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This new implementation has a smaller footprint than the previous implementation, due to replacing std::vector<_Cmpt> with a custom pimpl type that only needs a single pointer. The _M_type enumeration is also combined with the pimpl type, by using a tagged pointer, reducing sizeof(path) further still. Construction and modification of paths is now done more efficiently, by splitting the input into a stack-based buffer of string_view objects instead of a dynamically-allocated vector containing strings. Once the final size is known only a single allocation is needed to reserve space for it. The append and concat operations no longer require constructing temporary path objects, nor re-parsing the entire native pathname. This results in algorithmic improvements to path construction, and working with large paths is much faster. PR libstdc++/71044 * include/bits/fs_path.h (path::path(path&&)): Add noexcept when appropriate. Move _M_cmpts instead of reparsing the native pathname. (path::operator=(const path&)): Do not define as defaulted. (path::operator/=, path::append): Call _M_append. (path::concat): Call _M_concat. (path::path(string_type, _Type): Change type of first parameter to basic_string_view<value_type>. (path::_M_append(basic_string_view<value_type>)): New member function. (path::_M_concat(basic_string_view<value_type>)): New member function. (_S_convert(value_type*, __null_terminated)): Return string view. (_S_convert(const value_type*, __null_terminated)): Return string view. (_S_convert(value_type*, value_type*)) (_S_convert(const value_type*, const value_type*)): Add overloads for pairs of pointers. (_S_convert(_InputIterator, __null_terminated)): Construct string_type explicitly, for cases where _S_convert returns a string view. (path::_S_is_dir_sep): Replace with non-member is_dir_sep. (path::_M_trim, path::_M_add_root_name, path::_M_add_root_dir) (path::_M_add_filename): Remove. (path::_M_type()): New member function to replace _M_type data member. (path::_List): Define new struct type instead of using std::vector. (path::_Cmpt::_Cmpt(string_type, _Type, size_t)): Change type of first parameter to basic_string_view<value_type>. (path::operator+=(const path&)): Do not define inline. (path::operator+=(const string_type&)): Call _M_concat. (path::operator+=(const value_type*)): Likewise. (path::operator+=(value_type)): Likewise. (path::operator+=(basic_string_view<value_type>)): Likewise. (path::operator/=(const path&)): Do not define inline. (path::_M_append(path)): Remove. * python/libstdcxx/v6/printers.py (StdPathPrinter): New printer that understands the new path::_List type. * src/filesystem/std-path.cc (is_dir_sep): New function to replace path::_S_is_dir_sep. (path::_Parser): New helper class to parse strings as paths. (path::_List::_Impl): Define container type for path components. (path::_List): Define members. (path::operator=(const path&)): Define explicitly, to provide the strong exception safety guarantee. (path::operator/=(const path&)): Implement manually by processing each component of the argument, rather than using _M_split_cmpts to parse the entire string again. (path::_M_append(string_type)): Likewise. (path::operator+=(const path&)): Likewise. (path::_M_concat(string_type)): Likewise. (path::remove_filename()): Perform trim directly instead of calling _M_trim(). (path::_M_split_cmpts()): Rewrite in terms of _Parser class. (path::_M_trim, path::_M_add_root_name, path::_M_add_root_dir) (path::_M_add_filename): Remove. * testsuite/27_io/filesystem/path/append/source.cc: Test appending a string view that aliases the path. testsuite/27_io/filesystem/path/concat/strings.cc: Test concatenating a string view that aliases the path. From-SVN: r267106 |
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| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| intl | ||
| libada | ||
| libatomic | ||
| libbacktrace | ||
| libcc1 | ||
| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgo | ||
| libgomp | ||
| libhsail-rt | ||
| libiberty | ||
| libitm | ||
| libobjc | ||
| liboffloadmic | ||
| libphobos | ||
| libquadmath | ||
| libsanitizer | ||
| libssp | ||
| libstdc++-v3 | ||
| libvtv | ||
| lto-plugin | ||
| maintainer-scripts | ||
| zlib | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| ABOUT-NLS | ||
| ar-lib | ||
| ChangeLog | ||
| ChangeLog.jit | ||
| ChangeLog.tree-ssa | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| COPYING.LIB | ||
| COPYING.RUNTIME | ||
| depcomp | ||
| install-sh | ||
| libtool-ldflags | ||
| libtool.m4 | ||
| lt~obsolete.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| multilib.am | ||
| README | ||
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| test-driver | ||
| ylwrap | ||
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