Add maximum_results parameter to resolver::results()

Author: tstenner

src/lsl_resolver_c.cpp

@@ -86,13 +86,10 @@ LIBLSL_C_API lsl_continuous_resolver lsl_create_continuous_resolver_bypred(const
 */
 LIBLSL_C_API int32_t lsl_resolver_results(lsl_continuous_resolver res, lsl_streaminfo *buffer, uint32_t buffer_elements) {
 	try {
-		// query it
-		resolver_impl *resolver = res;
-		std::vector<stream_info_impl> tmp = resolver->results();
+		std::vector<stream_info_impl> tmp = res->results(buffer_elements);
 		// allocate new stream_info_impl's and assign to the buffer
-		uint32_t result = buffer_elements<tmp.size() ? buffer_elements : (uint32_t)tmp.size();
-		for (uint32_t k = 0; k < result; k++) buffer[k] = new stream_info_impl(tmp[k]);
-		return result;
+		for (uint32_t k = 0; k < tmp.size(); k++) buffer[k] = new stream_info_impl(tmp[k]);
+		return tmp.size();
 	} catch(std::exception &e) {
 		LOG_F(WARNING, "Unexpected error querying lsl_resolver_results: %s", e.what());
 		return lsl_internal_error;

src/resolver_impl.cpp

@@ -126,17 +126,18 @@ void resolver_impl::resolve_continuous(const std::string &query, double forget_a
 }
 
 /// Get the current set of results (e.g., during continuous operation).
-std::vector<stream_info_impl> resolver_impl::results() {
+std::vector<stream_info_impl> resolver_impl::results(uint32_t max_results) {
 	std::vector<stream_info_impl> output;
 	lslboost::lock_guard<lslboost::mutex> lock(results_mut_);
 	double expired_before = lsl_clock() - forget_after_;
-	for(result_container::iterator i=results_.begin(); i!=results_.end();) {
-		if (i->second.second < expired_before) {
-			result_container::iterator tmp = i++;
-			results_.erase(tmp);
-		} else {
-			output.push_back(i->second.first);
-			i++;
+
+	for (auto it = results_.begin(); it != results_.end();) {
+		if (it->second.second < expired_before)
+			it = results_.erase(it);
+		else {
+			if (output.size() < max_results)
+				output.push_back(it->second.first);
+			it++;
 		}
 	}
 	return output;

src/resolver_impl.h

@@ -75,7 +75,7 @@ namespace lsl {
 		void resolve_continuous(const std::string &query, double forget_after=5.0);
 
 		/// Get the current set of results (e.g., during continuous operation).
-		std::vector<stream_info_impl> results();
+		std::vector<stream_info_impl> results(uint32_t max_results = 4294967295);
 
 		/// Tear down any ongoing operations and render the resolver unusable.
 		/// This can be used to cancel a blocking resolve_oneshot() from another thread (e.g., to initiate teardown of the object).