Inflater

public class Inflater extends Object

This class provides support for general purpose decompression using the popular ZLIB compression library. The ZLIB compression library was initially developed as part of the PNG graphics standard and is not protected by patents. It is fully described in the specifications at the java.util.zip package description.

The following code fragment demonstrates a trivial compression and decompression of a string using Deflater and Inflater.

 try {
     // Encode a String into bytes
     String inputString = "blahblahblah€€";
     byte[] input = inputString.getBytes("UTF-8");

     // Compress the bytes
     byte[] output = new byte[100];
     Deflater compresser = new Deflater();
     compresser.setInput(input);
     compresser.finish();
     int compressedDataLength = compresser.deflate(output);

     // Decompress the bytes
     Inflater decompresser = new Inflater();
     decompresser.setInput(output, 0, compressedDataLength);
     byte[] result = new byte[100];
     int resultLength = decompresser.inflate(result);
     decompresser.end();

     // Decode the bytes into a String
     String outputString = new String(result, 0, resultLength, "UTF-8");
 } catch(java.io.UnsupportedEncodingException ex) {
     // handle
 } catch (java.util.zip.DataFormatException ex) {
     // handle
 }
 

See Also

Public Constructor Summary

Inflater(boolean nowrap)
Creates a new decompressor.
Inflater()
Creates a new decompressor.

Public Method Summary

void
end()
Closes the decompressor and discards any unprocessed input.
boolean
finished()
Returns true if the end of the compressed data stream has been reached.
int
getAdler()
Returns the ADLER-32 value of the uncompressed data.
long
getBytesRead()
Returns the total number of compressed bytes input so far.
long
getBytesWritten()
Returns the total number of uncompressed bytes output so far.
int
getRemaining()
Returns the total number of bytes remaining in the input buffer.
int
getTotalIn()
Returns the total number of compressed bytes input so far.
int
getTotalOut()
Returns the total number of uncompressed bytes output so far.
int
inflate(byte[] b)
Uncompresses bytes into specified buffer.
int
inflate(byte[] b, int off, int len)
Uncompresses bytes into specified buffer.
boolean
needsDictionary()
Returns true if a preset dictionary is needed for decompression.
boolean
needsInput()
Returns true if no data remains in the input buffer.
void
reset()
Resets inflater so that a new set of input data can be processed.
void
setDictionary(byte[] b, int off, int len)
Sets the preset dictionary to the given array of bytes.
void
setDictionary(byte[] b)
Sets the preset dictionary to the given array of bytes.
void
setInput(byte[] b, int off, int len)
Sets input data for decompression.
void
setInput(byte[] b)
Sets input data for decompression.

Protected Method Summary

void
finalize()
Closes the decompressor when garbage is collected.

Inherited Method Summary

Public Constructors

public Inflater (boolean nowrap)

Creates a new decompressor. If the parameter 'nowrap' is true then the ZLIB header and checksum fields will not be used. This provides compatibility with the compression format used by both GZIP and PKZIP.

Note: When using the 'nowrap' option it is also necessary to provide an extra "dummy" byte as input. This is required by the ZLIB native library in order to support certain optimizations.

Parameters
nowrap if true then support GZIP compatible compression

public Inflater ()

Creates a new decompressor.

Public Methods

public void end ()

Closes the decompressor and discards any unprocessed input. This method should be called when the decompressor is no longer being used, but will also be called automatically by the finalize() method. Once this method is called, the behavior of the Inflater object is undefined.

public boolean finished ()

Returns true if the end of the compressed data stream has been reached.

Returns
  • true if the end of the compressed data stream has been reached

public int getAdler ()

Returns the ADLER-32 value of the uncompressed data.

Returns
  • the ADLER-32 value of the uncompressed data

public long getBytesRead ()

Returns the total number of compressed bytes input so far.

Returns
  • the total (non-negative) number of compressed bytes input so far

public long getBytesWritten ()

Returns the total number of uncompressed bytes output so far.

Returns
  • the total (non-negative) number of uncompressed bytes output so far

public int getRemaining ()