UnsignedIntEncoder (JSimpleDB Utility Classes 2.1.7 API)

java.lang.Object
- org.jsimpledb.util.UnsignedIntEncoder

public final class UnsignedIntEncoder
extends Object

Encodes unsigned (i.e., non-negative) int values to/from self-delimited binary, preserving sort order, and such that the length of the encoding is optimized for values near zero and encoded values never begin with 0xff.

The encoding uses a simple prefixing format:

Encoded Bytes	Value
`0x00 ... 0xfa`	Same
`0xfb 0xWW`	`0xWW`
`0xfc 0xWW 0xXX`	`0xWWXX`
`0xfd 0xWW 0xXX 0xYY`	`0xWWXXYY`
`0xfe 0xWW 0xXX 0xYY 0xZZ`	`0xWWXXYYZZ`
`0xff`	Illegal

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`MAX_ENCODED_LENGTH` Maximum possible length of an encoded value.
`static int`	`MIN_MULTI_BYTE_VALUE` Minimum value that triggers a multi-byte encoding.

Method Summary

Methods
Modifier and Type	Method and Description
`static int`	`decode(byte[] data)` Decode the given value.
`static int`	`decodeLength(int first)` Determine the length (in bytes) of an encoded value based on the first byte.
`static byte[]`	`encode(int value)` Encode the given value.
`static int`	`encodeLength(int value)` Determine the length (in bytes) of the encoded value.
`static void`	`main(String[] args)` Test routine.
`static int`	`read(ByteBuffer buf)` Read and decode a value from the given `ByteBuffer`.
`static int`	`read(ByteReader reader)` Read and decode a value from the input.
`static int`	`read(InputStream input)` Read and decode a value from the given `InputStream`.
`static void`	`skip(ByteReader reader)` Skip a value from the input.
`static void`	`write(ByteBuffer buf, int value)` Encode the given value and write it to the given `ByteBuffer`.
`static void`	`write(ByteWriter writer, int value)` Encode the given value to the output.
`static void`	`write(OutputStream out, int value)` Encode the given value and write it to the given `OutputStream`.

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

- Field Detail
  - MAX_ENCODED_LENGTH
```
public static final int MAX_ENCODED_LENGTH
```
    Maximum possible length of an encoded value.
    
    See Also:
    Constant Field Values
  - MIN_MULTI_BYTE_VALUE
```
public static final int MIN_MULTI_BYTE_VALUE
```
    Minimum value that triggers a multi-byte encoding.
    
    See Also:
    Constant Field Values
- Method Detail
  - encode
```
public static byte[] encode(int value)
```
    Encode the given value.
    
    Parameters:
    value - value to encode
    
    Returns:
    encoded value
    
    Throws:
    
    IllegalArgumentException - if value is negative
  - decode
```
public static int decode(byte[] data)
```
    Decode the given value.
    
    Parameters:
    data - encoded value
    
    Returns:
    decoded value
    
    Throws:
    
    IllegalArgumentException - if bytes contains an invalid encoding, or extra trailing garbage
  - write
```
public static void write(ByteWriter writer,
         int value)
```
    Encode the given value to the output.
    
    Parameters:
    writer - destination for the encoded value
    value - value to encode
    
    Throws:
    
    IllegalArgumentException - if value is negative
  - write
```
public static void write(OutputStream out,
         int value)
                  throws IOException
```
    Encode the given value and write it to the given OutputStream.
    
    Parameters:
    out - destination for the encoded value
    value - value to encode
    
    Throws:
    
    IOException - if an I/O error occurs
    
    NullPointerException - if out is null
  - write
```
public static void write(ByteBuffer buf,
         int value)
```
    Encode the given value and write it to the given ByteBuffer.
    
    Parameters:
    buf - destination for the encoded value
    value - value to encode
    
    Throws:
    
    BufferOverflowException - if buf overflows
    
    ReadOnlyBufferException - if buf is read-only
    
    NullPointerException - if buf is null
  - read
```
public static int read(ByteReader reader)
```
    Read and decode a value from the input.
    
    Parameters:
    reader - input holding an encoded value
    
    Returns:
    the decoded value, always non-negative
    
    Throws:
    
    IllegalArgumentException - if the encoded value is truncated
    
    IllegalArgumentException - if an invalid encoding is encountered
  - read
```
public static int read(InputStream input)
                throws IOException
```
    Read and decode a value from the given InputStream.
    
    Parameters:
    input - input source for the encoded value
    
    Returns:
    the decoded value
    
    Throws:
    
    IOException - if an I/O error occurs
    
    EOFException - if an unexpected EOF is encountered
    
    IllegalArgumentException - if an invalid encoding is encountered
    
    NullPointerException - if input is null
  - read
```
public static int read(ByteBuffer buf)
```
    Read and decode a value from the given ByteBuffer.
    
    Parameters:
    buf - input source for the encoded value
    
    Returns:
    the decoded value
    
    Throws:
    
    BufferUnderflowException - if buf underflows
    
    IllegalArgumentException - if an invalid encoding is encountered
    
    NullPointerException - if buf is null
  - skip
```
public static void skip(ByteReader reader)
```
    Skip a value from the input.
    
    Parameters:
    reader - input holding an encoded value
  - decodeLength
```
public static int decodeLength(int first)
```
    Determine the length (in bytes) of an encoded value based on the first byte.
    
    Parameters:
    first - first byte of encoded value (in lower eight bits; other bits are ignored)
    
    Returns:
    the length of the encoded value (including first)
    
    Throws:
    
    IllegalArgumentException - if the lower eight bits of first equal 0xff
  - encodeLength
```
public static int encodeLength(int value)
```
    Determine the length (in bytes) of the encoded value.
    
    Parameters:
    value - value to encode
    
    Returns:
    the length of the encoded value, a value between one and MAX_ENCODED_LENGTH
    
    Throws:
    
    IllegalArgumentException - if value is negative
  - main
```
public static void main(String[] args)
```
    Test routine.
    
    Parameters:
    args - command line arguments

Class UnsignedIntEncoder

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

MAX_ENCODED_LENGTH

MIN_MULTI_BYTE_VALUE

Method Detail

encode

decode

write

write

write

read

read

read

skip

decodeLength

encodeLength

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