1//===-- llvm/ADT/APSInt.cpp - Arbitrary Precision Signed Int ---*- C++ -*--===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file implements the APSInt class, which is a simple class that
10// represents an arbitrary sized integer that knows its signedness.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/ADT/APSInt.h"
15#include "llvm/ADT/FoldingSet.h"
16#include "llvm/ADT/StringRef.h"
17#include <cassert>
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.getSignificantBits();
29    if (MinBits < NumBits)
30      Tmp = Tmp.trunc(std::max<unsigned>(1, MinBits));
31    *this = APSInt(Tmp, /*isUnsigned=*/false);
32    return;
33  }
34  unsigned ActiveBits = Tmp.getActiveBits();
35  if (ActiveBits < NumBits)
36    Tmp = Tmp.trunc(std::max<unsigned>(1, 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