public
class
Inflater
extends Object
| java.lang.Object | |
| ↳ | java.util.zip.Inflater |
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.
Developers
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 constructors | |
|---|---|
Inflater(boolean nowrap)
Creates a new decompressor. |
|
Inflater()
Creates a new decompressor. |
|
Public methods | |
|---|---|
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 methods | |
|---|---|
void
|
finalize()
Closes the decompressor when garbage is collected. |
Inherited methods | |
|---|---|
 From
class
java.lang.Object
| |
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 |
boolean:
if true then support GZIP compatible compression
|
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.
boolean finished ()
Returns true if the end of the compressed data stream has been reached.
| Returns | |
|---|---|
boolean |
true if the end of the compressed data stream has been reached |
int getAdler ()
Returns the ADLER-32 value of the uncompressed data.
| Returns | |
|---|---|
int |
the ADLER-32 value of the uncompressed data |
long getBytesRead ()
Returns the total number of compressed bytes input so far.
| Returns | |
|---|---|
long |
the total (non-negative) number of compressed bytes input so far |
long getBytesWritten ()
Returns the total number of uncompressed bytes output so far.
| Returns | |
|---|---|
long |
the total (non-negative) number of uncompressed bytes output so far |
int getRemaining ()
Returns the total number of bytes remaining in the input buffer. This can be used to find out what bytes still remain in the input buffer after decompression has finished.
| Returns | |
|---|---|
int |
the total number of bytes remaining in the input buffer |
int getTotalIn ()
Returns the total number of compressed bytes input so far.
Since the number of bytes may be greater than
Integer.MAX_VALUE, the getBytesRead() method is now
the preferred means of obtaining this information.
| Returns | |
|---|---|
int |
the total number of compressed bytes input so far |
int getTotalOut ()
Returns the total number of uncompressed bytes output so far.
Since the number of bytes may be greater than
Integer.MAX_VALUE, the getBytesWritten() method is now
the preferred means of obtaining this information.
| Returns | |
|---|---|
int |
the total number of uncompressed bytes output so far |
int inflate (byte[] b)
Uncompresses bytes into specified buffer. Returns actual number of bytes uncompressed. A return value of 0 indicates that needsInput() or needsDictionary() should be called in order to determine if more input data or a preset dictionary is required. In the latter case, getAdler() can be used to get the Adler-32 value of the dictionary required.
| Parameters | |
|---|---|
b |
byte:
the buffer for the uncompressed data |
| Returns | |
|---|---|
int |
the actual number of uncompressed bytes |
| Throws | |
|---|---|
DataFormatException |
if the compressed data format is invalid |
See also:
int inflate (byte[] b,
int off,
int len)
Uncompresses bytes into specified buffer. Returns actual number of bytes uncompressed. A return value of 0 indicates that needsInput() or needsDictionary() should be called in order to determine if more input data or a preset dictionary is required. In the latter case, getAdler() can be used to get the Adler-32 value of the dictionary required.
| Parameters | |
|---|---|
b |
byte:
the buffer for the uncompressed data |
off |
int:
the start offset of the data |
len |
int:
the maximum number of uncompressed bytes |
| Returns | |
|---|---|
int |
the actual number of uncompressed bytes |
| Throws | |
|---|---|
DataFormatException |
if the compressed data format is invalid |
See also:
boolean needsDictionary ()
Returns true if a preset dictionary is needed for decompression.
| Returns | |
|---|---|
boolean |
true if a preset dictionary is needed for decompression |
See also:
boolean needsInput ()
Returns true if no data remains in the input buffer. This can be used to determine if #setInput should be called in order to provide more input.
| Returns | |
|---|---|
boolean |
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. Should be called when inflate() returns 0 and needsDictionary() returns true indicating that a preset dictionary is required. The method getAdler() can be used to get the Adler-32 value of the dictionary needed.
| Parameters | |
|---|---|
b |
byte:
the dictionary data bytes |
off |
int:
the start offset of the data |
len |
int:
the length of the data |
See also:
void setDictionary (byte[] b)
Sets the preset dictionary to the given array of bytes. Should be called when inflate() returns 0 and needsDictionary() returns true indicating that a preset dictionary is required. The method getAdler() can be used to get the Adler-32 value of the dictionary needed.
| Parameters | |
|---|---|
b |
byte:
the dictionary data bytes |
See also:
void setInput (byte[] b,
int off,
int len)
Sets input data for decompression. Should be called whenever needsInput() returns true indicating that more input data is required.
| Parameters | |
|---|---|
b |
byte:
the input data bytes |
off |
int:
the start offset of the input data |
len |
int:
the length of the input data |
See also:
void setInput (byte[] b)
Sets input data for decompression. Should be called whenever needsInput() returns true indicating that more input data is required.
| Parameters | |
|---|---|
b |
byte:
the input data bytes |
See also: