inertial_inertia(0,0) = root->inertial->ixx;
      root_inertial_inertia(0,1) = root->inertial->ixy;
      root_inertial_inertia(0,2) = root->inertial->ixz;
  
      root_inertial_inertia(1,0) = root->inertial->ixy;
      root_inertial_inertia(1,1) = root->inertial->iyy;
      root_inertial_inertia(1,2) = root->inertial->iyz;
  
      root_inertial_inertia(2,0) = root->inertial->ixz;
      root_inertial_inertia(2,1) = root->inertial->iyz;
      root_inertial_inertia(2,2) = root->inertial->izz;
  
      root->inertial->origin.rotation.getRPY (root_inertial_rpy[0], root_inertial_rpy[1], root_inertial_rpy[2]);
  
      Body root_link = Body (root_inertial_mass,
          root_inertial_position,
          root_inertial_inertia);
  
      Joint root_joint (JointTypeFixed);
      if (floating_base) {
        root_joint = JointTypeFloatingBase;
      }
  
      SpatialTransform root_joint_frame = SpatialTransform ();
  
      if (verbose) {
        cout << "+ Adding Root Body " << endl;
        cout << "  joint frame: " << root_joint_frame << endl;
        if (floating_base) {
          cout << "  joint type : floating" << endl;
        } else {
          cout << "  joint type : fixed" << endl;
        }
        cout << "  body inertia: " << endl << root_link.mInertia << endl;
        cout << "  body mass   : " << root_link.mMass << endl;
        cout << "  body name   : " << root->name << endl;
      }
  
      rbdl_model->AppendBody(root_joint_frame,
          root_joint,
          root_link,
          root->name);
    }
  
    // depth first traversal: push the first child onto our joint_index_stack
    joint_index_stack.push(0);
  
    while (link_stack.size() > 0) {
      LinkPtr cur_link = link_stack.top();
  
      unsigned int joint_idx = joint_index_stack.top();
  
      // Add any child bodies and increment current joint index if we still have child joints to process.
      if (joint_idx < cur_link->child_joints.size()) {
        JointPtr cur_joint = cur_link->child_joints[joint_idx];
  
        // increment joint index
        joint_index_stack.pop();
        joint_index_stack.push (joint_idx + 1);
  
        link_stack.push (link_map[cur_joint->child_link_name]);
        joint_index_stack.push(0);
  
        if (verbose) {
          for (unsigned int i = 1; i < joint_index_stack.size() - 1; i++) {
            cout << "  ";
          }
          cout << "joint '" << cur_joint->name << "' child link '" << link_stack.top()->name << "' type = " << cur_joint->type << endl;
        }
  
        joint_names.push_back(cur_joint->name);
      } else {
        link_stack.pop();
        joint_index_stack.pop();
      }
    }
  
    unsigned int j;
    for (j = 0; j < joint_names.size(); j++) {
      JointPtr urdf_joint = joint_map[joint_names[j]];
      LinkPtr urdf_parent = link_map[urdf_joint->parent_link_name];
      LinkPtr urdf_child = link_map[urdf_joint->child_link_name];
  
      // determine where to add the current joint and child body
      unsigned int rbdl_parent_id = 0;
  
       // Resolve names of global reference frame parents
      if (urdf_parent->name != "base_link" 
          && urdf_parent->name != "world") {
        rbdl_parent_id = rbdl_model->GetBodyId (urdf_parent->name.c_str());
      }
  
  
      if (rbdl_parent_id == std::numeric_limits<unsigned int>::max())
        cerr << "Error while processing joint '" << urdf_joint->name
          << "': parent link '" << urdf_parent->name
          << "' could not be found." << endl;
  
      //cout << "joint: " << urdf_joint->name << "\tparent = " << urdf_parent->name << " child = " << urdf_child->name << " parent_id = " << rbdl_parent_id << endl;
  
      // create the joint
      Joint rbdl_joint;
      if (urdf_joint->type == urdf::Joint::REVOLUTE || urdf_joint->type == urdf::Joint::CONTINUOUS) {
        rbdl_joint = Joint (SpatialVector (urdf_joint->axis.x, urdf_joint->axis.y, urdf_joint->axis.z, 0., 0., 0.));
      } else if (urdf_joint->type == urdf::Joint::PRISMATIC) {
        rbdl_joint = Joint (SpatialVector (0., 0., 0., urdf_joint->axis.x, urdf_joint->axis.y, urdf_joint->axis.z));
      } else if (urdf_joint->type == urdf::Joint::FIXED) {
        rbdl_joint = Joint (JointTypeFixed);
      } else if (urdf_joint->type == urdf::Joint::FLOATING) {
        // todo: what order of DoF should be used?
        rbdl_joint = Joint (
            SpatialVector (0., 0., 0., 1., 0., 0.),
            SpatialVector (0., 0., 0., 0., 1., 0.),
            SpatialVector (0., 0., 0., 0., 0., 1.),
            SpatialVector (1., 0., 0., 0., 0., 0.),
            SpatialVector (0., 1., 0., 0., 0., 0.),
            SpatialVector (0., 0., 1., 0., 0., 0.));
      } else if (urdf_joint->type == urdf::Joint::PLANAR) {
        // todo: which two directions should be used that are perpendicular
        // to the specified axis?
        cerr << "Error while processing joint '" << urdf_joint->name << "': planar joints not yet supported!" << endl;
        return false;
      }
  
      // compute the joint transformation
      Vector3d joint_rpy;
      Vector3d joint_translation;
      urdf_joint->parent_to_joint_origin_transform.rotation.getRPY (joint_rpy[0], joint_rpy[1], joint_rpy[2]);
      joint_translation.set (
          urdf_joint->parent_to_joint_origin_transform.position.x,
          urdf_joint->parent_to_joint_origin_transform.position.y,
          urdf_joint->parent_to_joint_origin_transform.position.z
          );
      SpatialTransform rbdl_joint_frame =
            Xrot (joint_rpy[0], Vector3d (1., 0., 0.))
          * Xrot (joint_rpy[1], Vector3d (0., 1., 0.))
          * Xrot (joint_rpy[2], Vector3d (0., 0., 1.))
          * Xtrans (Vector3d (
                joint_translation
                ));
  
      // assemble the body
      Vector3d link_inertial_position;
      Vector3d link_inertial_rpy;
      Matrix3d link_inertial_inertia = Matrix3d::Zero();
      double link_inertial_mass = 0.;
  
      // but only if we actually have inertial data
      if (urdf_child->inertial) {
        link_inertial_mass = urdf_child->inertial->mass;
  
        link_inertial_position.set (
            urdf_child->inertial->origin.position.x,
            urdf_child->inertial->origin.position.y,
            urdf_child->inertial->origin.position.z
            );
        urdf_child->inertial->origin.rotation.getRPY (link_inertial_rpy[0], link_inertial_rpy[1], link_inertial_rpy[2]);
  
        link_inertial_inertia(0,0) = urdf_child->inertial->ixx;
        link_inertial_inertia(0,1) = urdf_child->inertial->ixy;
        link_inertial_inertia(0,2) = urdf_child->inertial->ixz;
  
        link_inertial_inertia(1,0) = urdf_child->inertial->ixy;
        link_inertial_inertia(1,1) = urdf_child->inertial->iyy;
        link_inertial_inertia(1,2) = urdf_child->inertial->iyz;
  
        link_inertial_inertia(2,0) = urdf_child->inertial->ixz;
        link_inertial_inertia(2,1) = urdf_child->inertial->iyz;
        link_inertial_inertia(2,2) = urdf_child->inertial->izz;
  
        if (link_inertial_rpy != Vector3d (0., 0., 0.)) {
          cerr << "Error while processing body '" << urdf_child->name << "': rotation of body frames not yet supported. Please rotate the joint frame instead." << endl;
          return false;
        }
      }
  
      Body rbdl_body = Body (link_inertial_mass, link_inertial_position, link_inertial_inertia);
  
      if (verbose) {
        cout << "+ Adding Body: " << urdf_child->name << endl;
        cout << "  parent_id  : " << rbdl_parent_id << endl;
        cout << "  joint frame: " << rbdl_joint_frame << endl;
        cout << "  joint dofs : " << rbdl_joint.mDoFCount << endl;
        for (unsigned int j = 0; j < rbdl_joint.mDoFCount; j++) {
          cout << "    " << j << ": " << rbdl_joint.mJointAxes[j].transpose() << endl;
        }
        cout << "  body inertia: " << endl << rbdl_body.mInertia << endl;
        cout << "  body mass   : " << rbdl_body.mMass << endl;
        cout << "  body name   : " << urdf_child->name << endl;
      }
  
      if (urdf_joint->type == urdf::Joint::FLOATING) {
        Matrix3d zero_matrix = Matrix3d::Zero();
        Body null_body (0., Vector3d::Zero(3), zero_matrix);
        Joint joint_txtytz(JointTypeTranslationXYZ);
        string trans_body_name = urdf_child->name + "_Translate";
        rbdl_model->AddBody (rbdl_parent_id, rbdl_joint_frame, joint_txtytz, null_body, trans_body_name);
  
        Joint joint_euler_zyx (JointTypeEulerXYZ);
        rbdl_model->AppendBody (SpatialTransform(), joint_euler_zyx, rbdl_body, urdf_child->name);
      } else {
        rbdl_model->AddBody (rbdl_parent_id, rbdl_joint_frame, rbdl_joint, rbdl_body, urdf_child->name);
      }
    }
  
    return true;
  }
  
  RBDL_DLLAPI bool URDFReadFromFile (const char* filename, Model* model, bool floating_base, bool verbose) {
    ifstream model_file (filename);
    if (!model_file) {
      cerr << "Error opening file '" << filename << "'." << endl;
      abort();
    }
    
    // reserve memory for the contents of the file
    string model_xml_string;
    model_file.seekg(0, std::ios::end);
    model_xml_string.reserve(model_file.tellg());
    model_file.seekg(0, std::ios::beg);
    model_xml_string.assign((std::istreambuf_iterator<char>(model_file)), std::istreambuf_iterator<char>());
  
    model_file.close();
  
    return URDFReadFromString (model_xml_string.c_str(), model, floating_base, verbose);
  }
  
  RBDL_DLLAPI bool URDFReadFromString (const char* model_xml_string, Model* model, bool floating_base, bool verbose) {
    assert (model);
  
    ModelPtr urdf_model = urdf::parseURDF (model_xml_string);
   
    if (!construct_model (model, urdf_model, floating_base, verbose)) {
      cerr << "Error constructing model from urdf file." << endl;
      return false;
    }
  
    model->gravity.set (0., 0., -9.81);
  
    return true;
  }
  
  }
  
  }
  