Re: Preallocate ostringstream buffer

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"Jeff F" <not@xxxxxxxxxxxx> wrote in message
news:eR5h3RbWGHA.3492@xxxxxxxxxxxxxxxxxxxxxxx

Tom Widmer [VC++ MVP] wrote:
Andrew Jarvis wrote:
Dear All,

I want to write about 8Mb of data to a ostringstream and I do not
want the stream continually reallocating ever larger chunks of
memory as the data is written.

With ostrstream I can map the stream onto a preallocated buffer, eg.

char *buffer = new char[length];
ostrstream os(buffer, length);

Is a this possible with ostringstream?

No, sadly there is no ostringstream::reserve. Either use ostrstream
(assuming you don't need wide characters) or roll your own.

And the latter is particularly easy with the boost iostreams library, see:
http://www.boost.org/libs/iostreams/doc/index.html.

And it's generally unnecessary with the library shipped with VC++
these days, since the buffer grows exponentially. Execution time
is not a problem. If space limitations are a problem, it's still
particularly easy to use strstream with a preallocated buffer.

P.J. Plauger
Dinkumware, Ltd.
http://www.dinkumware.com


.

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