zorba-coders team mailing list archive

["Paul J. Lucas" <paul@xxxxxxxxxxxxx>]

On Dec 16, 2012, at 8:43 PM, Markos Zaharioudakis <markos_za@xxxxxxxxx> wrote:

> The memory size of some std containers is underestimated, because the book-keeping overhead is not taken into account. I understand we cannot be 100% exact here, but should we try to consider some common std implementations and measure the mem size accordingly? For example, std::map is typically implemented as a red-black tree, which should add at least 2 pointers (or offsets) per entry into its memory size.

OK, I added sizeof(void*) * 2.

On Dec 16, 2012, at 8:53 PM, Markos Zaharioudakis <markos_za@xxxxxxxxx> wrote:

> I think we should define Base16::alloc_size() and Base64::alloc_size() methods. The Base16::alloc_size() method should then be used in HexBinaryItem::alloc_size() (which is not quite correct right now).
> 
> StructuralAnyUriItem::alloc_size() does not count theEncodedValue
> 
> StreamableStringItem::alloc_size() does not count theStreamableDependent

Fixed.

On Dec 16, 2012, at 10:00 PM, Markos Zaharioudakis <markos_za@xxxxxxxxx> wrote:

> The function alloc_sizeof( rstring<RepType> const &s ) does not count the book-keeping overhead for the various kinds of strings. For example, the default rep (which is used for zstrings) adds 12 bytes oberhead (on 32-bit machines).

I changed it to:

	return s.capacity() + (s.is_shared() ? 0 : sizeof( RepType ));

> Also, I think the null-terminating byte is not counted.

The alloc_size is its capacity.  The null byte is irrelevant.

On Dec 17, 2012, at 2:52 AM, Markos Zaharioudakis <markos_za@xxxxxxxxx> wrote:

> The size of XmlTree is not counted.

Right: because it's shared by all nodes in the tree.

> An instance of XmlTree is shared by all nodex in the same xml tree. Maybe the size of the XmlTree should be attribute only to the root node of the tree.


The problem is infinite recursion.  If I ask for the size of a tree, it's the sum of all the nodes.  If the root node includes the size of the tree, then it will recurse infinitely.

- Paul


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