Fix clz return value for zero

spnda · Oct 3, 2024 · 5f5b8af · 5f5b8af
1 parent e42df8b
commit 5f5b8af
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Showing 2 changed files with 2 additions and 1 deletion.
diff --git a/include/fastgltf/util.hpp b/include/fastgltf/util.hpp
@@ -288,7 +288,7 @@ namespace fastgltf {
 #else
         // Very naive but working implementation of counting zero bits. Any sane compiler will
         // optimise this away, like instead use the bsr x86 instruction.
-        if (value == 0) return 64;
+        if (value == 0) return sizeof(T) * 8;
         std::uint8_t count = 0;
         for (auto i = std::numeric_limits<T>::digits - 1; i > 0; --i) {
             if ((value >> i) == 1) {

diff --git a/tests/vector_tests.cpp b/tests/vector_tests.cpp
@@ -3,6 +3,7 @@
 #include <fastgltf/types.hpp>
 
 TEST_CASE("Verify clz", "[vector-tests]") {
+	REQUIRE(fastgltf::clz<std::uint8_t>(0b00000000) == 8);
 	REQUIRE(fastgltf::clz<std::uint8_t>(0b00000001) == 7);
 	REQUIRE(fastgltf::clz<std::uint8_t>(0b00000010) == 6);
 	REQUIRE(fastgltf::clz<std::uint8_t>(0b00000100) == 5);