Function StrCmp

MdePkg/Library/BaseLib/String.c:260–289

Compares two Null-terminated Unicode strings, and returns the difference between the first mismatched Unicode characters. This function compares the Null-terminated Unicode string FirstString to the Null-terminated Unicode string SecondString. If FirstString is identical to SecondString, then 0 is returned. Otherwise, the value returned is the first mismatched Unicode character in

**/
INTN
EFIAPI
StrCmp (
  IN      CONST CHAR16              *FirstString,
  IN      CONST CHAR16              *SecondString
  )
{
  //
  // ASSERT both strings are less long than PcdMaximumUnicodeStringLength
  //
//  ASSERT (StrSize (FirstString) != 0);
//  ASSERT (StrSize (SecondString) != 0);
  if ((StrSize (FirstString) == 0) && (StrSize (SecondString) == 0)) {
    return 0;
  }

  if (StrSize (FirstString) == 0) {
    return -1;
  }
  if (StrSize (SecondString) == 0) {
    return 1;
  }


  while ((*FirstString != L'\0') && (*FirstString == *SecondString)) {
    FirstString++;
    SecondString++;
  }
  return *FirstString - *SecondString;
}

/**
  Compares up to a specified length the contents of two Null-terminated Unicode strings,