1 // Copyright (c) 2009-2016 Vladimir Batov. 2 // Use, modification and distribution are subject to the Boost Software License, 3 // Version 1.0. See http://www.boost.org/LICENSE_1_0.txt. 4 5 #ifndef BOOST_CONVERT_PRINTF_HPP 6 #define BOOST_CONVERT_PRINTF_HPP 7 8 #include <boost/convert/base.hpp> 9 #include <boost/make_default.hpp> 10 #include <boost/mpl/vector.hpp> 11 #include <boost/mpl/find.hpp> 12 #include <boost/range/as_literal.hpp> 13 #include <string> 14 #include <cstdio> 15 16 namespace boost { namespace cnv 17 { 18 struct printf; 19 }} 20 21 struct boost::cnv::printf : boost::cnv::cnvbase<boost::cnv::printf> 22 { 23 using this_type = boost::cnv::printf; 24 using base_type = boost::cnv::cnvbase<this_type>; 25 26 using base_type::operator(); 27 28 template<typename in_type> 29 cnv::range<char*> to_strboost::cnv::printf30 to_str(in_type value_in, char* buf) const 31 { 32 char const* fmt = pformat(pos<in_type>()); 33 int const num_chars = snprintf(buf, bufsize_, fmt, precision_, value_in); 34 bool const success = num_chars < bufsize_; 35 36 return cnv::range<char*>(buf, success ? (buf + num_chars) : buf); 37 } 38 template<typename string_type, typename out_type> 39 void str_toboost::cnv::printf40 str_to(cnv::range<string_type> range, optional<out_type>& result_out) const 41 { 42 out_type result = boost::make_default<out_type>(); 43 int const num_read = sscanf(&*range.begin(), format(pos<out_type>()), &result); 44 45 if (num_read == 1) 46 result_out = result; 47 } 48 49 private: 50 posboost::cnv::printf51 template<typename Type> int pos() const 52 { 53 using managed_types = boost::mpl::vector<double, float, 54 int, unsigned int, 55 short int, unsigned short int, 56 long int, unsigned long int>; 57 using type_iterator = typename boost::mpl::find<managed_types, Type>::type; 58 using type_pos = typename type_iterator::pos; 59 60 return type_pos::value; 61 } 62 pformatboost::cnv::printf63 char const* pformat(int pos) const 64 { 65 static char const* d_fmt[] = { "%.*f", "%.*f", "%.*d", "%.*u", "%.*hd", "%.*hu", "%.*ld", "%.*lu" }; // Must match managed_types 66 static char const* x_fmt[] = { "%.*f", "%.*f", "%.*x", "%.*x", "%.*hx", "%.*hx", "%.*lx", "%.*lx" }; // Must match managed_types 67 static char const* o_fmt[] = { "%.*f", "%.*f", "%.*o", "%.*o", "%.*ho", "%.*ho", "%.*lo", "%.*lo" }; // Must match managed_types 68 char const* fmt = base_ == boost::cnv::base::dec ? d_fmt[pos] 69 : base_ == boost::cnv::base::hex ? x_fmt[pos] 70 : base_ == boost::cnv::base::oct ? o_fmt[pos] 71 : (BOOST_ASSERT(0), nullptr); 72 return fmt; 73 } formatboost::cnv::printf74 char const* format(int pos) const 75 { 76 static char const* d_fmt[] = { "%f", "%f", "%d", "%u", "%hd", "%hu", "%ld", "%lu" }; // Must match managed_types 77 static char const* x_fmt[] = { "%f", "%f", "%x", "%x", "%hx", "%hx", "%lx", "%lx" }; // Must match managed_types 78 static char const* o_fmt[] = { "%f", "%f", "%o", "%o", "%ho", "%ho", "%lo", "%lo" }; // Must match managed_types 79 char const* fmt = base_ == boost::cnv::base::dec ? d_fmt[pos] 80 : base_ == boost::cnv::base::hex ? x_fmt[pos] 81 : base_ == boost::cnv::base::oct ? o_fmt[pos] 82 : (BOOST_ASSERT(0), nullptr); 83 return fmt; 84 } 85 }; 86 87 #endif // BOOST_CONVERT_PRINTF_HPP 88