1 files changed, 51 insertions, 0 deletions
diff --git a/fesvr/option_parser.cc b/fesvr/option_parser.cc
new file mode 100644
index 0000000..72daec4
--- /dev/null
+++ b/fesvr/option_parser.cc
@@ -0,0 +1,51 @@
+// See LICENSE for license details.
+
+#include "option_parser.h"
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <cassert>
+
+void option_parser_t::option(char c, const char* s, int arg, std::function<void(const char*)> action)
+{
+  opts.push_back(option_t(c, s, arg, action));
+}
+
+const char* const* option_parser_t::parse(const char* const* argv0)
+{
+  assert(argv0);
+  const char* const* argv = argv0 + 1;
+  for (const char* opt; (opt = *argv) != NULL && opt[0] == '-'; argv++)
+  {
+    bool found = false;
+    for (auto it = opts.begin(); !found && it != opts.end(); it++)
+    {
+      size_t slen = it->str ? strlen(it->str) : 0;
+      bool chr_match = opt[1] != '-' && it->chr && opt[1] == it->chr;
+      bool str_match = opt[1] == '-' && slen && strncmp(opt+2, it->str, slen) == 0;
+      if (chr_match || (str_match && (opt[2+slen] == '=' || opt[2+slen] == '\0')))
+      {
+        const char* optarg =
+          chr_match ? (opt[2] ? &opt[2] : NULL) :
+          opt[2+slen] ? &opt[3+slen] :
+          it->arg ? *(++argv) : NULL;
+        if (optarg && !it->arg)
+          error("no argument allowed for option", *argv0, opt);
+        if (!optarg && it->arg)
+          error("argument required for option", *argv0, opt);
+        it->func(optarg);
+        found = true;
+      }
+    }
+    if (!found)
+      error("unrecognized option", *argv0, opt);
+  }
+  return argv;
+}
+
+void option_parser_t::error(const char* msg, const char* argv0, const char* arg)
+{
+  fprintf(stderr, "%s: %s %s\n", argv0, msg, arg ? arg : "");
+  if (helpmsg) helpmsg();
+  exit(1);
+}