> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On
Behalf
> Of James Newtons Massmind
> Sent: Friday, February 24, 2006 7:28 PM
> To: 'Microcontroller discussion list - Public.'
> Subject: [EE] selecting the right C++ STD library memory buffer
> 
> The programmer I hired to help with this is sick and make take some
time
> to
> reply so I'll write the list with this question in hopes of finding an
> answer faster.
> 
> I'm writing Win32 code in C/C++ (MS Visual C++ 2005 Express Edition)
and
> part of this code manipulates data that is handed to it in a memory
> buffer.
> I may have to insert things and thereby increase the size of the data
> beyond
> the size of the source buffer. So I need to allocate a buffer of my
own,
> copy from the source and insert my bits, the return the result in
place of
> the source. No problems so far.
> 
> The issue is what class to use for my buffer. Here are the
requirements:
> 1. It should be as efficient and fast as possible. E.g. I don't need
file
> IO
> so there is no reason to use a iostream class.
> 
> 2. The data is binary. By that I mean the byte values will range from
0 to
> 255. Some of the data I will put into the buffer is binary, but other
data
> will be text and some data will be binary values (int, short, etc...)
that
> I
> will need to convert to decimal characters and append. E.g. if it was
an
> std::basic_stringstream I would use:
> 
>  std::basic_stringstream<wchar_t> buffer;
>  int I = 123;
>  buffer << "I is:" << I;
> 
> So the issue is this combination of needs: copying in parts of a
binary
> char
> array, text, or decimal values of variables.
> 
> What class does all that? And more importantly, where is there any
> documentation that would help a poor newbie like me figure out what
they
> do
> and don't?
> 
> I've been advised to use vector but that doesn't support the << and
the
> copy
> as far as I can see.

Derive a class from any of the C++ STL and you can add any features you
want.

One of the annoying things about C++ is that they broke some of the
simplicity of C.  What do you want << to mean?  Do you mean send the
whole structure to an iostream?  Binary shift some or all of the
elements?

All C++ STL container classes can be copied.  What do you mean by that?

> I've also been advised not to use streams as they don't play well with
> binary?

Depends what you mean by play nice.  I use binary elements into streams
all the time.


> 
> Any advice appreciated.

STL container type choice depends upon what the most common operation
is.

I can help you with this on or off list but I'd need a better
specification of exactly what kind of data you want to handle.

Is it this sort of stuff?  This was a five minute type in using Visual
Studio.Net  (even though I hate .net)

// CharList.cpp : Defines the entry point for the console application.
//

#include <list>
#include <iostream>

typedef std::list < unsigned char > charList;

unsigned char a [] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
unsigned char b [];

int main(int , char* )
{
	charList l;

	for (unsigned idx = 0; idx <= sizeof(a); ++idx)
	{
		// an insert before for no particular reason
		if ( a [idx] == 2)
		{
			l.push_back(2);
		}
		l.push_back ( a [idx] );

		// an insert after again for no aprticular reason
		if (a [idx] == 7)
		{
			l.push_back( 11 );
		}
	}

	for ( charList::iterator itr = l.begin();
		itr != l.end();
		++itr )
	{
		if ( *itr == 6 )
		{
			l.insert ( itr, 250 );
		}
	}

	for ( charList::const_iterator itr = l.begin();
		  itr != l.end();
		  ++ itr)
	{
		std::cout << (unsigned)*itr << std::endl;
	}

	return 0;
}



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