DLS: add support to request DLS file re-read

A re-read of any of the used DLS files can now be requested by storing a
file with the same filename which is suffixed by `.REQUEST_DLS_REREAD`.

When the next PAD is going to be encoded and such a file is present, the
encoder changes the current DLS file to the related DLS file, if needed
(only applies if multiple DLS files are used). The DLS file is re-read
and the request file is deleted. The DLS is also immediately inserted
into the PAD transmission.

3 files changed, 19 insertions, 0 deletions

diff --git a/src/dls.cpp b/src/dls.cpp
index e5f6f27..74b1131 100644
--- a/src/dls.cpp
+++ b/src/dls.cpp
@@ -38,6 +38,7 @@ const std::string DLSEncoder::DL_PARAMS_OPEN  = "##### parameters { #####";
 const std::string DLSEncoder::DL_PARAMS_CLOSE = "##### parameters } #####";
 const int DLSEncoder::APPTYPE_START = 2;
 const int DLSEncoder::APPTYPE_CONT = 3;
+const std::string DLSEncoder::REQUEST_REREAD_SUFFIX = ".REQUEST_DLS_REREAD";
 
 
 
diff --git a/src/dls.h b/src/dls.h
index 84ff4c5..3b7387d 100644
--- a/src/dls.h
+++ b/src/dls.h
@@ -151,6 +151,7 @@ private:
 public:
     static const int APPTYPE_START;
     static const int APPTYPE_CONT;
+    static const std::string REQUEST_REREAD_SUFFIX;
 
     DLSEncoder(PADPacketizer* pad_packetizer) : pad_packetizer(pad_packetizer), dls_toggle(false) {}
     void encodeLabel(const std::string& dls_file, const DL_PARAMS& dl_params);
diff --git a/src/odr-padenc.cpp b/src/odr-padenc.cpp
index 379791d..e065755 100644
--- a/src/odr-padenc.cpp
+++ b/src/odr-padenc.cpp
@@ -522,6 +522,23 @@ int UniformPadEncoder::Encode() {
 
     // handle DLS
     if (options.DLSEnabled()) {
+        // check for DLS re-read request
+        for (size_t i = 0; i < options.dls_files.size(); i++) {
+            int reread = CheckRereadFile("DLS file '" + options.dls_files[i] + "'", options.dls_files[i] + DLSEncoder::REQUEST_REREAD_SUFFIX);
+            switch (reread) {
+            case 1:     // re-read requested
+                // switch to desired DLS file
+                curr_dls_file = i;
+                next_label = pad_timeline + std::chrono::seconds(options.label_interval);
+
+                // enforce label insertion
+                next_label_insertion = pad_timeline;
+                break;
+            case -1:    // error
+                return 1;
+            }
+        }
+
         if (options.dls_files.size() > 1 && pad_timeline >= next_label) {
             // switch to next DLS file
             curr_dls_file = (curr_dls_file + 1) % options.dls_files.size();