entry-id.hpp File Reference

Go to the source code of this file.

Description

Bare symbolic and hash ID used for accounting of asset like entries.

This ID can be used to register instances with an accounting table, without all the overhead of creating individual assets for each entry. The datafields in the symbolic part of the ID are similar to the asset identity tuple; the idea is to promote individual entries to full fledged assets on demand. Alongside with the symbolic identity, which can be reduced to just a Symbol and (compile time) type information, we store the derived hash value as LUID.

Note

as of 3/2010 this is an experimental setup and exists somewhat in parallel to the assets. We're still in the process of finding out what's really required to keep track of all the various kinds of objects. ///////////////////TICKET #739

Todo:

as of 11/2018 the basic design seems adequate, but the actual solution looks fishy. Even more so, since we now use subclasses of BareEntryID

• as identity tag within lib::diff::GenNode
• as identity tag for all tangible UI elements There are various quirks and hacks to make all of this happen, and especially the hashed-in type information feels gratuitous at places, when all we actually need is a distinct identity plus a human readable symbol.

See also

asset::Asset::Ident

entry-id-test.cpp

Definition in file entry-id.hpp.

#include "lib/error.hpp"
#include "lib/hash-indexed.hpp"
#include "lib/idi/genfunc.hpp"
#include "lib/util.hpp"
#include <boost/functional/hash.hpp>
#include <boost/operators.hpp>
#include <string>

Classes
class	BareEntryID
	type erased baseclass for building a combined hash and symbolic ID. More...
struct	EntryID< TY >
	typed symbolic and hash ID for asset-like position accounting. More...
struct	EntryID< TY >
	typed symbolic and hash ID for asset-like position accounting. More...
struct	RandID
	Entry-ID with a symbolic tag but just a plain random hash part. More...
struct	BareEntryID::UseEmbeddedHash
	using BareEntryID derived objects as keys within std::unordered_map More...

Functions
LuidH	buildHash (string const &sym, HashVal seed=0)
	build up a hash value, packaged as LUID. More...
bool	operator== (BareEntryID const &i1, BareEntryID const &i2)

Variables
const size_t	KNUTH_MAGIC = 2654435761
	lousy old tinkerer's trick: hash values with poor distribution can be improved by spreading the input with something close to the golden ratio. More...

Namespaces
	lib
	Implementation namespace for support and library code.
	lib::idi
	Identification Schemes.