*/
  public static BigInteger floorPowerOfTwo(BigInteger x) {
    return BigInteger.ZERO.setBit(log2(x, FLOOR));
  }

  /** Returns {@code true} if {@code x} represents a power of two. */
  public static boolean isPowerOfTwo(BigInteger x) {
    checkNotNull(x);
    return x.signum() > 0 && x.getLowestSetBit() == x.bitLength() - 1;
  }

  /**

And Pydantic's `Field` returns an instance of `FieldInfo` as well.

`Body` also returns objects of a subclass of `FieldInfo` directly. And there are others you will see later that are subclasses of the `Body` class.

Remember that when you import `Query`, `Path`, and others from `fastapi`, those are actually functions that return special classes.

///

/// tip

    if (map instanceof EnumBiMap) {
      return ((EnumBiMap<?, V>) map).valueTypeOrObjectUnderJ2cl;
    }
    checkArgument(!map.isEmpty());
    return getDeclaringClassOrObjectForJ2cl(map.values().iterator().next());
  }

  /** Returns the associated key type. */
  @GwtIncompatible
  public Class<K> keyType() {
    return keyTypeOrObjectUnderJ2cl;
  }

  /** Returns the associated value type. */
  @GwtIncompatible

    if (map instanceof EnumBiMap) {
      return ((EnumBiMap<?, V>) map).valueTypeOrObjectUnderJ2cl;
    }
    checkArgument(!map.isEmpty());
    return getDeclaringClassOrObjectForJ2cl(map.values().iterator().next());
  }

  /** Returns the associated key type. */
  @GwtIncompatible
  public Class<K> keyType() {
    return keyTypeOrObjectUnderJ2cl;
  }

  /** Returns the associated value type. */
  @GwtIncompatible

		if partNumber == part.Number {
			return i
		}
	}
	return -1
}

// objectPartIndexNums returns the index of the specified part number.
// Returns -1 if the part cannot be found.
func objectPartIndexNums(parts []int, partNumber int) int {
	for i, part := range parts {
		if part != 0 && partNumber == part {
			return i
		}
	}
	return -1
}

		return true
	}
	return false
}

// ParseHTTP parses the SSE-C copy headers and returns the SSE-C client key
// on success. Regular SSE-C headers are ignored.
func (ssecCopy) ParseHTTP(h http.Header) (key [32]byte, err error) {
	if h.Get(xhttp.AmzServerSideEncryptionCopyCustomerAlgorithm) != xhttp.AmzEncryptionAES {
		return key, ErrInvalidCustomerAlgorithm
	}
	if h.Get(xhttp.AmzServerSideEncryptionCopyCustomerKey) == "" {

            }
        }
        return flags;
    }


    /**
     * Returns the challenge for this message.
     *
     * @return A <code>byte[]</code> containing the challenge.
     */
    public byte[] getChallenge () {
        return this.challenge;
    }


    /**
     * Sets the challenge for this message.
     *

 *
 * <ul>
 *   <li>comparing each object against itself returns true
 *   <li>comparing each object against null returns false
 *   <li>comparing each object against an instance of an incompatible class returns false
 *   <li>comparing each pair of objects within the same equality group returns true
 *   <li>comparing each pair of objects from different equality groups returns false
 *   <li>the hash codes of any two equal objects are equal

        clazz = enumValue.getDeclaringClass();
    try {
      return clazz.getDeclaredField(enumValue.name());
    } catch (NoSuchFieldException impossible) {
      throw new AssertionError(impossible);
    }
  }

  /**
   * Returns an optional enum constant for the given type, using {@link Enum#valueOf}. If the
   * constant does not exist, {@link Optional#absent} is returned. A common use case is for parsing

// This will ensure that at most n bytes are returned and EOF is reached.
func HardLimitReader(r io.Reader, n int64) io.Reader { return &HardLimitedReader{r, n} }

// A HardLimitedReader reads from R but limits the amount of
// data returned to just N bytes. Each call to Read
// updates N to reflect the new amount remaining.
// Read returns EOF when N <= 0 or when the underlying R returns EOF.
type HardLimitedReader struct {
	R io.Reader // underlying reader