<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<p><br>
</p>
<div class="moz-cite-prefix">On 09/09/2022 15:02, Gavin Ray wrote:<br>
</div>
<blockquote type="cite" cite="mid:CAFtvWZNN-pW4tYyCBDCTvQVw=YeyZ=F0YinMQUbod+Jw4KhO4w@mail.gmail.com">
<div dir="ltr">Ah, I didn't realize that there was negligible
overhead for wrapping as a buffer
<div><br>
<div>That makes sense, so you're just allocating a single
Object wrapping a zero-copy slice of the underlying buffer
essentially?</div>
</div>
</div>
</blockquote>
<p>Yes, a direct buffer instance has some starting (off-heap)
address and a size. What MemorySegment::asByteBuffer does is
simply to create a new (direct) ByteBuffer instance, whose base
address is set to the base address of the segment, and the size is
set to the segment size. This way, the byte buffer can "see" all
the bytes in the memory segment.</p>
<p>Maurizio<br>
</p>
<blockquote type="cite" cite="mid:CAFtvWZNN-pW4tYyCBDCTvQVw=YeyZ=F0YinMQUbod+Jw4KhO4w@mail.gmail.com">
<div dir="ltr">
<div><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Sep 9, 2022 at 9:58 AM
Maurizio Cimadamore <<a href="mailto:maurizio.cimadamore@oracle.com" moz-do-not-send="true" class="moz-txt-link-freetext">maurizio.cimadamore@oracle.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hi
Gavin,<br>
for now we have no plans to provide I/O APIs to take memory
segments <br>
instead of buffers.<br>
<br>
When working with I/O it is preferrable to map the segment
into a buffer <br>
(which is a very cheap operation, no copy is required, only a
view is <br>
created).<br>
<br>
Maurizio<br>
<br>
On 09/09/2022 14:46, Gavin Ray wrote:<br>
> We can see in the JavaDoc for FileChannel that
"transferTo/From" is <br>
> the way to use potentially optimal I/O transfers<br>
> This requires a Readable/Writeable/SeekableByteChannel,
which have <br>
> "ByteBuffer" as the argument types<br>
><br>
> Are there any plans to eventually modify I/O API's to
take raw <br>
> MemorySegment's for better performance?<br>
> Or should folks just do MemorySegment.ofBuffer() etc?<br>
><br>
</blockquote>
</div>
</blockquote>
</body>
</html>