90 lines
3.6 KiB
C++
90 lines
3.6 KiB
C++
// Copyright (c) 2009-2016 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 <boost/range/as_literal.hpp>
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#include <string>
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#include <cstdio>
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namespace boost { namespace cnv
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{
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struct printf;
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}}
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struct boost::cnv::printf : public boost::cnv::cnvbase<boost::cnv::printf>
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{
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typedef boost::cnv::printf this_type;
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typedef boost::cnv::cnvbase<this_type> base_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 const* fmt = pformat(pos<in_type>());
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int const num_chars = snprintf(buf, bufsize_, fmt, precision_, value_in);
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bool const 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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int const num_read = sscanf(&*range.begin(), format(pos<out_type>()), &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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typedef boost::mpl::vector<double, float,
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int, unsigned int,
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short int, unsigned short int,
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long int, unsigned long int
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> managed_types;
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typedef typename boost::mpl::find<managed_types, Type>::type type_iterator;
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typedef typename type_iterator::pos type_pos;
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return type_pos::value;
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}
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char const* pformat(int pos) const
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{
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static char const* d_format[] = { "%.*f", "%.*f", "%.*d", "%.*u", "%.*hd", "%.*hu", "%.*ld", "%.*lu" }; // Must match managed_types
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static char const* x_format[] = { "%.*f", "%.*f", "%.*x", "%.*x", "%.*hx", "%.*hx", "%.*lx", "%.*lx" }; // Must match managed_types
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static char const* o_format[] = { "%.*f", "%.*f", "%.*o", "%.*o", "%.*ho", "%.*ho", "%.*lo", "%.*lo" }; // Must match managed_types
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char const* format = base_ == 10 ? d_format[pos]
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: base_ == 16 ? x_format[pos]
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: base_ == 8 ? o_format[pos]
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: (BOOST_ASSERT(0), (char const*) 0);
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return format;
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}
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char const* format(int pos) const
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{
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static char const* d_format[] = { "%f", "%f", "%d", "%u", "%hd", "%hu", "%ld", "%lu" }; // Must match managed_types
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static char const* x_format[] = { "%f", "%f", "%x", "%x", "%hx", "%hx", "%lx", "%lx" }; // Must match managed_types
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static char const* o_format[] = { "%f", "%f", "%o", "%o", "%ho", "%ho", "%lo", "%lo" }; // Must match managed_types
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char const* format = base_ == 10 ? d_format[pos]
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: base_ == 16 ? x_format[pos]
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: base_ == 8 ? o_format[pos]
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: (BOOST_ASSERT(0), (char const*) 0);
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return format;
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}
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};
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#endif // BOOST_CONVERT_PRINTF_HPP
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