Commit graph

7 commits

Author SHA1 Message Date
cc989d171f investigate hash collisions on 32bit platform
...while on the train back from FrOSCon.
still the same old problem: we need a better hash function
for generating our Entry-IDs. The default hash function from Boost performs
poor on strings with common prefix and trailing number.

We use a hackish workaround, which is sufficient to avoid collisions
among the first 10000 numbers.
2015-08-27 23:48:39 +02:00
150fdea7a0 improve spread of the hash function used for EntryID
basically this is the well known problem #587
Just it became more pressing with the Upgrade to Jessie and Boost 1.55
So I've pulled off the well known "Knuth trick" to spread the
input data more evenly within the hash domain.

And voilà: now we're able to use 100000 number suffixes without collision
2015-08-16 01:35:30 +02:00
9d42b58aae EntryID implementation changes for #956
- move the santitise operation up into EntryID's ctor
- turn the recast() operation into a real in-place cast

these changes should be transparent to the existing usages
of EntryID (within the asset framework), but allow for use
as attribute name holder in GenNode, since we're now able
to feed existing name/ID values directly into the ctor
of BareEntryID, without any spurious santitise operation.
2015-08-16 01:35:30 +02:00
16cc7e608c EntryID(#865): move into the support library
does no longer depend on the asset subsystem
2015-08-16 01:35:29 +02:00
dccc41f156 EntryID(#865): switch ID generation to the newly defined generic ID functions
...first step to get rid of the proc::asset dependency
2015-08-16 01:35:29 +02:00
fc488f3b56 extract a basic set of generic ID functions for #984
using the struct-scheme.hpp and the requirements for
EntryID as a guideline. The goal is to move EntryID
over into the support lib, which means we need to get rid
of all direct proc::asset dependencies. Thus, these generic
ID functions shall form a baseline implementation, while
asset::Struct may provide the previously used implementation
through specialisation -- so the behaviour of EntryID will
not change for the structural assets, but we'll get a more
sane and readable default implementation for all other types.
2015-08-16 01:35:29 +02:00
7ea4f739bd introduce a new header for #984 2015-08-16 01:35:29 +02:00