Support for caching values on filesystem

Use USCXML_NOCACHE_FILES=YES to prevent, I will make this a build flag

20 files changed, 617 insertions, 175 deletions

diff --git a/src/uscxml/CMakeLists.txt b/src/uscxml/CMakeLists.txt
index 3497b18..459fe23 100644
--- a/src/uscxml/CMakeLists.txt
+++ b/src/uscxml/CMakeLists.txt
@@ -32,6 +32,15 @@ file(GLOB_RECURSE USCXML_MISC
   util/*.c
 	util/*.h
 )
+
+# Add URL.mm for MacOS / iOS
+if(APPLE OR IOS)
+	file(GLOB USCXML_APPLE util/*.mm)
+	list (APPEND USCXML_MISC ${USCXML_APPLE})
+	find_library(FOUNDATION_FRAMEWORK Foundation)
+	list (APPEND USCXML_CORE_LIBS ${FOUNDATION_FRAMEWORK})
+endif()
+
 source_group("Interpreter" FILES ${USCXML_MISC})
 list (APPEND USCXML_FILES ${USCXML_MISC})
 
@@ -84,4 +93,5 @@ SET(USCXML_DATAMODELS ${USCXML_DATAMODELS} PARENT_SCOPE)
 # set(USCXML_OPT_LIBS ${USCXML_OPT_LIBS} PARENT_SCOPE)
 set(USCXML_FILES ${USCXML_FILES} PARENT_SCOPE)
 set(USCXML_TRANSFORM_FILES ${USCXML_TRANSFORM_FILES} PARENT_SCOPE)
+set(USCXML_CORE_LIBS ${USCXML_CORE_LIBS} PARENT_SCOPE)
 # SET(PLUMA ${PLUMA} PARENT_SCOPE)
\ No newline at end of file
diff --git a/src/uscxml/debug/DebugSession.cpp b/src/uscxml/debug/DebugSession.cpp
index 9fa09eb..f6b3ae1 100644
--- a/src/uscxml/debug/DebugSession.cpp
+++ b/src/uscxml/debug/DebugSession.cpp
@@ -228,11 +228,13 @@ Data DebugSession::debugStop(const Data& data) {
 
 	if (_isRunning && _interpreterThread != NULL) {
 		_isRunning = false;
+
+		// unblock
+		_resumeCond.notify_all();
+
 		_interpreterThread->join();
 		delete(_interpreterThread);
 	}
-	// unblock
-	_resumeCond.notify_all();
 
 	_skipTo = Breakpoint();
 	replyData.compound["status"] = Data("success", Data::VERBATIM);
@@ -377,6 +379,7 @@ Data DebugSession::enableAllBreakPoints() {
 
 	return replyData;
 }
+
 Data DebugSession::disableAllBreakPoints() {
 	Data replyData;
 
@@ -386,6 +389,38 @@ Data DebugSession::disableAllBreakPoints() {
 	return replyData;
 }
 
+Data DebugSession::getIssues() {
+	Data replyData;
+
+	std::list<InterpreterIssue> issues = _interpreter.validate();
+	replyData.compound["status"] = Data("success", Data::VERBATIM);
+	for (auto issue : issues) {
+		Data issueData;
+
+		issueData.compound["message"] = Data(issue.message, Data::VERBATIM);
+		issueData.compound["xPath"] = Data(issue.xPath, Data::VERBATIM);
+		issueData.compound["specRef"] = Data(issue.specRef, Data::VERBATIM);
+
+		switch (issue.severity) {
+		case InterpreterIssue::USCXML_ISSUE_FATAL:
+			issueData.compound["severity"] = Data("FATAL", Data::VERBATIM);
+			break;
+		case InterpreterIssue::USCXML_ISSUE_WARNING:
+			issueData.compound["severity"] = Data("WARN", Data::VERBATIM);
+			break;
+		case InterpreterIssue::USCXML_ISSUE_INFO:
+			issueData.compound["severity"] = Data("INFO", Data::VERBATIM);
+			break;
+		default:
+			break;
+		}
+
+		replyData.compound["issues"].array.push_back(issueData);
+	}
+
+	return replyData;
+}
+
 Data DebugSession::debugEval(const Data& data) {
 	Data replyData;
 
@@ -416,69 +451,69 @@ Data DebugSession::debugEval(const Data& data) {
 }
 
 std::shared_ptr<LoggerImpl> DebugSession::create() {
-    return shared_from_this();
+	return shared_from_this();
 }
 
 void DebugSession::log(LogSeverity severity, const Event& event) {
-    Data d;
-    d.compound["data"] = event.data;
-    d.compound["name"] = Data(event.name);
-    d.compound["origin"] = Data(event.origin);
-    d.compound["origintype"] = Data(event.origintype);
-    
-    switch (event.eventType) {
-        case Event::Type::INTERNAL:
-            d.compound["eventType"] = Data("INTERNAL");
-            break;
-        case Event::Type::EXTERNAL:
-            d.compound["eventType"] = Data("EXTERNAL");
-            break;
-        case Event::Type::PLATFORM:
-            d.compound["eventType"] = Data("PLATFORM");
-            break;
-        default:
-            break;
-    }
-    if (!event.hideSendId)
-        d.compound["sendid"] = Data(event.sendid);
-    if (event.invokeid.size() > 0)
-        d.compound["invokeid"] = Data(event.invokeid);
-
-    // handle params
-    Data& params = d.compound["params"];
-    bool convertedToArray = false;
-    for (auto param : event.params) {
-        if (params.compound.find(param.first) != d.compound.end()) {
-            // no such key, add as literal data
-            d.compound[param.first] = param.second;
-        } else if (params.compound[param.first].array.size() > 0 && convertedToArray) {
-            // key is already an array
-            params.compound[param.first].array.push_back(param.second);
-        } else {
-            // key already given as literal data, move to array
-            Data& existingParam = params.compound[param.first];
-            params.compound[param.first].array.push_back(existingParam);
-            params.compound[param.first].array.push_back(param.second);
-            params.compound[param.first].compound.clear();
-            convertedToArray = true;
-        }
-    }
-    
-    // handle namelist
-    Data& namelist = d.compound["namelist"];
-    for (auto name : event.namelist) {
-        namelist.compound[name.first] = name.second;
-    }
-    
-    _debugger->pushData(shared_from_this(), d);
+	Data d;
+	d.compound["data"] = event.data;
+	d.compound["name"] = Data(event.name);
+	d.compound["origin"] = Data(event.origin);
+	d.compound["origintype"] = Data(event.origintype);
+
+	switch (event.eventType) {
+	case Event::Type::INTERNAL:
+		d.compound["eventType"] = Data("INTERNAL");
+		break;
+	case Event::Type::EXTERNAL:
+		d.compound["eventType"] = Data("EXTERNAL");
+		break;
+	case Event::Type::PLATFORM:
+		d.compound["eventType"] = Data("PLATFORM");
+		break;
+	default:
+		break;
+	}
+	if (!event.hideSendId)
+		d.compound["sendid"] = Data(event.sendid);
+	if (event.invokeid.size() > 0)
+		d.compound["invokeid"] = Data(event.invokeid);
+
+	// handle params
+	Data& params = d.compound["params"];
+	bool convertedToArray = false;
+	for (auto param : event.params) {
+		if (params.compound.find(param.first) != d.compound.end()) {
+			// no such key, add as literal data
+			d.compound[param.first] = param.second;
+		} else if (params.compound[param.first].array.size() > 0 && convertedToArray) {
+			// key is already an array
+			params.compound[param.first].array.push_back(param.second);
+		} else {
+			// key already given as literal data, move to array
+			Data& existingParam = params.compound[param.first];
+			params.compound[param.first].array.push_back(existingParam);
+			params.compound[param.first].array.push_back(param.second);
+			params.compound[param.first].compound.clear();
+			convertedToArray = true;
+		}
+	}
+
+	// handle namelist
+	Data& namelist = d.compound["namelist"];
+	for (auto name : event.namelist) {
+		namelist.compound[name.first] = name.second;
+	}
+
+	_debugger->pushData(shared_from_this(), d);
 }
 
 void DebugSession::log(LogSeverity severity, const Data& data) {
-    _debugger->pushData(shared_from_this(), data);
+	_debugger->pushData(shared_from_this(), data);
 }
 
 void DebugSession::log(LogSeverity severity, const std::string& message) {
-    _debugger->pushData(shared_from_this(), Data(message));
+	_debugger->pushData(shared_from_this(), Data(message));
 }
 
 }
diff --git a/src/uscxml/debug/DebugSession.h b/src/uscxml/debug/DebugSession.h
index 9224163..e258568 100644
--- a/src/uscxml/debug/DebugSession.h
+++ b/src/uscxml/debug/DebugSession.h
@@ -66,6 +66,7 @@ public:
 	Data disableBreakPoint(const Data& data);
 	Data enableAllBreakPoints();
 	Data disableAllBreakPoints();
+	Data getIssues();
 	Data debugEval(const Data& data);
 
 	void setDebugger(Debugger* debugger) {
@@ -80,12 +81,12 @@ public:
 		_markedForDeletion = mark;
 	}
 
-    // Logger
-    virtual std::shared_ptr<LoggerImpl> create();
-    
-    virtual void log(LogSeverity severity, const Event& event);
-    virtual void log(LogSeverity severity, const Data& data);
-    virtual void log(LogSeverity severity, const std::string& message);
+	// Logger
+	virtual std::shared_ptr<LoggerImpl> create();
+
+	virtual void log(LogSeverity severity, const Event& event);
+	virtual void log(LogSeverity severity, const Data& data);
+	virtual void log(LogSeverity severity, const std::string& message);
 
 protected:
 	void breakExecution(Data replyData);
diff --git a/src/uscxml/debug/DebuggerServlet.cpp b/src/uscxml/debug/DebuggerServlet.cpp
index 016d67c..44255c0 100644
--- a/src/uscxml/debug/DebuggerServlet.cpp
+++ b/src/uscxml/debug/DebuggerServlet.cpp
@@ -134,6 +134,8 @@ bool DebuggerServlet::requestFromHTTP(const HTTPServer::Request& request) {
 	} else if (boost::starts_with(request.data.at("path").atom, "/debug/disconnect")) {
 		processDisconnect(request);
 
+	} else if (boost::starts_with(request.data.at("path").atom, "/debug/issues")) {
+		replyData = session->getIssues();
 	} else if (boost::starts_with(request.data.at("path").atom, "/debug/breakpoint/enable/all")) {
 		replyData = session->enableAllBreakPoints();
 	} else if (boost::starts_with(request.data.at("path").atom, "/debug/breakpoint/disable/all")) {
diff --git a/src/uscxml/debug/DebuggerServlet.h b/src/uscxml/debug/DebuggerServlet.h
index 3b117bf..4cd04bb 100644
--- a/src/uscxml/debug/DebuggerServlet.h
+++ b/src/uscxml/debug/DebuggerServlet.h
@@ -50,6 +50,8 @@ public:
 	void processConnect(const HTTPServer::Request& request);
 	void processListSessions(const HTTPServer::Request& request);
 
+	void processIssues(const HTTPServer::Request& request);
+
 //	void processDebugPrepare(const HTTPServer::Request& request);
 //	void processDebugAttach(const HTTPServer::Request& request);
 //	void processDebugStart(const HTTPServer::Request& request);
diff --git a/src/uscxml/debug/InterpreterIssue.cpp b/src/uscxml/debug/InterpreterIssue.cpp
index 90e06b4..4ee4442 100644
--- a/src/uscxml/debug/InterpreterIssue.cpp
+++ b/src/uscxml/debug/InterpreterIssue.cpp
@@ -385,7 +385,7 @@ std::list<InterpreterIssue> InterpreterIssue::forInterpreter(InterpreterImpl* in
 
 		// check whether state is reachable
 		if (!DOMUtils::isMember(state, reachable) && areFromSameMachine(state, interpreter->_scxml)) {
-			issues.push_back(InterpreterIssue("State with id '" + stateId + "' is unreachable", state, InterpreterIssue::USCXML_ISSUE_FATAL));
+			issues.push_back(InterpreterIssue("State with id '" + stateId + "' is unreachable", state, InterpreterIssue::USCXML_ISSUE_WARNING));
 		}
 
 		// check for uniqueness of id attribute
@@ -1044,4 +1044,4 @@ std::ostream& operator<< (std::ostream& os, const InterpreterIssue& issue) {
 }
 
 
-}
\ No newline at end of file
+}
diff --git a/src/uscxml/interpreter/BasicEventQueue.cpp b/src/uscxml/interpreter/BasicEventQueue.cpp
index 2f8bd48..519754e 100644
--- a/src/uscxml/interpreter/BasicEventQueue.cpp
+++ b/src/uscxml/interpreter/BasicEventQueue.cpp
@@ -35,17 +35,17 @@ Event BasicEventQueue::dequeue(size_t blockMs) {
 	std::lock_guard<std::recursive_mutex> lock(_mutex);
 
 	if (blockMs > 0) {
-        using namespace std::chrono;
+		using namespace std::chrono;
 
-        // TODO: do read http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2661.htm
-        system_clock::time_point now = system_clock::now();
-        system_clock::time_point endTime = now + milliseconds(blockMs);
+		// TODO: do read http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2661.htm
+		system_clock::time_point now = system_clock::now();
+		system_clock::time_point endTime = now + milliseconds(blockMs);
+
+		// now + milliseconds(blockMs) may not have fitted into a duration type - limit to maximum duration
+		if (blockMs > system_clock::duration::max().count() - duration_cast<milliseconds>(now.time_since_epoch()).count()) {
+			endTime = system_clock::time_point::max();
+		}
 
-        // now + milliseconds(blockMs) may not have fitted into a duration type - limit to maximum duration
-        if (blockMs > system_clock::duration::max().count() - duration_cast<milliseconds>(now.time_since_epoch()).count()) {
-            endTime = system_clock::time_point::max();
-        }
-        
 		// block for given milliseconds or until queue is non-empty
 		while (endTime > std::chrono::system_clock::now() && _queue.empty()) {
 			_cond.wait_until(_mutex, endTime);
diff --git a/src/uscxml/interpreter/FastMicroStep.cpp b/src/uscxml/interpreter/FastMicroStep.cpp
index ed11fca..e41e9f7 100644
--- a/src/uscxml/interpreter/FastMicroStep.cpp
+++ b/src/uscxml/interpreter/FastMicroStep.cpp
@@ -22,6 +22,7 @@
 #include "FastMicroStep.h"
 #include "uscxml/util/DOM.h"
 #include "uscxml/util/String.h"
+#include "uscxml/util/Base64.hpp"
 #include "uscxml/util/Predicates.h"
 #include "uscxml/util/Convenience.h"
 #include "uscxml/interpreter/InterpreterMonitor.h"
@@ -102,6 +103,8 @@ void FastMicroStep::resortStates(DOMElement* element, const X& xmlPrefix) {
 	 everything else
 	 */
 
+	// TODO: We can do this in one iteration
+
 	DOMElement* child = element->getFirstElementChild();
 	while(child) {
 		resortStates(child, xmlPrefix);
@@ -194,9 +197,11 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 		_xmlPrefix = std::string(_xmlPrefix) + ":";
 	}
 
+	bool withCache = !envVarIsTrue("USCXML_NOCACHE_FILES");
+
 	resortStates(_scxml, _xmlPrefix);
-//    assert(false);
-//    throw NULL;
+
+	Data& cache = _callbacks->getCache().compound["FastMicroStep"];
 
 	/** -- All things states -- */
 
@@ -243,7 +248,20 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 		_states[0]->data = DOMUtils::filterChildElements(_xmlPrefix.str() + "data", dataModels, false);
 	}
 
+	auto currState = cache.compound["states"].array.begin();
+	auto endState = cache.compound["states"].array.end();
+
 	for (i = 0; i < _states.size(); i++) {
+		Data* cachedState = NULL;
+		if (withCache) {
+			if (currState != endState) {
+				cachedState = &(*currState);
+				currState++;
+			} else {
+				cache.compound["states"].array.push_back(Data());
+				cachedState = &(*cache.compound["states"].array.rbegin());
+			}
+		}
 		// collect states with an id attribute
 		if (HAS_ATTR(_states[i]->element, "id")) {
 			_stateIds[ATTR(_states[i]->element, "id")] = i;
@@ -273,7 +291,6 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 			}
 		}
 
-
 		// set the states type
 		if (false) {
 		} else if (iequals(TAGNAME(_states[i]->element), _xmlPrefix.str() + "initial")) {
@@ -297,17 +314,22 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 		}
 
 		// establish the states' completion
-		std::list<DOMElement*> completion = getCompletion(_states[i]->element);
-		for (j = 0; j < _states.size(); j++) {
-			if (!completion.empty() && _states[j]->element == completion.front()) {
-				_states[i]->completion[j] = true;
-				completion.pop_front();
-			} else {
-				_states[i]->completion[j] = false;
+		if (withCache && cachedState->compound.find("completion") != cachedState->compound.end()) {
+			_states[i]->completion = fromBase64(cachedState->compound["completion"]);
+		} else {
+			std::list<DOMElement*> completion = getCompletion(_states[i]->element);
+			for (j = 0; j < _states.size(); j++) {
+				if (!completion.empty() && _states[j]->element == completion.front()) {
+					_states[i]->completion[j] = true;
+					completion.pop_front();
+				} else {
+					_states[i]->completion[j] = false;
+				}
 			}
+			assert(completion.size() == 0);
+			if (withCache)
+				cachedState->compound["completion"] = Data(toBase64(_states[i]->completion));
 		}
-		assert(completion.size() == 0);
-
 		// this is set when establishing the completion
 		if (_states[i]->element->getUserData(X("hasHistoryChild")) == _states[i]) {
 			_states[i]->type |= USCXML_STATE_HAS_HISTORY;
@@ -354,46 +376,78 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 	}
 	assert(tmp.size() == 0);
 
+	auto currTrans = cache.compound["transitions"].array.begin();
+	auto endTrans = cache.compound["transitions"].array.end();
+
 	for (i = 0; i < _transitions.size(); i++) {
 
+		Data* cachedTrans = NULL;
+		if (withCache) {
+			if (currTrans != endTrans) {
+				cachedTrans = &(*currTrans);
+				currTrans++;
+			} else {
+				cache.compound["transitions"].array.push_back(Data());
+				cachedTrans = &(*cache.compound["transitions"].array.rbegin());
+			}
+		}
 		// establish the transitions' exit set
 		assert(_transitions[i]->element != NULL);
-//		std::cout << "i: " << i << std::endl << std::flush;
-		std::list<DOMElement*> exitList = getExitSetCached(_transitions[i]->element, _scxml);
-		_cache.exitSet[_transitions[i]->element] = exitList;
-
-		for (j = 0; j < _states.size(); j++) {
-			if (!exitList.empty() && _states[j]->element == exitList.front()) {
-				_transitions[i]->exitSet[j] = true;
-				exitList.pop_front();
-			} else {
-				_transitions[i]->exitSet[j] = false;
+
+		if (withCache && cachedTrans->compound.find("exitset") != cachedTrans->compound.end()) {
+			_transitions[i]->exitSet = fromBase64(cachedTrans->compound["exitset"]);
+		} else {
+			std::list<DOMElement*> exitList = getExitSetCached(_transitions[i]->element, _scxml);
+
+			for (j = 0; j < _states.size(); j++) {
+				if (!exitList.empty() && _states[j]->element == exitList.front()) {
+					_transitions[i]->exitSet[j] = true;
+					exitList.pop_front();
+				} else {
+					_transitions[i]->exitSet[j] = false;
+				}
 			}
+			assert(exitList.size() == 0);
+
+			if (withCache)
+				cachedTrans->compound["exitset"] = Data(toBase64(_transitions[i]->exitSet));
 		}
-		assert(exitList.size() == 0);
 
 		// establish the transitions' conflict set
-		for (j = i; j < _transitions.size(); j++) {
-			if (conflictsCached(_transitions[i]->element, _transitions[j]->element, _scxml)) {
-				_transitions[i]->conflicts[j] = true;
-			} else {
-				_transitions[i]->conflicts[j] = false;
+		if (withCache && cachedTrans->compound.find("conflicts") != cachedTrans->compound.end()) {
+			_transitions[i]->conflicts = fromBase64(cachedTrans->compound["conflicts"]);
+		} else {
+			for (j = i; j < _transitions.size(); j++) {
+				if (conflictsCached(_transitions[i]->element, _transitions[j]->element, _scxml)) {
+					_transitions[i]->conflicts[j] = true;
+				} else {
+					_transitions[i]->conflicts[j] = false;
+				}
+				//            std::cout << ".";
 			}
-//            std::cout << ".";
-		}
 
-		// conflicts matrix is symmetric
-		for (j = 0; j < i; j++) {
-			_transitions[i]->conflicts[j] = _transitions[j]->conflicts[i];
-		}
+			// conflicts matrix is symmetric
+			for (j = 0; j < i; j++) {
+				_transitions[i]->conflicts[j] = _transitions[j]->conflicts[i];
+			}
+			if (withCache)
+				cachedTrans->compound["conflicts"] = Data(toBase64(_transitions[i]->conflicts));
 
+		}
 
 		// establish the transitions' target set
-		std::list<std::string> targets = tokenize(ATTR(_transitions[i]->element, "target"));
-		for (auto tIter = targets.begin(); tIter != targets.end(); tIter++) {
-			if (_stateIds.find(*tIter) != _stateIds.end()) {
-				_transitions[i]->target[_stateIds[*tIter]] = true;
+		if (withCache && cachedTrans->compound.find("target") != cachedTrans->compound.end()) {
+			_transitions[i]->target = fromBase64(cachedTrans->compound["target"]);
+		} else {
+			std::list<std::string> targets = tokenize(ATTR(_transitions[i]->element, "target"));
+			for (auto tIter = targets.begin(); tIter != targets.end(); tIter++) {
+				if (_stateIds.find(*tIter) != _stateIds.end()) {
+					_transitions[i]->target[_stateIds[*tIter]] = true;
+				}
 			}
+			if (withCache)
+				cachedTrans->compound["target"] = Data(toBase64(_transitions[i]->target));
+
 		}
 
 		// the transition's source
@@ -422,7 +476,6 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 			_transitions[i]->type |= USCXML_TRANS_INITIAL;
 		}
 
-
 		// the transitions event and condition
 		_transitions[i]->event = (HAS_ATTR(_transitions[i]->element, "event") ?
 		                          ATTR(_transitions[i]->element, "event") : "");
@@ -433,10 +486,39 @@ void FastMicroStep::init(XERCESC_NS::DOMElement* scxml) {
 		if (_transitions[i]->element->getChildElementCount() > 0) {
 			_transitions[i]->onTrans = _transitions[i]->element;
 		}
-
 	}
 	_cache.exitSet.clear();
 	_isInitialized = true;
+
+}
+
+std::string FastMicroStep::toBase64(const boost::dynamic_bitset<BITSET_BLOCKTYPE>& bitset) {
+	std::vector<boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type> bytes(bitset.num_blocks() + 1);
+	boost::to_block_range(bitset, bytes.begin());
+
+	std::string encoded;
+	encoded.resize(sizeof(boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type) * bytes.size());
+	bytes[bytes.size() - 1] = static_cast<boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type>(bitset.size());
+
+	static_assert(sizeof(boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type) >= sizeof(size_t), "Block type too small to encode dynamic_bitset length");
+
+	memcpy(&encoded[0], &bytes[0], sizeof(boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type) * bytes.size());
+	return base64Encode(encoded.c_str(), encoded.size(), true);
+}
+
+boost::dynamic_bitset<BITSET_BLOCKTYPE> FastMicroStep::fromBase64(const std::string& encoded) {
+
+	std::string decoded = base64Decode(encoded);
+	assert(decoded.size() % sizeof(boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type) == 0);
+	std::vector<boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type> bytes(decoded.size() / sizeof(boost::dynamic_bitset<BITSET_BLOCKTYPE>::block_type));
+
+	memcpy(&bytes[0], &decoded[0], decoded.size());
+
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> bitset;
+	bitset.init_from_block_range(bytes.begin(), --bytes.end());
+	bitset.resize(bytes[bytes.size() - 1]);
+
+	return bitset;
 }
 
 void FastMicroStep::markAsCancelled() {
@@ -451,13 +533,13 @@ InterpreterState FastMicroStep::step(size_t blockMs) {
 
 	size_t i, j, k;
 
-	boost::dynamic_bitset<> exitSet(_states.size(), false);
-	boost::dynamic_bitset<> entrySet(_states.size(), false);
-	boost::dynamic_bitset<> targetSet(_states.size(), false);
-	boost::dynamic_bitset<> tmpStates(_states.size(), false);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> exitSet(_states.size(), false);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> entrySet(_states.size(), false);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> targetSet(_states.size(), false);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> tmpStates(_states.size(), false);
 
-	boost::dynamic_bitset<> conflicts(_transitions.size(), false);
-	boost::dynamic_bitset<> transSet(_transitions.size(), false);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> conflicts(_transitions.size(), false);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> transSet(_transitions.size(), false);
 
 #ifdef USCXML_VERBOSE
 	std::cerr << "Config: ";
@@ -675,14 +757,14 @@ ESTABLISH_ENTRYSET:
 
 	/* iterate for ancestors */
 	i = entrySet.find_first();
-	while(i != boost::dynamic_bitset<>::npos) {
+	while(i != boost::dynamic_bitset<BITSET_BLOCKTYPE>::npos) {
 		entrySet |= USCXML_GET_STATE(i).ancestors;
 		i = entrySet.find_next(i);
 	}
 
 	/* iterate for descendants */
 	i = entrySet.find_first();
-	while(i != boost::dynamic_bitset<>::npos) {
+	while(i != boost::dynamic_bitset<BITSET_BLOCKTYPE>::npos) {
 
 
 		switch (USCXML_STATE_MASK(USCXML_GET_STATE(i).type)) {
@@ -813,7 +895,7 @@ ESTABLISH_ENTRYSET:
 
 	/* TAKE_TRANSITIONS: */
 	i = transSet.find_first();
-	while(i != boost::dynamic_bitset<>::npos) {
+	while(i != boost::dynamic_bitset<BITSET_BLOCKTYPE>::npos) {
 		if ((USCXML_GET_TRANS(i).type & (USCXML_TRANS_HISTORY | USCXML_TRANS_INITIAL)) == 0) {
 			USCXML_MONITOR_CALLBACK1(_callbacks->getMonitors(), beforeTakingTransition, USCXML_GET_TRANS(i).element);
 
@@ -841,7 +923,7 @@ ESTABLISH_ENTRYSET:
 
 	/* ENTER_STATES: */
 	i = entrySet.find_first();
-	while(i != boost::dynamic_bitset<>::npos) {
+	while(i != boost::dynamic_bitset<BITSET_BLOCKTYPE>::npos) {
 
 		if (BIT_HAS(i, _configuration)) {
 			// already active
@@ -924,7 +1006,7 @@ ESTABLISH_ENTRYSET:
 				            BIT_HAS(j, USCXML_GET_STATE(i).ancestors)) {
 					tmpStates.reset();
 					k = _configuration.find_first();
-					while (k != boost::dynamic_bitset<>::npos) {
+					while (k != boost::dynamic_bitset<BITSET_BLOCKTYPE>::npos) {
 						if (BIT_HAS(j, USCXML_GET_STATE(k).ancestors)) {
 							if (USCXML_STATE_MASK(USCXML_GET_STATE(k).type) == USCXML_STATE_FINAL) {
 								tmpStates ^= USCXML_GET_STATE(k).ancestors;
@@ -981,7 +1063,7 @@ bool FastMicroStep::isInState(const std::string& stateId) {
 std::list<XERCESC_NS::DOMElement*> FastMicroStep::getConfiguration() {
 	std::list<XERCESC_NS::DOMElement*> config;
 	size_t i = _configuration.find_first();
-	while(i != boost::dynamic_bitset<>::npos) {
+	while(i != boost::dynamic_bitset<BITSET_BLOCKTYPE>::npos) {
 		config.push_back(_states[i]->element);
 		i = _configuration.find_next(i);
 	}
@@ -1038,7 +1120,7 @@ std::list<DOMElement*> FastMicroStep::getHistoryCompletion(const DOMElement* his
 /**
  * Print name of states contained in a (debugging).
  */
-void FastMicroStep::printStateNames(const boost::dynamic_bitset<>& a) {
+void FastMicroStep::printStateNames(const boost::dynamic_bitset<BITSET_BLOCKTYPE>& a) {
 	size_t i;
 	const char* seperator = "";
 	for (i = 0; i < a.size(); i++) {
diff --git a/src/uscxml/interpreter/FastMicroStep.h b/src/uscxml/interpreter/FastMicroStep.h
index 810b793..db3e724 100644
--- a/src/uscxml/interpreter/FastMicroStep.h
+++ b/src/uscxml/interpreter/FastMicroStep.h
@@ -33,6 +33,12 @@
 
 #include <boost/dynamic_bitset.hpp>
 
+#ifdef _WIN32
+#define BITSET_BLOCKTYPE size_t
+#else
+#define BITSET_BLOCKTYPE
+#endif
+
 namespace uscxml {
 
 /**
@@ -57,11 +63,11 @@ protected:
 		Transition() : element(NULL), source(0), onTrans(NULL), type(0) {}
 
 		XERCESC_NS::DOMElement* element;
-		boost::dynamic_bitset<> conflicts;
-		boost::dynamic_bitset<> exitSet;
+		boost::dynamic_bitset<BITSET_BLOCKTYPE> conflicts;
+		boost::dynamic_bitset<BITSET_BLOCKTYPE> exitSet;
 
 		uint32_t source;
-		boost::dynamic_bitset<> target;
+		boost::dynamic_bitset<BITSET_BLOCKTYPE> target;
 
 		XERCESC_NS::DOMElement* onTrans;
 
@@ -77,9 +83,9 @@ protected:
 		State() : element(NULL), parent(0), documentOrder(0), doneData(NULL), type(0) {}
 
 		XERCESC_NS::DOMElement* element;
-		boost::dynamic_bitset<> completion;
-		boost::dynamic_bitset<> children;
-		boost::dynamic_bitset<> ancestors;
+		boost::dynamic_bitset<BITSET_BLOCKTYPE> completion;
+		boost::dynamic_bitset<BITSET_BLOCKTYPE> children;
+		boost::dynamic_bitset<BITSET_BLOCKTYPE> ancestors;
 		uint32_t parent;
 		uint32_t documentOrder;
 
@@ -108,12 +114,12 @@ protected:
 	std::vector<Transition*> _transitions;
 	std::list<XERCESC_NS::DOMElement*> _globalScripts;
 
-	boost::dynamic_bitset<> _configuration;
-	boost::dynamic_bitset<> _invocations;
-	boost::dynamic_bitset<> _history;
-	boost::dynamic_bitset<> _initializedData;
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> _configuration;
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> _invocations;
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> _history;
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> _initializedData;
 
-	std::set<boost::dynamic_bitset<> > _microstepConfigurations;
+	std::set<boost::dynamic_bitset<BITSET_BLOCKTYPE> > _microstepConfigurations;
 
 	Binding _binding;
 	XERCESC_NS::DOMElement* _scxml;
@@ -130,13 +136,16 @@ private:
 
 	bool conflictsCached(const XERCESC_NS::DOMElement* t1, const XERCESC_NS::DOMElement* t2, const XERCESC_NS::DOMElement* root); ///< overrides implementation Predicates::conflicts for speed
 
+	std::string toBase64(const boost::dynamic_bitset<BITSET_BLOCKTYPE>& bitset);
+	boost::dynamic_bitset<BITSET_BLOCKTYPE> fromBase64(const std::string& encoded);
+
 	std::list<XERCESC_NS::DOMElement*> getExitSetCached(const XERCESC_NS::DOMElement* transition,
 	        const XERCESC_NS::DOMElement* root);
 
 	CachedPredicates _cache;
 
 #ifdef USCXML_VERBOSE
-	void printStateNames(const boost::dynamic_bitset<>& bitset);
+	void printStateNames(const boost::dynamic_bitset<BITSET_BLOCKTYPE>& bitset);
 #endif
 
 };
diff --git a/src/uscxml/interpreter/InterpreterImpl.cpp b/src/uscxml/interpreter/InterpreterImpl.cpp
index 43059bf..8762b95 100644
--- a/src/uscxml/interpreter/InterpreterImpl.cpp
+++ b/src/uscxml/interpreter/InterpreterImpl.cpp
@@ -27,11 +27,13 @@
 #include "uscxml/messages/Event.h"
 #include "uscxml/util/String.h"
 #include "uscxml/util/Predicates.h"
+#include "uscxml/util/MD5.hpp"
 #include "uscxml/plugins/InvokerImpl.h"
 
 #include "uscxml/interpreter/Logging.h"
 
 #include <iostream>
+#include <fstream>
 
 #include <assert.h>
 #include <algorithm>
@@ -108,6 +110,15 @@ InterpreterImpl::~InterpreterImpl() {
 //    assert(_invokers.size() == 0);
 //    ::xercesc_3_1::XMLPlatformUtils::Terminate();
 
+	if (!envVarIsTrue("USCXML_NOCACHE_FILES")) {
+		// save our cache
+		std::string sharedTemp = URL::getTempDir(true);
+		std::ofstream dataFS(sharedTemp + PATH_SEPERATOR + md5(_baseURL) + ".uscxml.cache");
+		if (dataFS) {
+			dataFS << _cache;
+			dataFS.close();
+		}
+	}
 }
 
 void InterpreterImpl::cancel() {
@@ -159,7 +170,6 @@ SCXML_STOP_SEARCH:
 		_binding = (HAS_ATTR(_scxml, "binding") && iequals(ATTR(_scxml, "binding"), "late") ? LATE : EARLY);
 
 	}
-
 }
 
 void InterpreterImpl::init() {
@@ -169,6 +179,33 @@ void InterpreterImpl::init() {
 
 	setupDOM();
 
+	if (!envVarIsTrue("USCXML_NOCACHE_FILES")) {
+		// try to open chached data from resource directory
+		std::string sharedTemp = URL::getTempDir(true);
+		std::ifstream dataFS(sharedTemp + PATH_SEPERATOR + md5(_baseURL) + ".uscxml.cache");
+		if (dataFS.is_open()) {
+			std::string cacheStr((std::istreambuf_iterator<char>(dataFS)),
+			                     std::istreambuf_iterator<char>());
+			_cache = Data::fromJSON(cacheStr);
+		}
+
+		// get md5 of current document
+		std::stringstream ss;
+		ss << *_document;
+		_md5 = md5(ss.str());
+
+		if (_cache.compound.find("InterpreterImpl") != _cache.compound.end() &&
+		        _cache.compound["InterpreterImpl"].compound.find("md5") != _cache.compound["InterpreterImpl"].compound.end() &&
+		        _cache.compound["InterpreterImpl"].compound["md5"].atom != _md5) {
+
+			// that's not our cache!
+			_cache.clear();
+		}
+
+		_cache.compound["InterpreterImpl"].compound["baseURL"] = Data(std::string(_baseURL));
+		_cache.compound["InterpreterImpl"].compound["md5"] = Data(_md5);
+	}
+
 	// register io processors
 	std::map<std::string, IOProcessorImpl*> ioProcs = _factory->getIOProcessors();
 	for (auto ioProcIter = ioProcs.begin(); ioProcIter != ioProcs.end(); ioProcIter++) {
diff --git a/src/uscxml/interpreter/InterpreterImpl.h b/src/uscxml/interpreter/InterpreterImpl.h
index 1243f7c..0efc70a 100644
--- a/src/uscxml/interpreter/InterpreterImpl.h
+++ b/src/uscxml/interpreter/InterpreterImpl.h
@@ -143,6 +143,10 @@ public:
 		return Interpreter(shared_from_this());
 	}
 
+	virtual Data& getCache() {
+		return _cache;
+	}
+
 	/**
 	 DataModelCallbacks
 	 */
@@ -284,6 +288,7 @@ protected:
 	Factory* _factory;
 
 	URL _baseURL;
+	std::string _md5;
 
 	MicroStep _microStepper;
 	DataModel _dataModel;
@@ -305,6 +310,8 @@ protected:
 	std::set<std::string> _autoForwarders;
 	std::set<InterpreterMonitor*> _monitors;
 
+	Data _cache;
+
 private:
 	void setupDOM();
 };
diff --git a/src/uscxml/interpreter/MicroStepImpl.h b/src/uscxml/interpreter/MicroStepImpl.h
index 1544e78..e3f8299 100644
--- a/src/uscxml/interpreter/MicroStepImpl.h
+++ b/src/uscxml/interpreter/MicroStepImpl.h
@@ -60,6 +60,9 @@ public:
 	virtual std::set<InterpreterMonitor*> getMonitors() = 0;
 	virtual Interpreter getInterpreter() = 0;
 	virtual Logger getLogger() = 0;
+
+	/** Saved State */
+	virtual Data& getCache() = 0;
 };
 
 /**
diff --git a/src/uscxml/messages/Data.cpp b/src/uscxml/messages/Data.cpp
index b2d08e4..de9644b 100644
--- a/src/uscxml/messages/Data.cpp
+++ b/src/uscxml/messages/Data.cpp
@@ -283,8 +283,6 @@ std::string Data::toJSON(const Data& data) {
 	} else {
 		if (data.type == Data::VERBATIM) {
 			os << "\"\""; // empty string
-		} else {
-			os << "null";
 		}
 	}
 	return os.str();
diff --git a/src/uscxml/messages/Data.h b/src/uscxml/messages/Data.h
index 2cf1945..17d37cb 100644
--- a/src/uscxml/messages/Data.h
+++ b/src/uscxml/messages/Data.h
@@ -73,6 +73,16 @@ public:
 
 	~Data() {}
 
+	void clear() {
+		type = VERBATIM;
+		compound.clear();
+		array.clear();
+		atom.clear();
+		adoptedDoc.reset();
+		binary = Blob();
+		node = NULL;
+	}
+
 	bool empty() const {
 		bool hasContent = (atom.length() > 0 || !compound.empty() || !array.empty() || binary || node);
 		return !hasContent;
@@ -101,18 +111,20 @@ public:
 		return (!compound.empty() && compound.find(key) != compound.end());
 	}
 
-	Data& operator[](const std::string& key) {
-		return operator[](key.c_str());
-	}
+#ifndef SWIGIMPORTED
 
-	const Data& operator[](const std::string& key) const {
-		return operator[](key.c_str());
+	Data& operator[](const std::string& key) {
+		return compound[key];
 	}
 
 	Data& operator[](const char* key) {
 		return compound[key];
 	}
 
+	const Data& operator[](const std::string& key) const {
+		return compound.at(key);
+	}
+
 	const Data& operator[](const char* key) const {
 		return compound.at(key);
 	}
@@ -125,6 +137,7 @@ public:
 		for (size_t i = 0; i < index; i++, arrayIter++) {}
 		return *arrayIter;
 	}
+#endif
 
 	const Data at(const std::string& key) const {
 		return at(key.c_str());
@@ -179,14 +192,6 @@ public:
 	static std::string toJSON(const Data& data);
 	std::string asJSON() const;
 
-
-	std::map<std::string, Data> getCompound() {
-		return compound;
-	}
-	void setCompound(const std::map<std::string, Data>& compound) {
-		this->compound = compound;
-	}
-
 	std::list<Data> getArray() {
 		return array;
 	}
@@ -215,6 +220,15 @@ public:
 		this->type = type;
 	}
 
+	// Bug in SWIG 3.0.8 Python: Data in a map has to be fully qualified!
+	std::map<std::string, uscxml::Data> getCompound() {
+		return compound;
+	}
+
+	void setCompound(const std::map<std::string, uscxml::Data>& compound) {
+		this->compound = compound;
+	}
+
 #ifdef SWIGIMPORTED
 protected:
 #endif
diff --git a/src/uscxml/util/Base64.hpp b/src/uscxml/util/Base64.hpp
index e3cbe03..d9f9ac1 100644
--- a/src/uscxml/util/Base64.hpp
+++ b/src/uscxml/util/Base64.hpp
@@ -40,9 +40,9 @@ USCXML_API inline std::string base64Decode(const std::string& data) {
 	base64_init_decodestate(ctx);
 	
 	char* out = (char*)malloc(data.size());
-	base64_decode_block(data.data(), data.size(), out, ctx);
+	size_t size = base64_decode_block(data.data(), data.size(), out, ctx);
 	free(ctx);
-	std::string result(out);
+	std::string result(out, size);
 	free(out);
 	return result;
 }
diff --git a/src/uscxml/util/Convenience.cpp b/src/uscxml/util/Convenience.cpp
index a0263d2..4f47449 100644
--- a/src/uscxml/util/Convenience.cpp
+++ b/src/uscxml/util/Convenience.cpp
@@ -24,22 +24,22 @@
 namespace uscxml {
 
 NumAttr::NumAttr(const std::string& str) {
-    size_t valueStart = str.find_first_of("0123456789.");
-    if (valueStart != std::string::npos) {
-        size_t valueEnd = str.find_last_of("0123456789.");
-        if (valueEnd != std::string::npos) {
-            value = str.substr(valueStart, (valueEnd - valueStart) + 1);
-            size_t unitStart = str.find_first_not_of(" \t", valueEnd + 1);
-            if (unitStart != std::string::npos) {
-                size_t unitEnd = str.find_last_of(" \t");
-                if (unitEnd != std::string::npos && unitEnd > unitStart) {
-                    unit = str.substr(unitStart, unitEnd - unitStart);
-                } else {
-                    unit = str.substr(unitStart, str.length() - unitStart);
-                }
-            }
-        }
-    }
+	size_t valueStart = str.find_first_of("0123456789.");
+	if (valueStart != std::string::npos) {
+		size_t valueEnd = str.find_last_of("0123456789.");
+		if (valueEnd != std::string::npos) {
+			value = str.substr(valueStart, (valueEnd - valueStart) + 1);
+			size_t unitStart = str.find_first_not_of(" \t", valueEnd + 1);
+			if (unitStart != std::string::npos) {
+				size_t unitEnd = str.find_last_of(" \t");
+				if (unitEnd != std::string::npos && unitEnd > unitStart) {
+					unit = str.substr(unitStart, unitEnd - unitStart);
+				} else {
+					unit = str.substr(unitStart, str.length() - unitStart);
+				}
+			}
+		}
+	}
 }
 
 
diff --git a/src/uscxml/util/Convenience.h b/src/uscxml/util/Convenience.h
index cb4416d..c12e0e4 100644
--- a/src/uscxml/util/Convenience.h
+++ b/src/uscxml/util/Convenience.h
@@ -45,7 +45,7 @@ template <typename T> T strTo(std::string tmp) {
 
 class USCXML_API NumAttr {
 public:
-    NumAttr(const std::string& str);
+	NumAttr(const std::string& str);
 	std::string value;
 	std::string unit;
 };
diff --git a/src/uscxml/util/URL.cpp b/src/uscxml/util/URL.cpp
index 0885b47..845a972 100644
--- a/src/uscxml/util/URL.cpp
+++ b/src/uscxml/util/URL.cpp
@@ -29,14 +29,17 @@
 #include <curl/curl.h>
 #include <uriparser/Uri.h>
 
+#include <sys/types.h>
+#include <sys/stat.h>
 
 #ifdef _WIN32
 #include <direct.h>
+#include <Shlobj.h>
 
 #define getcwd _getcwd
 #else
 #include <unistd.h> // getcwd
-//#include <pwd.h>
+#include <pwd.h> // getpwuid
 #endif
 
 #define DOWNLOAD_IF_NECESSARY if (!_isDownloaded) { download(true); }
@@ -44,6 +47,157 @@
 
 namespace uscxml {
 
+std::string URL::currTmpDir;
+
+std::string URL::getTempDir(bool shared) {
+
+#ifdef _WIN32
+	struct stat st = { 0 };
+	TCHAR tmpPrefix [MAX_PATH];
+
+	// retrieve and optionally create temporary directory
+	if (!GetTempPath(MAX_PATH, tmpPrefix)) {
+		ERROR_EXECUTION_THROW(std::string("Cannot retrieve temporary directory"));
+	}
+	if (stat(tmpPrefix, &st) == -1) {
+		CreateDirectory(tmpPrefix, NULL);
+		if (GetLastError() == ERROR_PATH_NOT_FOUND) {
+			ERROR_EXECUTION_THROW(std::string("Cannot create a temporary directory at '") + tmpPrefix + "'");
+		}
+	}
+
+	if (shared) {
+		// create uscxml folder in temporary directory
+		std::string sharedTmpDir = std::string(tmpPrefix) + PATH_SEPERATOR + "uscxml";
+
+		if (stat(sharedTmpDir.c_str(), &st) == -1) {
+			CreateDirectory (sharedTmpDir.c_str(), NULL);
+			if (GetLastError() == ERROR_PATH_NOT_FOUND) {
+				ERROR_EXECUTION_THROW(std::string("Cannot create a temporary directory at '") + sharedTmpDir + "'");
+			}
+		}
+		return sharedTmpDir;
+
+	} else {
+		if (currTmpDir.size() == 0) {
+			// create random folder in temporary directory
+			// http://stackoverflow.com/questions/6287475/creating-a-unique-temporary-directory-from-pure-c-in-windows
+			// https://msdn.microsoft.com/en-us/library/windows/desktop/aa363875(v=vs.85).aspx
+			TCHAR tempFileName[MAX_PATH];
+			if (GetTempFileName(tmpPrefix, // directory for tmp files
+			                    TEXT("uscxml."),     // temp file name prefix
+			                    0,                // create unique name
+			                    tempFileName)) {
+				DeleteFile(tempFileName);
+
+				if (stat(tempFileName, &st) == -1) {
+					CreateDirectory(tempFileName, NULL);
+					if (GetLastError() == ERROR_PATH_NOT_FOUND) {
+						ERROR_EXECUTION_THROW(std::string("Cannot create a temporary directory at '") + tempFileName + "'");
+					}
+				}
+
+				currTmpDir = tempFileName;
+			} else {
+				ERROR_EXECUTION_THROW(std::string("Cannot create a temporary directory at '") + tmpPrefix + "'");
+			}
+		}
+		return currTmpDir;
+	}
+
+#else
+	std::string tmpPrefix = "/tmp";
+	const char* tmpEnv = getenv("TMPDIR");
+	if (tmpEnv != NULL)
+		tmpPrefix = tmpEnv;
+
+	if (tmpPrefix[tmpPrefix.size() - 1] != PATH_SEPERATOR)
+		tmpPrefix += PATH_SEPERATOR;
+
+	if (shared) {
+		struct stat st = {0};
+
+		std::string sharedTmpDir = tmpPrefix + "uscxml";
+		if (stat(sharedTmpDir.c_str(), &st) == -1) {
+			int err = mkdir(sharedTmpDir.c_str(), S_IRWXU | S_IRWXG | S_IRWXO); // 777
+			if (err)
+				ERROR_EXECUTION_THROW(std::string("Cannot create a temporary directory at '") + sharedTmpDir + "':" + strerror(errno));
+
+		}
+		return sharedTmpDir;
+
+	} else {
+		if (currTmpDir.size() == 0) {
+			std::string tmpPrefix = "/tmp";
+			const char* tmpEnv = getenv("TMPDIR");
+			if (tmpEnv != NULL)
+				tmpPrefix = tmpEnv;
+			const char* tmpName = mkdtemp((char*)std::string(tmpPrefix + "uscxml.XXXXXX").c_str()); // can we merely drop the constness?
+			if (tmpName != NULL) {
+				currTmpDir = tmpName;
+			} else {
+				ERROR_EXECUTION_THROW(std::string("Cannot create a temporary directory:") + strerror(errno));
+			}
+		}
+		return currTmpDir;
+	}
+#endif
+}
+
+// Version for MacOSX in URL.mm
+#if (!defined APPLE && !defined IOS)
+std::string URL::getResourceDir() {
+#ifdef _WIN32
+	TCHAR szPath[MAX_PATH];
+	std::string resourceDir;
+	if (SHGetFolderPath(NULL, CSIDL_APPDATA, NULL, 0, szPath) == S_OK) {
+		resourceDir = std::string(szPath) + PATH_SEPERATOR + "uscxml";
+	} else {
+		char* envData = getenv("APPDATA");
+		if (envData) {
+			resourceDir = std::string(envData) + PATH_SEPERATOR + "uscxml";
+		} else {
+			ERROR_EXECUTION_THROW("Could not get resource directory");
+		}
+	}
+
+	struct stat st = { 0 };
+
+	if (stat(resourceDir.c_str(), &st) == -1) {
+		CreateDirectory(resourceDir.c_str(), NULL);
+		if (GetLastError() == ERROR_PATH_NOT_FOUND) {
+			ERROR_EXECUTION_THROW(std::string("Cannot create a resource directory at '") + resourceDir + "'");
+		}
+	}
+	return resourceDir;
+
+#else
+	struct passwd* pw = getpwuid(getuid());
+	std::string homedir(pw->pw_dir);
+	struct stat dirStat;
+	int err = 0;
+
+	err = stat(std::string(homedir + PATH_SEPERATOR + ".config").c_str(), &dirStat);
+	if (err == ENOENT) {
+		err = mkdir(std::string(homedir + PATH_SEPERATOR + ".config").c_str(), S_IWUSR | S_IRUSR | S_IROTH);
+	}
+
+	err = stat(std::string(homedir + PATH_SEPERATOR + ".config" + PATH_SEPERATOR + "uscxml").c_str(), &dirStat);
+	if (err != 0) {
+		// std::cout << std::string(homedir + PATH_SEPERATOR + ".config" + PATH_SEPERATOR + "uscxml") << std::endl;
+		err = mkdir(std::string(homedir + PATH_SEPERATOR + ".config" + PATH_SEPERATOR + "uscxml").c_str(),
+		            S_IWUSR | S_IRUSR | S_IROTH | S_IRGRP | S_IXUSR | S_IXOTH | S_IXGRP);
+	}
+
+	err = stat(std::string(homedir + PATH_SEPERATOR + ".config" + PATH_SEPERATOR + "uscxml").c_str(), &dirStat);
+	if (err == 0) {
+		return homedir + PATH_SEPERATOR + ".config" + PATH_SEPERATOR + "uscxml";
+	}
+	return "";
+#endif
+}
+#endif
+
 void URLImpl::prepareException(ErrorEvent& exception, int errorCode, const std::string& origUri, void* parser) {
 	exception.data.compound["uri"].atom = origUri;
 
@@ -808,9 +962,19 @@ void URLFetcher::perform() {
 		rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep, &timeout);
 
 		switch(rc) {
-		case -1:
+		case -1: {
 			/* select error */
+#ifdef _WIN32
+			char *s = NULL;
+			FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+			              NULL, WSAGetLastError(),
+			              MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+			              (LPSTR)&s, 0, NULL);
+			LOGD(USCXML_WARN) << "select: " << s;
+			LocalFree(s);
+#endif
 			break;
+		}
 		case 0: /* timeout */
 		default: { /* action */
 			std::lock_guard<std::recursive_mutex> lock(_mutex);
diff --git a/src/uscxml/util/URL.h b/src/uscxml/util/URL.h
index c83e3b1..9ad2f8e 100644
--- a/src/uscxml/util/URL.h
+++ b/src/uscxml/util/URL.h
@@ -136,6 +136,19 @@ public:
 
 	URL(const std::string url) : _impl(new URLImpl(url)) {}
 
+	/**
+	 * Get a persistant, shared directory for resources
+	 * @return A path to an existing directory for resources.
+	 */
+	static std::string getResourceDir();
+
+	/**
+	 * Get a temporary, shared or private directory for resources
+	 * @param shared Whether the temporary directory is shared among instances.
+	 * @return A path to an existing directory for temporary files.
+	 */
+	static std::string getTempDir(bool shared = true);
+
 	bool isAbsolute() {
 		return _impl->isAbsolute();
 	}
@@ -241,6 +254,8 @@ public:
 protected:
 	std::shared_ptr<URLImpl> _impl;
 	friend class URLFetcher;
+	static std::string currTmpDir;
+
 };
 
 class USCXML_API URLFetcher {
@@ -270,6 +285,7 @@ protected:
 	std::map<void*, void*> _handlesToHeaders;
 	void* _multiHandle = NULL;
 	char* _envProxy = NULL;
+
 };
 
 }
diff --git a/src/uscxml/util/URL.mm b/src/uscxml/util/URL.mm
new file mode 100644
index 0000000..881b3e2
--- /dev/null
+++ b/src/uscxml/util/URL.mm
@@ -0,0 +1,62 @@
+/**
+ *  @file
+ *  @author     2012-2013 Stefan Radomski (stefan.radomski@cs.tu-darmstadt.de)
+ *  @copyright  Simplified BSD
+ *
+ *  @cond
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the FreeBSD license as published by the FreeBSD
+ *  project.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *  You should have received a copy of the FreeBSD license along with this
+ *  program. If not, see <http://www.opensource.org/licenses/bsd-license>.
+ *  @endcond
+ */
+
+#include "URL.h"
+#include "Foundation/Foundation.h"
+
+#ifdef __has_feature
+# if __has_feature(objc_arc)
+#   define(HAS_AUTORELEASE_POOL)
+# endif
+#endif
+
+namespace uscxml {
+
+std::string URL::getResourceDir() {
+	std::string path;
+#if HAS_AUTORELEASE_POOL
+  @autoreleasepool {
+#else
+    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
+#endif
+    NSString *bundleId = [[NSBundle mainBundle] bundleIdentifier];
+    if (bundleId != nil) {
+        NSString *resourcePath = [[NSBundle mainBundle] resourcePath];
+        path = [resourcePath cStringUsingEncoding:NSUTF8StringEncoding];
+    } else {
+        // we are not actually in a bundle, fall back to /tmp
+        NSFileManager *fm = [NSFileManager defaultManager];
+        NSURL* resURL = [[fm homeDirectoryForCurrentUser] URLByAppendingPathComponent:@".uscxml"];
+        NSString* resPath = [NSString stringWithUTF8String:[resURL fileSystemRepresentation]];
+        
+        if (![fm fileExistsAtPath:resPath]) {
+            [fm createDirectoryAtPath:resPath withIntermediateDirectories:YES attributes:nil error:nil];
+        }
+        path = [resPath cStringUsingEncoding:NSUTF8StringEncoding];
+    }
+
+#if HAS_AUTORELEASE_POOL
+  }
+#else
+  [pool drain];
+#endif
+	return path;
+}
+	
+}