com.google.flatbuffers

Class Utf8Safe

java.lang.Object

com.google.flatbuffers.Utf8

com.google.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.

Constructor Summary

Constructors

Constructor and Description
Utf8Safe()

Method Summary

Modifier and Type	Method and Description
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.
void	encodeUtf8(CharSequence in, ByteBuffer out) Encodes the given characters to the target ByteBuffer using UTF-8 encoding.

Methods inherited from class com.google.flatbuffers.Utf8

getDefault, setDefault

Methods inherited from class java.lang.Object

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

Constructor Detail

Utf8Safe

public Utf8Safe()

Method Detail

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.

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.