## org.apache.lucene.util
Class IndexableBinaryStringTools

    java.lang.Object
      org.apache.lucene.util.IndexableBinaryStringTools

    public final class IndexableBinaryStringTools

extends Object

Provides support for converting byte sequences to Strings and back again. The resulting Strings preserve the original byte sequences' sort order.

The Strings are constructed using a Base 8000h encoding of the original binary data - each char of an encoded String represents a 15-bit chunk from the byte sequence. Base 8000h was chosen because it allows for all lower 15 bits of char to be used without restriction; the surrogate range [U+D8000-U+DFFF] does not represent valid chars, and would require complicated handling to avoid them and allow use of char's high bit.

Although unset bits are used as padding in the final char, the original byte sequence could contain trailing bytes with no set bits (null bytes): padding is indistinguishable from valid information. To overcome this problem, a char is appended, indicating the number of encoded bytes in the final content char.

Some methods in this class are defined over CharBuffers and ByteBuffers, but these are deprecated in favor of methods that operate directly on byte[] and char[] arrays. Note that this class calls array() and arrayOffset() on the CharBuffers and ByteBuffers it uses, so only wrapped arrays may be used. This class interprets the arrayOffset() and limit() values returned by its input buffers as beginning and end+1 positions on the wrapped array, respectively; similarly, on the output buffer, arrayOffset() is the first position written to, and limit() is set to one past the final output array position.

WARNING: This means that the deprecated Buffer-based methods only work correctly with buffers that have an offset of 0. For example, they will not correctly interpret buffers returned by `ByteBuffer.slice()`.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Method Summary
`static void` `decode(char[] inputArray, int inputOffset, int inputLength, byte[] outputArray, int outputOffset, int outputLength)` Decodes the input char sequence into the output byte sequence.
`static ByteBuffer` `decode(CharBuffer input)` Deprecated. Use `decode(char[], int, int, byte[], int, int)` instead. This method will be removed in Lucene 4.0
`static void` `decode(CharBuffer input, ByteBuffer output)` Deprecated. Use `decode(char[], int, int, byte[], int, int)` instead. This method will be removed in Lucene 4.0
`static void` `encode(byte[] inputArray, int inputOffset, int inputLength, char[] outputArray, int outputOffset, int outputLength)` Encodes the input byte sequence into the output char sequence.
`static CharBuffer` `encode(ByteBuffer input)` Deprecated. Use `encode(byte[], int, int, char[], int, int)` instead. This method will be removed in Lucene 4.0
`static void` `encode(ByteBuffer input, CharBuffer output)` Deprecated. Use `encode(byte[], int, int, char[], int, int)` instead. This method will be removed in Lucene 4.0
`static int` `getDecodedLength(char[] encoded, int offset, int length)` Returns the number of bytes required to decode the given char sequence.
`static int` `getDecodedLength(CharBuffer encoded)` Deprecated. Use `getDecodedLength(char[], int, int)` instead. This method will be removed in Lucene 4.0
`static int` `getEncodedLength(byte[] inputArray, int inputOffset, int inputLength)` Returns the number of chars required to encode the given bytes.
`static int` `getEncodedLength(ByteBuffer original)` Deprecated. Use `getEncodedLength(byte[], int, int)` instead. This method will be removed in Lucene 4.0

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Method Detail

### getEncodedLength

    @Deprecated
    public static int getEncodedLength(ByteBuffer original)
                                throws IllegalArgumentException

  Deprecated. Use `getEncodedLength(byte[], int, int)` instead. This method will be removed in Lucene 4.0

  Returns the number of chars required to encode the given byte sequence.

  Parameters:
    `original` - The byte sequence to be encoded. Must be backed by an array.
  Returns:
    The number of chars required to encode the given byte sequence
  Throws:
    `IllegalArgumentException` - If the given ByteBuffer is not backed by an array

### getEncodedLength

    public static int getEncodedLength(byte[] inputArray,
                                       int inputOffset,
                                       int inputLength)

  Returns the number of chars required to encode the given bytes.

  Parameters:
    `inputArray` - byte sequence to be encoded
    `inputOffset` - initial offset into inputArray
    `inputLength` - number of bytes in inputArray
  Returns:
    The number of chars required to encode the number of bytes.

### getDecodedLength

    @Deprecated
    public static int getDecodedLength(CharBuffer encoded)
                                throws IllegalArgumentException

  Deprecated. Use `getDecodedLength(char[], int, int)` instead. This method will be removed in Lucene 4.0

  Returns the number of bytes required to decode the given char sequence.

  Parameters:
    `encoded` - The char sequence to be decoded. Must be backed by an array.
  Returns:
    The number of bytes required to decode the given char sequence
  Throws:
    `IllegalArgumentException` - If the given CharBuffer is not backed by an array

### getDecodedLength

    public static int getDecodedLength(char[] encoded,
                                       int offset,
                                       int length)

  Returns the number of bytes required to decode the given char sequence.

  Parameters:
    `encoded` - char sequence to be decoded
    `offset` - initial offset
    `length` - number of characters
  Returns:
    The number of bytes required to decode the given char sequence

### encode

    @Deprecated
    public static void encode(ByteBuffer input,
                                         CharBuffer output)

  Deprecated. Use `encode(byte[], int, int, char[], int, int)` instead. This method will be removed in Lucene 4.0

  Encodes the input byte sequence into the output char sequence. Before calling this method, ensure that the output CharBuffer has sufficient capacity by calling `getEncodedLength(java.nio.ByteBuffer)`.

  Parameters:
    `input` - The byte sequence to encode
    `output` - Where the char sequence encoding result will go. The limit is set to one past the position of the final char.
  Throws:
    `IllegalArgumentException` - If either the input or the output buffer is not backed by an array

### encode

    public static void encode(byte[] inputArray,
                              int inputOffset,
                              int inputLength,
                              char[] outputArray,
                              int outputOffset,
                              int outputLength)

  Encodes the input byte sequence into the output char sequence. Before calling this method, ensure that the output array has sufficient capacity by calling `getEncodedLength(byte[], int, int)`.

  Parameters:
    `inputArray` - byte sequence to be encoded
    `inputOffset` - initial offset into inputArray
    `inputLength` - number of bytes in inputArray
    `outputArray` - char sequence to store encoded result
    `outputOffset` - initial offset into outputArray
    `outputLength` - length of output, must be getEncodedLength

### decode

    @Deprecated
    public static void decode(CharBuffer input,
                                         ByteBuffer output)

  Deprecated. Use `decode(char[], int, int, byte[], int, int)` instead. This method will be removed in Lucene 4.0

  Decodes the input char sequence into the output byte sequence. Before calling this method, ensure that the output ByteBuffer has sufficient capacity by calling `getDecodedLength(java.nio.CharBuffer)`.

  Parameters:
    `input` - The char sequence to decode
    `output` - Where the byte sequence decoding result will go. The limit is set to one past the position of the final char.
  Throws:
    `IllegalArgumentException` - If either the input or the output buffer is not backed by an array

### decode

    public static void decode(char[] inputArray,
                              int inputOffset,
                              int inputLength,
                              byte[] outputArray,
                              int outputOffset,
                              int outputLength)

  Decodes the input char sequence into the output byte sequence. Before calling this method, ensure that the output array has sufficient capacity by calling `getDecodedLength(char[], int, int)`.

  Parameters:
    `inputArray` - char sequence to be decoded
    `inputOffset` - initial offset into inputArray
    `inputLength` - number of chars in inputArray
    `outputArray` - byte sequence to store encoded result
    `outputOffset` - initial offset into outputArray
    `outputLength` - length of output, must be getDecodedLength(inputArray, inputOffset, inputLength)

### decode

    @Deprecated
    public static ByteBuffer decode(CharBuffer input)

  Deprecated. Use `decode(char[], int, int, byte[], int, int)` instead. This method will be removed in Lucene 4.0

  Decodes the given char sequence, which must have been encoded by `encode(java.nio.ByteBuffer)` or `encode(java.nio.ByteBuffer, java.nio.CharBuffer)`.

  Parameters:
    `input` - The char sequence to decode
  Returns:
    A byte sequence containing the decoding result. The limit is set to one past the position of the final char.
  Throws:
    `IllegalArgumentException` - If the input buffer is not backed by an array

### encode

    @Deprecated
    public static CharBuffer encode(ByteBuffer input)

  Deprecated. Use `encode(byte[], int, int, char[], int, int)` instead. This method will be removed in Lucene 4.0

  Encodes the input byte sequence.

  Parameters:
    `input` - The byte sequence to encode
  Returns:
    A char sequence containing the encoding result. The limit is set to one past the position of the final char.
  Throws:
    `IllegalArgumentException` - If the input buffer is not backed by an array