UnicodeDecompressor (ICU4J 76)

java.lang.Object
- com.ibm.icu.text.UnicodeDecompressor

public final class UnicodeDecompressor
extends Object

A decompression engine implementing the Standard Compression Scheme for Unicode (SCSU) as outlined in Unicode Technical Report #6.

USAGE

The static methods on UnicodeDecompressor may be used in a straightforward manner to decompress simple strings:

  byte [] compressed = ... ; // get compressed bytes from somewhere
  String result = UnicodeDecompressor.decompress(compressed);

The static methods have a fairly large memory footprint. For finer-grained control over memory usage, UnicodeDecompressor offers more powerful APIs allowing iterative decompression:

  // Decompress an array "bytes" of length "len" using a buffer of 512 chars
  // to the Writer "out"

  UnicodeDecompressor myDecompressor         = new UnicodeDecompressor();
  final static int    BUFSIZE                = 512;
  char []             charBuffer             = new char [ BUFSIZE ];
  int                 charsWritten           = 0;
  int []              bytesRead              = new int [1];
  int                 totalBytesDecompressed = 0;
  int                 totalCharsWritten      = 0;

  do {
    // do the decompression
    charsWritten = myDecompressor.decompress(bytes, totalBytesDecompressed, 
                                             len, bytesRead,
                                             charBuffer, 0, BUFSIZE);

    // do something with the current set of chars
    out.write(charBuffer, 0, charsWritten);

    // update the no. of bytes decompressed
    totalBytesDecompressed += bytesRead[0];

    // update the no. of chars written
    totalCharsWritten += charsWritten;

  } while(totalBytesDecompressed < len);

  myDecompressor.reset(); // reuse decompressor

Decompression is performed according to the standard set forth in Unicode Technical Report #6

Author:: Stephen F. Booth
See Also:: UnicodeCompressor
Status:: Stable ICU 2.4.

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`ARMENIANINDEX`
`static int`	`COMPRESSIONOFFSET`
`static int`	`GREEKINDEX`
`static int`	`HALFWIDTHKATAKANAINDEX`
`static int`	`HIRAGANAINDEX`
`static int`	`INVALIDCHAR`
`static int`	`INVALIDWINDOW`
`static int`	`IPAEXTENSIONINDEX`
`static int`	`KATAKANAINDEX`
`static int`	`LATININDEX`
`static int`	`MAXINDEX`
`static int`	`NUMSTATICWINDOWS`
`static int`	`NUMWINDOWS`
`static int`	`RESERVEDINDEX`
`static int`	`SCHANGE0`
`static int`	`SCHANGE1`
`static int`	`SCHANGE2`
`static int`	`SCHANGE3`
`static int`	`SCHANGE4`
`static int`	`SCHANGE5`
`static int`	`SCHANGE6`
`static int`	`SCHANGE7`
`static int`	`SCHANGEU`
`static int`	`SDEFINE0`
`static int`	`SDEFINE1`
`static int`	`SDEFINE2`
`static int`	`SDEFINE3`
`static int`	`SDEFINE4`
`static int`	`SDEFINE5`
`static int`	`SDEFINE6`
`static int`	`SDEFINE7`
`static int`	`SDEFINEX`
`static int`	`SINGLEBYTEMODE`
`static int[]`	`sOffsets` Static compression window offsets
`static int[]`	`sOffsetTable` For window offset mapping
`static int`	`SQUOTE0`
`static int`	`SQUOTE1`
`static int`	`SQUOTE2`
`static int`	`SQUOTE3`
`static int`	`SQUOTE4`
`static int`	`SQUOTE5`
`static int`	`SQUOTE6`
`static int`	`SQUOTE7`
`static int`	`SQUOTEU`
`static int`	`SRESERVED`
`static int`	`UCHANGE0`
`static int`	`UCHANGE1`
`static int`	`UCHANGE2`
`static int`	`UCHANGE3`
`static int`	`UCHANGE4`
`static int`	`UCHANGE5`
`static int`	`UCHANGE6`
`static int`	`UCHANGE7`
`static int`	`UDEFINE0`
`static int`	`UDEFINE1`
`static int`	`UDEFINE2`
`static int`	`UDEFINE3`
`static int`	`UDEFINE4`
`static int`	`UDEFINE5`
`static int`	`UDEFINE6`
`static int`	`UDEFINE7`
`static int`	`UDEFINEX`
`static int`	`UNICODEMODE`
`static int`	`UQUOTEU`
`static int`	`URESERVED`

Constructor Summary

Constructors
Constructor and Description

UnicodeDecompressor()
Create a UnicodeDecompressor.

Constructors
Constructor and Description
`UnicodeDecompressor()` Create a UnicodeDecompressor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static String`	`decompress(byte[] buffer)` Decompress a byte array into a String.
`static char[]`	`decompress(byte[] buffer, int start, int limit)` Decompress a byte array into a Unicode character array.
`int`	`decompress(byte[] byteBuffer, int byteBufferStart, int byteBufferLimit, int[] bytesRead, char[] charBuffer, int charBufferStart, int charBufferLimit)` Decompress a byte array into a Unicode character array.
`void`	`reset()` Reset the decompressor to its initial state.

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

- Field Detail
  - COMPRESSIONOFFSET
```
public static final int COMPRESSIONOFFSET
```
    See Also:
    
    Constant Field Values
  - NUMWINDOWS
```
public static final int NUMWINDOWS
```
    See Also:
    
    Constant Field Values
  - NUMSTATICWINDOWS
```
public static final int NUMSTATICWINDOWS
```
    See Also:
    
    Constant Field Values
  - INVALIDWINDOW
```
public static final int INVALIDWINDOW
```
    See Also:
    
    Constant Field Values
  - INVALIDCHAR
```
public static final int INVALIDCHAR
```
    See Also:
    
    Constant Field Values
  - SINGLEBYTEMODE
```
public static final int SINGLEBYTEMODE
```
    See Also:
    
    Constant Field Values
  - UNICODEMODE
```
public static final int UNICODEMODE
```
    See Also:
    
    Constant Field Values
  - MAXINDEX
```
public static final int MAXINDEX
```
    See Also:
    
    Constant Field Values
  - RESERVEDINDEX
```
public static final int RESERVEDINDEX
```
    See Also:
    
    Constant Field Values
  - LATININDEX
```
public static final int LATININDEX
```
    See Also:
    
    Constant Field Values
  - IPAEXTENSIONINDEX
```
public static final int IPAEXTENSIONINDEX
```
    See Also:
    
    Constant Field Values
  - GREEKINDEX
```
public static final int GREEKINDEX
```
    See Also:
    
    Constant Field Values
  - ARMENIANINDEX
```
public static final int ARMENIANINDEX
```
    See Also:
    
    Constant Field Values
  - HIRAGANAINDEX
```
public static final int HIRAGANAINDEX
```
    See Also:
    
    Constant Field Values
  - KATAKANAINDEX
```
public static final int KATAKANAINDEX
```
    See Also:
    
    Constant Field Values
  - HALFWIDTHKATAKANAINDEX
```
public static final int HALFWIDTHKATAKANAINDEX
```
    See Also:
    
    Constant Field Values
  - SDEFINEX
```
public static final int SDEFINEX
```
    See Also:
    
    Constant Field Values
  - SRESERVED
```
public static final int SRESERVED
```
    See Also:
    
    Constant Field Values
  - SQUOTEU
```
public static final int SQUOTEU
```
    See Also:
    
    Constant Field Values
  - SCHANGEU
```
public static final int SCHANGEU
```
    See Also:
    
    Constant Field Values
  - SQUOTE0
```
public static final int SQUOTE0
```
    See Also:
    
    Constant Field Values
  - SQUOTE1
```
public static final int SQUOTE1
```
    See Also:
    
    Constant Field Values
  - SQUOTE2
```
public static final int SQUOTE2
```
    See Also:
    
    Constant Field Values
  - SQUOTE3
```
public static final int SQUOTE3
```
    See Also:
    
    Constant Field Values
  - SQUOTE4
```
public static final int SQUOTE4
```
    See Also:
    
    Constant Field Values
  - SQUOTE5
```
public static final int SQUOTE5
```
    See Also:
    
    Constant Field Values
  - SQUOTE6
```
public static final int SQUOTE6
```
    See Also:
    
    Constant Field Values
  - SQUOTE7
```
public static final int SQUOTE7
```
    See Also:
    
    Constant Field Values
  - SCHANGE0
```
public static final int SCHANGE0
```
    See Also:
    
    Constant Field Values
  - SCHANGE1
```
public static final int SCHANGE1
```
    See Also:
    
    Constant Field Values
  - SCHANGE2
```
public static final int SCHANGE2
```
    See Also:
    
    Constant Field Values
  - SCHANGE3
```
public static final int SCHANGE3
```
    See Also:
    
    Constant Field Values
  - SCHANGE4
```
public static final int SCHANGE4
```
    See Also:
    
    Constant Field Values
  - SCHANGE5
```
public static final int SCHANGE5
```
    See Also:
    
    Constant Field Values
  - SCHANGE6
```
public static final int SCHANGE6
```
    See Also:
    
    Constant Field Values
  - SCHANGE7
```
public static final int SCHANGE7
```
    See Also:
    
    Constant Field Values
  - SDEFINE0
```
public static final int SDEFINE0
```
    See Also:
    
    Constant Field Values
  - SDEFINE1
```
public static final int SDEFINE1
```
    See Also:
    
    Constant Field Values
  - SDEFINE2
```
public static final int SDEFINE2
```
    See Also:
    
    Constant Field Values
  - SDEFINE3
```
public static final int SDEFINE3
```
    See Also:
    
    Constant Field Values
  - SDEFINE4
```
public static final int SDEFINE4
```
    See Also:
    
    Constant Field Values
  - SDEFINE5
```
public static final int SDEFINE5
```
    See Also:
    
    Constant Field Values
  - SDEFINE6
```
public static final int SDEFINE6
```
    See Also:
    
    Constant Field Values
  - SDEFINE7
```
public static final int SDEFINE7
```
    See Also:
    
    Constant Field Values
  - UCHANGE0
```
public static final int UCHANGE0
```
    See Also:
    
    Constant Field Values
  - UCHANGE1
```
public static final int UCHANGE1
```
    See Also:
    
    Constant Field Values
  - UCHANGE2
```
public static final int UCHANGE2
```
    See Also:
    
    Constant Field Values
  - UCHANGE3
```
public static final int UCHANGE3
```
    See Also:
    
    Constant Field Values
  - UCHANGE4
```
public static final int UCHANGE4
```
    See Also:
    
    Constant Field Values
  - UCHANGE5
```
public static final int UCHANGE5
```
    See Also:
    
    Constant Field Values
  - UCHANGE6
```
public static final int UCHANGE6
```
    See Also:
    
    Constant Field Values
  - UCHANGE7
```
public static final int UCHANGE7
```
    See Also:
    
    Constant Field Values
  - UDEFINE0
```
public static final int UDEFINE0
```
    See Also:
    
    Constant Field Values
  - UDEFINE1
```
public static final int UDEFINE1
```
    See Also:
    
    Constant Field Values
  - UDEFINE2
```
public static final int UDEFINE2
```
    See Also:
    
    Constant Field Values
  - UDEFINE3
```
public static final int UDEFINE3
```
    See Also:
    
    Constant Field Values
  - UDEFINE4
```
public static final int UDEFINE4
```
    See Also:
    
    Constant Field Values
  - UDEFINE5
```
public static final int UDEFINE5
```
    See Also:
    
    Constant Field Values
  - UDEFINE6
```
public static final int UDEFINE6
```
    See Also:
    
    Constant Field Values
  - UDEFINE7
```
public static final int UDEFINE7
```
    See Also:
    
    Constant Field Values
  - UQUOTEU
```
public static final int UQUOTEU
```
    See Also:
    
    Constant Field Values
  - UDEFINEX
```
public static final int UDEFINEX
```
    See Also:
    
    Constant Field Values
  - URESERVED
```
public static final int URESERVED
```
    See Also:
    
    Constant Field Values
  - sOffsetTable
```
public static final int[] sOffsetTable
```
    For window offset mapping
  - sOffsets
```
public static final int[] sOffsets
```
    Static compression window offsets
- Constructor Detail
  - UnicodeDecompressor
```
public UnicodeDecompressor()
```
    Create a UnicodeDecompressor. Sets all windows to their default values.
    
    See Also:
    
    reset()
    
    Status:
    Stable ICU 2.4.
- Method Detail
  - decompress
```
public static String decompress(byte[] buffer)
```
    Decompress a byte array into a String.
    
    Parameters:
    
    buffer - The byte array to decompress.
    
    Returns:
    
    A String containing the decompressed characters.
    
    See Also:
    
    decompress(byte [], int, int)
    
    Status:
    Stable ICU 2.4.
  - decompress
```
public static char[] decompress(byte[] buffer,
                                int start,
                                int limit)
```
    Decompress a byte array into a Unicode character array.
    
    Parameters:
    
    buffer - The byte array to decompress.
    
    start - The start of the byte run to decompress.
    
    limit - The limit of the byte run to decompress.
    
    Returns:
    
    A character array containing the decompressed bytes.
    
    See Also:
    
    decompress(byte [])
    
    Status:
    Stable ICU 2.4.
  - decompress
```
public int decompress(byte[] byteBuffer,
                      int byteBufferStart,
                      int byteBufferLimit,
                      int[] bytesRead,
                      char[] charBuffer,
                      int charBufferStart,
                      int charBufferLimit)
```
    Decompress a byte array into a Unicode character array. This function will either completely fill the output buffer, or consume the entire input.
    
    Parameters:
    
    byteBuffer - The byte buffer to decompress.
    
    byteBufferStart - The start of the byte run to decompress.
    
    byteBufferLimit - The limit of the byte run to decompress.
    
    bytesRead - A one-element array. If not null, on return the number of bytes read from byteBuffer.
    
    charBuffer - A buffer to receive the decompressed data. This buffer must be at minimum two characters in size.
    
    charBufferStart - The starting offset to which to write decompressed data.
    
    charBufferLimit - The limiting offset for writing decompressed data.
    
    Returns:
    
    The number of Unicode characters written to charBuffer.
    
    Status:
    Stable ICU 2.4.
  - reset
```
public void reset()
```
    Reset the decompressor to its initial state.
    
    Status:
    Stable ICU 2.4.

Class UnicodeDecompressor

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

COMPRESSIONOFFSET

NUMWINDOWS

NUMSTATICWINDOWS

INVALIDWINDOW

INVALIDCHAR

SINGLEBYTEMODE

UNICODEMODE

MAXINDEX

RESERVEDINDEX

LATININDEX

IPAEXTENSIONINDEX

GREEKINDEX

ARMENIANINDEX

HIRAGANAINDEX

KATAKANAINDEX

HALFWIDTHKATAKANAINDEX

SDEFINEX

SRESERVED

SQUOTEU

SCHANGEU

SQUOTE0

SQUOTE1

SQUOTE2

SQUOTE3

SQUOTE4

SQUOTE5

SQUOTE6

SQUOTE7

SCHANGE0

SCHANGE1

SCHANGE2

SCHANGE3

SCHANGE4

SCHANGE5

SCHANGE6

SCHANGE7

SDEFINE0

SDEFINE1

SDEFINE2

SDEFINE3

SDEFINE4

SDEFINE5

SDEFINE6

SDEFINE7

UCHANGE0

UCHANGE1

UCHANGE2

UCHANGE3

UCHANGE4

UCHANGE5

UCHANGE6

UCHANGE7

UDEFINE0

UDEFINE1

UDEFINE2

UDEFINE3

UDEFINE4

UDEFINE5

UDEFINE6

UDEFINE7

UQUOTEU

UDEFINEX

URESERVED

sOffsetTable

sOffsets

Constructor Detail

UnicodeDecompressor

Method Detail

decompress

decompress

decompress

reset