1 files changed, 39 insertions, 0 deletions
diff --git a/src/catch2/internal/catch_test_case_info_hasher.cpp b/src/catch2/internal/catch_test_case_info_hasher.cpp
new file mode 100644
index 0000000..e1731eb
--- /dev/null
+++ b/src/catch2/internal/catch_test_case_info_hasher.cpp
@@ -0,0 +1,39 @@
+
+//              Copyright Catch2 Authors
+// Distributed under the Boost Software License, Version 1.0.
+//   (See accompanying file LICENSE.txt or copy at
+//        https://www.boost.org/LICENSE_1_0.txt)
+
+// SPDX-License-Identifier: BSL-1.0
+
+#include <catch2/catch_test_case_info.hpp>
+#include <catch2/internal/catch_test_case_info_hasher.hpp>
+
+namespace Catch {
+    TestCaseInfoHasher::TestCaseInfoHasher( hash_t seed ): m_seed( seed ) {}
+
+    uint32_t TestCaseInfoHasher::operator()( TestCaseInfo const& t ) const {
+        // FNV-1a hash algorithm that is designed for uniqueness:
+        const hash_t prime = 1099511628211u;
+        hash_t hash = 14695981039346656037u;
+        for ( const char c : t.name ) {
+            hash ^= c;
+            hash *= prime;
+        }
+        for ( const char c : t.className ) {
+            hash ^= c;
+            hash *= prime;
+        }
+        for ( const Tag& tag : t.tags ) {
+            for ( const char c : tag.original ) {
+                hash ^= c;
+                hash *= prime;
+            }
+        }
+        hash ^= m_seed;
+        hash *= prime;
+        const uint32_t low{ static_cast<uint32_t>( hash ) };
+        const uint32_t high{ static_cast<uint32_t>( hash >> 32 ) };
+        return low * high;
+    }
+} // namespace Catch