1 files changed, 172 insertions, 0 deletions
diff --git a/contrib/llvm-project/libcxx/include/__random/discard_block_engine.h b/contrib/llvm-project/libcxx/include/__random/discard_block_engine.h
new file mode 100644
index 000000000000..07f599067279
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__random/discard_block_engine.h
@@ -0,0 +1,172 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_DISCARD_BLOCK_ENGINE_H
+#define _LIBCPP___RANDOM_DISCARD_BLOCK_ENGINE_H
+
+#include <__config>
+#include <__random/is_seed_sequence.h>
+#include <__type_traits/enable_if.h>
+#include <__type_traits/is_convertible.h>
+#include <__utility/move.h>
+#include <cstddef>
+#include <iosfwd>
+#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
+
+template <class _Engine, size_t __p, size_t __r>
+class _LIBCPP_TEMPLATE_VIS discard_block_engine {
+  _Engine __e_;
+  int __n_;
+
+  static_assert(0 < __r, "discard_block_engine invalid parameters");
+  static_assert(__r <= __p, "discard_block_engine invalid parameters");
+#ifndef _LIBCPP_CXX03_LANG // numeric_limits::max() is not constexpr in C++03
+  static_assert(__r <= numeric_limits<int>::max(), "discard_block_engine invalid parameters");
+#endif
+
+public:
+  // types
+  typedef typename _Engine::result_type result_type;
+
+  // engine characteristics
+  static _LIBCPP_CONSTEXPR const size_t block_size = __p;
+  static _LIBCPP_CONSTEXPR const size_t used_block = __r;
+
+#ifdef _LIBCPP_CXX03_LANG
+  static const result_type _Min = _Engine::_Min;
+  static const result_type _Max = _Engine::_Max;
+#else
+  static constexpr result_type _Min = _Engine::min();
+  static constexpr result_type _Max = _Engine::max();
+#endif
+
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type min() { return _Engine::min(); }
+  _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR result_type max() { return _Engine::max(); }
+
+  // constructors and seeding functions
+  _LIBCPP_HIDE_FROM_ABI discard_block_engine() : __n_(0) {}
+  _LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(const _Engine& __e) : __e_(__e), __n_(0) {}
+#ifndef _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(_Engine&& __e) : __e_(std::move(__e)), __n_(0) {}
+#endif // _LIBCPP_CXX03_LANG
+  _LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(result_type __sd) : __e_(__sd), __n_(0) {}
+  template <
+      class _Sseq,
+      __enable_if_t<__is_seed_sequence<_Sseq, discard_block_engine>::value && !is_convertible<_Sseq, _Engine>::value,
+                    int> = 0>
+  _LIBCPP_HIDE_FROM_ABI explicit discard_block_engine(_Sseq& __q) : __e_(__q), __n_(0) {}
+  _LIBCPP_HIDE_FROM_ABI void seed() {
+    __e_.seed();
+    __n_ = 0;
+  }
+  _LIBCPP_HIDE_FROM_ABI void seed(result_type __sd) {
+    __e_.seed(__sd);
+    __n_ = 0;
+  }
+  template <class _Sseq, __enable_if_t<__is_seed_sequence<_Sseq, discard_block_engine>::value, int> = 0>
+  _LIBCPP_HIDE_FROM_ABI void seed(_Sseq& __q) {
+    __e_.seed(__q);
+    __n_ = 0;
+  }
+
+  // generating functions
+  _LIBCPP_HIDE_FROM_ABI result_type operator()();
+  _LIBCPP_HIDE_FROM_ABI void discard(unsigned long long __z) {
+    for (; __z; --__z)
+      operator()();
+  }
+
+  // property functions
+  _LIBCPP_HIDE_FROM_ABI const _Engine& base() const _NOEXCEPT { return __e_; }
+
+  template <class _Eng, size_t _Pp, size_t _Rp>
+  friend bool
+  operator==(const discard_block_engine<_Eng, _Pp, _Rp>& __x, const discard_block_engine<_Eng, _Pp, _Rp>& __y);
+
+  template <class _Eng, size_t _Pp, size_t _Rp>
+  friend bool
+  operator!=(const discard_block_engine<_Eng, _Pp, _Rp>& __x, const discard_block_engine<_Eng, _Pp, _Rp>& __y);
+
+  template <class _CharT, class _Traits, class _Eng, size_t _Pp, size_t _Rp>
+  friend basic_ostream<_CharT, _Traits>&
+  operator<<(basic_ostream<_CharT, _Traits>& __os, const discard_block_engine<_Eng, _Pp, _Rp>& __x);
+
+  template <class _CharT, class _Traits, class _Eng, size_t _Pp, size_t _Rp>
+  friend basic_istream<_CharT, _Traits>&
+  operator>>(basic_istream<_CharT, _Traits>& __is, discard_block_engine<_Eng, _Pp, _Rp>& __x);
+};
+
+template <class _Engine, size_t __p, size_t __r>
+_LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::block_size;
+
+template <class _Engine, size_t __p, size_t __r>
+_LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::used_block;
+
+template <class _Engine, size_t __p, size_t __r>
+typename discard_block_engine<_Engine, __p, __r>::result_type discard_block_engine<_Engine, __p, __r>::operator()() {
+  if (__n_ >= static_cast<int>(__r)) {
+    __e_.discard(__p - __r);
+    __n_ = 0;
+  }
+  ++__n_;
+  return __e_();
+}
+
+template <class _Eng, size_t _Pp, size_t _Rp>
+inline _LIBCPP_HIDE_FROM_ABI bool
+operator==(const discard_block_engine<_Eng, _Pp, _Rp>& __x, const discard_block_engine<_Eng, _Pp, _Rp>& __y) {
+  return __x.__n_ == __y.__n_ && __x.__e_ == __y.__e_;
+}
+
+template <class _Eng, size_t _Pp, size_t _Rp>
+inline _LIBCPP_HIDE_FROM_ABI bool
+operator!=(const discard_block_engine<_Eng, _Pp, _Rp>& __x, const discard_block_engine<_Eng, _Pp, _Rp>& __y) {
+  return !(__x == __y);
+}
+
+template <class _CharT, class _Traits, class _Eng, size_t _Pp, size_t _Rp>
+_LIBCPP_HIDE_FROM_ABI basic_ostream<_CharT, _Traits>&
+operator<<(basic_ostream<_CharT, _Traits>& __os, const discard_block_engine<_Eng, _Pp, _Rp>& __x) {
+  __save_flags<_CharT, _Traits> __lx(__os);
+  typedef basic_ostream<_CharT, _Traits> _Ostream;
+  __os.flags(_Ostream::dec | _Ostream::left);
+  _CharT __sp = __os.widen(' ');
+  __os.fill(__sp);
+  return __os << __x.__e_ << __sp << __x.__n_;
+}
+
+template <class _CharT, class _Traits, class _Eng, size_t _Pp, size_t _Rp>
+_LIBCPP_HIDE_FROM_ABI basic_istream<_CharT, _Traits>&
+operator>>(basic_istream<_CharT, _Traits>& __is, discard_block_engine<_Eng, _Pp, _Rp>& __x) {
+  __save_flags<_CharT, _Traits> __lx(__is);
+  typedef basic_istream<_CharT, _Traits> _Istream;
+  __is.flags(_Istream::dec | _Istream::skipws);
+  _Eng __e;
+  int __n;
+  __is >> __e >> __n;
+  if (!__is.fail()) {
+    __x.__e_ = __e;
+    __x.__n_ = __n;
+  }
+  return __is;
+}
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___RANDOM_DISCARD_BLOCK_ENGINE_H