.. _program_listing_file_cif++_format.hpp:

Program Listing for File format.hpp
===================================

|exhale_lsh| :ref:`Return to documentation for file <file_cif++_format.hpp>` (``cif++/format.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   /*-
    * SPDX-License-Identifier: BSD-2-Clause
    *
    * Copyright (c) 2022 NKI/AVL, Netherlands Cancer Institute
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions are met:
    *
    * 1. Redistributions of source code must retain the above copyright notice, this
    *    list of conditions and the following disclaimer
    * 2. Redistributions in binary form must reproduce the above copyright notice,
    *    this list of conditions and the following disclaimer in the documentation
    *    and/or other materials provided with the distribution.
    *
    * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
    * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
    * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
    * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
    * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
    * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
    * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
    * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    */
   
   #pragma once
   
   #include <string>
   
   namespace cif
   {
   
   namespace detail
   {
       template <typename T>
       struct to_varg
       {
           using type = T;
   
           to_varg(const T &v)
               : m_value(v)
           {
           }
   
           type operator*() { return m_value; }
   
           T m_value;
       };
   
       template <>
       struct to_varg<const char *>
       {
           using type = const char *;
   
           to_varg(const char *v)
               : m_value(v)
           {
           }
   
           type operator*() { return m_value.c_str(); }
   
           std::string m_value;
       };
   
       template <>
       struct to_varg<std::string>
       {
           using type = const char *;
   
           to_varg(const std::string &v)
               : m_value(v)
           {
           }
   
           type operator*() { return m_value.c_str(); }
   
           std::string m_value;
       };
   
   } // namespace
   
   template <typename... Args>
   class format_plus_arg
   {
     public:
       using args_vector_type = std::tuple<detail::to_varg<Args>...>;
       using vargs_vector_type = std::tuple<typename detail::to_varg<Args>::type...>;
   
       format_plus_arg(const format_plus_arg &) = delete;
       format_plus_arg &operator=(const format_plus_arg &) = delete;
   
   
       format_plus_arg(std::string_view fmt, Args... args)
           : m_fmt(fmt)
           , m_args(std::forward<Args>(args)...)
       {
           auto ix = std::make_index_sequence<sizeof...(Args)>();
           copy_vargs(ix);
       }
   
       std::string str()
       {
           char buffer[1024];
           std::string::size_type r = std::apply(snprintf, std::tuple_cat(std::make_tuple(buffer, sizeof(buffer), m_fmt.c_str()), m_vargs));
           return { buffer, r };
       }
   
       friend std::ostream &operator<<(std::ostream &os, const format_plus_arg &f)
       {
           char buffer[1024];
           std::string::size_type r = std::apply(snprintf, std::tuple_cat(std::make_tuple(buffer, sizeof(buffer), f.m_fmt.c_str()), f.m_vargs));
           os.write(buffer, r);
           return os;
       }
   
     private:
   
       template <std::size_t... I>
       void copy_vargs(std::index_sequence<I...>)
       {
           ((std::get<I>(m_vargs) = *std::get<I>(m_args)), ...);
       }
   
       std::string m_fmt;
       args_vector_type m_args;
       vargs_vector_type m_vargs;
   };
   
   template <typename... Args>
   constexpr auto format(std::string_view fmt, Args... args)
   {
       return format_plus_arg(fmt, std::forward<Args>(args)...);
   }
   
   // --------------------------------------------------------------------
   
   class fill_out_streambuf : public std::streambuf
   {
     public:
   
       using base_type = std::streambuf;
       using int_type = base_type::int_type;
       using char_type = base_type::char_type;
       using traits_type = base_type::traits_type;
   
       fill_out_streambuf(std::ostream &os, int width = 80)
           : m_os(os)
           , m_upstream(os.rdbuf())
           , m_width(width)
       {
       }
   
       ~fill_out_streambuf()
       {
           m_os.rdbuf(m_upstream);
       }
   
       virtual int_type
       overflow(int_type ic = traits_type::eof())
       {
           char ch = traits_type::to_char_type(ic);
   
           int_type result = ic;
   
           if (ch == '\n')
           {
               for (int i = m_column_count; result != traits_type::eof() and i < m_width; ++i)
                   result = m_upstream->sputc(' ');
           }
   
           if (result != traits_type::eof())
               result = m_upstream->sputc(ch);
   
           if (result != traits_type::eof())
           {
               if (ch == '\n')
               {
                   m_column_count = 0;
                   ++m_line_count;
               }
               else
                   ++m_column_count;
           }
   
           return result;
       }
   
       std::streambuf *get_upstream() const { return m_upstream; }
   
       int get_line_count() const { return m_line_count; }
   
     private:
       std::ostream &m_os;
       std::streambuf *m_upstream;
       int m_width;
       int m_line_count = 0;
       int m_column_count = 0;
   };
   
   } // namespace pdbx