Attaching basic_string to preallocated buffer

[Alvin777]

I'd like to have data file with many strings and load them at once
using MapViewOfFile[Ex] and unload with UnmapViewOfFile . So I wouldn't
have to allocate memory for each string on heap.

How can I use basic_string<> attaching them to pointer to string
within mapped space so it wouldn't copy that string to internal
buffer?

--
Alvin777

[John Harrison]

Re: Attaching basic_string to preallocated buffer


"Alvin777" <alvin777@mail. ru> wrote in message
news:1c9319e1.0 402210051.175e5 827@posting.goo gle.com...[color=blue]
> I'd like to have data file with many strings and load them at once
> using MapViewOfFile[Ex] and unload with UnmapViewOfFile . So I wouldn't
> have to allocate memory for each string on heap.
>
> How can I use basic_string<> attaching them to pointer to string
> within mapped space so it wouldn't copy that string to internal
> buffer?
>[/color]

You cannot. Obviously there would be difficulties if, for instance,
std::string wanted to reallocate its buffer. It would be awkward to keep
track of whether it had a reallocated buffer, or one that was supplied by
the user.

I suggest you write your own string class that does what you want
(presumably one that never reallocates its buffer).

class StaticString
{
public:
StaticString(co nst char*);
...
private:
const char* buffer;
};

john

[Bob Hairgrove]

Re: Attaching basic_string to preallocated buffer

On 21 Feb 2004 00:51:58 -0800, alvin777@mail.r u (Alvin777) wrote:
[color=blue]
>I'd like to have data file with many strings and load them at once
>using MapViewOfFile[Ex] and unload with UnmapViewOfFile . So I wouldn't
>have to allocate memory for each string on heap.
>
>How can I use basic_string<> attaching them to pointer to string
>within mapped space so it wouldn't copy that string to internal
>buffer?[/color]

You might find it easier to use std::iostream etc.

I don't think you can do this with basic_string. But I would be gladly
poven wrong <g>.


--
Bob Hairgrove
NoSpamPlease@Ho me.com