Actually, the layout is the same, but we move the control block. To prevent
padding of the short string, we use pragma pack(1). To align the pointer
again, we add some dummy data with the size of a pointer minus a control
block because alignas is not working like expected on GCC.
Change-Id: Ide86ace243dab5f487da63492ebac018da45098a
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
There can be quite some copies with the swap method for the default case
that the string is inside the small string area. Instead now we minimize
copies of the smallstring area at the expense of more branches.
The swap approch needs no self tests and it uses the destructor to
remove allocated resources but it can copy three times more often. And
the destructor still has an additional branch in the copy case. Only in
the move case we can use the destructor of the other instance. This can
be surprising for some users which expect that the instance is empty
after a move(actually assuming that a instance is empty after a move is
undefined behavior).
Because SmallString is designed to hold the string in almost all cases
inside the small string area that case should be optimized.
Change-Id: I22cb62aa99b9713a221f103971f149c05e9ff6fa
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Using a value after the move is undefined. For example, if you move an
integer, it is not set to zero after the move. So you have to initialize
it again. Adding the take method to SmallString makes this explicit.
So if there is a case that you want to use the string again after
a move, use take or initialize it yourself.
Change-Id: I174116df9639d6a3f63c6f2c2a3bd184852927ce
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
GCC 12 was producing a huge warning log about this, thinking we were
overflowing the buffer. I don't see how.
In function ‘std::_Require<std::__not_<std::__is_tuple_like<_Tp> >, std::is_move_constructible<_Tp>, std::is_move_assignable<_Tp> > std::swap(_Tp&, _Tp&) [with _Tp = char]’,
inlined from ‘void std::iter_swap(_ForwardIterator1, _ForwardIterator2) [with _ForwardIterator1 = char*; _ForwardIterator2 = char*]’ at /usr/include/c++/12/bits/stl_algobase.h:182:11,
inlined from ‘void std::__reverse(_RandomAccessIterator, _RandomAccessIterator, random_access_iterator_tag) [with _RandomAccessIterator = char*]’ at /usr/include/c++/12/bits/stl_algo.h:1107:18,
inlined from ‘void std::reverse(_BIter, _BIter) [with _BIter = char*]’ at /usr/include/c++/12/bits/stl_algo.h:1134:21,
inlined from ‘static std::size_t Utils::BasicSmallString<Size>::itoa(long long int, char*, uint) [with unsigned int Size = 31]’ at smallstring.h:956:21,
[... many more frames ...]
move.h:205:11: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
smallstring.h:615:14: note: at offset 46 into destination object ‘buffer’ of size 22
615 | char buffer[22];
| ^~~~~~
smallstring.h:615:14: note: at offset [14, 22] into destination object ‘buffer’ of size 22
smallstring.h:615:14: note: at offset 46 into destination object ‘buffer’ of size 22
Change-Id: Iba16e8ea451b444ab213fffd16f491e608ee713a
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Skip the creation auf a QByteArray. Use QStringEncoder instead.
Change-Id: I3d2297b1fef27acb2136a64587c5af9099d92aa6
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
If you write
Utils::SmallStringView view;
Utils::SmallString text{view};
it selects the std::initializer_list contructor. Not the didicated
constructore. It is much to easy to get it wrong so it is better
to make it explicit.
Change-Id: I4240eaf1f39cf71d37df4480fea1ecfa3ea83cb0
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
There are still some methods missing but with C++20 we can maybe remove
SmallStringView.
Change-Id: I65a1eacda0a07cec824f1837e385faa01fc825e9
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Use more C++ api and constexpr. With C++ 17 we can use even more.
Change-Id: I33934cd7e087c311bf98501442df848bdb108279
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>
If there is a newer file than the last indexing or if a file is added or
removed from the project or system PCH we have to reindex the project and
maybe the system PCH.
Change-Id: Ibce2a244190a79b5c422c469c065ddc11e44b2cb
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Failing test:
SymbolsCollector.CollectUsedMacrosWithoutExternalDefine
std::stable_partition can move-assigne object to itself
which was not properly handled in SmallString.
Change-Id: I719f3cb78cdace5fdbd9fcac3f5f099baa58a8c2
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>
The small string control block moved to the beginning, so it is more cache
local. The control block is cleanup too, so it should be easier to read.
The alignment is removed because it is creating to big holes.
Change-Id: I401aeb9d55455cbaa5e722dd8192e54b525ddc40
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>
If a class has a data method that returns a char pointer it can be
used to construct a SmallString and a SmallStringView.
Change-Id: I02dcba50babb3074b58998e5f907799e84361ed7
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>
Before the string was simply swapped with the other string which can lead
to an unexpected behavior for xvalues. Now the destructor of the source is
called and it is default initialized.
foo = std::move(bar);
bar would now hold the value of foo.
Change-Id: Ibea3f18333a168634b7faf2fdaf9b5b52c82d5cc
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
The database is using file path integer ids to handle file paths because
otherwise we would save many redundant data. This patch is improving it
further with the introduction of a database based file path cache. The
entries are now divided in a directory path and file name. This is quite
handy for directory based file watching.
Change-Id: I03f2e388e43f3d521d6bf8e39dfb95eb2309dc73
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
The reserve function is quite complicated because it is implementing a
grow pattern. Something we seldom need. So we now align to the next cache
line size.
Change-Id: I14bb88c12bd740a7afa7cd08969a4e07fb0f9add
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
We called reserve for even if we do not found anything to replace.
Change-Id: I01dfbb9e8152605c01fa007eb93586f9a30cf56e
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
You need to allocate the memory before you replace a smaller text with
a larger one. It has some overhead because you go two times over the text
but it is anyway not designed for a large text.
Change-Id: I2f56f1300a5daf9e26632b5b0667023a09ff4bd2
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
It has it's advantages if the text grows otherwise we maybe waste memory.
Change-Id: Ic76d25207c2ef18182069fbf64bc0fb955a85353
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
If you call reserve on a read only reference we always allocated on the
heap which is not that smart.
Change-Id: Ib9653c6fc87bc65716a966545c13f7ecb3712039
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
The bug was that we returned the new end() but not the old reallocated
after a reallocation of the memory. The return value is used to move the
string after the found sub string to the next found sub string to the
new position of after the replaced sub string. Because the new end moved
more to the right we moved a much bigger chunk of memory. So we
accessed memory outside of the allocated memory.
Change-Id: I9ac276e201eabee896190da0cf0ee1d86860777d
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
It should not be used for chained concatenation. Use initializer list
instead.
auto text = in + 'x';
auto text = Utils::SmallString{in, "x", other, ", "};
Change-Id: I453d986913eae89fd5e1f525b9f4e0c4bd089467
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
We use std::to_string except for integer where we want a low overhead
solution.
Change-Id: I16ce7d575d83ff56e61a5038aa7f9a1febfaf34f
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
The argument parsing has some considerable overhead. We try to avoid that
with merging all content together in one file.
Change-Id: Icf426bb5d6a5569d59c180f94c7eab66a22a251c
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
It is much more performant to have a overload of char instead of providing
a string all the time.
Change-Id: I1a4ed82bf056f6af0c1f91c236b3fc30afa7f5d8
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
We used only 6 bit to save the short size but for SmallString with a size
over 64 it is not enough. So we have now to use a uint16 instead of a
uint8 if the size if over 64.
Change-Id: I53558e492b6cb40b739b23a8af83d192a2e11bd2
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
You can now write
SmallString text = {"Oh ", women[4], " how much I miss you"};
if it can be casted to SmallStringView.
Change-Id: I86b69ee8d735017cac4391e7c4e68355eb5f227b
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
