What is under the hood of .Net String.GetHashCode()?

Ever wonder what is the hashing algorithm used inside the .Net String class's GetHashCode() override? Well, here is the fruit of a couple of hours of my labour.
C++ (Unmanaged):
ULONG HashString(LPCWSTR szStr)
{
ULONG hash = 5381;
int c;

while ((c = *szStr) != 0)
{
hash = ((hash << 5) + hash) ^ c;
++szStr;
}
return hash;
}

C++ Managed:

int Class1::HashString(String *szStr)
{
int hash = 5381;
int c;
int len = szStr->Length;
for (int i = 0; i < len; i++)
{
char f = szStr->get_Chars(i);
int c = f;
if (c < 0) c += 256; // Some characters like '£', '¬' are returned with a negative values!
hash = ((hash << 5) + hash) ^ c;
}
return hash;
}

C#:
int HashString(string szStr)
{
int hash = 5381;
int c;
int i = 0;

while(i < szStr.Length)
{
c = (int)szStr[i];

hash = ((hash << 5) + hash) ^ c;
i++;
}
return hash;
}

Enjoy!