bundles/org.tukani.xz/src/org/tukaani/xz/SeekableXZInputStream.java
public void seekToBlock(int blockNumber) throws IOException {
        if (in == null)
            throw new XZIOException("Stream closed");

        if (blockNumber < 0 || blockNumber >= blockCount)
            throw new XZIOException("Invalid XZ Block number: " + blockNumber);

        // This is a bit silly implementation. Here we locate the uncompressed
        // offset of the specified Block, then when doing the actual seek in
        // seek(), we need to find the Block number based on seekPos.
        seekPos = getBlockPos(blockNumber);
        seekNeeded = true;
    }
public void seekToBlock(int blockNumber) throws IOException {
        if (in == null)
            throw new XZIOException("Stream closed");

        if (blockNumber < 0 || blockNumber >= blockCount)
            throw new XZIOException("Invalid XZ Block number: " + blockNumber);

        // This is a bit silly implementation. Here we locate the uncompressed
        // offset of the specified Block, then when doing the actual seek in
        // seek(), we need to find the Block number based on seekPos.
        seekPos = getBlockPos(blockNumber);
        seekNeeded = true;
    }
Seeks to the beginning of the given XZ Block.

@throws      XZIOException
if <code>blockNumber&nbsp;&lt;&nbsp;0</code> or
<code>blockNumber&nbsp;&gt;=&nbsp;getBlockCount()</code>,
or if stream has been closed

@since 1.3