pw_random: Make explicit narrowing conversion explicit

Make implicit conversion of uint64_t to uint32_t in XorShiftStarRng64::InjectEntropyBits explicit. This fixes an error in builds configured with the flags [-Werror,-Wshorten-64-to-32], such as the Fuchsia build. Change-Id: I0e172cb35597b11df2ab4be496815c3556d707b1 Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/125050 Reviewed-by: Keir Mierle <[email protected]> Commit-Queue: Ben Lawson <[email protected]>
google · Dec 21, 2022 · 7e9aa2d · 7e9aa2d
1 parent 19b7f07
commit 7e9aa2d
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/pw_random/public/pw_random/xor_shift.h b/pw_random/public/pw_random/xor_shift.h
@@ -61,7 +61,8 @@ class XorShiftStarRng64 : public RandomGenerator {
     uint64_t untouched_state = state_ >> (kNumStateBits - num_bits);
     state_ = untouched_state | (state_ << num_bits);
     // Zero-out all irrelevant bits, then XOR entropy into state.
-    uint32_t mask = (static_cast<uint64_t>(1) << num_bits) - 1;
+    uint32_t mask =
+        static_cast<uint32_t>((static_cast<uint64_t>(1) << num_bits) - 1);
     state_ ^= (data & mask);
   }