Create the y2021_bot3 folder

It builds! yay

Change-Id: I732955c018ce2988de64486e2457e673efd2cbb8
diff --git a/y2021_bot3/constants.cc b/y2021_bot3/constants.cc
new file mode 100644
index 0000000..984b844
--- /dev/null
+++ b/y2021_bot3/constants.cc
@@ -0,0 +1,84 @@
+#include "y2021_bot3/constants.h"
+
+#include <inttypes.h>
+
+#include <map>
+
+#if __has_feature(address_sanitizer)
+#include "sanitizer/lsan_interface.h"
+#endif
+
+#include "absl/base/call_once.h"
+#include "aos/logging/logging.h"
+#include "aos/mutex/mutex.h"
+#include "aos/network/team_number.h"
+
+namespace y2021_bot3 {
+namespace constants {
+
+const int Values::kZeroingSampleSize;
+
+namespace {
+
+const uint16_t kCompTeamNumber = 971;
+const uint16_t kPracticeTeamNumber = 9971;
+const uint16_t kCodingRobotTeamNumber = 7971;
+
+const Values *DoGetValuesForTeam(uint16_t team) {
+  Values *const r = new Values();
+
+  switch (team) {
+    // A set of constants for tests.
+    case 1:
+      break;
+
+    case kCompTeamNumber:
+      break;
+
+    case kPracticeTeamNumber:
+      break;
+
+    case kCodingRobotTeamNumber:
+      break;
+
+    default:
+      AOS_LOG(FATAL, "unknown team #%" PRIu16 "\n", team);
+  }
+
+  return r;
+}
+
+void DoGetValues(const Values **result) {
+  uint16_t team = ::aos::network::GetTeamNumber();
+  AOS_LOG(INFO, "creating a Constants for team %" PRIu16 "\n", team);
+  *result = DoGetValuesForTeam(team);
+}
+
+}  // namespace
+
+const Values &GetValues() {
+  static absl::once_flag once;
+  static const Values *result;
+  absl::call_once(once, DoGetValues, &result);
+  return *result;
+}
+
+const Values &GetValuesForTeam(uint16_t team_number) {
+  static ::aos::Mutex mutex;
+  ::aos::MutexLocker locker(&mutex);
+
+  // IMPORTANT: This declaration has to stay after the mutex is locked to avoid
+  // race conditions.
+  static ::std::map<uint16_t, const Values *> values;
+
+  if (values.count(team_number) == 0) {
+    values[team_number] = DoGetValuesForTeam(team_number);
+#if __has_feature(address_sanitizer)
+    __lsan_ignore_object(values[team_number]);
+#endif
+  }
+  return *values[team_number];
+}
+
+}  // namespace constants
+}  // namespace y2021_bot3