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LUMIERA.clone/tests/library/entry-id-test.cpp
Ichthyostega 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

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/*
EntryID(Test) - proof-of-concept test for a combined hash+symbolic ID
Copyright (C) Lumiera.org
2010, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
* *****************************************************/
#include "lib/test/run.hpp"
#include "lib/test/test-helper.hpp"
#include "lib/idi/entry-id.hpp"
#include "proc/asset/struct-scheme.hpp"
#include "proc/mobject/session/clip.hpp"
#include "proc/mobject/session/fork.hpp"
#include "lib/meta/trait-special.hpp"
#include "lib/util-foreach.hpp"
#include "lib/symbol.hpp"
#include <unordered_map>
#include <iostream>
#include <string>
using lib::test::showSizeof;
using lib::test::randStr;
using util::isSameObject;
using util::contains;
using util::and_all;
using lib::Literal;
using std::string;
using std::cout;
using std::endl;
namespace lib {
namespace idi {
namespace test{
using lumiera::error::LUMIERA_ERROR_WRONG_TYPE;
namespace { // Test definitions...
struct Dummy { };
}
using DummyID = EntryID<Dummy>;
using ForkID = EntryID<proc::mobject::session::Fork>;
using ClipID = EntryID<proc::mobject::session::Clip>;
/***********************************************************************//**
* @test proof-of-concept test for a combined symbolic and hash based ID.
* - create some symbolic IDs
* - check default assignment works properly
* - check comparisons
* - check hashing
* - use the embedded hash ID (LUID) as hashtable key
*
* @see lib::HashIndexed::Id
* @see mobject::Placement real world usage example
*/
class EntryID_test : public Test
{
virtual void
run (Arg)
{
checkCreation();
checkBasicProperties();
checkComparisions();
checkErasure();
buildHashtable();
}
void
checkCreation ()
{
DummyID dID1;
DummyID dID2("strange");
DummyID dID3;
CHECK (dID1.isValid());
CHECK (dID2.isValid());
CHECK (dID3.isValid());
CHECK (dID1 != dID2); CHECK (dID2 != dID1);
CHECK (dID2 != dID3); CHECK (dID3 != dID2);
CHECK (dID1 != dID3); CHECK (dID3 != dID1);
ForkID tID1;
ForkID tID2;
ForkID tID3("special");
CHECK (tID1.isValid());
CHECK (tID2.isValid());
CHECK (tID3.isValid());
CHECK (tID1 != tID2); CHECK (tID2 != tID1);
CHECK (tID2 != tID3); CHECK (tID3 != tID2);
CHECK (tID1 != tID3); CHECK (tID3 != tID1);
cout << dID1 << endl;
cout << dID2 << endl;
cout << dID3 << endl;
cout << tID1 << endl;
cout << tID2 << endl;
cout << tID3 << endl;
DummyID x (dID2); // copy ctor
CHECK (x == dID2);
CHECK (!isSameObject (x, dID2));
}
void
checkBasicProperties ()
{
using proc::asset::Asset;
using proc::asset::STRUCT;
using proc::asset::Category;
using proc::asset::idi::getAssetIdent;
ForkID tID(" test ⚡ ☠ ☭ ⚡ track ");
CHECK (getAssetIdent(tID) == Asset::Ident("test_track", Category(STRUCT,"forks"), "lumi", 0));
CHECK (tID.getHash() == ForkID("☢ test ☢ track ☢").getHash());
CHECK (tID.getSym() == getAssetIdent(tID).name);
CHECK (getAssetIdent(ForkID()).category == Category (STRUCT,"forks"));
CHECK (getAssetIdent(ClipID()).category == Category (STRUCT,"clips"));
ClipID cID2,cID3;
CHECK (cID2.getSym() < cID3.getSym());
CHECK (ClipID("x").getSym() == ClipID(" x ").getSym());
for (uint i=0; i<10000; ++i)
{
ForkID arbitrary(randStr(30));
CHECK (0 < arbitrary.getHash());
CHECK (tID.getHash() != arbitrary.getHash());
tID = arbitrary;
CHECK (tID.getHash() == arbitrary.getHash());
CHECK (tID.getSym() == arbitrary.getSym());
CHECK (getAssetIdent(tID)== getAssetIdent(arbitrary));
}
cout << showSizeof<ForkID>() << endl;
cout << showSizeof<BareEntryID>() << endl;
CHECK (sizeof(ForkID) == sizeof(BareEntryID));
CHECK (sizeof(ForkID) == sizeof(lumiera_uid) + sizeof(void*));
}
void
checkComparisions ()
{
ForkID tID1("a1");
ForkID tID2("a1");
ForkID tID3("a2");
ForkID tID4("b");
CHECK (tID1 == tID2);
CHECK (tID2 < tID3);
CHECK (tID2 <= tID3);
CHECK (tID3 >= tID2);
CHECK (tID3 > tID2);
CHECK (tID3 < tID4);
CHECK (tID3 <= tID4);
CHECK (tID4 >= tID3);
CHECK (tID4 > tID3);
ForkID trackID1, trackID2;
CHECK (trackID1 < trackID2); // auto generated IDs are prefix + running counter
}
/** @test handling of EntryIDs through their common base class,
* which means erasing the specific type information.
* While this type information can't be recovered
* after erasure, we can try to upcast back
* to a known type; this upcast is safe,
* because the embedded hash-ID
* is based on the type info.
*/
void
checkErasure ()
{
ForkID fID("suspicious");
ClipID cID("suspicious");
CHECK (fID.getHash() != cID.getHash());
CHECK (fID.getSym() == cID.getSym());
BareEntryID bIDf (fID);
BareEntryID bIDc (cID);
CHECK (bIDf != bIDc);
CHECK (bIDf.getHash() != bIDc.getHash());
CHECK (bIDf.getSym() == bIDc.getSym());
CHECK ("suspicious" == bIDc.getSym());
using proc::mobject::session::Fork;
using proc::mobject::session::Clip;
ForkID tIDnew = bIDf.recast<Fork>();
ClipID cIDnew = bIDc.recast<Clip>();
CHECK (tIDnew == fID);
CHECK (cIDnew == cID);
VERIFY_ERROR (WRONG_TYPE, bIDf.recast<Clip>());
VERIFY_ERROR (WRONG_TYPE, bIDc.recast<Fork>());
VERIFY_ERROR (WRONG_TYPE, bIDc.recast<Dummy>());
VERIFY_ERROR (WRONG_TYPE, bIDf.recast<Dummy>());
CHECK (fID == ForkID::recast (bIDf)); // equivalent static API on typed subclass
VERIFY_ERROR (WRONG_TYPE, ForkID::recast(bIDc));
VERIFY_ERROR (WRONG_TYPE, ClipID::recast(bIDf));
VERIFY_ERROR (WRONG_TYPE, DummyID::recast(bIDc));
VERIFY_ERROR (WRONG_TYPE, DummyID::recast(bIDf));
// mixed equality comparisons (based on the hash)
BareEntryID bIDt_copy (bIDf);
CHECK (bIDf == bIDt_copy);
CHECK (!isSameObject (bIDf, bIDt_copy));
CHECK (fID != bIDc);
CHECK (cID != bIDt_copy);
CHECK (fID == bIDt_copy);
CHECK (bIDf == ForkID ("suspicious"));
CHECK (bIDf != ClipID ("suspicious"));
CHECK (bIDc == ClipID ("suspicious"));
CHECK (ForkID ("suspicious") != ClipID ("suspicious"));
}
//---key--+-value-+-hash-function---
typedef std::unordered_map<DummyID, string, DummyID::UseEmbeddedHash> Hashtable;
/** @test build a hashtable, using EntryID as key,
* thereby using the embedded hash-ID
* @note there is a known weakness of the boost::hash
* when used on IDs with a running number suffix. /////TICKET #587
* We use a trick to spread the numbers better.
* @see HashGenerator_test#verify_Knuth_workaround
*/
void
buildHashtable ()
{
Hashtable tab;
for (uint i=0; i<100000; ++i)
{
DummyID dummy;
tab[dummy] = string(dummy);
}
CHECK (and_all (tab, verifyEntry));
CHECK (100000 == tab.size());
}
static bool
verifyEntry (Hashtable::value_type entry)
{
return checkForHashCollision(string(entry.first), entry.second);
}
static bool
checkForHashCollision(string const& key, string const& val)
{
if (key != val) cout << "Hash collision: "<<key<<" != "<<val<< endl;
return key == val;
}
};
/** Register this test class... */
LAUNCHER (EntryID_test, "unit common");
}}} // namespace lib::idi::test
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