// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___FORMAT_FORMATTER_OUTPUT_H
#define _LIBCPP___FORMAT_FORMATTER_OUTPUT_H
#include <__algorithm/copy.h>
#include <__algorithm/copy_n.h>
#include <__algorithm/fill_n.h>
#include <__algorithm/transform.h>
#include <__config>
#include <__format/formatter.h>
#include <__format/parser_std_format_spec.h>
#include <__utility/move.h>
#include <__utility/unreachable.h>
#include <cstddef>
#include <string>
#include <string_view>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
namespace __formatter {
_LIBCPP_HIDE_FROM_ABI constexpr char __hex_to_upper(char __c) {
switch (__c) {
case 'a':
return 'A';
case 'b':
return 'B';
case 'c':
return 'C';
case 'd':
return 'D';
case 'e':
return 'E';
case 'f':
return 'F';
}
return __c;
}
struct _LIBCPP_TYPE_VIS __padding_size_result {
size_t __before_;
size_t __after_;
};
_LIBCPP_HIDE_FROM_ABI constexpr __padding_size_result
__padding_size(size_t __size, size_t __width, __format_spec::__alignment __align) {
_LIBCPP_ASSERT(__width > __size, "don't call this function when no padding is required");
_LIBCPP_ASSERT(__align != __format_spec::__alignment::__zero_padding,
"the caller should have handled the zero-padding");
size_t __fill = __width - __size;
switch (__align) {
case __format_spec::__alignment::__zero_padding:
__libcpp_unreachable();
case __format_spec::__alignment::__left:
return {0, __fill};
case __format_spec::__alignment::__center: {
// The extra padding is divided per [format.string.std]/3
// __before = floor(__fill, 2);
// __after = ceil(__fill, 2);
size_t __before = __fill / 2;
size_t __after = __fill - __before;
return {__before, __after};
}
case __format_spec::__alignment::__default:
case __format_spec::__alignment::__right:
return {__fill, 0};
}
__libcpp_unreachable();
}
template <class _OutIt, class _CharT>
_LIBCPP_HIDE_FROM_ABI _OutIt __write_using_decimal_separators(_OutIt __out_it, const char* __begin, const char* __first,
const char* __last, string&& __grouping, _CharT __sep,
__format_spec::__parsed_specifications<_CharT> __specs) {
int __size = (__first - __begin) + // [sign][prefix]
(__last - __first) + // data
(__grouping.size() - 1); // number of separator characters
__padding_size_result __padding = {0, 0};
if (__specs.__alignment_ == __format_spec::__alignment::__zero_padding) {
// Write [sign][prefix].
__out_it = _VSTD::copy(__begin, __first, _VSTD::move(__out_it));
if (__specs.__width_ > __size) {
// Write zero padding.
__padding.__before_ = __specs.__width_ - __size;
__out_it = _VSTD::fill_n(_VSTD::move(__out_it), __specs.__width_ - __size, _CharT('0'));
}
} else {
if (__specs.__width_ > __size) {
// Determine padding and write padding.
__padding = __padding_size(__size, __specs.__width_, __specs.__alignment_);
__out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_);
}
// Write [sign][prefix].
__out_it = _VSTD::copy(__begin, __first, _VSTD::move(__out_it));
}
auto __r = __grouping.rbegin();
auto __e = __grouping.rend() - 1;
_LIBCPP_ASSERT(__r != __e, "The slow grouping formatting is used while "
"there will be no separators written.");
// The output is divided in small groups of numbers to write:
// - A group before the first separator.
// - A separator and a group, repeated for the number of separators.
// - A group after the last separator.
// This loop achieves that process by testing the termination condition
// midway in the loop.
//
// TODO FMT This loop evaluates the loop invariant `__parser.__type !=
// _Flags::_Type::__hexadecimal_upper_case` for every iteration. (This test
// happens in the __write call.) Benchmark whether making two loops and
// hoisting the invariant is worth the effort.
while (true) {
if (__specs.__std_.__type_ == __format_spec::__type::__hexadecimal_upper_case) {
__last = __first + *__r;
__out_it = _VSTD::transform(__first, __last, _VSTD::move(__out_it), __hex_to_upper);
__first = __last;
} else {
__out_it = _VSTD::copy_n(__first, *__r, _VSTD::move(__out_it));
__first += *__r;
}
if (__r == __e)
break;
++__r;
*__out_it++ = __sep;
}
return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_);
}
/// Writes the input to the output with the required padding.
///
/// Since the output column width is specified the function can be used for
/// ASCII and Unicode output.
///
/// \pre [\a __first, \a __last) is a valid range.
/// \pre \a __size <= \a __width. Using this function when this pre-condition
/// doesn't hold incurs an unwanted overhead.
///
/// \param __first Pointer to the first element to write.
/// \param __last Pointer beyond the last element to write.
/// \param __out_it The output iterator to write to.
/// \param __specs The parsed formatting specifications.
/// \param __size The (estimated) output column width. When the elements
/// to be written are ASCII the following condition holds
/// \a __size == \a __last - \a __first.
///
/// \returns An iterator pointing beyond the last element written.
///
/// \note The type of the elements in range [\a __first, \a __last) can differ
/// from the type of \a __specs. Integer output uses \c std::to_chars for its
/// conversion, which means the [\a __first, \a __last) always contains elements
/// of the type \c char.
template <class _CharT, class _ParserCharT>
_LIBCPP_HIDE_FROM_ABI auto __write(const _CharT* __first, const _CharT* __last,
output_iterator<const _CharT&> auto __out_it,
__format_spec::__parsed_specifications<_ParserCharT> __specs, ptrdiff_t __size)
-> decltype(__out_it) {
_LIBCPP_ASSERT(__first <= __last, "Not a valid range");
if (__size >= __specs.__width_)
return _VSTD::copy(__first, __last, _VSTD::move(__out_it));
__padding_size_result __padding = __formatter::__padding_size(__size, __specs.__width_, __specs.__std_.__alignment_);
__out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_);
__out_it = _VSTD::copy(__first, __last, _VSTD::move(__out_it));
return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_);
}
/// \overload
/// Calls the function above where \a __size = \a __last - \a __first.
template <class _CharT, class _ParserCharT>
_LIBCPP_HIDE_FROM_ABI auto __write(const _CharT* __first, const _CharT* __last,
output_iterator<const _CharT&> auto __out_it,
__format_spec::__parsed_specifications<_ParserCharT> __specs) -> decltype(__out_it) {
return __write(__first, __last, _VSTD::move(__out_it), __specs, __last - __first);
}
template <class _CharT, class _ParserCharT, class _UnaryOperation>
_LIBCPP_HIDE_FROM_ABI auto __write_transformed(const _CharT* __first, const _CharT* __last,
output_iterator<const _CharT&> auto __out_it,
__format_spec::__parsed_specifications<_ParserCharT> __specs,
_UnaryOperation __op) -> decltype(__out_it) {
_LIBCPP_ASSERT(__first <= __last, "Not a valid range");
ptrdiff_t __size = __last - __first;
if (__size >= __specs.__width_)
return _VSTD::transform(__first, __last, _VSTD::move(__out_it), __op);
__padding_size_result __padding = __padding_size(__size, __specs.__width_, __specs.__alignment_);
__out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_);
__out_it = _VSTD::transform(__first, __last, _VSTD::move(__out_it), __op);
return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_);
}
/// Writes additional zero's for the precision before the exponent.
/// This is used when the precision requested in the format string is larger
/// than the maximum precision of the floating-point type. These precision
/// digits are always 0.
///
/// \param __exponent The location of the exponent character.
/// \param __num_trailing_zeros The number of 0's to write before the exponent
/// character.
template <class _CharT, class _ParserCharT>
_LIBCPP_HIDE_FROM_ABI auto __write_using_trailing_zeros(
const _CharT* __first,
const _CharT* __last,
output_iterator<const _CharT&> auto __out_it,
__format_spec::__parsed_specifications<_ParserCharT> __specs,
size_t __size,
const _CharT* __exponent,
size_t __num_trailing_zeros) -> decltype(__out_it) {
_LIBCPP_ASSERT(__first <= __last, "Not a valid range");
_LIBCPP_ASSERT(__num_trailing_zeros > 0, "The overload not writing trailing zeros should have been used");
__padding_size_result __padding =
__padding_size(__size + __num_trailing_zeros, __specs.__width_, __specs.__alignment_);
__out_it = _VSTD::fill_n(_VSTD::move(__out_it), __padding.__before_, __specs.__fill_);
__out_it = _VSTD::copy(__first, __exponent, _VSTD::move(__out_it));
__out_it = _VSTD::fill_n(_VSTD::move(__out_it), __num_trailing_zeros, _CharT('0'));
__out_it = _VSTD::copy(__exponent, __last, _VSTD::move(__out_it));
return _VSTD::fill_n(_VSTD::move(__out_it), __padding.__after_, __specs.__fill_);
}
# ifndef _LIBCPP_HAS_NO_UNICODE
template <class _CharT>
_LIBCPP_HIDE_FROM_ABI auto __write_unicode_no_precision(basic_string_view<_CharT> __str,
output_iterator<const _CharT&> auto __out_it,
__format_spec::__parsed_specifications<_CharT> __specs)
-> decltype(__out_it) {
_LIBCPP_ASSERT(!__specs.__has_precision(), "use __write_unicode");
// No padding -> copy the string
if (!__specs.__has_width())
return _VSTD::copy(__str.begin(), __str.end(), _VSTD::move(__out_it));
// Non Unicode part larger than width -> copy the string
auto __last = __format_spec::__detail::__estimate_column_width_fast(__str.begin(), __str.end());
ptrdiff_t __size = __last - __str.begin();
if (__size >= __specs.__width_)
return _VSTD::copy(__str.begin(), __str.end(), _VSTD::move(__out_it));
// Is there a non Unicode part?
if (__last != __str.end()) {
// Non Unicode and Unicode part larger than width -> copy the string
__format_spec::__detail::__column_width_result __column_width =
__format_spec::__detail::__estimate_column_width(__last, __str.end(), __specs.__width_);
__size += __column_width.__width; // Note this new size is used when __size < __specs.__width_
if (__size >= __specs.__width_)
return _VSTD::copy(__str.begin(), __str.end(), _VSTD::move(__out_it));
}
return __formatter::__write(__str.begin(), __str.end(), _VSTD::move(__out_it), __specs, __size);
}
# endif
template <class _CharT>
_LIBCPP_HIDE_FROM_ABI auto __write_unicode(basic_string_view<_CharT> __str,
output_iterator<const _CharT&> auto __out_it,
__format_spec::__parsed_specifications<_CharT> __specs)
-> decltype(__out_it) {
# ifndef _LIBCPP_HAS_NO_UNICODE
if (!__specs.__has_precision())
return __formatter::__write_unicode_no_precision(__str, _VSTD::move(__out_it), __specs);
// Non unicode part larger than precision -> truncate the output and use the normal write operation.
auto __last = __format_spec::__detail::__estimate_column_width_fast(__str.begin(), __str.end());
ptrdiff_t __size = __last - __str.begin();
if (__size >= __specs.__precision_)
return __formatter::__write(__str.begin(), __str.begin() + __specs.__precision_, _VSTD::move(__out_it), __specs,
__specs.__precision_);
// No non Unicode part, implies __size < __specs.__precision_ -> use normal write operation
if (__last == __str.end())
return __formatter::__write(__str.begin(), __str.end(), _VSTD::move(__out_it), __specs, __str.size());
__format_spec::__detail::__column_width_result __column_width =
__format_spec::__detail::__estimate_column_width(__last, __str.end(), __specs.__precision_ - __size);
__size += __column_width.__width;
// Truncate the output
if (__column_width.__ptr != __str.end())
__str.remove_suffix(__str.end() - __column_width.__ptr);
return __formatter::__write(__str.begin(), __str.end(), _VSTD::move(__out_it), __specs, __size);
# else
if (__specs.__has_precision()) {
ptrdiff_t __size = __str.size();
if (__size > __specs.__precision_)
return __formatter::__write(__str.begin(), __str.begin() + __specs.__precision_, _VSTD::move(__out_it), __specs,
__specs.__precision_);
}
return __formatter::__write(__str.begin(), __str.end(), _VSTD::move(__out_it), __specs, __str.size());
# endif
}
} // namespace __formatter
#endif //_LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FORMAT_FORMATTER_OUTPUT_H
