53 lines
1.5 KiB
C
53 lines
1.5 KiB
C
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/*
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* Copyright 2016 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkSafe_math_DEFINED
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#define SkSafe_math_DEFINED
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// This file protects against known bugs in ucrt\math.h.
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// Namely, that header defines inline methods without marking them static,
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// which makes it very easy to cause ODR violations and ensuing chaos.
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//
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// TODO: other headers? Here are some potential problem headers:
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// $ grep -R __inline * | grep -v static | cut -f 1 -d: | sort | uniq
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// corecrt.h
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// corecrt_stdio_config.h
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// ctype.h
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// fenv.h
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// locale.h
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// malloc.h
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// math.h
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// tchar.h
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// wchar.h
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// I took a quick look through other headers outside math.h.
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// Nothing looks anywhere near as likely to be used by Skia as math.h.
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#if defined(_MSC_VER) && !defined(_INC_MATH)
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// Our strategy here is to simply inject "static" into the headers
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// where it should have been written, just before __inline.
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//
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// Most inline-but-not-static methods in math.h are 32-bit only,
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// but not all of them (see frexpf, hypothf, ldexpf...). So to
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// be safe, 32- and 64-bit builds both get this treatment.
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#define __inline static __inline
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#include <math.h>
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#undef __inline
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#if !defined(_INC_MATH)
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#error Hmm. Looks like math.h has changed its header guards.
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#endif
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#define INC_MATH_IS_SAFE_NOW
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#else
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#include <math.h>
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#endif
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#endif//SkSafe_math_DEFINED
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