f.offset += int64(n)
	return n, nil
}

func (f *openMapFile) Seek(offset int64, whence int) (int64, error) {
	switch whence {
	case 0:
		// offset += 0
	case 1:
		offset += f.offset
	case 2:
		offset += int64(len(f.f.Data))
	}
	if offset < 0 || offset > int64(len(f.f.Data)) {
		return 0, &fs.PathError{Op: "seek", Path: f.path, Err: fs.ErrInvalid}
	}
	f.offset = offset

// is a list of ranges with an accompanying value. Given a matching range r,
// the value for b is by r.value + (b - r.lo) * stride.
func (t *sparseBlocks) lookup(n uint32, b byte) uint16 {
	offset := t.offset[n]
	header := t.values[offset]
	lo := offset + 1
	hi := lo + uint16(header.lo)
	for lo < hi {
		m := lo + (hi-lo)/2
		r := t.values[m]
		if r.lo <= b && b <= r.hi {
			return r.value + uint16(b-r.lo)*header.value
		}

    private final int offset;
    private final int length;

    public DefaultOffsetInFileLocation(String path, int offset, int length) {
        super(path);
        this.offset = offset;
        this.length = length;
    }

    @Override
    public int getOffset() {
        return offset;
    }

    @Override
    public int getLength() {

	const (
		min  = 16
		max  = 128
		step = 32
	)

	rangeSize := pr.Size
	// offset should always be smaller than the range size
	if rangeSize <= min {
		return 0
	}

	offset := rangeSize / step
	if offset < min {
		return min
	}
	if offset > max {
		return max
	}
	return int(offset)

    this.elementSet = elementSet;
    this.cumulativeCounts = cumulativeCounts;
    this.offset = offset;
    this.length = length;
  }

  private int getCount(int index) {
    return (int) (cumulativeCounts[offset + index + 1] - cumulativeCounts[offset + index]);
  }

  @Override
  Entry<E> getEntry(int index) {

     */
    public static int sizeOfCommonPrefix(String path1, String path2, int offset) {
        return sizeOfCommonPrefix(path1, path2, offset, File.separatorChar);
    }

    /**
     * Does not include the separator char.
     */
    public static int sizeOfCommonPrefix(String path1, String path2, int offset, char separatorChar) {
        int pos = 0;
        int lastSeparator = 0;

	Flmagic    [SAIAMAG]byte // Archive magic string
	Flmemoff   [20]byte      // Member table offset
	Flgstoff   [20]byte      // 32-bits global symtab offset
	Flgst64off [20]byte      // 64-bits global symtab offset
	Flfstmoff  [20]byte      // First member offset
	Fllstmoff  [20]byte      // Last member offset
	Flfreeoff  [20]byte      // First member on free list offset
}

type bigarMemberHeader struct {
	Arsize   [20]byte // File member size

	// Check offset overflow. Must fit in int32.
	MOVQ 2147483647+1(AX), AX       // ERROR "offset too large"
	MOVQ 3395469782(R10), R8        // ERROR "offset too large"
	LEAQ 3395469782(AX), AX         // ERROR "offset too large"
	ADDQ 3395469782(AX), AX         // ERROR "offset too large"
	ADDL 3395469782(AX), AX         // ERROR "offset too large"

    /**
     * Return the byte or character offset into the input source this location
     * is pointing to. If the input source is a file or a byte stream then
     * this is the byte offset into that stream, but if the input source is
     * a character media then the offset is the character offset.
     * Returns -1 if there is no offset available.
     * @return the current offset
     */
    int getCharacterOffset();

    /**

	if offset < 0 || length < 0 {
		return -1, errInvalidArgument
	}
	if offset+length > totalLength {
		return -1, errInvalidArgument
	}

	if length == 0 {
		return 0, nil
	}

	reader := newParallelReader(readers, e, offset, totalLength)
	if len(prefer) == len(readers) {