1 //===-- llvm/ADT/APSInt.cpp - Arbitrary Precision Signed Int ---*- C++ -*--===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements the APSInt class, which is a simple class that 11 // represents an arbitrary sized integer that knows its signedness. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/ADT/APSInt.h" 16 #include "llvm/ADT/FoldingSet.h" 17 #include "llvm/ADT/StringRef.h" 18 19 using namespace llvm; 20 21 APSInt::APSInt(StringRef Str) { 22 assert(!Str.empty() && "Invalid string length"); 23 24 // (Over-)estimate the required number of bits. 25 unsigned NumBits = ((Str.size() * 64) / 19) + 2; 26 APInt Tmp(NumBits, Str, /*Radix=*/10); 27 if (Str[0] == '-') { 28 unsigned MinBits = Tmp.getMinSignedBits(); 29 if (MinBits > 0 && MinBits < NumBits) 30 Tmp = Tmp.trunc(MinBits); 31 *this = APSInt(Tmp, /*IsUnsigned=*/false); 32 return; 33 } 34 unsigned ActiveBits = Tmp.getActiveBits(); 35 if (ActiveBits > 0 && ActiveBits < NumBits) 36 Tmp = Tmp.trunc(ActiveBits); 37 *this = APSInt(Tmp, /*IsUnsigned=*/true); 38 } 39 40 void APSInt::Profile(FoldingSetNodeID& ID) const { 41 ID.AddInteger((unsigned) (IsUnsigned ? 1 : 0)); 42 APInt::Profile(ID); 43 } 44
