From aa225a7dc44d61516a20163c90b12dfecb8bd030 Mon Sep 17 00:00:00 2001
From: MerryMage <MerryMage@users.noreply.github.com>
Date: Thu, 2 Apr 2020 12:51:35 +0100
Subject: [PATCH] bit_util: Add CountLeadingZeros

---
 src/common/bit_util.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/common/bit_util.h b/src/common/bit_util.h
index 4eea814c..05da355f 100644
--- a/src/common/bit_util.h
+++ b/src/common/bit_util.h
@@ -150,6 +150,17 @@ inline size_t BitCount(Integral value) {
     return std::bitset<BitSize<Integral>()>(value).count();
 }
 
+template <typename T>
+constexpr size_t CountLeadingZeros(T value) {
+    auto x = static_cast<std::make_unsigned_t<T>>(value);
+    size_t result = BitSize<T>();
+    while (x != 0) {
+        x >>= 1;
+        result--;
+    }
+    return result;
+}
+
 template <typename T>
 constexpr int HighestSetBit(T value) {
     auto x = static_cast<std::make_unsigned_t<T>>(value);