61 lines
2.3 KiB
C
61 lines
2.3 KiB
C
// Copyright(c) 2019 ZettaScale Technology and others
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//
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// This program and the accompanying materials are made available under the
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// terms of the Eclipse Public License v. 2.0 which is available at
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// http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
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// v. 1.0 which is available at
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// http://www.eclipse.org/org/documents/edl-v10.php.
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//
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// SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
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#ifndef DDSRT_STATIC_ASSERT_H
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#define DDSRT_STATIC_ASSERT_H
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/* There are many tricks to use a constant expression to yield an
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illegal type or expression at compile time, such as zero-sized
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arrays and duplicate case or enum labels. So this is but one of the
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many tricks. */
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#define DDSRT_STATIC_ASSERT2(line, pred) \
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struct static_assert_##line { \
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char cond[(pred) ? 1 : -1]; \
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}
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#define DDSRT_STATIC_ASSERT1(line, pred) \
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DDSRT_STATIC_ASSERT2 (line, pred)
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#define DDSRT_STATIC_ASSERT(pred) \
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DDSRT_STATIC_ASSERT1 (__LINE__, pred)
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#ifndef _MSC_VER
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#define DDSRT_STATIC_ASSERT_CODE(pred) do { switch(0) { case 0: case (pred): ; } } while (0)
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#else
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/* Temporarily disabling warning C6326: Potential comparison of a
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constant with another constant. */
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#define DDSRT_STATIC_ASSERT_CODE(pred) do { \
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__pragma (warning (push)) \
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__pragma (warning (disable : 6326)) \
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switch(0) { case 0: case (pred): ; } \
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__pragma (warning (pop)) \
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} while (0)
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#endif
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// _Generic is C11, gcc and clang have supported it for a long time already
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// and will happily do it also when compiling C99 code. Microsoft did add
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// it eventually, but only when compiling with /std:c11 according to the
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// docs.
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//
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// Skipping the test for non-whitelisted cases means this should work on
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// all Linux and macOS builds without breaking other platforms. That is
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// a reasonable compromise.
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#if (__STDC__ == 1 && __STDC_VERSION__ >= 201112L) || \
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(__GNUC__*10000 + __GNUC_MINOR__*100 + __GNUC_PATCHLEVEL__) >= 40900 || \
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(__clang_major__*10000 + __clang_minor__*100 + __clang_patchlevel__) >= 30000
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#define DDSRT_STATIC_ASSERT_IS_UNSIGNED(v_) \
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DDSRT_STATIC_ASSERT(_Generic(v_, \
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uint8_t: 1, uint16_t: 1, uint32_t: 1, uint64_t: 1, \
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default: 0))
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#else
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#define DDSRT_STATIC_ASSERT_IS_UNSIGNED(v_) DDSRT_STATIC_ASSERT(1)
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#endif
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#endif
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