public class XZInputStream extends InputStream
Use this to decompress regular standalone .xz files. This reads from its input stream until the end of the input or until an error occurs. This supports decompressing concatenated .xz files.
Getting an input stream to decompress a .xz file:
InputStream infile = new FileInputStream("foo.xz");
XZInputStream inxz = new XZInputStream(infile);
It's important to keep in mind that decompressor memory usage depends on the settings used to compress the file. The worst-case memory usage of XZInputStream is currently 1.5 GiB. Still, very few files will require more than about 65 MiB because that's how much decompressing a file created with the highest preset level will need, and only a few people use settings other than the predefined presets.
It is possible to specify a memory usage limit for
XZInputStream. If decompression requires more memory than
the specified limit, MemoryLimitException will be thrown when reading
from the stream. For example, the following sets the memory usage limit
to 100 MiB:
InputStream infile = new FileInputStream("foo.xz");
XZInputStream inxz = new XZInputStream(infile, 100 * 1024);
If you are decompressing complete files and your application knows
exactly how much uncompressed data there should be, it is good to try
reading one more byte by calling read() and checking
that it returns -1. This way the decompressor will parse the
file footers and verify the integrity checks, giving the caller more
confidence that the uncompressed data is valid. (This advice seems to
apply to
java.util.zip.GZIPInputStream too.)
SingleXZInputStream| Constructor and Description |
|---|
XZInputStream(InputStream in)
Creates a new XZ decompressor without a memory usage limit.
|
XZInputStream(InputStream in,
int memoryLimit)
Creates a new XZ decompressor with an optional memory usage limit.
|
| Modifier and Type | Method and Description |
|---|---|
int |
available()
Returns the number of uncompressed bytes that can be read
without blocking.
|
void |
close()
Closes the stream and calls
in.close(). |
int |
read()
Decompresses the next byte from this input stream.
|
int |
read(byte[] buf,
int off,
int len)
Decompresses into an array of bytes.
|
mark, markSupported, read, reset, skippublic XZInputStream(InputStream in) throws IOException
This constructor reads and parses the XZ Stream Header (12 bytes)
from in. The header of the first Block is not read
until read is called.
in - input stream from which XZ-compressed
data is readXZFormatException - input is not in the XZ formatCorruptedInputException - XZ header CRC32 doesn't matchUnsupportedOptionsException - XZ header is valid but specifies options
not supported by this implementationEOFException - less than 12 bytes of input was available
from inIOException - may be thrown by inpublic XZInputStream(InputStream in, int memoryLimit) throws IOException
This is identical to XZInputStream(InputStream) except
that this takes also the memoryLimit argument.
in - input stream from which XZ-compressed
data is readmemoryLimit - memory usage limit in kibibytes (KiB)
or -1 to impose no
memory usage limitXZFormatException - input is not in the XZ formatCorruptedInputException - XZ header CRC32 doesn't matchUnsupportedOptionsException - XZ header is valid but specifies options
not supported by this implementationEOFException - less than 12 bytes of input was available
from inIOException - may be thrown by inpublic int read()
throws IOException
Reading lots of data with read() from this input stream
may be inefficient. Wrap it in BufferedInputStream
if you need to read lots of data one byte at a time.
read in class InputStream-1
to indicate the end of the compressed streamCorruptedInputExceptionUnsupportedOptionsExceptionMemoryLimitExceptionXZIOException - if the stream has been closedEOFException - compressed input is truncated or corruptIOException - may be thrown by inpublic int read(byte[] buf,
int off,
int len)
throws IOException
If len is zero, no bytes are read and 0
is returned. Otherwise this will try to decompress len
bytes of uncompressed data. Less than len bytes may
be read only in the following situations:
len
bytes have already been successfully decompressed.
The next call with non-zero len will immediately
throw the pending exception.read in class InputStreambuf - target buffer for uncompressed dataoff - start offset in buflen - maximum number of uncompressed bytes to read-1 to indicate
the end of the compressed streamCorruptedInputExceptionUnsupportedOptionsExceptionMemoryLimitExceptionXZIOException - if the stream has been closedEOFException - compressed input is truncated or corruptIOException - may be thrown by inpublic int available()
throws IOException
CorruptedInputException may get
thrown before the number of bytes claimed to be available have
been read from this input stream.available in class InputStreamIOExceptionpublic void close()
throws IOException
in.close().
If the stream was already closed, this does nothing.close in interface Closeableclose in interface AutoCloseableclose in class InputStreamIOException - if thrown by in.close()Copyright © 2016 Internet2. All rights reserved.