Class Column

unittests/catch.hpp:5281–5444

    class Columns;

    class Column {
        std::vector<std::string> m_strings;
        size_t m_width = CATCH_CLARA_TEXTFLOW_CONFIG_CONSOLE_WIDTH;
        size_t m_indent = 0;
        size_t m_initialIndent = std::string::npos;

    public:
        class iterator {
            friend Column;

            Column const& m_column;
            size_t m_stringIndex = 0;
            size_t m_pos = 0;

            size_t m_len = 0;
            size_t m_end = 0;
            bool m_suffix = false;

            iterator( Column const& column, size_t stringIndex )
            :   m_column( column ),
                m_stringIndex( stringIndex )
            {}

            auto line() const -> std::string const& { return m_column.m_strings[m_stringIndex]; }

            auto isBoundary( size_t at ) const -> bool {
                assert( at > 0 );
                assert( at <= line().size() );

                return at == line().size() ||
                       ( isWhitespace( line()[at] ) && !isWhitespace( line()[at-1] ) ) ||
                       isBreakableBefore( line()[at] ) ||
                       isBreakableAfter( line()[at-1] );
            }

            void calcLength() {
                assert( m_stringIndex < m_column.m_strings.size() );

                m_suffix = false;
                auto width = m_column.m_width-indent();
                m_end = m_pos;
                while( m_end < line().size() && line()[m_end] != '\n' )
                    ++m_end;

                if( m_end < m_pos + width ) {
                    m_len = m_end - m_pos;
                }
                else {
                    size_t len = width;
                    while (len > 0 && !isBoundary(m_pos + len))
                        --len;
                    while (len > 0 && isWhitespace( line()[m_pos + len - 1] ))
                        --len;

                    if (len > 0) {
                        m_len = len;
                    } else {
                        m_suffix = true;