Start by creating a vector to hold a unique values of the input range. We
expect that in most cases, there will be relatively few duplicates, so
reserving enough memory for a complete copy is worthwhile. Unlike a solution
involving a std::set, this algorithm allocates all the memory it needs
in one go and in one place, so it is more cache friendly.
Populate the unique copy with a lower_bound insert algorithm and record the
indices of duplicates. This is the same complexity as the std::set insert
algorithm, but without the need to allocate memory on the heap and other
disadvantages of std::set.
Remove the duplicates with the cmRemoveIndices algorithm.
Implement ContainerAlgorithms::RemoveN to remove N elements to the
end of a container by rotating. The rotate is implemented in terms
of the efficient swap algorithm, optimized even more in the standard
library implementation when the compiler supports the rvalue-references
feature to move elements. Implement cmRemoveN with a Range API
for completeness.
std::rotate in C++11 is specified to return an iterator, but
c++98 specifies it to return void. libstdc++ 5.0 will be the first
version to have the correct return type. Implement
ContainerAlgorithms::Rotate in terms of std::rotate and return the
correct iterator from it. While std::rotate requires forward iterators,
this workaround means cmRotate requires bidirectional iterators. As
most of CMake uses random access iterators anyway, this should not
be a problem.
Implement cmRemoveIndices in terms of the RemoveN algorithm, such
that each element which is not removed is rotated only once. This
can not use the cmRemoveN range-API algorithm because that would
require creating a new range, but the range must be taken by reference
and so it can't be a temporary.
These remove algorithms are not part of the STL and I couldn't find them
anywhere else either.
Use a ostringstream to account for the input being a variable of type
size_t as a result of using std::distance. There is no single
format string which portably accepts a size_t.
b5f98e50 cmMacroCommand: Manipulate target string directly.
83414d5a cmMacroCommand: Move computation of ARGV%n names out of double loop.
9a1f8f35 cmMacroCommand: Move ARGV replacement out of condition.
4aa7bd2a cmMacroCommand: Remove condition around ARGN replacement.
6774c92b cmMacroCommand: Declare tmps in the scope that it's used.
2c4a7298 cmMacroCommand: Declare arg in the scope that it is used.
a551851a cmMacroCommand: Inline variable computation.
f79c0f76 cmMacroCommand: Compute variables outside of two loops.
8e0827b6 cmMacroCommand: Remove intermediate arg variables.
f2c49f59 cmMacroCommand: Remove condition around ARGN computation.
3250a7e5 cmMacroCommand: Remove conditional append of semicolon.
081a13f7 cmMacroCommand: Declare arg variables where used and initialized.
17b5ebd3 cmMacroCommand: Join the args strings outside of the loops.
7c3f6376 Convert loop into two algorithms.
8a399c8c Convert loop to the common pattern.
abfca975 Move loop inside of condition.
0b61b86d Handle last element outside of the loop.
e21f7829 cmTarget: Use a sorted vector in place of a set.
559dc155 cmSet: Replace loop with cmJoin.
0ea71932 cmFindBase: Replace loop with cmJoin on range.
9380e85f Convert loops to cmJoin algorithm with cmRange.
bb10012f cmStringCommand: Accumulate with cmJoin and range adaptors.
0c12f1ea cmAlgorithms: Add a range adaptor and API for adjusting a range.
27c6f017 Use cmJoin to accumulate string ranges.
4e78ebbd cmAlgorithms: Add a Range container and adaptor method.
89102249 Replace common loop pattern with cmJoin
7b8725bf Convert loops populating maybe-empty content into the common pattern.
7ee56f03 Convert loops into the commonly used pattern.
0a4e5674 cmMacroCommand: Remove counting variable.
...
f30022eb install: Allow generator expressions in TARGETS DESTINATION (#14317)
7607c3d1 cmInstallGenerator: Pass destination explicitly to AddInstallRule
ebd556ca cmInstallGenerator: Fix check for absolute install destinations
290ca8e2 cmInstallGenerator: Refactor computation of absolute install dest
f99991db cmInstallGenerator: Move GetDestination to subclasses that need it
It can make sense to declare objects outside of loops if
the size required by the object can grow (eg std::string when
using getline), but that is not the case here.
Avoid using the std::accumulate algorithm which is designed for
numeric types, not complex types. It introduces unneccessary
copies.
Initialize variables where they are populated.
This can make a pair of iterators API compatible with the
cmJoin algorithm and other range-based algorithms.
Accept different iterator types in the cmRange adaptor so that
a const and non-const iterator are accepted.
Stephen Kelly
Brad King
Kitware Robot
Gregor Jasny