1 files changed, 37 insertions, 0 deletions
diff --git a/src/util/random.cpp b/src/util/random.cpp
new file mode 100644
index 00000000..ae543765
--- /dev/null
+++ b/src/util/random.cpp
@@ -0,0 +1,37 @@
+/*
+ * Copyright 2023 jacqueline <me@jacqueline.id.au>
+ *
+ * SPDX-License-Identifier: GPL-3.0-only
+ */
+
+#include "random.hpp"
+
+#include <cstdint>
+
+#include "esp_random.h"
+#include "komihash.h"
+
+namespace util {
+
+IRandom* sRandom = new Random();
+
+Random::Random() {
+  esp_fill_random(&seed1_, sizeof(seed1_));
+  seed2_ = seed1_;
+
+  // komirand needs four iterations to properly self-start.
+  for (int i = 0; i < 4; i++) {
+    Next();
+  }
+}
+
+auto Random::Next() -> std::uint64_t {
+  return komirand(&seed1_, &seed2_);
+}
+
+auto Random::RangeInclusive(std::uint64_t lower, std::uint64_t upper)
+    -> std::uint64_t {
+  return (Next() % (upper - lower + 1)) + lower;
+}
+
+}  // namespace util