root compression algo as option

src/main.cpp

@@ -128,6 +128,7 @@ int main(int argc, char** argv) {
     std::string input_file;
     std::string output_file;
     int verbose_level = -1;
+    std::string root_compression_algorithm = "LZMA";
 
     CLI::App app{"mclient"};
 
@@ -152,7 +153,10 @@ int main(int argc, char** argv) {
             ->check(CLI::Range(0, 4));
     app.add_flag("--read-only", readOnly, "Read-only mode")
             ->group("General");
-    // format option, defaults to "root", can be any value of "root", "aqs", "ascii" or multiple
+    app.add_flag("--share-buffer", shareBuffer, "Share buffer")->group("General");
+    app.add_option("--root-compression-algorithm", root_compression_algorithm, "Root compression algorithm (default: LZMA)")
+            ->group("File Options")
+            ->check(CLI::IsMember({"ZLIB", "LZMA", "LZ4"}));
 
     CLI11_PARSE(app, argc, argv);
 
@@ -161,6 +165,8 @@ int main(int argc, char** argv) {
         verbose = 1;
     }
 
+    mclient_storage::StorageManager::Instance().compression_algorithm = root_compression_algorithm;
+
     femarray.verbose = verbose;
     cmdfetcher.verbose = verbose;
 

src/root/storage.cpp

@@ -37,7 +37,17 @@ void StorageManager::Initialize(const string& filename) {
     }
 
     file = std::make_unique<TFile>(filename.c_str(), "RECREATE");
-    file->SetCompressionAlgorithm(ROOT::kLZMA); // biggest compression ratio but slowest
+
+    if (compression_algorithm == "ZLIB") {
+        file->SetCompressionAlgorithm(ROOT::kZLIB); // good compression ratio and fast (old root default)
+    } else if (compression_algorithm == "LZ4") {
+        file->SetCompressionAlgorithm(ROOT::kLZ4); // good compression ratio and fast (new root default)
+    } else if (compression_algorithm == "LZMA") {
+        file->SetCompressionAlgorithm(ROOT::kLZMA); // biggest compression ratio but slowest
+    } else {
+        throw std::runtime_error("Unknown compression algorithm: " + compression_algorithm);
+    }
+
     // file->SetCompressionLevel(9);               // max compression level, but it's very slow, probably not worth it
 
     cout << "ROOT file will be saved to " << file->GetName() << endl;

src/root/storage.h

@@ -71,6 +71,8 @@ class StorageManager {
     std::unique_ptr<TTree> run_tree;
     Event event;
 
+    std::string compression_algorithm;
+
     unsigned long long run_number = 0;
     unsigned long long run_time_start = 0;