array to container

[keith]

Hi all,
I'm one of those with about twenty years of experience writing in C,
who is hacking his way through the paradigm shift toward C++, so bear
with me here...

I'm trying to figure out the 'least evil' way of dealing with the
following situation. I have a library of functions written in C (as
it happens, it's an encryption library), which is written in C. A
large number of the functions in that library expect arguments of type
'unsigned char *', i.e. arrays of binary data.

I am writing a C++ application which needs to use this library, but I
am told that 'arrays are evil; bad things will happen to you', so I
looked at the standard containers. If in my application I use vectors
of unsigned char, how do I pass the contained data to the C library
functions? Or should I take the view that if the library wants arrays
of unsigned chars, that's what I should be using and to hell with
being evil?!

I imagine this particular wheel has been invented many many times, so
the wisdom of those who have gone before would be appreciated.

[Stefan Naewe]

On 6/28/2007 12:15 PM, ke***@bytebrothers.co.uk wrote:

Hi all,
I'm one of those with about twenty years of experience writing in C,
who is hacking his way through the paradigm shift toward C++, so bear
with me here...

I'm trying to figure out the 'least evil' way of dealing with the
following situation. I have a library of functions written in C (as
it happens, it's an encryption library), which is written in C. A
large number of the functions in that library expect arguments of type
'unsigned char *', i.e. arrays of binary data.

I am writing a C++ application which needs to use this library, but I
am told that 'arrays are evil; bad things will happen to you', so I
looked at the standard containers. If in my application I use vectors
of unsigned char, how do I pass the contained data to the C library
functions? Or should I take the view that if the library wants arrays
of unsigned chars, that's what I should be using and to hell with
being evil?!

I imagine this particular wheel has been invented many many times, so
the wisdom of those who have gone before would be appreciated.

void your_c_function(unsigned char* p, size_t len);

std::vector<unsigned charvuc;
/// populate vuc;

your_c_function(&vuc[0], vic.size());
Regards,
Stefan
--
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