ceph/src/boost/libs/test/example/const_string.hpp

   1 //  (C) Copyright Gennadiy Rozental 2001-2014.
   2 //  Distributed under the Boost Software License, Version 1.0.
   3 //  (See accompanying file LICENSE_1_0.txt or copy at
   4 //  http://www.boost.org/LICENSE_1_0.txt)
   5
   6 //  See http://www.boost.org/libs/test for the library home page.
   7 //
   8 //  File        : $RCSfile$
   9 //
  10 //  Version     : $Revision$
  11 //
  12 //  Description : simple string class definition
  13 // ***************************************************************************
  14
  15 #ifndef  CONST_STRING_HPP
  16 #define  CONST_STRING_HPP
  17
  18 // STL
  19 #include <iterator>
  20 #include <string>
  21 #include <cstring>
  22 using std::string;
  23
  24 namespace common_layer {
  25
  26 // ************************************************************************** //
  27 // **************                 const_string                 ************** //
  28 // ************************************************************************** //
  29
  30 class const_string {
  31 public:
  32     // Subtypes
  33     typedef     char const*                     iterator;
  34     typedef     char const*                     const_iterator;
  35     typedef     std::reverse_iterator<iterator> reverse_iterator;
  36     typedef     reverse_iterator                const_reverse_iterator;
  37
  38     // Constructor
  39     const_string()
  40     : m_begin( "" ), m_end( m_begin )                      {}
  41
  42     // Copy constructor is generated by compiler
  43
  44     const_string( const std::string& s )
  45     : m_begin( s.c_str() ),
  46       m_end( m_begin + s.length() )                        {}
  47
  48     const_string( char const* s )
  49     : m_begin( s ? s : "" )
  50     , m_end( s ? m_begin + std::strlen( s ) : m_begin )
  51     {}
  52
  53     const_string( char const* s, size_t length )
  54     : m_begin( s ), m_end( m_begin + length )              { if( length == 0 ) erase(); }
  55
  56     const_string( char const* first, char const* last )
  57     : m_begin( first ), m_end( last )                      {}
  58
  59     // data access methods
  60     char            operator[]( size_t index ) const        { return m_begin[index]; }
  61     char            at( size_t index ) const                { return m_begin[index]; }
  62
  63     char const*     data() const                            { return m_begin; }
  64
  65     // length operators
  66     size_t          length() const                          { return m_end - m_begin; }
  67     bool            is_empty() const                        { return m_end == m_begin; }
  68
  69     void            erase()                                 { m_begin = m_end = ""; }
  70     void            resize( size_t new_len )                { if( m_begin + new_len < m_end ) m_end = m_begin + new_len; }
  71     void            rshorten( size_t shift = 1 )            { m_end  -= shift; if( m_end <= m_begin ) erase(); }
  72     void            lshorten( size_t shift = 1 )            { m_begin += shift; if( m_end <= m_begin ) erase(); }
  73
  74     // Assignment operators
  75     const_string&   operator=( const_string const& s );
  76     const_string&   operator=( string const& s )            { return *this = const_string( s ); }
  77     const_string&   operator=( char const* s )              { return *this = const_string( s ); }
  78
  79     const_string&   assign( const_string const& s )         { return *this = s; }
  80     const_string&   assign( string const& s, size_t len )   { return *this = const_string( s.data(), len ); }
  81     const_string&   assign( string const& s )               { return *this = const_string( s ); }
  82     const_string&   assign( char const* s )                 { return *this = const_string( s ); }
  83     const_string&   assign( char const* s, size_t len )     { return *this = const_string( s, len ); }
  84     const_string&   assign( char const* f, char const* l )  { return *this = const_string( f, l ); }
  85
  86     void            swap( const_string& s )                 {
  87        // do not want to include alogrithm
  88         char const* tmp1 = m_begin;
  89         char const* tmp2 = m_end;
  90
  91         m_begin     = s.m_begin;
  92         m_end       = s.m_end;
  93
  94         s.m_begin   = tmp1;
  95         s.m_end     = tmp2;
  96     }
  97
  98     // Comparison operators
  99     friend bool     operator==( const_string const& s1, const_string const& s2 )
 100     {
 101          return s1.length() == s2.length() && std::strncmp( s1.data(), s2.data(), s1.length() ) == 0;
 102     }
 103     friend bool     operator==( const_string const& s1, char const* s2 )            { return s1 == const_string( s2 ); }
 104     friend bool     operator==( const_string const& s1, const string& s2 )          { return s1 == const_string( s2 ); }
 105
 106     friend bool     operator!=( const_string const& s1, const_string const& s2 )    { return !(s1 == s2); }
 107     friend bool     operator!=( const_string const& s1, char const* s2 )            { return !(s1 == s2); }
 108     friend bool     operator!=( const_string const& s1, const string& s2 )          { return !(s1 == s2); }
 109
 110     friend bool     operator==( char const* s2,         const_string const& s1 )    { return s1 == s2; }
 111     friend bool     operator==( const string& s2,       const_string const& s1 )    { return s1 == s2; }
 112
 113     friend bool     operator!=( char const* s2,         const_string const& s1 )    { return !(s1 == s2); }
 114     friend bool     operator!=( const string& s2,       const_string const& s1 )    { return !(s1 == s2); }
 115
 116     // Iterators
 117     iterator        begin() const                           { return m_begin; }
 118     iterator        end() const                             { return m_end;   }
 119     reverse_iterator rbegin() const                         { return reverse_iterator( m_end );   }
 120     reverse_iterator rend() const                           { return reverse_iterator( m_begin ); }
 121
 122 private:
 123
 124     // Data members
 125     char const*     m_begin;
 126     char const*     m_end;
 127 };
 128
 129 //____________________________________________________________________________//
 130
 131 // first character
 132 class first_char {
 133 public:
 134     char operator()( const_string source, char default_char = '\0' ) const {
 135         return source.is_empty() ? default_char : *source.data();
 136     }
 137 };
 138
 139 //____________________________________________________________________________//
 140
 141 // last character
 142 class last_char {
 143 public:
 144     char operator()( const_string source, char default_char = '\0' ) const {
 145         return source.is_empty() ? default_char : *source.rbegin();
 146     }
 147 };
 148
 149 //____________________________________________________________________________//
 150
 151 inline const_string&
 152 const_string::operator=( const_string const& s ) {
 153     if( &s != this ) {
 154         m_begin = s.m_begin;
 155         m_end  = s.m_end;
 156     }
 157
 158     return *this;
 159 }
 160
 161 //____________________________________________________________________________//
 162
 163 typedef const_string const literal;
 164
 165 //____________________________________________________________________________//
 166
 167 inline std::ostream&
 168 operator<<( std::ostream& os, const_string const& str )
 169 {
 170     os << std::string( str.begin(), str.length() );
 171
 172     return os;
 173 }
 174
 175 //____________________________________________________________________________//
 176
 177 }; // namespace common_layer
 178
 179 #endif // CONST_STRING_HPP