113 lines
4.5 KiB
C++
113 lines
4.5 KiB
C++
// Copyright (c) 2009-2020 Vladimir Batov.
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// Use, modification and distribution are subject to the Boost Software License,
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// Version 1.0. See http://www.boost.org/LICENSE_1_0.txt.
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#ifndef BOOST_CONVERT_PRINTF_HPP
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#define BOOST_CONVERT_PRINTF_HPP
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#include <boost/convert/base.hpp>
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#include <boost/make_default.hpp>
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#include <boost/mpl/vector.hpp>
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#include <boost/mpl/find.hpp>
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#include <string>
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#include <cstdio>
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namespace boost::cnv { struct printf; }
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struct boost::cnv::printf : boost::cnv::cnvbase<boost::cnv::printf>
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{
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using this_type = boost::cnv::printf;
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using base_type = boost::cnv::cnvbase<this_type>;
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using base_type::operator();
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template<typename in_type>
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cnv::range<char*>
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to_str(in_type value_in, char* buf) const
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{
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char_cptr fmt = printf_format(pos<in_type>());
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int num_chars = snprintf(buf, bufsize_, fmt, precision_, value_in);
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bool success = num_chars < bufsize_;
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return cnv::range<char*>(buf, success ? (buf + num_chars) : buf);
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}
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template<typename string_type, typename out_type>
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void
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str_to(cnv::range<string_type> range, optional<out_type>& result_out) const
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{
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out_type result = boost::make_default<out_type>();
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char_cptr fmt = sscanf_format(pos<out_type>());
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int num_read = sscanf(&*range.begin(), fmt, &result);
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if (num_read == 1)
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result_out = result;
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}
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private:
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template<typename Type> int pos() const
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{
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// C1. The orders of types and formats must match.
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using types = boost::mpl::vector<
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double, float, int, unsigned int, short int,
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unsigned short int, long int, unsigned long int>;
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using found = typename boost::mpl::find<types, Type>::type;
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using pos = typename found::pos;
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return pos::value;
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}
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char_cptr printf_format(int type_pos) const
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{
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char_cptr BOOST_CONSTEXPR_OR_CONST d_fmt[3][8] =
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{
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{ "%.*f", "%.*f", "%.*d", "%.*u", "%.*hd", "%.*hu", "%.*ld", "%.*lu" }, //C1. fxd
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{ "%.*e", "%.*e", "%.*d", "%.*u", "%.*hd", "%.*hu", "%.*ld", "%.*lu" }, //C1. sci
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{ "%.*a", "%.*a", "%.*d", "%.*u", "%.*hd", "%.*hu", "%.*ld", "%.*lu" } //C1. hex
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};
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char_cptr BOOST_CONSTEXPR_OR_CONST x_fmt[3][8] =
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{
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{ "%.*f", "%.*f", "%.*x", "%.*x", "%.*hx", "%.*hx", "%.*lx", "%.*lx" }, //C1. fxd
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{ "%.*e", "%.*e", "%.*x", "%.*x", "%.*hx", "%.*hx", "%.*lx", "%.*lx" }, //C1. sci
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{ "%.*a", "%.*a", "%.*x", "%.*x", "%.*hx", "%.*hx", "%.*lx", "%.*lx" } //C1. hex
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};
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char_cptr BOOST_CONSTEXPR_OR_CONST o_fmt[3][8] =
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{
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{ "%.*f", "%.*f", "%.*o", "%.*o", "%.*ho", "%.*ho", "%.*lo", "%.*lo" }, //C1. fxd
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{ "%.*e", "%.*e", "%.*o", "%.*o", "%.*ho", "%.*ho", "%.*lo", "%.*lo" }, //C1. sci
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{ "%.*a", "%.*a", "%.*o", "%.*o", "%.*ho", "%.*ho", "%.*lo", "%.*lo" } //C1. hex
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};
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return base_ == base::dec ? d_fmt[int(notation_)][type_pos]
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: base_ == base::hex ? x_fmt[int(notation_)][type_pos]
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: base_ == base::oct ? o_fmt[int(notation_)][type_pos]
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: (BOOST_ASSERT(0), nullptr);
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}
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char_cptr sscanf_format(int type_pos) const
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{
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char_cptr BOOST_CONSTEXPR_OR_CONST d_fmt[3][8] =
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{
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{ "%lf", "%f", "%d", "%u", "%hd", "%hu", "%ld", "%lu" }, //C1. fxd
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{ "%le", "%e", "%d", "%u", "%hd", "%hu", "%ld", "%lu" }, //C1. sci
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{ "%la", "%a", "%d", "%u", "%hd", "%hu", "%ld", "%lu" } //C1. hex
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};
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char_cptr BOOST_CONSTEXPR_OR_CONST x_fmt[3][8] =
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{
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{ "%lf", "%f", "%x", "%x", "%hx", "%hx", "%lx", "%lx" }, //C1. fxd
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{ "%le", "%e", "%x", "%x", "%hx", "%hx", "%lx", "%lx" }, //C1. sci
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{ "%la", "%a", "%x", "%x", "%hx", "%hx", "%lx", "%lx" } //C1. hex
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};
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char_cptr BOOST_CONSTEXPR_OR_CONST o_fmt[3][8] =
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{
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{ "%lf", "%f", "%o", "%o", "%ho", "%ho", "%lo", "%lo" }, //C1. fxd
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{ "%le", "%e", "%o", "%o", "%ho", "%ho", "%lo", "%lo" }, //C1. sci
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{ "%la", "%a", "%o", "%o", "%ho", "%ho", "%lo", "%lo" } //C1. hex
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};
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return base_ == base::dec ? d_fmt[int(notation_)][type_pos]
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: base_ == base::hex ? x_fmt[int(notation_)][type_pos]
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: base_ == base::oct ? o_fmt[int(notation_)][type_pos]
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: (BOOST_ASSERT(0), nullptr);
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}
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};
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#endif // BOOST_CONVERT_PRINTF_HPP
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