arguments for the filter

.gitmodules

@@ -1,3 +1,7 @@
 [submodule "third-party/c-flags"]
 	path = third-party/c-flags
 	url = https://github.com/DieTime/c-flags.git
+[submodule "third-party/cxxopts"]
+	path = third-party/cxxopts
+	url = https://github.com/jarro2783/cxxopts.git
+	branch = v3.2.1

CMakeLists.txt

@@ -4,7 +4,11 @@ project(pico-radio)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS true)
 
-include_directories(include /opt/picoscope/include third-party/c-flags/single-header)
+include_directories(include
+  /opt/picoscope/include
+  third-party/c-flags/single-header
+  third-party/cxxopts/include)
+  
 link_directories(/opt/picoscope/lib)
 
 add_subdirectory(src/recorder)

src/filter/main.cpp

@@ -6,15 +6,30 @@
 #include <filter/filter/low_pass_filter.hpp>
 #include <filter/window/hamming_window.hpp>
 
-#include <c-flags.h>
+#include <cxxopts.hpp>
 
 const std::size_t BUFFER_SIZE = 256;
 
 using namespace Filter;
 
 int main(int argc, char** argv) {
-  (void)argc;
-  (void)argv;
+  // parse arguments
+  cxxopts::Options options("filter", "filter signals; stdin->stdout");
+  options.add_options()("c,cutoff", "Cutoff frequency in Hz.", cxxopts::value<size_t>()->no_implicit_value())("s,sample_rate", "Sample rate of input in Hz.",
+                                                                                                              cxxopts::value<size_t>()->no_implicit_value());
+
+  cxxopts::ParseResult result;
+  try {
+    result = options.parse(argc, argv);
+  } catch (cxxopts::exceptions::exception e) {
+    std::cerr << e.what() << std::endl;
+    return -1;
+  }
+
+  if (result.count("cutoff") + result.count("sample_rate") != 2) {
+    std::cerr << options.help() << std::endl;
+    return -1;
+  }
 
   // prepare pipes for binary data
   std::freopen(nullptr, "rb", stdin);
@@ -30,7 +45,7 @@ int main(int argc, char** argv) {
   }
 
   // create low pass filter
-  LowPassFilter lpf(BUFFER_SIZE, 1000, 10000, HammingWindow(BUFFER_SIZE).getWindow());
+  LowPassFilter lpf(BUFFER_SIZE, result["cutoff"].as<std::size_t>(), result["sample_rate"].as<std::size_t>(), HammingWindow(BUFFER_SIZE).getWindow());
 
   // read data
   std::vector<float> inputBuffer;

third-party/cxxopts

@@ -0,0 +1 @@
+Subproject commit 4bf61f08697b110d9e3991864650a405b3dd515d