Decompresses a .xz file in streamed mode (no seeking).

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.

Typical use cases

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);

When uncompressed size is known beforehand

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
{@link java.util.zip.GZIPInputStream java.util.zip.GZIPInputStream} too.)

@see SingleXZInputStream

Creates a new XZ decompressor without a memory usage limit.

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.

@param in input stream from which XZ-compressed
data is read

@throws XZFormatException
input is not in the XZ format

@throws CorruptedInputException
XZ header CRC32 doesn't match

@throws UnsupportedOptionsException
XZ header is valid but specifies options
not supported by this implementation

@throws EOFException
less than 12 bytes of input was available
from in

@throws IOException may be thrown by in

Creates a new XZ decompressor with an optional memory usage limit.

This is identical to XZInputStream(InputStream) except
that this takes also the memoryLimit argument.

@param in input stream from which XZ-compressed
data is read

@param memoryLimit memory usage limit in kibibytes (KiB)
or -1 to impose no
memory usage limit

@throws XZFormatException
input is not in the XZ format

@throws CorruptedInputException
XZ header CRC32 doesn't match

@throws UnsupportedOptionsException
XZ header is valid but specifies options
not supported by this implementation

@throws EOFException
less than 12 bytes of input was available
from in

@throws IOException may be thrown by in

Decompresses the next byte from this input stream.

Reading lots of data with read() from this input stream
may be inefficient. Wrap it in {@link java.io.BufferedInputStream}
if you need to read lots of data one byte at a time.

@return the next decompressed byte, or -1
to indicate the end of the compressed stream

@throws CorruptedInputException
@throws UnsupportedOptionsException
@throws MemoryLimitException

@throws XZIOException if the stream has been closed

@throws EOFException
compressed input is truncated or corrupt

@throws IOException may be thrown by in

Decompresses into an array of bytes.

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:

• The end of the compressed data was reached successfully.


• An error is detected after at least one but less len
  bytes have already been successfully decompressed.
  The next call with non-zero len will immediately
  throw the pending exception.


• An exception is thrown.

@param buf target buffer for uncompressed data
@param off start offset in buf
@param len maximum number of uncompressed bytes to read

@return number of bytes read, or -1 to indicate
the end of the compressed stream

@throws CorruptedInputException
@throws UnsupportedOptionsException
@throws MemoryLimitException

@throws XZIOException if the stream has been closed

@throws EOFException
compressed input is truncated or corrupt

@throws IOException may be thrown by in

Returns the number of uncompressed bytes that can be read
without blocking. The value is returned with an assumption
that the compressed input data will be valid. If the compressed
data is corrupt, CorruptedInputException may get
thrown before the number of bytes claimed to be available have
been read from this input stream.
return   the number of uncompressed bytes that can be read
without blocking

Closes the stream and calls in.close().
If the stream was already closed, this does nothing.
throws   IOException if thrown by in.close()