bool parseByteRangeSpec()

in proxygen/lib/http/RFC2616.cpp [101:166]

• 53 lines of code
• 13 McCabe index (conditional complexity)

bool parseByteRangeSpec(folly::StringPiece value,
                        unsigned long& outFirstByte,
                        unsigned long& outLastByte,
                        unsigned long& outInstanceLength) {
  // We should start with "bytes "
  if (!value.startsWith("bytes ")) {
    return false;
  }

  const char* curs = value.begin() + 6 /* strlen("bytes ") */;
  const char* end = value.end();

  unsigned long firstByte = ULONG_MAX;
  unsigned long lastByte = ULONG_MAX;
  unsigned long instanceLength = ULONG_MAX;

  if (!strtoulWrapper(curs, end, firstByte)) {
    if (*curs != '*') {
      return false;
    }

    firstByte = 0;
    lastByte = ULONG_MAX;
    ++curs;
  } else {
    if (*curs != '-') {
      return false;
    }

    ++curs;

    if (!strtoulWrapper(curs, end, lastByte)) {
      return false;
    }
  }

  if (*curs != '/') {
    return false;
  }

  ++curs;
  if (*curs != '*') {
    if (!strtoulWrapper(curs, end, instanceLength)) {
      return false;
    }
  } else {
    ++curs;
  }

  if (curs < end && *curs != '\0') {
    return false;
  }

  if (lastByte < firstByte) {
    return false;
  }

  if ((lastByte - firstByte + 1) > instanceLength) {
    return false;
  }

  outFirstByte = firstByte;
  outLastByte = lastByte;
  outInstanceLength = instanceLength;
  return true;
}