split step map generator from converter

gen/CMakeLists.txt

@@ -0,0 +1,2 @@
+add_executable(smap smap.cc)
+target_link_libraries(smap PRIVATE args)

gen/smap.cc

@@ -0,0 +1,93 @@
+#include <cassert>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <unordered_map>
+
+#include <args.hxx>
+
+
+namespace param {
+using namespace ::args;
+
+ArgumentParser parser {
+  "converter: feature indices + host -> stego"
+};
+HelpFlag help {
+  parser, "help", "display this menu", {'h', "help"},
+};
+
+ValueFlag<size_t> dur {
+  parser, "100", "duration", {"dur"}, 100,
+};
+ValueFlag<size_t> fcnum {
+  parser, "50", "number of feature code alphabet", {"fc-num"}, 50,
+};
+ValueFlag<size_t> branch {
+  parser, "2", "number of branch", {"branch"}, 2,
+};
+
+enum Algo {
+  kIncrement,
+};
+const std::unordered_map<std::string, Algo> kAlgo = {
+  {"inc", kIncrement},
+};
+MapFlag<std::string, Algo> algo {
+  parser, "inc", "generator algorithm", {"algo", "algorithm"}, kAlgo,
+};
+
+Group inc {
+  parser, "increment algorithm parameters"
+};
+ValueFlag<size_t> inc_min {
+  inc, "0", "min stride of each move", {"inc-min"}, 0,
+};
+Flag inc_time {
+  inc, "inc-time", "add current time value", {"inc-time"},
+};
+
+}  // namespace param
+
+
+size_t Step(size_t t, size_t c, size_t b) {
+  const auto fcnum = args::get(param::fcnum);
+
+  size_t ret;
+  switch (args::get(param::algo)) {
+  case param::kIncrement:
+    ret = c+b+args::get(param::inc_min);
+    if (param::inc_time) {
+      ret += t;
+    }
+    return ret%fcnum;
+
+  default:
+    assert(false);
+    std::abort();
+  }
+}
+
+void Exec() {
+  for (size_t t = 0; t < args::get(param::dur); ++t) {
+    for (size_t c = 0; c < args::get(param::fcnum); ++c) {
+      for (size_t b = 0; b < args::get(param::branch); ++b) {
+        std::cout << Step(t, c, b) << ' ';
+      }
+      std::cout << '\n';
+    }
+  }
+}
+
+int main(int argc, char** argv)
+try {
+  param::parser.ParseCLI(argc, argv);
+  Exec();
+  return EXIT_SUCCESS;
+} catch (const args::Help&) {
+  std::cout << param::parser << std::endl;
+  return EXIT_SUCCESS;
+} catch (const std::exception& e) {
+  std::cerr << e.what() << std::endl;
+  return EXIT_FAILURE;
+}