OpenEuphoria

RE: allocated memory enlargement

• Posted by CoJaBo <cojabo at suscom.net> Mar 27, 2004
• 501 views

Kat wrote:
> 
> 
> On 26 Mar 2004, at 18:48, Allen Robnett wrote:
> 
> > 
> > http://click.topica.com/caab4CEb1dd66b6816za/ Crazy Aaron Enterprises
> > 
> > 
> > Tommy Carlier wrote:
> > 
> > >kat wrote
> > >  
> > >
> > >>Er,, i ever thought i'd be asking this, but if i have a block of memory 
> > >>allocated
> > >>on windows, and i want to enlarge it without changing it contents, can 
> > >>i? How?
> > >>
> > >>Kat
> > >>    
> > >>
> > >If you have allocated it with the Euphoria-function allocate, you could 
> > >do it
> > >like this:
> > >
> > >function resize_memblock(atom old_mem, integer old_size, integer 
> > >new_size)
> > >	atom new_mem 	if old_size = new_size then return old_mem end if  
> > >new_mem =
> > >allocate(new_size) 	if old_size < new_size then 		mem_copy(new_mem, 
> > >old_mem,
> > >old_size) 	else 		mem_copy(new_mem, old_mem, new_size) 	end if  
> > >free(old_mem)
> > >	return new_mem end function
> > >
> > >-- Using the function:
> > >
> > >pointer = resize_memblock(pointer, size, size + 1000) -- adds 1000 bytes 
> > >
> > >to the memory block
> > >  
> > >
> > I am very pleased to see this. Not being familiar with mem_copy, I had 
> > wondered about a subject that Kat raised earlier regarding inserting a 
> > new new record into a memory buffered file. mem_copy makes it easy to 
> > make room for the new record. (if you are building the file in a 
> > specific order, alphabetical, for instance.)
> 
> But the code above is not *expand* file, it's *making another new* file! 
> 
> Freeing the space the file occupies is definitely changing the contents 
> of the 
> existing space.
> 
> Try to do that on a 385 megabyte system when you need to do a few 
> hundred inserts real fast in a 200 meg ramdisk. The OS will page the 
> files to 
> disk (if you are lucky, but dos won't page to virtual ram), and your 
> speed will 
> be slower than if you used a disk-based system in the first place. Nix 
> may 
> be faster than Windows in this regard.
> 
> Kat
> 


Euphoria can't resize memory directly, there is probably a .DLL somewere 
that can do that(Maybe in the Win32 API). Even if there isn't you could 
probably make a C .DLL.