feat: multi-user system, bug fixes, security & performance fixes, and more

2026-03-14 13:28:46 +01:00
parent 576ad34f95
commit 261b536041
389 changed files with 231853 additions and 591 deletions
@@ -0,0 +1,148 @@
+// Saturation arithmetic -*- C++ -*-
+
+// Copyright The GNU Toolchain Authors.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/bits/sat_arith.h
+ *  This is an internal header file, included by other library headers.
+ *  Do not attempt to use it directly. @headername{numeric}
+ */
+
+#ifndef _GLIBCXX_SAT_ARITH_H
+#define _GLIBCXX_SAT_ARITH_H 1
+
+#pragma GCC system_header
+
+#include <bits/version.h>
+
+#ifdef __glibcxx_saturation_arithmetic // C++ >= 26
+
+#include <concepts>
+#include <ext/numeric_traits.h>
+
+namespace std _GLIBCXX_VISIBILITY(default)
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+  /// Add two integers, with saturation in case of overflow.
+  template<typename _Tp> requires __is_standard_integer<_Tp>::value
+    constexpr _Tp
+    add_sat(_Tp __x, _Tp __y) noexcept
+    {
+      _Tp __z;
+      if (!__builtin_add_overflow(__x, __y, &__z))
+	return __z;
+      if constexpr (is_unsigned_v<_Tp>)
+	return __gnu_cxx::__int_traits<_Tp>::__max;
+      else if (__x < 0)
+	return __gnu_cxx::__int_traits<_Tp>::__min;
+      else
+	return __gnu_cxx::__int_traits<_Tp>::__max;
+    }
+
+  /// Subtract one integer from another, with saturation in case of overflow.
+  template<typename _Tp> requires __is_standard_integer<_Tp>::value
+    constexpr _Tp
+    sub_sat(_Tp __x, _Tp __y) noexcept
+    {
+      _Tp __z;
+      if (!__builtin_sub_overflow(__x, __y, &__z))
+	return __z;
+      if constexpr (is_unsigned_v<_Tp>)
+	return __gnu_cxx::__int_traits<_Tp>::__min;
+      else if (__x < 0)
+	return __gnu_cxx::__int_traits<_Tp>::__min;
+      else
+	return __gnu_cxx::__int_traits<_Tp>::__max;
+    }
+
+  /// Multiply two integers, with saturation in case of overflow.
+  template<typename _Tp> requires __is_standard_integer<_Tp>::value
+    constexpr _Tp
+    mul_sat(_Tp __x, _Tp __y) noexcept
+    {
+      _Tp __z;
+      if (!__builtin_mul_overflow(__x, __y, &__z))
+	return __z;
+      if constexpr (is_unsigned_v<_Tp>)
+	return __gnu_cxx::__int_traits<_Tp>::__max;
+      else if (__x < 0 != __y < 0)
+	return __gnu_cxx::__int_traits<_Tp>::__min;
+      else
+	return __gnu_cxx::__int_traits<_Tp>::__max;
+    }
+
+  /// Divide one integer by another, with saturation in case of overflow.
+  template<typename _Tp> requires __is_standard_integer<_Tp>::value
+    constexpr _Tp
+    div_sat(_Tp __x, _Tp __y) noexcept
+    {
+      __glibcxx_assert(__y != 0);
+      if constexpr (is_signed_v<_Tp>)
+	if (__x == __gnu_cxx::__int_traits<_Tp>::__min && __y == _Tp(-1))
+	  return __gnu_cxx::__int_traits<_Tp>::__max;
+      return __x / __y;
+    }
+
+  /// Divide one integer by another, with saturation in case of overflow.
+  template<typename _Res, typename _Tp>
+    requires __is_standard_integer<_Res>::value
+      && __is_standard_integer<_Tp>::value
+    constexpr _Res
+    saturate_cast(_Tp __x) noexcept
+    {
+      constexpr int __digits_R = __gnu_cxx::__int_traits<_Res>::__digits;
+      constexpr int __digits_T = __gnu_cxx::__int_traits<_Tp>::__digits;
+      constexpr _Res __max_Res = __gnu_cxx::__int_traits<_Res>::__max;
+
+      if constexpr (is_signed_v<_Res> == is_signed_v<_Tp>)
+	{
+	  if constexpr (__digits_R < __digits_T)
+	    {
+	      constexpr _Res __min_Res = __gnu_cxx::__int_traits<_Res>::__min;
+
+	      if (__x < static_cast<_Tp>(__min_Res))
+		return __min_Res;
+	      else if (__x > static_cast<_Tp>(__max_Res))
+		return __max_Res;
+	    }
+	}
+      else if constexpr (is_signed_v<_Tp>) // Res is unsigned
+	{
+	  if (__x < 0)
+	    return 0;
+	  else if (make_unsigned_t<_Tp>(__x) > __max_Res)
+	    return __gnu_cxx::__int_traits<_Res>::__max;
+	}
+      else // Tp is unsigned, Res is signed
+	{
+	  if (__x > make_unsigned_t<_Res>(__max_Res))
+	    return __max_Res;
+	}
+      return static_cast<_Res>(__x);
+    }
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace
+
+#endif // __glibcxx_saturation_arithmetic
+#endif /* _GLIBCXX_SAT_ARITH_H */