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
19using namespace llvm;
20
21APSInt::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
40void APSInt::Profile(FoldingSetNodeID& ID) const {
41  ID.AddInteger((unsigned) (IsUnsigned ? 1 : 0));
42  APInt::Profile(ID);
43}
44