Function AsciiStrCmp

MdePkg/Library/BaseLib/String.c:1281–1309

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

**/
INTN
EFIAPI
AsciiStrCmp(
  IN      CONST CHAR8               *FirstString,
  IN      CONST CHAR8               *SecondString
  )
{
  //
  // ASSERT both strings are less long than PcdMaximumAsciiStringLength
  //
//  ASSERT (AsciiStrSize (FirstString));
//  ASSERT (AsciiStrSize (SecondString));
  if (!AsciiStrSize (FirstString) && !AsciiStrSize (SecondString)) {
    return 0;
  }
  if (!AsciiStrSize (FirstString)) {
    return -1;
  }
  if (!AsciiStrSize (SecondString)) {
    return 1;
  }

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

  return *FirstString - *SecondString;
}

/**
  Converts a lowercase Ascii character to upper one.