On Thu, 14 Oct 2010 06:36:17 +0400, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
On 10/13/10 21:20 CDT, Denis Koroskin wrote:
On Thu, 14 Oct 2010 03:47:12 +0400, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
On 10/13/2010 06:23 PM, Denis Koroskin wrote:
On Thu, 14 Oct 2010 03:06:30 +0400, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
Gnu offers two specialized routines:
http://www.gnu.org/s/libc/manual/html_node/Line-Input.html. It is
many
times more efficient than anything that can be done in client code
using the stdio API. I'm thinking along those lines.
I can easily implement similar interface on top of chunked read:
ubyte[] readLine(ubyte[] lineBuffer); or bool readLine(ref ubyte[]
lineBuffer);
You can't.
I've quickly looked through an implementation, too, and it's still
filling a buffer first, and then copying character byte-by-byte to the
output string (making realloc when needed) until a delimiter is found.
It is exactly as efficient as implemented externally.
Except you don't have an interface to copy byte by byte. Oops...
It does the same
amount of copying and memory allocations. "Many times more efficient"
is
just an overestimation.
It's not. I measured because it was important in an application I was
working on. It's shocking how some seemingly minor changes can make a
big difference in throughput.
BTW, did you see my message about std.concurrency?
Yes, but I'll need to leave the bulk of it to Sean. Thanks.
Andrei
Okay. Now give me your best and tell me mine is slower (sorry for a lack
of comments):
[snip]
If you're satisfied with this, then my point has been lost in the
midstream. I was saying it's impossible to implement a line reader on
top of a read(ubyte[]) interface without extra buffering and copying.
You provided a careful implementation that at the end of the day
inevitably does the extra buffering and copying.
Andrei
You must have missed it somehow, but I did say many times that buffering
needs to be done externally (e.g. in byLine and BufferedStream).
Can we outline basic Stream interface now so that we could move on?
