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//===-- SaveAndRestore.h - Utility -------------------------------*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file provides utility classes that use RAII to save and restore
/// values.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_SAVEANDRESTORE_H
#define LLVM_SUPPORT_SAVEANDRESTORE_H
namespace llvm {
/// A utility class that uses RAII to save and restore the value of a variable.
template <typename T> struct SaveAndRestore {
SaveAndRestore(T &X) : X(X), OldValue(X) {}
SaveAndRestore(T &X, const T &NewValue) : X(X), OldValue(X) {
X = NewValue;
}
~SaveAndRestore() { X = OldValue; }
T get() { return OldValue; }
private:
T &X;
T OldValue;
};
/// Similar to \c SaveAndRestore. Operates only on bools; the old value of a
/// variable is saved, and during the dstor the old value is or'ed with the new
/// value.
struct SaveOr {
SaveOr(bool &X) : X(X), OldValue(X) { X = false; }
~SaveOr() { X |= OldValue; }
private:
bool &X;
const bool OldValue;
};
} // namespace llvm
#endif
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