creating fread&fwrite like functions

[Gyiove]

Hello everyone!

I have this here:

		int write( void *in, int insize, int count )
		{
			if( !isbinary ) return size; 
			int adsize = insize * count;
			char *ad = new char[adsize];
			ad = (char *)in;
			char *p = new char[size + adsize];
			if(size) 
			{
				spstr::copy( p, size + adsize, data, size );
				delete data; 
			}
			data = p;
			spstr::copy( size, data, size + adsize, ad, adsize );
			size = size + adsize;
		}

		int read( void *out, int outsize, int count )
		{
			if( pos >= size ) return -1;
			char *d = new char[outsize*count];
			spstr::copy( pos, d, outsize*count, data, size );
			out = (void *)&d;
			pos += outsize*count;
			return pos;
		}

write works fine but read doesn't work at all.
What am i doing wrong here?
Thanks!


Edit:
Got it working.
All i had to do was
out[0] = d[0]
out[1] = d[1]
and so on ...

now the function is like this:

		int read( void *out, int outsize, int count )
		{
			if( pos >= size ) return -1;
			spstr::copy( pos, (char *)out, outsize*count, data, size );
			pos += outsize*count;
			return pos;
		}

Anyways... if you see something in my code what should i do differently then please let me know.
Thanks

[dhayden]

Your original post leaks the memory allocated at line 5.

What is data at line 10 and why do you delete it at line 11? It's generally a bad design idea to have a function delete random bits of memory.

[tipaye]

I think you haven't considered pass-by-value semantics. To work in the original way you intended, you need an etra level of indirection for out:

		int read( void **out, int outsize, int count )
		{
			if( pos >= size ) return -1;
			char *d = new char[outsize*count];
			spstr::copy( pos, d, outsize*count, data, size );
// It is suggestive that you need to garbage-collect out at this point
			*out = (void *)&d;
			pos += outsize*count;
			return pos;
		}