corecel/cont/SpanIO.hh

0001 //----------------------------------*-C++-*----------------------------------//
0002 // Copyright 2020-2024 UT-Battelle, LLC, and other Celeritas developers.
0003 // See the top-level COPYRIGHT file for details.
0004 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0005 //---------------------------------------------------------------------------//
0006 //! \file corecel/cont/SpanIO.hh
0007 //---------------------------------------------------------------------------//
0008 #pragma once
0009
0010 #include <iomanip>
0011 #include <ostream>
0012
0013 #include "Span.hh"
0014
0015 namespace celeritas
0016 {
0017 //---------------------------------------------------------------------------//
0018 /*!
0019  * Write the elements of span \a s to stream \a os.
0020  */
0021 template<class T, std::size_t E>
0022 std::ostream& operator<<(std::ostream& os, Span<T, E> const& s)
0023 {
0024     std::streamsize size = s.size();
0025     std::streamsize width = os.width();
0026     std::streamsize remainder = 0;
0027
0028     os.width(0);
0029     os << '{';
0030     if (width > 2 + (size - 1))
0031     {
0032         // Subtract width for spaces and braces
0033         width -= 2 + (size - 1);
0034         // Individual width is 1/N of that, rounded down, keep remainder
0035         // separate
0036         remainder = width % size;
0037         width = width / size;
0038     }
0039     else
0040     {
0041         width = 0;
0042     }
0043
0044     // First element gets the remainder
0045     os.width(width + remainder);
0046     if (!s.empty())
0047     {
0048         os << s[0];
0049     }
0050
0051     for (std::streamsize i = 1; i < size; ++i)
0052     {
0053         os << ',';
0054         os.width(width);
0055         os << s[i];
0056     }
0057     os << '}';
0058
0059     return os;
0060 }
0061
0062 //---------------------------------------------------------------------------//
0063 }  // namespace celeritas