bundles/org.tukani.xz/src/org/tukaani/xz/SeekableXZInputStream.java
private void locateBlockByPos(BlockInfo info, long pos) {
        if (pos < 0 || pos >= uncompressedSize)
            throw new IndexOutOfBoundsException(
                    "Invalid uncompressed position: " + pos);

        // Locate the Stream that contains the target position.
        IndexDecoder index;
        for (int i = 0; ; ++i) {
            index = streams.get(i);
            if (index.hasUncompressedOffset(pos))
                break;
        }

        // Locate the Block from the Stream that contains the target position.
        index.locateBlock(info, pos);

        assert (info.compressedOffset & 3) == 0;
        assert info.uncompressedSize > 0;
        assert pos >= info.uncompressedOffset;
        assert pos < info.uncompressedOffset + info.uncompressedSize;
    }
private void locateBlockByPos(BlockInfo info, long pos) {
        if (pos < 0 || pos >= uncompressedSize)
            throw new IndexOutOfBoundsException(
                    "Invalid uncompressed position: " + pos);

        // Locate the Stream that contains the target position.
        IndexDecoder index;
        for (int i = 0; ; ++i) {
            index = streams.get(i);
            if (index.hasUncompressedOffset(pos))
                break;
        }

        // Locate the Block from the Stream that contains the target position.
        index.locateBlock(info, pos);

        assert (info.compressedOffset & 3) == 0;
        assert info.uncompressedSize > 0;
        assert pos >= info.uncompressedOffset;
        assert pos < info.uncompressedOffset + info.uncompressedSize;
    }
Locates the Block that contains the given uncompressed position.