how to read long[] from data input stream ?

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Jimmy Zhang - 31 Oct 2003 10:22 GMT

I am looking for ways to read data into a long array from data input stream
directly. I feel that wrapping Fileinputstream
using DataInputStream filter is kinda inefficient, if there is a way to let
the datainputstream to arrange 8 bytes into a long directly, it wouild be
really nice.

Any suggestions on how to realize this?

Thanks,
Jimmy

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Marco Schmidt - 31 Oct 2003 10:50 GMT

Jimmy Zhang:

>I am looking for ways to read data into a long array from data input stream
>directly. I feel that wrapping Fileinputstream
>using DataInputStream filter is kinda inefficient, if there is a way to let
>the datainputstream to arrange 8 bytes into a long directly, it wouild be
>really nice.

Why do you think it's not efficient? It's a normal approach in Java to
wrap I/O objects into other I/O objects. Just try the
DataInputStream/FileInputStream combination. However, make sure you
also include a buffering stream:

DataInput in = new DataInputStream(new BufferedInputStream(new
FileInputStream("file.dat")));
long l1 = in.readLong();
long l2 = in.readLong();
...

Regards,
Marco

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ak - 31 Oct 2003 14:44 GMT

you could also at first read data in byte array and then convert bytes in
longs

> I am looking for ways to read data into a long array from data input stream
> directly. I feel that wrapping Fileinputstream
[quoted text clipped - 6 lines]
> Thanks,
> Jimmy

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Roedy Green - 31 Oct 2003 20:28 GMT

>using DataInputStream filter is kinda inefficient, if there is a way to let
>the datainputstream to arrange 8 bytes into a long directly,

Have a look at the source code for DataInputStream to see how it does
it. If you can't find that look at the code for the little-endian
version at http://mindprod.com/products.html#LEADATASTREAM

For sample code for packing and unpacking bytes see
http://mindprod.com/jgloss/endian.html

--
Canadian Mind Products, Roedy Green.
Coaching, problem solving, economical contract programming.
See http://mindprod.com/jgloss/jgloss.html for The Java Glossary.

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how to read long[] from data input stream ?

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