mirror of git://gcc.gnu.org/git/gcc.git
libstdc++: Implement _Escaping_sink to avoid construction of string
This patch implements _Escaping_sink that stores characters in a local (stack) buffer. When the buffer is full, the range of characters is escaped and written to the underlying sink. To support above, the __write_escaped_unicode_part function are defined. It takes __str and __prev_esc by reference. The __prev_esc value is updated based on the last character written. If the buffer ends with an incomplete code point sequence, __str is left non-empty and last code points are not written. _Escaping_sink then copies these characters to the front of the buffer to reconstruct the full code point. __formatter__str::_M_format_range now uses _Escaping_sink to escape any non-continuous character sequences. libstdc++-v3/ChangeLog: * include/std/format (__format::__write_escape_seqs) (__format::_Escaping_sink): Define. (__format::__write_escaped_unicode_part): Extract from __format::__write_escaped_unicode. (__format::__write_escaped_unicode): Forward to __write_escaped_unicode_part. (__formatter_str::_M_format_range): Use _Escaping sink. * testsuite/std/format/ranges/string.cc: New tests for character which codepoints will be split in buffer and escaping. Invoked test_padding. Reviewed-by: Patrick Palka <ppalka@redhat.com> Reviewed-by: Jonathan Wakely <jwakely@redhat.com> Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>
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@ -105,6 +105,7 @@ namespace __format
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template<typename _CharT> class _Sink;
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template<typename _CharT> class _Fixedbuf_sink;
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template<typename _Out, typename _CharT> class _Padding_sink;
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template<typename _Out, typename _CharT> class _Escaping_sink;
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// Output iterator that writes to a type-erase character sink.
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template<typename _CharT>
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@ -1066,6 +1067,17 @@ namespace __format
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return ++__out;
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}
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template<typename _Out, typename _CharT>
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_Out
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__write_escape_seqs(_Out __out, basic_string_view<_CharT> __units)
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{
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using _UChar = make_unsigned_t<_CharT>;
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for (_CharT __c : __units)
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__out = __format::__write_escape_seq(
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__out, static_cast<_UChar>(__c), _Escapes<_CharT>::_S_x());
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return __out;
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}
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template<typename _Out, typename _CharT>
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_Out
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__write_escaped_char(_Out __out, _CharT __c)
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@ -1124,12 +1136,10 @@ namespace __format
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template<typename _CharT, typename _Out>
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_Out
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__write_escaped_unicode(_Out __out,
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basic_string_view<_CharT> __str,
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_Term_char __term)
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__write_escaped_unicode_part(_Out __out, basic_string_view<_CharT>& __str,
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bool& __prev_esc, _Term_char __term)
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{
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using _Str_view = basic_string_view<_CharT>;
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using _UChar = make_unsigned_t<_CharT>;
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using _Esc = _Escapes<_CharT>;
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static constexpr char32_t __replace = U'\uFFFD';
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@ -1143,10 +1153,10 @@ namespace __format
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}();
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__unicode::_Utf_view<char32_t, _Str_view> __v(std::move(__str));
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__str = {};
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auto __first = __v.begin();
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auto const __last = __v.end();
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bool __prev_esc = true;
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while (__first != __last)
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{
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bool __esc_ascii = false;
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@ -1185,15 +1195,32 @@ namespace __format
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__out = __format::__write_escaped_char(__out, *__first.base());
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else if (__esc_unicode)
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__out = __format::__write_escape_seq(__out, *__first, _Esc::_S_u());
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else // __esc_replace
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for (_CharT __c : _Str_view(__first.base(), __first._M_units()))
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__out = __format::__write_escape_seq(__out,
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static_cast<_UChar>(__c),
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_Esc::_S_x());
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// __esc_replace
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else if (_Str_view __units(__first.base(), __first._M_units());
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__units.end() != __last.base())
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__out = __format::__write_escape_seqs(__out, __units);
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else
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{
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__str = __units;
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return __out;
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}
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__prev_esc = true;
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++__first;
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}
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return __out;
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}
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template<typename _CharT, typename _Out>
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_Out
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__write_escaped_unicode(_Out __out, basic_string_view<_CharT> __str,
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_Term_char __term)
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{
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bool __prev_escape = true;
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__out = __format::__write_escaped_unicode_part(__out, __str,
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__prev_escape, __term);
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__out = __format::__write_escape_seqs(__out, __str);
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return __out;
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}
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@ -1412,55 +1439,28 @@ namespace __format
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size_t(ranges::distance(__rg)));
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return format(__str, __fc);
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}
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else if (!_M_spec._M_debug)
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else
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{
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auto __handle_debug = [this, &__rg]<typename _NOut>(_NOut __nout)
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{
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if (!_M_spec._M_debug)
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return ranges::copy(__rg, std::move(__nout)).out;
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_Escaping_sink<_NOut, _CharT>
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__sink(std::move(__nout), _Term_quote);
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ranges::copy(__rg, __sink.out());
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return __sink._M_finish();
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};
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const size_t __padwidth = _M_spec._M_get_width(__fc);
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if (__padwidth == 0 && _M_spec._M_prec_kind == _WP_none)
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return ranges::copy(__rg, __fc.out()).out;
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return __handle_debug(__fc.out());
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_Padding_sink<_Out, _CharT> __sink(__fc.out(), __padwidth,
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_M_spec._M_get_precision(__fc));
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ranges::copy(__rg, __sink.out());
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_Padding_sink<_Out, _CharT>
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__sink(__fc.out(), __padwidth, _M_spec._M_get_precision(__fc));
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__handle_debug(__sink.out());
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return __sink._M_finish(_M_spec._M_align, _M_spec._M_fill);
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}
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else if constexpr (ranges::forward_range<_Rg> || ranges::sized_range<_Rg>)
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{
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const size_t __n(ranges::distance(__rg));
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size_t __w = __n;
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if constexpr (!__unicode::__literal_encoding_is_unicode<_CharT>())
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if (size_t __max = _M_spec._M_get_precision(__fc); __n > __max)
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__w == __max;
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if (__w <= __format::__stackbuf_size<_CharT>)
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{
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_CharT __buf[__format::__stackbuf_size<_CharT>];
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ranges::copy_n(ranges::begin(__rg), __w, __buf);
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return _M_format_escaped(_String_view(__buf, __n), __fc);
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}
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else if constexpr (ranges::random_access_range<_Rg>)
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{
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ranges::iterator_t<_Rg> __first = ranges::begin(__rg);
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ranges::subrange __sub(__first, ranges::next(__first, __w));
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return _M_format_escaped(_String(from_range, __sub), __fc);
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}
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else if (__w <= __n)
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{
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ranges::subrange __sub(
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counted_iterator(ranges::begin(__rg), __w),
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default_sentinel);
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return _M_format_escaped(_String(from_range, __sub), __fc);
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}
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else if constexpr (ranges::sized_range<_Rg>)
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return _M_format_escaped(_String(from_range, __rg), __fc);
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else
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{
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// N.B. preserve the computed size
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ranges::subrange __sub(__rg, __n);
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return _M_format_escaped(_String(from_range, __sub), __fc);
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}
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}
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else
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return _M_format_escaped(_String(from_range, __rg), __fc);
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}
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constexpr void
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@ -3997,6 +3997,93 @@ namespace __format
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}
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};
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template<typename _Out, typename _CharT>
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class _Escaping_sink : public _Buf_sink<_CharT>
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{
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using _Esc = _Escapes<_CharT>;
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_Out _M_out;
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_Term_char _M_term : 2;
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unsigned _M_prev_escape : 1;
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unsigned _M_out_discards : 1;
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void
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_M_sync_discarding()
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{
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if constexpr (is_same_v<_Out, _Sink_iter<_CharT>>)
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_M_out_discards = _M_out._M_discarding();
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}
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void
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_M_write()
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{
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span<_CharT> __bytes = this->_M_used();
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basic_string_view<_CharT> __str(__bytes.data(), __bytes.size());
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size_t __rem = 0;
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if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
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{
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bool __prev_escape = _M_prev_escape;
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_M_out = __format::__write_escaped_unicode_part(
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std::move(_M_out), __str, __prev_escape, _M_term);
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_M_prev_escape = __prev_escape;
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__rem = __str.size();
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if (__rem > 0 && __str.data() != this->_M_buf) [[unlikely]]
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ranges::move(__str, this->_M_buf);
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}
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else
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_M_out = __format::__write_escaped_ascii(
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std::move(_M_out), __str, _M_term);
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this->_M_reset(this->_M_buf, __rem);
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_M_sync_discarding();
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}
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void
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_M_overflow() override
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{
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if (_M_out_discards)
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this->_M_rewind();
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else
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_M_write();
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}
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bool
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_M_discarding() const override
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{ return _M_out_discards; }
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public:
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[[__gnu__::__always_inline__]]
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explicit
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_Escaping_sink(_Out __out, _Term_char __term)
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: _M_out(std::move(__out)), _M_term(__term),
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_M_prev_escape(true), _M_out_discards(false)
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{
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_M_out = __format::__write(std::move(_M_out), _Esc::_S_term(_M_term));
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_M_sync_discarding();
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}
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_Out
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_M_finish()
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{
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if (_M_out_discards)
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return std::move(_M_out);
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if (!this->_M_used().empty())
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{
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_M_write();
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if constexpr (__unicode::__literal_encoding_is_unicode<_CharT>())
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if (auto __rem = this->_M_used(); !__rem.empty())
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{
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basic_string_view<_CharT> __str(__rem.data(), __rem.size());
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_M_out = __format::__write_escape_seqs(std::move(_M_out), __str);
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}
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}
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return __format::__write(std::move(_M_out), _Esc::_S_term(_M_term));
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}
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};
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enum class _Arg_t : unsigned char {
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_Arg_none, _Arg_bool, _Arg_c, _Arg_i, _Arg_u, _Arg_ll, _Arg_ull,
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_Arg_flt, _Arg_dbl, _Arg_ldbl, _Arg_str, _Arg_sv, _Arg_ptr, _Arg_handle,
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@ -279,6 +279,93 @@ void test_padding()
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VERIFY( strip_prefix(resv, 46, '*') );
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VERIFY( strip_quotes(resv) );
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VERIFY( resv == in );
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// width is 5, size is 15
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in = "\u2160\u2161\u2162\u2163\u2164";
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in += in; // width is 10, size is 30
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in += in; // width is 20, size is 60
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in += in; // width is 40, size is 120
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in += in; // width is 80, size is 240
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in += in; // width is 160, size is 480
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lc.assign_range(in);
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resv = res = std::format("{:s}", lc);
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VERIFY( resv == in );
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resv = res = std::format("{:*>10s}", lc);
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VERIFY( resv == in );
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resv = res = std::format("{:*>200s}", lc);
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VERIFY( strip_prefix(resv, 40, '*') );
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VERIFY( resv == in );
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resv = res = std::format("{:?s}", lc);
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VERIFY( strip_quotes(resv) );
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VERIFY( resv == in );
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resv = res = std::format("{:*>10?s}", lc);
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VERIFY( strip_quotes(resv) );
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VERIFY( resv == in );
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resv = res = std::format("{:*>200?s}", lc);
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VERIFY( strip_prefix(resv, 38, '*') );
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VERIFY( strip_quotes(resv) );
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VERIFY( resv == in );
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}
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void test_escaping()
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{
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std::string res;
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std::string_view resv;
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const std::string_view input =
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"\t\n\r\\\""
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"\u008a" // Cc, Control, Line Tabulation Set,
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"\u00ad" // Cf, Format, Soft Hyphen
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"\u1d3d" // Lm, Modifier letter, Modifier Letter Capital Ou
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"\u00a0" // Zs, Space Separator, No-Break Space (NBSP)
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"\u2029" // Zp, Paragraph Separator, Paragraph Separator
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"\U0001f984" // So, Other Symbol, Unicorn Face
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;
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const std::string_view output =
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R"(\t\n\r\\\")"
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R"(\u{8a})"
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R"(\u{ad})"
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"\u1d3d"
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R"(\u{a0})"
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R"(\u{2029})"
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"\U0001f984";
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std::forward_list<char> lc(std::from_range, input);
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resv = res = std::format("{:s}", lc);
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VERIFY( resv == input );
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resv = res = std::format("{:?s}", lc);
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VERIFY( strip_quotes(resv) );
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VERIFY( resv == output );
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// width is 5, size is 15
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std::string in = "\u2160\u2161\u2162\u2163\u2164";
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in += in; // width is 10, size is 30
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in += in; // width is 20, size is 60
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in += in; // width is 40, size is 120
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in += in; // width is 80, size is 240
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in += in; // width is 160, size is 480
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std::string_view inv = in;
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// last charcter is incomplete
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lc.assign_range(inv.substr(0, 479));
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// non-debug format, chars copied as is
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resv = res = std::format("{:s}", lc);
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VERIFY( resv == inv.substr(0, 479) );
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// debug-format, incomplete code-point sequence is esaped
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resv = res = std::format("{:?s}", lc);
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VERIFY( strip_quotes(resv) );
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VERIFY( resv.substr(0, 477) == inv.substr(0, 477) );
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resv.remove_prefix(477);
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VERIFY( resv == R"(\x{e2}\x{85})" );
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}
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int main()
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@ -287,4 +374,6 @@ int main()
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test_outputs<char>();
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test_outputs<wchar_t>();
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test_nested();
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test_padding();
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test_escaping();
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}
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