44 lines
1.4 KiB
C++
44 lines
1.4 KiB
C++
//===-- llvm/ADT/APSInt.cpp - Arbitrary Precision Signed Int ---*- 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 implements the APSInt class, which is a simple class that
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// represents an arbitrary sized integer that knows its signedness.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/ADT/APSInt.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/StringRef.h"
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using namespace llvm;
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APSInt::APSInt(StringRef Str) {
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assert(!Str.empty() && "Invalid string length");
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// (Over-)estimate the required number of bits.
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unsigned NumBits = ((Str.size() * 64) / 19) + 2;
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APInt Tmp(NumBits, Str, /*Radix=*/10);
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if (Str[0] == '-') {
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unsigned MinBits = Tmp.getMinSignedBits();
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if (MinBits > 0 && MinBits < NumBits)
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Tmp = Tmp.trunc(MinBits);
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*this = APSInt(Tmp, /*IsUnsigned=*/false);
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return;
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}
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unsigned ActiveBits = Tmp.getActiveBits();
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if (ActiveBits > 0 && ActiveBits < NumBits)
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Tmp = Tmp.trunc(ActiveBits);
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*this = APSInt(Tmp, /*IsUnsigned=*/true);
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}
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void APSInt::Profile(FoldingSetNodeID& ID) const {
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ID.AddInteger((unsigned) (IsUnsigned ? 1 : 0));
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APInt::Profile(ID);
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}
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