59 lines
1.6 KiB
C++
59 lines
1.6 KiB
C++
//===-- Optional.h - Simple variant for passing optional values ---*- C++ -*-=//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file provides Optional, a template class modeled in the spirit of
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// OCaml's 'opt' variant. The idea is to strongly type whether or not
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// a value can be optional.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_ANALYSIS_OPTIONAL
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#define LLVM_CLANG_ANALYSIS_OPTIONAL
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namespace clang {
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template<typename T>
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class Optional {
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const T x;
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unsigned hasVal : 1;
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public:
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explicit Optional() : hasVal(false) {}
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Optional(const T &y) : x(y), hasVal(true) {}
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static inline Optional create(const T* y) {
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return y ? Optional(*y) : Optional();
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}
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const T* getPointer() const { assert(hasVal); return &x; }
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operator bool() const { return hasVal; }
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const T* operator->() const { return getPointer(); }
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const T& operator*() const { assert(hasVal); return x; }
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};
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} //end clang namespace
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namespace llvm {
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template<typename T> struct simplify_type;
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template <typename T>
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struct simplify_type<const ::clang::Optional<T> > {
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typedef const T* SimpleType;
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static SimpleType getSimplifiedValue(const ::clang::Optional<T> &Val) {
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return Val.getPointer();
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}
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};
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template <typename T>
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struct simplify_type< ::clang::Optional<T> >
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: public simplify_type<const ::clang::Optional<T> > {};
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} // end llvm namespace
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#endif
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