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Move 'Optional' class from Clang to LLVM/ADT.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100889 91177308-0d34-0410-b5e6-96231b3b80d8
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//===-- Optional.h - Simple variant for passing optional values ---*- C++ -*-=// | ||
// | ||
// The LLVM Compiler Infrastructure | ||
// | ||
// This file is distributed under the University of Illinois Open Source | ||
// License. See LICENSE.TXT for details. | ||
// | ||
//===----------------------------------------------------------------------===// | ||
// | ||
// This file provides Optional, a template class modeled in the spirit of | ||
// OCaml's 'opt' variant. The idea is to strongly type whether or not | ||
// a value can be optional. | ||
// | ||
//===----------------------------------------------------------------------===// | ||
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#ifndef LLVM_ADT_OPTIONAL | ||
#define LLVM_ADT_OPTIONAL | ||
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#include <cassert> | ||
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namespace llvm { | ||
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template<typename T> | ||
class Optional { | ||
T x; | ||
unsigned hasVal : 1; | ||
public: | ||
explicit Optional() : x(), hasVal(false) {} | ||
Optional(const T &y) : x(y), hasVal(true) {} | ||
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static inline Optional create(const T* y) { | ||
return y ? Optional(*y) : Optional(); | ||
} | ||
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Optional &operator=(const T &y) { | ||
x = y; | ||
hasVal = true; | ||
return *this; | ||
} | ||
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const T* getPointer() const { assert(hasVal); return &x; } | ||
const T& getValue() const { assert(hasVal); return x; } | ||
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operator bool() const { return hasVal; } | ||
bool hasValue() const { return hasVal; } | ||
const T* operator->() const { return getPointer(); } | ||
const T& operator*() const { assert(hasVal); return x; } | ||
}; | ||
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template<typename T> struct simplify_type; | ||
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template <typename T> | ||
struct simplify_type<const Optional<T> > { | ||
typedef const T* SimpleType; | ||
static SimpleType getSimplifiedValue(const Optional<T> &Val) { | ||
return Val.getPointer(); | ||
} | ||
}; | ||
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template <typename T> | ||
struct simplify_type<Optional<T> > | ||
: public simplify_type<const Optional<T> > {}; | ||
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} // end llvm namespace | ||
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#endif |