This is a new type for C++17, with no impact on anything in non-C++17
dialects. This is intentionally only defined in <cstddef> and not
<stddef.h>.
To keep <cstddef> small I didn't include <type_traits> to get
std::is_integral, I just defined a new helper for std::byte. For GCC 8
stage 1 we might want to refactor this so the list of integral types
is only in one place, and share the code between std::byte and
std::is_integral. I don't want to make changes to std::is_integral at
this point in Stage 4 though.
* doc/xml/manual/status_cxx2017.xml: Document std::byte support.
* include/c_global/cstddef (std::byte): Define for C++17.
* testsuite/18_support/byte/global_neg.cc: New test.
* testsuite/18_support/byte/ops.cc: New test.
* testsuite/18_support/byte/requirements.cc: New test.
Tested powerpc64le-linux, committed to trunk.
commit 0b59aead20e5f54890e135ac06d76c096b99e264
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Mar 9 14:52:15 2017 +0000
Define std::byte for C++17 (P0298R3)
* doc/xml/manual/status_cxx2017.xml: Document std::byte support.
* include/c_global/cstddef (std::byte): Define for C++17.
* testsuite/18_support/byte/global_neg.cc: New test.
* testsuite/18_support/byte/ops.cc: New test.
* testsuite/18_support/byte/requirements.cc: New test.
diff --git a/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
b/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
index 1053f2d..e0e4e8e 100644
--- a/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
+++ b/libstdc++-v3/doc/xml/manual/status_cxx2017.xml
@@ -460,18 +460,6 @@ Feature-testing recommendations for C++</link>.
</row>
<row>
- <?dbhtml bgcolor="#C8B0B0" ?>
- <entry> Ordered by default </entry>
- <entry>
- <link xmlns:xlink="http://www.w3.org/1999/xlink";
xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0181r1.html";>
- P0181R1
- </link>
- </entry>
- <entry align="center"> No </entry>
- <entry><code> __cpp_lib_default_order >= 201606</code></entry>
- </row>
-
- <row>
<entry> Polishing <code><chrono></code> </entry>
<entry>
<link xmlns:xlink="http://www.w3.org/1999/xlink";
xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0092r1.html";>
@@ -729,6 +717,19 @@ Feature-testing recommendations for C++</link>.
<entry><code> __cpp_lib_scoped_lock >= 201703 </code></entry>
</row>
+ <row>
+ <?dbhtml bgcolor="#C8B0B0" ?>
+ <entry> </entry> byte type definition
+ <entry>
+ <link xmlns:xlink="http://www.w3.org/1999/xlink";
xlink:href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0298r3.pdf";>
+ P0298R3
+ </link>
+ </entry>
+ <entry align="center"> 7 </entry>
+ <entry><code> ??? </code></entry>
+ </row>
+
+
</tbody>
</tgroup>
</table>
diff --git a/libstdc++-v3/include/c_global/cstddef
b/libstdc++-v3/include/c_global/cstddef
index a571e80..09754ee 100644
--- a/libstdc++-v3/include/c_global/cstddef
+++ b/libstdc++-v3/include/c_global/cstddef
@@ -57,4 +57,133 @@ namespace std
}
#endif
+#if __cplusplus > 201402L
+namespace std
+{
+ /// std::byte
+ enum class byte : unsigned char {};
+
+ template<typename _IntegerType> struct __byte_operand;
+ template<> struct __byte_operand<bool> { using __type = byte; };
+ template<> struct __byte_operand<char> { using __type = byte; };
+ template<> struct __byte_operand<signed char> { using __type = byte; };
+ template<> struct __byte_operand<unsigned char> { using __type = byte; };
+#ifdef _GLIBCXX_USE_WCHAR_T
+ template<> struct __byte_operand<wchar_t> { using __type = byte; };
+#endif
+ template<> struct __byte_operand<char16_t> { using __type = byte; };
+ template<> struct __byte_operand<char32_t> { using __type = byte; };
+ template<> struct __byte_operand<short> { using __type = byte; };
+ template<> struct __byte_operand<unsigned short> { using __type = byte; };
+ template<> struct __byte_operand<int> { using __type = byte; };
+ template<> struct __byte_operand<unsigned int> { using __type = byte; };
+ template<> struct __byte_operand<long> { using __type = byte; };
+ template<> struct __byte_operand<unsigned long> { using __type = byte; };
+ template<> struct __byte_operand<long long> { using __type = byte; };
+ template<> struct __byte_operand<unsigned long long> { using __type = byte;
};
+#if defined(__GLIBCXX_TYPE_INT_N_0)
+ template<> struct __byte_operand<__GLIBCXX_TYPE_INT_N_0>
+ { using __type = byte; };
+ template<> struct __byte_operand<unsigned __GLIBCXX_TYPE_INT_N_0>
+ { using __type = byte; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_1)
+ template<> struct __byte_operand<__GLIBCXX_TYPE_INT_N_1>
+ { using __type = byte; };
+ template<> struct __byte_operand<unsigned __GLIBCXX_TYPE_INT_N_1>
+ { using __type = byte; };
+#endif
+#if defined(__GLIBCXX_TYPE_INT_N_2)
+ template<> struct __byte_operand<__GLIBCXX_TYPE_INT_N_2>
+ { using __type = byte; };
+ template<> struct __byte_operand<unsigned __GLIBCXX_TYPE_INT_N_2>
+ { using __type = byte; };
+#endif
+ template<typename _IntegerType>
+ struct __byte_operand<const _IntegerType>
+ : __byte_operand<_IntegerType> { };
+ template<typename _IntegerType>
+ struct __byte_operand<volatile _IntegerType>
+ : __byte_operand<_IntegerType> { };
+ template<typename _IntegerType>
+ struct __byte_operand<const volatile _IntegerType>
+ : __byte_operand<_IntegerType> { };
+
+ template<typename _IntegerType>
+ using __byte_op_t = typename __byte_operand<_IntegerType>::__type;
+
+ template<typename _IntegerType>
+ constexpr __byte_op_t<_IntegerType>&
+ operator<<=(byte& __b, _IntegerType __shift) noexcept
+ { return __b = byte(static_cast<unsigned char>(__b) << __shift); }
+
+ template<typename _IntegerType>
+ constexpr __byte_op_t<_IntegerType>
+ operator<<(byte __b, _IntegerType __shift) noexcept
+ { return byte(static_cast<unsigned char>(__b) << __shift); }
+
+ template<typename _IntegerType>
+ constexpr __byte_op_t<_IntegerType>&
+ operator>>=(byte& __b, _IntegerType __shift) noexcept
+ { return __b = byte(static_cast<unsigned char>(__b) >> __shift); }
+
+ template<typename _IntegerType>
+ constexpr __byte_op_t<_IntegerType>
+ operator>>(byte __b, _IntegerType __shift) noexcept
+ { return byte(static_cast<unsigned char>(__b) >> __shift); }
+
+ constexpr byte&
+ operator|=(byte& __l, byte __r) noexcept
+ {
+ return __l =
+ byte(static_cast<unsigned char>(__l) | static_cast<unsigned char>(__r));
+ }
+
+ constexpr byte
+ operator|(byte __l, byte __r) noexcept
+ {
+ return
+ byte(static_cast<unsigned char>(__l) | static_cast<unsigned char>(__r));
+ }
+
+ constexpr byte&
+ operator&=(byte& __l, byte __r) noexcept
+ {
+ return __l =
+ byte(static_cast<unsigned char>(__l) & static_cast<unsigned char>(__r));
+ }
+
+ constexpr byte
+ operator&(byte __l, byte __r) noexcept
+ {
+ return
+ byte(static_cast<unsigned char>(__l) & static_cast<unsigned char>(__r));
+ }
+
+ constexpr byte&
+ operator^=(byte& __l, byte __r) noexcept
+ {
+ return __l =
+ byte(static_cast<unsigned char>(__l) ^ static_cast<unsigned char>(__r));
+ }
+
+ constexpr byte
+ operator^(byte __l, byte __r) noexcept
+ {
+ return
+ byte(static_cast<unsigned char>(__l) ^ static_cast<unsigned char>(__r));
+ }
+
+ constexpr byte
+ operator~(byte __b) noexcept
+ { return byte(~static_cast<unsigned char>(__b)); }
+
+ template<typename _IntegerType>
+ constexpr _IntegerType
+ to_integer(__byte_op_t<_IntegerType> __b) noexcept
+ { return _IntegerType(__b); }
+
+} // namespace std
+#endif
+
#endif // _GLIBCXX_CSTDDEF
diff --git a/libstdc++-v3/testsuite/18_support/byte/global_neg.cc
b/libstdc++-v3/testsuite/18_support/byte/global_neg.cc
new file mode 100644
index 0000000..722f658
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/byte/global_neg.cc
@@ -0,0 +1,24 @@
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// 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.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++1z } }
+
+#include <stddef.h>
+
+byte b; // { dg-error "does not name a type" }
+using std::byte; // { dg-error "has not been declared" }
diff --git a/libstdc++-v3/testsuite/18_support/byte/ops.cc
b/libstdc++-v3/testsuite/18_support/byte/ops.cc
new file mode 100644
index 0000000..6573bd9
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/byte/ops.cc
@@ -0,0 +1,224 @@
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// 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.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++1z } }
+
+#include <cstddef>
+
+constexpr bool is_byte(std::byte) { return true; }
+template<typename T> constexpr bool is_byte(T) { return false; }
+
+template<typename T>
+constexpr bool test_lshift_assign(unsigned char c, T t)
+{
+ std::byte b{c};
+ b <<= t;
+ return b == std::byte(c << t);
+}
+
+static_assert( test_lshift_assign(0, 1) );
+static_assert( test_lshift_assign(0, 1u) );
+static_assert( test_lshift_assign(0, 1ll) );
+static_assert( test_lshift_assign(4, 1) );
+static_assert( test_lshift_assign(9, 2u) );
+static_assert( test_lshift_assign(16, 3ll) );
+static_assert( test_lshift_assign(127, 1) );
+static_assert( test_lshift_assign(255, 2u) );
+static_assert( test_lshift_assign(63, 3ll) );
+
+template<typename T>
+constexpr bool test_lshift(unsigned char c, T t)
+{
+ const std::byte b{c};
+ const std::byte b2 = b << t;
+ return b2 == std::byte(c << t);
+}
+
+static_assert( test_lshift(0, 1) );
+static_assert( test_lshift(0, 1u) );
+static_assert( test_lshift(0, 1ll) );
+static_assert( test_lshift(4, 1) );
+static_assert( test_lshift(9, 2u) );
+static_assert( test_lshift(16, 3ll) );
+static_assert( test_lshift(127, 1) );
+static_assert( test_lshift(255, 2u) );
+static_assert( test_lshift(63, 3ll) );
+
+template<typename T>
+constexpr bool test_rshift_assign(unsigned char c, T t)
+{
+ std::byte b{c};
+ b >>= t;
+ return b == std::byte(c >> t);
+}
+
+static_assert( test_rshift_assign(0, 1) );
+static_assert( test_rshift_assign(0, 1u) );
+static_assert( test_rshift_assign(0, 1ll) );
+static_assert( test_rshift_assign(4, 1) );
+static_assert( test_rshift_assign(9, 2u) );
+static_assert( test_rshift_assign(16, 3ll) );
+static_assert( test_rshift_assign(127, 1) );
+static_assert( test_rshift_assign(255, 2u) );
+static_assert( test_rshift_assign(63, 3ll) );
+
+template<typename T>
+constexpr bool test_rshift(unsigned char c, T t)
+{
+ const std::byte b{c};
+ const std::byte b2 = b >> t;
+ return b2 == std::byte(c >> t);
+}
+
+static_assert( test_rshift(0, 1) );
+static_assert( test_rshift(0, 1u) );
+static_assert( test_rshift(0, 1ll) );
+static_assert( test_rshift(4, 1) );
+static_assert( test_rshift(9, 2u) );
+static_assert( test_rshift(16, 3ll) );
+static_assert( test_rshift(127, 1) );
+static_assert( test_rshift(255, 2u) );
+static_assert( test_rshift(63, 3ll) );
+
+constexpr bool test_or_assign(unsigned char l, unsigned char r)
+{
+ std::byte b{l};
+ b |= std::byte{r};
+ return b == std::byte(l | r);
+}
+
+static_assert( test_or_assign(0, 1) );
+static_assert( test_or_assign(4, 1) );
+static_assert( test_or_assign(9, 2) );
+static_assert( test_or_assign(16, 3) );
+static_assert( test_or_assign(63, 3) );
+static_assert( test_or_assign(127, 1) );
+static_assert( test_or_assign(255, 2) );
+
+constexpr bool test_or(unsigned char l, unsigned char r)
+{
+ const std::byte b1{l};
+ const std::byte b2{r};
+ return (b1 | b2) == std::byte(l | r);
+}
+
+static_assert( test_or(0, 1) );
+static_assert( test_or(0, 1u) );
+static_assert( test_or(0, 1ll) );
+static_assert( test_or(4, 1) );
+static_assert( test_or(9, 2u) );
+static_assert( test_or(16, 3ll) );
+static_assert( test_or(127, 1) );
+static_assert( test_or(255, 2u) );
+static_assert( test_or(63, 3ll) );
+
+constexpr bool test_and_assign(unsigned char l, unsigned char r)
+{
+ std::byte b{l};
+ b &= std::byte{r};
+ return b == std::byte(l & r);
+}
+
+static_assert( test_and_assign(0, 1) );
+static_assert( test_and_assign(0, 1u) );
+static_assert( test_and_assign(0, 1ll) );
+static_assert( test_and_assign(4, 1) );
+static_assert( test_and_assign(9, 2u) );
+static_assert( test_and_assign(16, 3ll) );
+static_assert( test_and_assign(127, 1) );
+static_assert( test_and_assign(255, 2u) );
+static_assert( test_and_assign(63, 3ll) );
+
+constexpr bool test_and(unsigned char l, unsigned char r)
+{
+ const std::byte b1{l};
+ const std::byte b2{r};
+ return (b1 & b2) == std::byte(l & r);
+}
+
+static_assert( test_and(0, 1) );
+static_assert( test_and(0, 1u) );
+static_assert( test_and(0, 1ll) );
+static_assert( test_and(4, 1) );
+static_assert( test_and(9, 2u) );
+static_assert( test_and(16, 3ll) );
+static_assert( test_and(127, 1) );
+static_assert( test_and(255, 2u) );
+static_assert( test_and(63, 3ll) );
+
+constexpr bool test_xor_assign(unsigned char l, unsigned char r)
+{
+ std::byte b{l};
+ b ^= std::byte{r};
+ return b == std::byte(l ^ r);
+}
+
+static_assert( test_xor_assign(0, 1) );
+static_assert( test_xor_assign(0, 1u) );
+static_assert( test_xor_assign(0, 1ll) );
+static_assert( test_xor_assign(4, 1) );
+static_assert( test_xor_assign(9, 2u) );
+static_assert( test_xor_assign(16, 3ll) );
+static_assert( test_xor_assign(127, 1) );
+static_assert( test_xor_assign(255, 2u) );
+static_assert( test_xor_assign(63, 3ll) );
+
+constexpr bool test_xor(unsigned char l, unsigned char r)
+{
+ const std::byte b1{l};
+ const std::byte b2{r};
+ return (b1 ^ b2) == std::byte(l ^ r);
+}
+
+static_assert( test_xor(0, 1) );
+static_assert( test_xor(0, 1u) );
+static_assert( test_xor(0, 1ll) );
+static_assert( test_xor(4, 1) );
+static_assert( test_xor(9, 2u) );
+static_assert( test_xor(16, 3ll) );
+static_assert( test_xor(127, 1) );
+static_assert( test_xor(255, 2u) );
+static_assert( test_xor(63, 3ll) );
+
+constexpr bool test_complement(unsigned char c)
+{
+ const std::byte b{c};
+ return ~b == std::byte(~c);
+}
+
+static_assert( test_complement(0) );
+static_assert( test_complement(4) );
+static_assert( test_complement(9) );
+static_assert( test_complement(16) );
+static_assert( test_complement(63) );
+static_assert( test_complement(127) );
+static_assert( test_complement(255) );
+
+template<typename T>
+constexpr bool test_to_integer(unsigned char c)
+{
+ std::byte b{c};
+ return std::to_integer<T>(b) == T(c);
+}
+
+static_assert( test_to_integer<int>(0) );
+static_assert( test_to_integer<int>(255) );
+static_assert( test_to_integer<signed char>(255) );
+static_assert( test_to_integer<unsigned>(0) );
+static_assert( test_to_integer<unsigned>(255) );
+
diff --git a/libstdc++-v3/testsuite/18_support/byte/requirements.cc
b/libstdc++-v3/testsuite/18_support/byte/requirements.cc
new file mode 100644
index 0000000..da5fc91
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/byte/requirements.cc
@@ -0,0 +1,27 @@
+// Copyright (C) 2017 Free Software Foundation, Inc.
+//
+// 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.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3. If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17" }
+// { dg-do compile { target c++1z } }
+
+#include <cstddef>
+
+static_assert( sizeof(std::byte) == sizeof(unsigned char) );
+static_assert( alignof(std::byte) == alignof(unsigned char) );
+
+// Use the built-in to avoid depending on <type_traits>
+__underlying_type(std::byte)* p = (unsigned char*)nullptr;
