add a retrieveAllMatches function as a multi result optimization

include/rs232.hpp

@@ -168,6 +168,21 @@ namespace sakurajin {
         [[nodiscard]] [[maybe_unused]]
         std::string retrieveFirstMatch(const std::regex& pattern);
 
+        /**
+         * @brief load the read buffer and return all matches with a regex
+         * This does essentially the same as retrieveFirstMatch but returns all matches instead of just the first one.
+         * If care about more than one result use this function since it is more efficient than calling retrieveFirstMatch multiple
+         * times. If no match is found or no data is in the read buffer, an empty vector is returned.
+         * @note this function clears the read buffer until the end of the last match.
+         * @note The read buffer is not updated during this function call. If the read buffer is large and many pattern matches are
+         * found this function might take a long time to complete. During this time more data might be queued for adding to the
+         * read buffer. This data will not be considered by this function.
+         * @param pattern the regex pattern that should be used
+         * @return std::vector<std::string> all matches of the read buffer
+         */
+        [[nodiscard]] [[maybe_unused]]
+        std::vector<std::string> retrieveAllMatches(const std::regex& pattern);
+
         /**
          * @brief print a string to the currently connected device
          * This function adds the string to the write buffer and then returns.

src/rs232.cpp

@@ -197,6 +197,28 @@ std::string sakurajin::RS232::retrieveFirstMatch(const std::regex& pattern) {
     return s_match_result.str();
 }
 
+std::vector<std::string> sakurajin::RS232::retrieveAllMatches(const std::regex& pattern) {
+    if (!readBufferHasData) {
+        return std::vector<std::string>{};
+    }
+
+    std::scoped_lock lock(readBufferMutex);
+
+    std::string              searchString = readBuffer;
+    std::smatch              curr_match;
+    std::vector<std::string> matches{};
+
+    std::regex_search(searchString, curr_match, pattern);
+    while(!curr_match.empty()){
+        matches.emplace_back(curr_match.str());
+        searchString = curr_match.suffix();
+        std::regex_search(searchString, curr_match, pattern);
+    }
+
+    readBuffer = searchString;
+    return matches;
+}
+
 // device access functions
 std::shared_ptr<sakurajin::RS232_native> sakurajin::RS232::getNativeDevice(size_t index) const {
     if (rs232Devices.empty()) {