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Multi return statement STRANGE?

开发者 https://www.devze.com 2023-04-02 23:17 出处:网络
Today while playing with a De-compiler, i Decompiled the .NET C# Char Class and there is a strange case which i don\'t Understand

Today while playing with a De-compiler, i Decompiled the .NET C# Char Class and there is a strange case which i don't Understand

public static bool IsDigit(char c)
{
    if (char.IsLatin1(c) || c开发者_StackOverflow社区 >= 48)
    {
        return c <= 57;
    }
    return false;
    return CharUnicodeInfo.GetUnicodeCategory(c) == 8;//Is this Line Reachable if Yes How does it work !
}

i Used Telerik JustDecompile


Think your decompiler might be dodgy... With Reflector I get:

public static bool IsDigit(char c)
{
   if (!IsLatin1(c))
   {
       return (CharUnicodeInfo.GetUnicodeCategory(c) == UnicodeCategory.DecimalDigitNumber);
   }
   return ((c >= '0') && (c <= '9'));
}

And with ILSpy I get:

public static bool IsDigit(char c)
{
   if (char.IsLatin1(c))
   {
      return c >= '0' && c <= '9';
   }
   return CharUnicodeInfo.GetUnicodeCategory(c) == UnicodeCategory.DecimalDigitNumber;
}


I assume that this is a bug in the decompiler you used.

In the .NET 4.0 framework, IL Spy shows the following code:

public static bool IsDigit(char c)
{
    if (char.IsLatin1(c))
    {
        return c >= '0' && c <= '9';
    }
    return CharUnicodeInfo.GetUnicodeCategory(c)
           == UnicodeCategory.DecimalDigitNumber;
}


It looks like the decompiler you used isn't very good at what it's doing.

Here's the output of dotPeek for that method:

public static bool IsDigit(char c)
{
  if (!char.IsLatin1(c))
    return CharUnicodeInfo.GetUnicodeCategory(c) == UnicodeCategory.DecimalDigitNumber;
  if ((int) c >= 48)
    return (int) c <= 57;
  else
    return false;
}


I think your decompiler lies.

dotPeek code:

public static bool IsDigit(char c)
    {
      if (char.IsLatin1(c))
      {
        if ((int) c >= 48)
          return (int) c <= 57;
        else
          return false;
      }
      else
        return CharUnicodeInfo.GetUnicodeCategory(c) == UnicodeCategory.DecimalDigitNumber;
    }
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