OrderedBytes (Apache HBase 1.4.11 API)

java.lang.Object
- org.apache.hadoop.hbase.util.OrderedBytes

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class OrderedBytes
extends Object

Utility class that handles ordered byte arrays. That is, unlike Bytes, these methods produce byte arrays which maintain the sort order of the original values.

Encoding Format summary

Each value is encoded as one or more bytes. The first byte of the encoding, its meaning, and a terse description of the bytes that follow is given by the following table:

Content Type	Encoding
NULL	0x05
negative infinity	0x07
negative large	0x08, ~E, ~M
negative medium	0x13-E, ~M
negative small	0x14, -E, ~M
zero	0x15
positive small	0x16, ~-E, M
positive medium	0x17+E, M
positive large	0x22, E, M
positive infinity	0x23
NaN	0x25
fixed-length 32-bit integer	0x27, I
fixed-length 64-bit integer	0x28, I
fixed-length 8-bit integer	0x29
fixed-length 16-bit integer	0x2a
fixed-length 32-bit float	0x30, F
fixed-length 64-bit float	0x31, F
TEXT	0x33, T
variable length BLOB	0x35, B
byte-for-byte BLOB	0x36, X

Null Encoding

Each value that is a NULL encodes as a single byte of 0x05. Since every other value encoding begins with a byte greater than 0x05, this forces NULL values to sort first.

Text Encoding

Each text value begins with a single byte of 0x33 and ends with a single byte of 0x00. There are zero or more intervening bytes that encode the text value. The intervening bytes are chosen so that the encoding will sort in the desired collating order. The intervening bytes may not contain a 0x00 character; the only 0x00 byte allowed in a text encoding is the final byte.

The text encoding ends in 0x00 in order to ensure that when there are two strings where one is a prefix of the other that the shorter string will sort first.

Binary Encoding

There are two encoding strategies for binary fields, referred to as "BlobVar" and "BlobCopy". BlobVar is less efficient in both space and encoding time. It has no limitations on the range of encoded values. BlobCopy is a byte-for-byte copy of the input data followed by a termination byte. It is extremely fast to encode and decode. It carries the restriction of not allowing a 0x00 value in the input byte[] as this value is used as the termination byte.

BlobVar

"BlobVar" encodes the input byte[] in a manner similar to a variable length integer encoding. As with the other OrderedBytes encodings, the first encoded byte is used to indicate what kind of value follows. This header byte is 0x37 for BlobVar encoded values. As with the traditional varint encoding, the most significant bit of each subsequent encoded byte is used as a continuation marker. The 7 remaining bits contain the 7 most significant bits of the first unencoded byte. The next encoded byte starts with a continuation marker in the MSB. The least significant bit from the first unencoded byte follows, and the remaining 6 bits contain the 6 MSBs of the second unencoded byte. The encoding continues, encoding 7 bytes on to 8 encoded bytes. The MSB of the final encoded byte contains a termination marker rather than a continuation marker, and any remaining bits from the final input byte. Any trailing bits in the final encoded byte are zeros.

BlobCopy

"BlobCopy" is a simple byte-for-byte copy of the input data. It uses 0x38 as the header byte, and is terminated by 0x00 in the DESCENDING case. This alternative encoding is faster and more space-efficient, but it cannot accept values containing a 0x00 byte in DESCENDING order.

Variable-length Numeric Encoding

Numeric values must be coded so as to sort in numeric order. We assume that numeric values can be both integer and floating point values. Clients must be careful to use inspection methods for encoded values (such as isNumericInfinite(PositionedByteRange) and isNumericNaN(PositionedByteRange) to protect against decoding values into object which do not support these numeric concepts (such as Long and BigDecimal).

Simplest cases first: If the numeric value is a NaN, then the encoding is a single byte of 0x25. This causes NaN values to sort after every other numeric value.

If the numeric value is a negative infinity then the encoding is a single byte of 0x07. Since every other numeric value except NaN has a larger initial byte, this encoding ensures that negative infinity will sort prior to every other numeric value other than NaN.

If the numeric value is a positive infinity then the encoding is a single byte of 0x23. Every other numeric value encoding begins with a smaller byte, ensuring that positive infinity always sorts last among numeric values. 0x23 is also smaller than 0x33, the initial byte of a text value, ensuring that every numeric value sorts before every text value.

If the numeric value is exactly zero then it is encoded as a single byte of 0x15. Finite negative values will have initial bytes of 0x08 through 0x14 and finite positive values will have initial bytes of 0x16 through 0x22.

For all numeric values, we compute a mantissa M and an exponent E. The mantissa is a base-100 representation of the value. The exponent E determines where to put the decimal point.

Each centimal digit of the mantissa is stored in a byte. If the value of the centimal digit is X (hence X≥0 and X≤99) then the byte value will be 2*X+1 for every byte of the mantissa, except for the last byte which will be 2*X+0. The mantissa must be the minimum number of bytes necessary to represent the value; trailing X==0 digits are omitted. This means that the mantissa will never contain a byte with the value 0x00.

If we assume all digits of the mantissa occur to the right of the decimal point, then the exponent E is the power of one hundred by which one must multiply the mantissa to recover the original value.

Values are classified as large, medium, or small according to the value of E. If E is 11 or more, the value is large. For E between 0 and 10, the value is medium. For E less than zero, the value is small.

Large positive values are encoded as a single byte 0x22 followed by E as a varint and then M. Medium positive values are a single byte of 0x17+E followed by M. Small positive values are encoded as a single byte 0x16 followed by the ones-complement of the varint for -E followed by M.

Small negative values are encoded as a single byte 0x14 followed by -E as a varint and then the ones-complement of M. Medium negative values are encoded as a byte 0x13-E followed by the ones-complement of M. Large negative values consist of the single byte 0x08 followed by the ones-complement of the varint encoding of E followed by the ones-complement of M.

Fixed-length Integer Encoding

All 4-byte integers are serialized to a 5-byte, fixed-width, sortable byte format. All 8-byte integers are serialized to the equivelant 9-byte format. Serialization is performed by writing a header byte, inverting the integer sign bit and writing the resulting bytes to the byte array in big endian order.

Fixed-length Floating Point Encoding

32-bit and 64-bit floating point numbers are encoded to a 5-byte and 9-byte encoding format, respectively. The format is identical, save for the precision respected in each step of the operation.

This format ensures the following total ordering of floating point values: Float.NEGATIVE_INFINITY < -Float.MAX_VALUE < ... < -Float.MIN_VALUE < -0.0 < +0.0; < Float.MIN_VALUE < ... < Float.MAX_VALUE < Float.POSITIVE_INFINITY < Float.NaN

Floating point numbers are encoded as specified in IEEE 754. A 32-bit single precision float consists of a sign bit, 8-bit unsigned exponent encoded in offset-127 notation, and a 23-bit significand. The format is described further in the Single Precision Floating Point Wikipedia page

The value of a normal float is -1 ^{sign bit} × 2^{exponent - 127} × 1.significand

The IEE754 floating point format already preserves sort ordering for positive floating point numbers when the raw bytes are compared in most significant byte order. This is discussed further at http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm

Thus, we need only ensure that negative numbers sort in the the exact opposite order as positive numbers (so that say, negative infinity is less than negative 1), and that all negative numbers compare less than any positive number. To accomplish this, we invert the sign bit of all floating point numbers, and we also invert the exponent and significand bits if the floating point number was negative.

More specifically, we first store the floating point bits into a 32-bit int j using Float.floatToIntBits(float). This method collapses all NaNs into a single, canonical NaN value but otherwise leaves the bits unchanged. We then compute

 j ˆ= (j >> (Integer.SIZE - 1)) | Integer.MIN_SIZE

which inverts the sign bit and XOR's all other bits with the sign bit itself. Comparing the raw bytes of j in most significant byte order is equivalent to performing a single precision floating point comparison on the underlying bits (ignoring NaN comparisons, as NaNs don't compare equal to anything when performing floating point comparisons).

The resulting integer is then converted into a byte array by serializing the integer one byte at a time in most significant byte order. The serialized integer is prefixed by a single header byte. All serialized values are 5 bytes in length.

OrderedBytes encodings are heavily influenced by the SQLite4 Key Encoding. Slight deviations are make in the interest of order correctness and user extensibility. Fixed-width Long and Double encodings are based on implementations from the now defunct Orderly library.

Field Summary

Fields
Modifier and Type	Field and Description
`static MathContext`	`DEFAULT_MATH_CONTEXT` The context used to normalize `BigDecimal` values.
`static int`	`MAX_PRECISION` Max precision guaranteed to fit into a `long`.
`static Charset`	`UTF8`

Constructor Summary

Constructors
Constructor and Description

OrderedBytes()

Constructors
Constructor and Description
`OrderedBytes()`

Method Summary

Methods
Modifier and Type	Method and Description
`static int`	`blobVarEncodedLength(int len)` Calculate the expected BlobVar encoded length based on unencoded length.
`static byte[]`	`decodeBlobCopy(PositionedByteRange src)` Decode a Blob value, byte-for-byte copy.
`static byte[]`	`decodeBlobVar(PositionedByteRange src)` Decode a blob value that was encoded using BlobVar encoding.
`static float`	`decodeFloat32(PositionedByteRange src)` Decode a 32-bit floating point value using the fixed-length encoding.
`static double`	`decodeFloat64(PositionedByteRange src)` Decode a 64-bit floating point value using the fixed-length encoding.
`static short`	`decodeInt16(PositionedByteRange src)` Decode an `int16` value.
`static int`	`decodeInt32(PositionedByteRange src)` Decode an `int32` value.
`static long`	`decodeInt64(PositionedByteRange src)` Decode an `int64` value.
`static byte`	`decodeInt8(PositionedByteRange src)` Decode an `int8` value.
`static BigDecimal`	`decodeNumericAsBigDecimal(PositionedByteRange src)` Decode a `BigDecimal` value from the variable-length encoding.
`static double`	`decodeNumericAsDouble(PositionedByteRange src)` Decode a primitive `double` value from the Numeric encoding.
`static long`	`decodeNumericAsLong(PositionedByteRange src)` Decode a primitive `long` value from the Numeric encoding.
`static String`	`decodeString(PositionedByteRange src)` Decode a String value.
`static int`	`encodeBlobCopy(PositionedByteRange dst, byte[] val, int voff, int vlen, Order ord)` Encode a Blob value as a byte-for-byte copy.
`static int`	`encodeBlobCopy(PositionedByteRange dst, byte[] val, Order ord)` Encode a Blob value as a byte-for-byte copy.
`static int`	`encodeBlobVar(PositionedByteRange dst, byte[] val, int voff, int vlen, Order ord)` Encode a Blob value using a modified varint encoding scheme.
`static int`	`encodeBlobVar(PositionedByteRange dst, byte[] val, Order ord)` Encode a blob value using a modified varint encoding scheme.
`static int`	`encodeFloat32(PositionedByteRange dst, float val, Order ord)` Encode a 32-bit floating point value using the fixed-length encoding.
`static int`	`encodeFloat64(PositionedByteRange dst, double val, Order ord)` Encode a 64-bit floating point value using the fixed-length encoding.
`static int`	`encodeInt16(PositionedByteRange dst, short val, Order ord)` Encode an `int16` value using the fixed-length encoding.
`static int`	`encodeInt32(PositionedByteRange dst, int val, Order ord)` Encode an `int32` value using the fixed-length encoding.
`static int`	`encodeInt64(PositionedByteRange dst, long val, Order ord)` Encode an `int64` value using the fixed-length encoding.
`static int`	`encodeInt8(PositionedByteRange dst, byte val, Order ord)` Encode an `int8` value using the fixed-length encoding.
`static int`	`encodeNull(PositionedByteRange dst, Order ord)` Encode a null value.
`static int`	`encodeNumeric(PositionedByteRange dst, BigDecimal val, Order ord)` Encode a numerical value using the variable-length encoding.
`static int`	`encodeNumeric(PositionedByteRange dst, double val, Order ord)` Encode a numerical value using the variable-length encoding.
`static int`	`encodeNumeric(PositionedByteRange dst, long val, Order ord)` Encode a numerical value using the variable-length encoding.
`static int`	`encodeString(PositionedByteRange dst, String val, Order ord)` Encode a String value.
`static boolean`	`isBlobCopy(PositionedByteRange src)` Return true when the next encoded value in `src` uses BlobCopy encoding, false otherwise.
`static boolean`	`isBlobVar(PositionedByteRange src)` Return true when the next encoded value in `src` uses BlobVar encoding, false otherwise.
`static boolean`	`isEncodedValue(PositionedByteRange src)` Returns true when `src` appears to be positioned an encoded value, false otherwise.
`static boolean`	`isFixedFloat32(PositionedByteRange src)` Return true when the next encoded value in `src` uses fixed-width Float32 encoding, false otherwise.
`static boolean`	`isFixedFloat64(PositionedByteRange src)` Return true when the next encoded value in `src` uses fixed-width Float64 encoding, false otherwise.
`static boolean`	`isFixedInt16(PositionedByteRange src)` Return true when the next encoded value in `src` uses fixed-width Int16 encoding, false otherwise.
`static boolean`	`isFixedInt32(PositionedByteRange src)` Return true when the next encoded value in `src` uses fixed-width Int32 encoding, false otherwise.
`static boolean`	`isFixedInt64(PositionedByteRange src)` Return true when the next encoded value in `src` uses fixed-width Int64 encoding, false otherwise.
`static boolean`	`isFixedInt8(PositionedByteRange src)` Return true when the next encoded value in `src` uses fixed-width Int8 encoding, false otherwise.
`static boolean`	`isNull(PositionedByteRange src)` Return true when the next encoded value in `src` is null, false otherwise.
`static boolean`	`isNumeric(PositionedByteRange src)` Return true when the next encoded value in `src` uses Numeric encoding, false otherwise.
`static boolean`	`isNumericInfinite(PositionedByteRange src)` Return true when the next encoded value in `src` uses Numeric encoding and is `Infinite`, false otherwise.
`static boolean`	`isNumericNaN(PositionedByteRange src)` Return true when the next encoded value in `src` uses Numeric encoding and is `NaN`, false otherwise.
`static boolean`	`isNumericZero(PositionedByteRange src)` Return true when the next encoded value in `src` uses Numeric encoding and is `0`, false otherwise.
`static boolean`	`isText(PositionedByteRange src)` Return true when the next encoded value in `src` uses Text encoding, false otherwise.
`static int`	`length(PositionedByteRange buff)` Return the number of encoded entries remaining in `buff`.
`static int`	`skip(PositionedByteRange src)` Skip `buff`'s position forward over one encoded value.

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

- Field Detail
  - UTF8
```
public static final Charset UTF8
```
  - MAX_PRECISION
```
public static final int MAX_PRECISION
```
    Max precision guaranteed to fit into a long.
    
    See Also:
    Constant Field Values
  - DEFAULT_MATH_CONTEXT
```
public static final MathContext DEFAULT_MATH_CONTEXT
```
    The context used to normalize BigDecimal values.
- Constructor Detail
  - OrderedBytes
```
public OrderedBytes()
```
- Method Detail
  - encodeNumeric
```
public static int encodeNumeric(PositionedByteRange dst,
                long val,
                Order ord)
```
    Encode a numerical value using the variable-length encoding.
    
    Parameters:
    dst - The destination to which encoded digits are written.
    val - The value to encode.
    ord - The Order to respect while encoding val.
    
    Returns:
    the number of bytes written.
  - encodeNumeric
```
public static int encodeNumeric(PositionedByteRange dst,
                double val,
                Order ord)
```
    Encode a numerical value using the variable-length encoding.
    
    Parameters:
    dst - The destination to which encoded digits are written.
    val - The value to encode.
    ord - The Order to respect while encoding val.
    
    Returns:
    the number of bytes written.
  - encodeNumeric
```
public static int encodeNumeric(PositionedByteRange dst,
                BigDecimal val,
                Order ord)
```
    Encode a numerical value using the variable-length encoding.
    
    Parameters:
    dst - The destination to which encoded digits are written.
    val - The value to encode.
    ord - The Order to respect while encoding val.
    
    Returns:
    the number of bytes written.
  - decodeNumericAsDouble
```
public static double decodeNumericAsDouble(PositionedByteRange src)
```
    Decode a primitive double value from the Numeric encoding. Numeric encoding is based on BigDecimal; in the event the encoded value is larger than can be represented in a double, this method performs an implicit narrowing conversion as described in BigDecimal.doubleValue().
    
    Throws:
    
    NullPointerException - when the encoded value is NULL.
    
    IllegalArgumentException - when the encoded value is not a Numeric.
    See Also:
    encodeNumeric(PositionedByteRange, double, Order), BigDecimal.doubleValue()
  - decodeNumericAsLong
```
public static long decodeNumericAsLong(PositionedByteRange src)
```
    Decode a primitive long value from the Numeric encoding. Numeric encoding is based on BigDecimal; in the event the encoded value is larger than can be represented in a long, this method performs an implicit narrowing conversion as described in BigDecimal.doubleValue().
    
    Throws:
    
    NullPointerException - when the encoded value is NULL.
    
    IllegalArgumentException - when the encoded value is not a Numeric.
    See Also:
    encodeNumeric(PositionedByteRange, long, Order), BigDecimal.longValue()
  - decodeNumericAsBigDecimal
```
public static BigDecimal decodeNumericAsBigDecimal(PositionedByteRange src)
```
    Decode a BigDecimal value from the variable-length encoding.
    
    Throws:
    
    IllegalArgumentException - when the encoded value is not a Numeric.
    See Also:
    encodeNumeric(PositionedByteRange, BigDecimal, Order)
  - encodeString
```
public static int encodeString(PositionedByteRange dst,
               String val,
               Order ord)
```
    Encode a String value. String encoding is 0x00-terminated and so it does not support codepoints in the value.
    
    Parameters:
    dst - The destination to which the encoded value is written.
    val - The value to encode.
    ord - The Order to respect while encoding val.
    
    Returns:
    the number of bytes written.
    
    Throws:
    
    IllegalArgumentException - when val contains a .
  - decodeString
```
public static String decodeString(PositionedByteRange src)
```
    Decode a String value.
  - blobVarEncodedLength
```
public static int blobVarEncodedLength(int len)
```
    Calculate the expected BlobVar encoded length based on unencoded length.
  - encodeBlobVar
```
public static int encodeBlobVar(PositionedByteRange dst,
                byte[] val,
                int voff,
                int vlen,
                Order ord)
```
    Encode a Blob value using a modified varint encoding scheme.
    This format encodes a byte[] value such that no limitations on the input value are imposed. The first byte encodes the encoding scheme that follows, BLOB_VAR. Each encoded byte thereafter consists of a header bit followed by 7 bits of payload. A header bit of '1' indicates continuation of the encoding. A header bit of '0' indicates this byte contains the last of the payload. An empty input value is encoded as the header byte immediately followed by a termination byte 0x00. This is not ambiguous with the encoded value of [], which results in [0x80, 0x00].
    
    Returns:
    the number of bytes written.
  - encodeBlobVar
```
public static int encodeBlobVar(PositionedByteRange dst,
                byte[] val,
                Order ord)
```
    Encode a blob value using a modified varint encoding scheme.
    
    Returns:
    the number of bytes written.
    See Also:
    encodeBlobVar(PositionedByteRange, byte[], int, int, Order)
  - decodeBlobVar
```
public static byte[] decodeBlobVar(PositionedByteRange src)
```
    Decode a blob value that was encoded using BlobVar encoding.
  - encodeBlobCopy
```
public static int encodeBlobCopy(PositionedByteRange dst,
                 byte[] val,
                 int voff,
                 int vlen,
                 Order ord)
```
    Encode a Blob value as a byte-for-byte copy. BlobCopy encoding in DESCENDING order is NULL terminated so as to preserve proper sorting of [] and so it does not support 0x00 in the value.
    
    Returns:
    the number of bytes written.
    
    Throws:
    
    IllegalArgumentException - when ord is DESCENDING and val contains a 0x00 byte.
  - encodeBlobCopy
```
public static int encodeBlobCopy(PositionedByteRange dst,
                 byte[] val,
                 Order ord)
```
    Encode a Blob value as a byte-for-byte copy. BlobCopy encoding in DESCENDING order is NULL terminated so as to preserve proper sorting of [] and so it does not support 0x00 in the value.
    
    Returns:
    the number of bytes written.
    
    Throws:
    
    IllegalArgumentException - when ord is DESCENDING and val contains a 0x00 byte.
    See Also:
    encodeBlobCopy(PositionedByteRange, byte[], int, int, Order)
  - decodeBlobCopy
```
public static byte[] decodeBlobCopy(PositionedByteRange src)
```
    Decode a Blob value, byte-for-byte copy.
    
    See Also:
    encodeBlobCopy(PositionedByteRange, byte[], int, int, Order)
  - encodeNull
```
public static int encodeNull(PositionedByteRange dst,
             Order ord)
```
    Encode a null value.
    
    Parameters:
    dst - The destination to which encoded digits are written.
    ord - The Order to respect while encoding val.
    
    Returns:
    the number of bytes written.
  - encodeInt8
```
public static int encodeInt8(PositionedByteRange dst,
             byte val,
             Order ord)
```
    Encode an int8 value using the fixed-length encoding.
    
    Returns:
    the number of bytes written.
    See Also:
    encodeInt64(PositionedByteRange, long, Order), decodeInt8(PositionedByteRange)
  - decodeInt8
```
public static byte decodeInt8(PositionedByteRange src)
```
    Decode an int8 value.
    
    See Also:
    encodeInt8(PositionedByteRange, byte, Order)
  - encodeInt16
```
public static int encodeInt16(PositionedByteRange dst,
              short val,
              Order ord)
```
    Encode an int16 value using the fixed-length encoding.
    
    Returns:
    the number of bytes written.
    See Also:
    encodeInt64(PositionedByteRange, long, Order), decodeInt16(PositionedByteRange)
  - decodeInt16
```
public static short decodeInt16(PositionedByteRange src)
```
    Decode an int16 value.
    
    See Also:
    encodeInt16(PositionedByteRange, short, Order)
  - encodeInt32
```
public static int encodeInt32(PositionedByteRange dst,
              int val,
              Order ord)
```
    Encode an int32 value using the fixed-length encoding.
    
    Returns:
    the number of bytes written.
    See Also:
    encodeInt64(PositionedByteRange, long, Order), decodeInt32(PositionedByteRange)
  - decodeInt32
```
public static int decodeInt32(PositionedByteRange src)
```
    Decode an int32 value.
    
    See Also:
    encodeInt32(PositionedByteRange, int, Order)
  - encodeInt64
```
public static int encodeInt64(PositionedByteRange dst,
              long val,
              Order ord)
```
    Encode an int64 value using the fixed-length encoding.
    This format ensures that all longs sort in their natural order, as they would sort when using signed long comparison.
    
    All Longs are serialized to an 8-byte, fixed-width sortable byte format. Serialization is performed by inverting the integer sign bit and writing the resulting bytes to the byte array in big endian order. The encoded value is prefixed by the FIXED_INT64 header byte. This encoding is designed to handle java language primitives and so Null values are NOT supported by this implementation.
    
    For example:
```
 Input:   0x0000000000000005 (5)
 Result:  0x288000000000000005

 Input:   0xfffffffffffffffb (-4)
 Result:  0x280000000000000004

 Input:   0x7fffffffffffffff (Long.MAX_VALUE)
 Result:  0x28ffffffffffffffff

 Input:   0x8000000000000000 (Long.MIN_VALUE)
 Result:  0x287fffffffffffffff
 
```
    This encoding format, and much of this documentation string, is based on Orderly's FixedIntWritableRowKey.
    Returns:
    the number of bytes written.
    See Also:
    decodeInt64(PositionedByteRange)
  - decodeInt64
```
public static long decodeInt64(PositionedByteRange src)
```
    Decode an int64 value.
    
    See Also:
    encodeInt64(PositionedByteRange, long, Order)
  - encodeFloat32
```
public static int encodeFloat32(PositionedByteRange dst,
                float val,
                Order ord)
```
    Encode a 32-bit floating point value using the fixed-length encoding. Encoding format is described at length in encodeFloat64(PositionedByteRange, double, Order).
    
    Returns:
    the number of bytes written.
    See Also:
    decodeFloat32(PositionedByteRange), encodeFloat64(PositionedByteRange, double, Order)
  - decodeFloat32
```
public static float decodeFloat32(PositionedByteRange src)
```
    Decode a 32-bit floating point value using the fixed-length encoding.
    
    See Also:
    encodeFloat32(PositionedByteRange, float, Order)
  - encodeFloat64
```
public static int encodeFloat64(PositionedByteRange dst,
                double val,
                Order ord)
```
    Encode a 64-bit floating point value using the fixed-length encoding.
    This format ensures the following total ordering of floating point values: Double.NEGATIVE_INFINITY < -Double.MAX_VALUE < ... < -Double.MIN_VALUE < -0.0 < +0.0; < Double.MIN_VALUE < ... < Double.MAX_VALUE < Double.POSITIVE_INFINITY < Double.NaN
    
    Floating point numbers are encoded as specified in IEEE 754. A 64-bit double precision float consists of a sign bit, 11-bit unsigned exponent encoded in offset-1023 notation, and a 52-bit significand. The format is described further in the Double Precision Floating Point Wikipedia page
    
    The value of a normal float is -1 ^{sign bit} × 2^{exponent - 1023} × 1.significand
    
    The IEE754 floating point format already preserves sort ordering for positive floating point numbers when the raw bytes are compared in most significant byte order. This is discussed further at http://www.cygnus-software.com/papers/comparingfloats/comparingfloats. htm
    
    Thus, we need only ensure that negative numbers sort in the the exact opposite order as positive numbers (so that say, negative infinity is less than negative 1), and that all negative numbers compare less than any positive number. To accomplish this, we invert the sign bit of all floating point numbers, and we also invert the exponent and significand bits if the floating point number was negative.
    
    More specifically, we first store the floating point bits into a 64-bit long l using Double.doubleToLongBits(double). This method collapses all NaNs into a single, canonical NaN value but otherwise leaves the bits unchanged. We then compute
```
 l ˆ= (l >> (Long.SIZE - 1)) | Long.MIN_SIZE
 
```
    which inverts the sign bit and XOR's all other bits with the sign bit itself. Comparing the raw bytes of l in most significant byte order is equivalent to performing a double precision floating point comparison on the underlying bits (ignoring NaN comparisons, as NaNs don't compare equal to anything when performing floating point comparisons).
    
    The resulting long integer is then converted into a byte array by serializing the long one byte at a time in most significant byte order. The serialized integer is prefixed by a single header byte. All serialized values are 9 bytes in length.
    
    This encoding format, and much of this highly detailed documentation string, is based on Orderly's DoubleWritableRowKey.
    Returns:
    the number of bytes written.
    See Also:
    decodeFloat64(PositionedByteRange)
  - decodeFloat64
```
public static double decodeFloat64(PositionedByteRange src)
```
    Decode a 64-bit floating point value using the fixed-length encoding.
    
    See Also:
    encodeFloat64(PositionedByteRange, double, Order)
  - isEncodedValue
```
public static boolean isEncodedValue(PositionedByteRange src)
```
    Returns true when src appears to be positioned an encoded value, false otherwise.
  - isNull
```
public static boolean isNull(PositionedByteRange src)
```
    Return true when the next encoded value in src is null, false otherwise.
  - isNumeric
```
public static boolean isNumeric(PositionedByteRange src)
```
    Return true when the next encoded value in src uses Numeric encoding, false otherwise. NaN, +/-Inf are valid Numeric values.
  - isNumericInfinite
```
public static boolean isNumericInfinite(PositionedByteRange src)
```
    Return true when the next encoded value in src uses Numeric encoding and is Infinite, false otherwise.
  - isNumericNaN
```
public static boolean isNumericNaN(PositionedByteRange src)
```
    Return true when the next encoded value in src uses Numeric encoding and is NaN, false otherwise.
  - isNumericZero
```
public static boolean isNumericZero(PositionedByteRange src)
```
    Return true when the next encoded value in src uses Numeric encoding and is 0, false otherwise.
  - isFixedInt8
```
public static boolean isFixedInt8(PositionedByteRange src)
```
    Return true when the next encoded value in src uses fixed-width Int8 encoding, false otherwise.
  - isFixedInt16
```
public static boolean isFixedInt16(PositionedByteRange src)
```
    Return true when the next encoded value in src uses fixed-width Int16 encoding, false otherwise.
  - isFixedInt32
```
public static boolean isFixedInt32(PositionedByteRange src)
```
    Return true when the next encoded value in src uses fixed-width Int32 encoding, false otherwise.
  - isFixedInt64
```
public static boolean isFixedInt64(PositionedByteRange src)
```
    Return true when the next encoded value in src uses fixed-width Int64 encoding, false otherwise.
  - isFixedFloat32
```
public static boolean isFixedFloat32(PositionedByteRange src)
```
    Return true when the next encoded value in src uses fixed-width Float32 encoding, false otherwise.
  - isFixedFloat64
```
public static boolean isFixedFloat64(PositionedByteRange src)
```
    Return true when the next encoded value in src uses fixed-width Float64 encoding, false otherwise.
  - isText
```
public static boolean isText(PositionedByteRange src)
```
    Return true when the next encoded value in src uses Text encoding, false otherwise.
  - isBlobVar
```
public static boolean isBlobVar(PositionedByteRange src)
```
    Return true when the next encoded value in src uses BlobVar encoding, false otherwise.
  - isBlobCopy
```
public static boolean isBlobCopy(PositionedByteRange src)
```
    Return true when the next encoded value in src uses BlobCopy encoding, false otherwise.
  - skip
```
public static int skip(PositionedByteRange src)
```
    Skip buff's position forward over one encoded value.
    
    Returns:
    number of bytes skipped.
  - length
```
public static int length(PositionedByteRange buff)
```
    Return the number of encoded entries remaining in buff. The state of buff is not modified through use of this method.

Class OrderedBytes

Encoding Format summary

Null Encoding

Text Encoding

Binary Encoding

BlobVar

BlobCopy

Variable-length Numeric Encoding

Fixed-length Integer Encoding

Fixed-length Floating Point Encoding

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

UTF8

MAX_PRECISION

DEFAULT_MATH_CONTEXT

Constructor Detail

OrderedBytes

Method Detail

encodeNumeric

encodeNumeric

encodeNumeric

decodeNumericAsDouble

decodeNumericAsLong

decodeNumericAsBigDecimal

encodeString

decodeString

blobVarEncodedLength

encodeBlobVar

encodeBlobVar

decodeBlobVar

encodeBlobCopy

encodeBlobCopy

decodeBlobCopy

encodeNull

encodeInt8

decodeInt8

encodeInt16

decodeInt16

encodeInt32

decodeInt32

encodeInt64

decodeInt64

encodeFloat32

decodeFloat32

encodeFloat64

decodeFloat64

isEncodedValue

isNull

isNumeric

isNumericInfinite

isNumericNaN

isNumericZero

isFixedInt8

isFixedInt16

isFixedInt32

isFixedInt64

isFixedFloat32

isFixedFloat64

isText

isBlobVar

isBlobCopy

skip

length