Package io.objectbox.flatbuffers

Class Utf8Safe

java.lang.Object

io.objectbox.flatbuffers.Utf8

io.objectbox.flatbuffers.Utf8Safe

public final class Utf8Safe
extends Utf8

A set of low-level, high-performance static utility methods related to the UTF-8 character encoding. This class has no dependencies outside of the core JDK libraries.

There are several variants of UTF-8. The one implemented by this class is the restricted definition of UTF-8 introduced in Unicode 3.1, which mandates the rejection of "overlong" byte sequences as well as rejection of 3-byte surrogate codepoint byte sequences. Note that the UTF-8 decoder included in Oracle's JDK has been modified to also reject "overlong" byte sequences, but (as of 2011) still accepts 3-byte surrogate codepoint byte sequences.

The byte sequences considered valid by this class are exactly those that can be roundtrip converted to Strings and back to bytes using the UTF-8 charset, without loss:

 
 Arrays.equals(bytes, new String(bytes, Internal.UTF_8).getBytes(Internal.UTF_8))
 

See the Unicode Standard,
Table 3-6. UTF-8 Bit Distribution,
Table 3-7. Well Formed UTF-8 Byte Sequences.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	Utf8Safe.UnpairedSurrogateException

Nested classes/interfaces inherited from class io.objectbox.flatbuffers.Utf8

Utf8.DecodeUtil

Constructor Summary

Constructors

Constructor	Description
Utf8Safe()

Method Summary

Modifier and Type	Method	Description
private static int	computeEncodedLength(CharSequence sequence)	Returns the number of bytes in the UTF-8-encoded form of sequence.
String	decodeUtf8(ByteBuffer buffer, int offset, int length)	Decodes the given UTF-8 portion of the ByteBuffer into a String.
static String	decodeUtf8Array(byte[] bytes, int index, int size)
static String	decodeUtf8Buffer(ByteBuffer buffer, int offset, int length)
int	encodedLength(CharSequence in)	Returns the number of bytes in the UTF-8-encoded form of sequence.
private static int	encodedLengthGeneral(CharSequence sequence, int start)
void	encodeUtf8(CharSequence in, ByteBuffer out)	Encodes the given characters to the target ByteBuffer using UTF-8 encoding.
private static int	encodeUtf8Array(CharSequence in, byte[] out, int offset, int length)
private static void	encodeUtf8Buffer(CharSequence in, ByteBuffer out)

Methods inherited from class io.objectbox.flatbuffers.Utf8

encodeUtf8CodePoint, getDefault, setDefault

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Utf8Safe

public Utf8Safe()

Method Details

computeEncodedLength

private static int computeEncodedLength(CharSequence sequence)

Returns the number of bytes in the UTF-8-encoded form of sequence. For a string, this method is equivalent to string.getBytes(UTF_8).length, but is more efficient in both time and space.

Throws:

IllegalArgumentException - if sequence contains ill-formed UTF-16 (unpaired surrogates)

encodedLengthGeneral

private static int encodedLengthGeneral(CharSequence sequence,
 int start)

decodeUtf8Array

public static String decodeUtf8Array(byte[] bytes,
 int index,
 int size)

decodeUtf8Buffer

public static String decodeUtf8Buffer(ByteBuffer buffer,
 int offset,
 int length)

encodedLength

public int encodedLength(CharSequence in)

Description copied from class: Utf8

Returns the number of bytes in the UTF-8-encoded form of sequence. For a string, this method is equivalent to string.getBytes(UTF_8).length, but is more efficient in both time and space.

Specified by:

encodedLength in class Utf8

decodeUtf8

public String decodeUtf8(ByteBuffer buffer,
 int offset,
 int length)
                  throws IllegalArgumentException

Decodes the given UTF-8 portion of the ByteBuffer into a String.

Specified by:

decodeUtf8 in class Utf8

Throws:

IllegalArgumentException - if the input is not valid UTF-8.

encodeUtf8Buffer

private static void encodeUtf8Buffer(CharSequence in,
 ByteBuffer out)

encodeUtf8Array

private static int encodeUtf8Array(CharSequence in,
 byte[] out,
 int offset,
 int length)

encodeUtf8

public void encodeUtf8(CharSequence in,
 ByteBuffer out)

Encodes the given characters to the target ByteBuffer using UTF-8 encoding.

Selects an optimal algorithm based on the type of ByteBuffer (i.e. heap or direct) and the capabilities of the platform.

Specified by:

encodeUtf8 in class Utf8

Parameters:

in - the source string to be encoded

out - the target buffer to receive the encoded string.