1 files changed, 51 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__random/generate_canonical.h b/contrib/llvm-project/libcxx/include/__random/generate_canonical.h
new file mode 100644
index 000000000000..738de1517e28
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__random/generate_canonical.h
@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___RANDOM_GENERATE_CANONICAL_H
+#define _LIBCPP___RANDOM_GENERATE_CANONICAL_H
+
+#include <__config>
+#include <__random/log2.h>
+#include <cstdint>
+#include <initializer_list>
+#include <limits>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+// generate_canonical
+
+template <class _RealType, size_t __bits, class _URNG>
+_LIBCPP_HIDE_FROM_ABI _RealType generate_canonical(_URNG& __g) {
+  const size_t __dt = numeric_limits<_RealType>::digits;
+  const size_t __b  = __dt < __bits ? __dt : __bits;
+#ifdef _LIBCPP_CXX03_LANG
+  const size_t __log_r = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value;
+#else
+  const size_t __log_r = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value;
+#endif
+  const size_t __k     = __b / __log_r + (__b % __log_r != 0) + (__b == 0);
+  const _RealType __rp = static_cast<_RealType>(_URNG::max() - _URNG::min()) + _RealType(1);
+  _RealType __base     = __rp;
+  _RealType __sp       = __g() - _URNG::min();
+  for (size_t __i = 1; __i < __k; ++__i, __base *= __rp)
+    __sp += (__g() - _URNG::min()) * __base;
+  return __sp / __base;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANDOM_GENERATE_CANONICAL_H