add real-time safe Inverse Dynamics library+test+utils

an example for the example browser will follow.
thanks to Thomas Buschmann

Extras/InverseDynamics/MultiBodyNameMap.cpp

@@ -0,0 +1,78 @@
+#include "MultiBodyNameMap.hpp"
+
+namespace btInverseDynamics {
+
+MultiBodyNameMap::MultiBodyNameMap() {}
+
+int MultiBodyNameMap::addBody(const int index, const std::string& name) {
+    if (m_index_to_body_name.count(index) > 0) {
+        error_message("trying to add index %d again\n", index);
+        return -1;
+    }
+    if (m_body_name_to_index.count(name) > 0) {
+        error_message("trying to add name %s again\n", name.c_str());
+        return -1;
+    }
+
+    m_index_to_body_name[index] = name;
+    m_body_name_to_index[name] = index;
+
+    return 0;
+}
+
+int MultiBodyNameMap::addJoint(const int index, const std::string& name) {
+    if (m_index_to_joint_name.count(index) > 0) {
+        error_message("trying to add index %d again\n", index);
+        return -1;
+    }
+    if (m_joint_name_to_index.count(name) > 0) {
+        error_message("trying to add name %s again\n", name.c_str());
+        return -1;
+    }
+
+    m_index_to_joint_name[index] = name;
+    m_joint_name_to_index[name] = index;
+
+    return 0;
+}
+
+int MultiBodyNameMap::getBodyName(const int index, std::string* name) const {
+    std::map<int, std::string>::const_iterator it = m_index_to_body_name.find(index);
+    if (it == m_index_to_body_name.end()) {
+        error_message("index %d not known\n", index);
+        return -1;
+    }
+    *name = it->second;
+    return 0;
+}
+
+int MultiBodyNameMap::getJointName(const int index, std::string* name) const {
+    std::map<int, std::string>::const_iterator it = m_index_to_joint_name.find(index);
+    if (it == m_index_to_joint_name.end()) {
+        error_message("index %d not known\n", index);
+        return -1;
+    }
+    *name = it->second;
+    return 0;
+}
+
+int MultiBodyNameMap::getBodyIndex(const std::string& name, int* index) const {
+    std::map<std::string, int>::const_iterator it = m_body_name_to_index.find(name);
+    if (it == m_body_name_to_index.end()) {
+        error_message("name %s not known\n", name.c_str());
+        return -1;
+    }
+    *index = it->second;
+    return 0;
+}
+
+int MultiBodyNameMap::getJointIndex(const std::string& name, int* index) const {
+    std::map<std::string, int>::const_iterator it = m_joint_name_to_index.find(name);
+    if (it == m_joint_name_to_index.end()) {
+        error_message("name %s not known\n", name.c_str());
+        return -1;
+    }
+    *index = it->second;
+    return 0;
+}
+}