Port of Robin's work from I0a53aa4581e25b351b9cb5033415b5163d05fe71
on top of the new qHash patches (the original commit just introduced
lots of conflicts, so I redid it from scratch).
This is based on the work done in the QHash benchmark over the past
few months experimenting with the performance of the string hashing
algorithm used by Java.
The Java algorithm, in turn, appears to have been based off a
variant of djb's work at http://cr.yp.to/cdb/cdb.txt.
This commit provides a performance boost of ~12-33% on the
QHash benchmark.
Unfortunately, the rcc test depends on QHash ordering.
Randomizing QHash or changing qHash will cause the test to fail
(see QTBUG-25078), so for now the testdata is changed as well.
Done-with: Robin Burchell
Change-Id: Ie05d8e21588d1b2d4bd555ef254e1eb101864b75
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
The implementation of the various qHash overloads offered by
Qt can change at any time for any reason
(speed, quality, security, ...).
Therefore, relying on the fact that qHash will always give
an identical result across Qt versions (... across different
processes, etc.), given identical input, is wrong.
Note that this also implies that one cannot rely on QHash
having a stable ordering (even without the random qHash seed).
For such use cases, one must use f.i. a private hash function
that will never change outside his own control.
This patch adds a private hash function for QStrings,
which is identical to the Qt(4) qHash(QString) implementation.
A couple of spots in Qt where the results of a qHash call were
actually saved on disk are ported to use the new function,
and a bit of documentation is added to QHash docs.
Change-Id: Ia3731ea26ac68649b535b95e9f36fbec3df693c8
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
It was never introduced in Qt 4, probably because of the implicit
conversion to QString (that is, adding the qHash overload for
QLatin1String in Qt 4 would have been a BIC).
Change-Id: I2ebc8e73a85be497866820e0ca416dd11167bb53
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Algorithmic complexity attacks against hash tables have been known
since 2003 (cf. [1, 2]), and they have been left unpatched for years
until the 2011 attacks [3] against many libraries /
(reference) implementations of programming languages.
This patch adds a qHash overload taking two arguments: the value to
be hashed, and a uint to be used as a seed for the hash function
itself (support the global QHash seed was added in a previous patch).
The seed itself is not used just yet; instead, 0 is passed.
Compatibility with the one-argument qHash(T) implementation is kept
through a catch-all template.
[1] http://www.cs.rice.edu/~scrosby/hash/CrosbyWallach_UsenixSec2003.pdf
[2] http://perldoc.perl.org/perlsec.html#Algorithmic-Complexity-Attacks
[3] http://www.ocert.org/advisories/ocert-2011-003.html
Task-number: QTBUG-23529
Change-Id: I1d0a84899476d134db455418c8043a349a7e5317
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>
Algorithmic complexity attacks against hash tables have been known
since 2003 (cf. [1, 2]), and they have been left unpatched for years
until the 2011 attacks [3] against many libraries /
(reference) implementations of programming languages.
This patch adds a global integer, to be used as a seed for the hash
function itself. The seed is randomly initialized the first time a
QHash detaches from shared_null.
Right now the seed is not used at all -- another patch will modify
qHash to make use of it.
[1] http://www.cs.rice.edu/~scrosby/hash/CrosbyWallach_UsenixSec2003.pdf
[2] http://perldoc.perl.org/perlsec.html#Algorithmic-Complexity-Attacks
[3] http://www.ocert.org/advisories/ocert-2011-003.html
Task-number: QTBUG-23529
Change-Id: I7519e4c02b9c2794d1c14079b01330eb356e9c65
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
C++11 adds cbegin()/cend() functions for the same reason Qt has
constBegin()/constEnd(). This patch adds these functions to the
Qt containers with the same implementation as constBegin()/constEnd().
It also fixes the return types in the documentation of existing
constFind() functions (documentation only).
C++11 only adds cbegin()/cend() (and crbegin()/crend(), which Qt doesn't have).
In particular, it doesn't add cfind(), so I didn't supply these, even though
Qt comes with constFind().
This is a forward-port of https://qt.gitorious.org/qt/qt/merge_requests/1365.
Change-Id: Ida086b64246b24e25254eafbcb06c8e33388502b
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
QDoc now has support for Doxygen style commands for italics, bold
and list items. This change applies that change in QDoc to the
actual documentation.
Task-number: QTBUG-24578
Change-Id: I519bf9c29b14092e3ab6067612f42bf749eeedf5
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
I'm sure 'line' can't contain anything resembling a format string,
but better safe than sorry.
Change-Id: I0aa0f4a5a03d97b18d6a866c27fa721fcbe0f77b
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>
As in the past, to avoid rewriting various autotests that contain
line-number information, an extra blank line has been inserted at the
end of the license text to ensure that this commit does not change the
total number of lines in the license header.
Change-Id: I311e001373776812699d6efc045b5f742890c689
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>
We're trying to deprecate these, so don't use them anymore.
The inline uses of these have been left intact, for the moment. Inline code will
need to create their own non-inline allocation methods (for future-proofing to
allow alterations in how e.g. individual containers allocate)
Change-Id: I1071a487c25e95b7bb81a3327b20c5481fb5ed22
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Bradley T. Hughes <bradley.hughes@nokia.com>
This was only being used to initialize static read-only RefCount
instances, where the value is hard-wired to -1. Instead of allowing
initialization with arbitrary values (which for a reference count can be
error prone) the intent of the macro is made explicit with its
replacement Q_REFCOUNT_INITIALIZE_STATIC.
Change-Id: I5b0f3f1eb58c3d010e49e9259ff4d06cbab2fd35
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>
, and make it strictly a POD struct.
Since this operator was only being used to set the initial (owned) value
of the reference count, the name of the function introduced here to
replace it makes that use case explicit.
Change-Id: I2feadd2ac35dcb75ca211471baf5044a5f57cd62
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Dealt with all necessary changes that are marked in the code: removing
methods left only for binary compatibility with earlier Qt 4 versions
and other methods marked for removal.
Change-Id: I47109ccd9ed40addc345416be9e172570723955e
Reviewed-on: http://codereview.qt-project.org/4534
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
Similar to QLinkedList QList, QMap, QVector, QByteArray and QString,
keep the shared_null in shareable memory and never modify it.
Change-Id: Ia8b72ef0288575bed658153d9d54434580988bda
Reviewed-on: http://codereview.qt-project.org/4533
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>
This is the beginning of revision history for this module. If you
want to look at revision history older than this, please refer to the
Qt Git wiki for how to use Git history grafting. At the time of
writing, this wiki is located here:
http://qt.gitorious.org/qt/pages/GitIntroductionWithQt
If you have already performed the grafting and you don't see any
history beyond this commit, try running "git log" with the "--follow"
argument.
Branched from the monolithic repo, Qt master branch, at commit
896db169ea224deb96c59ce8af800d019de63f12
Giuseppe D'Angelo
Marcel Krems
Kent Hansen
Marc Mutz
João Abecasis
Casper van Donderen
Jason McDonald
Robin Burchell
Bradley T. Hughes
Jyri Tahtela
Qt by Nokia