Ответы на задачи со стенда PVS-Studio на конференциях 2018-2019

2018

С++

static const int kDaysInMonth[13] = {
  0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
bool ValidateDateTime(const DateTime& time) {
  if (time.year < 1 || time.year > 9999 ||
      time.month < 1 || time.month > 12 ||
      time.day < 1 || time.day > 31 ||
      time.hour < 0 || time.hour > 23 ||
      time.minute < 0 || time.minute > 59 ||
      time.second < 0 || time.second > 59) {
    return false;
  }
  if (time.month == 2 && IsLeapYear(time.year)) {
    return time.month <= kDaysInMonth[time.month] + 1;
  } else {
    return time.month <= kDaysInMonth[time.month];
  }
}

if (time.month == 2 && IsLeapYear(time.year)) {
  return time.month <= kDaysInMonth[time.month] + 1;  // <= day
} else {
  return time.month <= kDaysInMonth[time.month];      // <= day
}

bool VertInfluencedByActiveBone(
  FParticleEmitterInstance* Owner,
  USkeletalMeshComponent* InSkelMeshComponent,
  int32 InVertexIndex,
  int32* OutBoneIndex = NULL);

void UParticleModuleLocationSkelVertSurface::Spawn(....)
{
  ....
  int32 BoneIndex1, BoneIndex2, BoneIndex3;
  BoneIndex1 = BoneIndex2 = BoneIndex3 = INDEX_NONE;

  if(!VertInfluencedByActiveBone(
        Owner, SourceComponent, VertIndex[0], &BoneIndex1) &&
     !VertInfluencedByActiveBone(
        Owner, SourceComponent, VertIndex[1], &BoneIndex2) && 
     !VertInfluencedByActiveBone(
        Owner, SourceComponent, VertIndex[2]) &BoneIndex3)
  {
  ....
}

if (!foo(....) && !foo(....) && !foo(....) & arg)

if(!VertInfluencedByActiveBone(
      Owner, SourceComponent, VertIndex[0], &BoneIndex1) &&
   !VertInfluencedByActiveBone(
      Owner, SourceComponent, VertIndex[1], &BoneIndex2) && 
   !VertInfluencedByActiveBone(
      Owner, SourceComponent, VertIndex[2], &BoneIndex3))

void TagMonitor::parseTagsToMonitor(String8 tagNames) {
  std::lock_guard<std::mutex> lock(mMonitorMutex);

  // Expand shorthands
  if (ssize_t idx = tagNames.find("3a") != -1) {
    ssize_t end = tagNames.find(",", idx);
    char* start = tagNames.lockBuffer(tagNames.size());
    start[idx] = '\0';
    ....
  }
  ....
}

if (ssize_t idx = (tagNames.find("3a") != -1))

ssize_t idx = tagNames.find("3a");
if (idx != -1)

typedef int32_t  GGLfixed;
GGLfixed gglFastDivx(GGLfixed n, GGLfixed d)
{
  if ((d>>24) && ((d>>24)+1)) {
    n >>= 8;
    d >>= 8;
  }
  return gglMulx(n, gglRecip(d));
}

2019

С++

int foo(const unsigned char *s)
{
  int r = 0;
  while(*s) {
    r += ((r * 20891 + *s *200) | *s ^ 4 | *s ^ 3) ^ (r >> 1);
    s++;
  }
  return r & 0x7fffffff;
}

static inline const QMetaObjectPrivate *priv(const uint* data)
{ return reinterpret_cast<const QMetaObjectPrivate*>(data); }

bool QMetaEnum::isFlag() const
{
  const int offset = priv(mobj->d.data)->revision >= 8 ? 2 : 1;
  return mobj && mobj->d.data[handle + offset] & EnumIsFlag;
}

C#

public static void 
  WriteAttribute(TextWriter writer,
                 string name,
                 object defaultValue, 
                 object value, 
                 Func<object, string> converter = null)
{
  if (   defaultValue == null && value == null 
      || value.Equals(defaultValue))
  {
    return;
  }
  string stringValue = converter == null ? value.ToString() : 
                                           converter(value);
  writer.Write($"{name}=\"{stringValue}\" ");
}

public class FastString
{
  private const int initCapacity = 32;
  private void Init(int iniCapacity)
  { sb = new StringBuilder(iniCapacity); .... }
  public FastString() { Init(initCapacity); }
  public FastString(int iniCapacity) { Init(initCapacity); }
  public StringBuilder StringBuilder => sb;
}
....
Console.WriteLine(new FastString(256).StringBuilder.Capacity);

public FastString(int iniCapacity){ Init(initCapacity); }

private SyntaxNode GetNode(SyntaxNode root)
{
  var current = root;
  ....
  while (current.FullSpan.Contains(....))
  {
    ....
    var nodeOrToken = current.ChildThatContainsPosition(....);
    ....
    current = nodeOrToken.AsNode();
  }
  ....
}

public SyntaxNode AsNode()
{
  if (_token != null)
  {
    return null;
  }
  
  return _nodeOrParent;
}

....
staticFields = packedSnapshot.typeDescriptions
               .Where(t => 
                      t.staticFieldBytes != null & 
                      t.staticFieldBytes.Length > 0)
               .Select(t => UnpackStaticFields(t))
               .ToArray()
....

Java

private static boolean checkSentenceCapitalization(@NotNull String value) {
  List<String> words = StringUtil.split(value, " ");
  ....
  int capitalized = 1;
  ....
  return capitalized / words.size() < 0.2; // allow reasonable amount of
                                           // capitalized words
}

public static String getXMLType(@WillNotClose InputStream in) throws IOException
{
  ....
  String s;
  int count = 0;
  while (count < 4) {
    s = r.readLine();
    if (s == null) {
      break;
    }
    Matcher m = tag.matcher(s);
    if (m.find()) {
      return m.group(1);
    }
  }
  throw new IOException("Didn't find xml tag");
  ....
}