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| From | Jan Burse <janburse@fastmail.fm> |
| Newsgroups | comp.lang.java.programmer |
| Subject | Re: Fav. Memory Stream Impl. |
| Date | Sat, 28 Jan 2012 00:11:13 +0100 |
| Organization | albasani.net |
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Roedy Green schrieb:
> On Fri, 25 Nov 2011 18:39:23 +0100, Jan Burse<janburse@fastmail.fm>
> wrote, quoted or indirectly quoted someone who said :
>
>> Would be interested in a good memory stream
>> implementation. Requirement will be multiple
>> readers / writers and positioning.
>
> What do you use it for? What does it do for you?
> Is it just an ram-resident InputStream?
Dear All,
I found an interesting implementation. On linux
level there is ashmem for Android. And then on Java
level there is an implementation of a class called
MemoryFile. The memory file acts as a factory for
input/output streams:
http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/2.2_r1.1/android/os/MemoryFile.java#MemoryFile
public InputStream getInputStream() {
return new MemoryInputStream();
}
public OutputStream getOutputStream() {
return new MemoryOutputStream();
}
The above two streams account for sequential access,
and via mark/release some pseudo random access.
But there is also an api for random access. Namely
the following two beasts:
public int readBytes(byte[] buffer, int srcOffset,
int destOffset, int count);
public void writeBytes(byte[] buffer, int srcOffset,
int destOffset, int count)
Compare to a normal read/write there is an additional
parameter for the offset inside the memory file. But
the implementation is not really light weight. Namely
the memory file can shared accross processes, which
I do not need:
http://elinux.org/Android_Kernel_Features#ashmem
But at least it gives an idea how to bootstrap a
memory file implementation. Namely the input/output
streams are implemented based on the read/write with
the extra argument. Makes for examples mark/release
quite simple....
Cool!
Bye
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Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-25 18:39 +0100
Re: Fav. Memory Stream Impl. markspace <-@.> - 2011-11-25 10:34 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-25 20:59 +0100
Re: Fav. Memory Stream Impl. markspace <-@.> - 2011-11-25 12:16 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-25 21:23 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-25 21:23 +0100
Re: Fav. Memory Stream Impl. markspace <-@.> - 2011-11-25 13:00 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-25 22:32 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-25 22:36 +0100
Re: Fav. Memory Stream Impl. Robert Klemme <shortcutter@googlemail.com> - 2011-11-25 23:22 +0100
Re: Fav. Memory Stream Impl. Arne Vajhøj <arne@vajhoej.dk> - 2011-11-25 17:00 -0500
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-26 12:10 +0100
Re: Fav. Memory Stream Impl. Robert Klemme <shortcutter@googlemail.com> - 2011-11-27 21:43 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-28 00:13 +0100
Re: Fav. Memory Stream Impl. Robert Klemme <shortcutter@googlemail.com> - 2011-11-28 08:14 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-28 09:10 +0100
Re: Fav. Memory Stream Impl. Robert Klemme <shortcutter@googlemail.com> - 2011-11-28 02:47 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-28 14:58 +0100
Re: Fav. Memory Stream Impl. Robert Klemme <shortcutter@googlemail.com> - 2011-11-28 19:52 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-29 00:22 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-29 00:39 +0100
Re: Fav. Memory Stream Impl. Gene Wirchenko <genew@ocis.net> - 2011-11-28 17:03 -0800
Re: Fav. Memory Stream Impl. Arne Vajhøj <arne@vajhoej.dk> - 2012-02-06 21:06 -0500
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2012-02-07 09:59 +0100
Re: Fav. Memory Stream Impl. Daniel Pitts <newsgroup.nospam@virtualinfinity.net> - 2012-02-07 09:59 -0800
Re: Fav. Memory Stream Impl. Arne Vajhøj <arne@vajhoej.dk> - 2012-02-07 21:02 -0500
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2012-02-08 09:55 +0100
Re: Fav. Memory Stream Impl. "John B. Matthews" <nospam@nospam.invalid> - 2012-02-08 12:18 -0500
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2012-02-08 20:23 +0100
Re: Fav. Memory Stream Impl. Gene Wirchenko <genew@ocis.net> - 2012-02-08 13:18 -0800
Re: Fav. Memory Stream Impl. Gene Wirchenko <genew@ocis.net> - 2012-02-08 13:18 -0800
Re: Fav. Memory Stream Impl. Mayeul <mayeul.marguet@free.fr> - 2011-11-29 12:25 +0100
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-29 14:37 +0100
Re: Fav. Memory Stream Impl. Lew <lewbloch@gmail.com> - 2011-11-29 07:37 -0800
Re: Fav. Memory Stream Impl. Martin Gregorie <martin@address-in-sig.invalid> - 2011-11-29 20:26 +0000
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-29 21:34 +0100
Re: Fav. Memory Stream Impl. Martin Gregorie <martin@address-in-sig.invalid> - 2011-11-29 21:05 +0000
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-29 22:59 +0100
Re: Fav. Memory Stream Impl. markspace <-@.> - 2011-11-29 14:06 -0800
Re: Fav. Memory Stream Impl. "John B. Matthews" <nospam@nospam.invalid> - 2011-11-29 21:23 -0500
Re: Fav. Memory Stream Impl. Martin Gregorie <martin@address-in-sig.invalid> - 2011-11-30 01:08 +0000
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-30 14:03 +0100
Re: Fav. Memory Stream Impl. Arne Vajhøj <arne@vajhoej.dk> - 2012-02-06 20:59 -0500
Re: Fav. Memory Stream Impl. Roedy Green <see_website@mindprod.com.invalid> - 2011-11-26 00:26 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-26 12:05 +0100
Re: Fav. Memory Stream Impl. Lew <lewbloch@gmail.com> - 2011-11-26 11:22 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2011-11-26 20:44 +0100
Re: Fav. Memory Stream Impl. Lew <lewbloch@gmail.com> - 2011-11-26 17:15 -0800
Re: Fav. Memory Stream Impl. Jan Burse <janburse@fastmail.fm> - 2012-01-28 00:11 +0100
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