__gnu_cxx::__rc_string_base< _CharT, _Traits, _Alloc > Class Template Reference

Inherits __gnu_cxx::__vstring_utility< _CharT, _Traits, _Alloc >.

## Public Types

typedef _Util_Base::_CharT_alloc_type | _CharT_alloc_type
typedef __vstring_utility < _CharT, _Traits, _Alloc > | _Util_Base
typedef _Alloc | allocator_type
typedef _CharT_alloc_type::size_type | size_type
typedef _Traits | traits_type
typedef _Traits::char_type | value_type

## Public Member Functions

| __rc_string_base (const _Alloc &__a)
| __rc_string_base (const __rc_string_base &__rcs)
| __rc_string_base (__rc_string_base &&__rcs)
| __rc_string_base (size_type __n, _CharT __c, const _Alloc &__a)
template<typename _InputIterator >
| __rc_string_base (_InputIterator __beg, _InputIterator __end, const _Alloc &__a)
void | _M_assign (const __rc_string_base &__rcs)
size_type | _M_capacity () const
void | _M_clear ()
bool | _M_compare (const __rc_string_base &) const
template<>
bool | _M_compare (const __rc_string_base &__rcs) const
template<>
bool | _M_compare (const __rc_string_base &__rcs) const
_CharT * | _M_data () const
void | _M_erase (size_type __pos, size_type __n)
allocator_type & | _M_get_allocator ()
const allocator_type & | _M_get_allocator () const
bool | _M_is_shared () const
void | _M_leak ()
size_type | _M_length () const
size_type | _M_max_size () const
void | _M_mutate (size_type __pos, size_type __len1, const _CharT *__s, size_type __len2)
void | _M_reserve (size_type __res)
void | _M_set_leaked ()
void | _M_set_length (size_type __n)
void | _M_swap (__rc_string_base &__rcs)
template<typename _InIterator >
_CharT * | _S_construct (_InIterator __beg, _InIterator __end, const _Alloc &__a, std::input_iterator_tag)
template<typename _InIterator >
_CharT * | _S_construct (_InIterator __beg, _InIterator __end, const _Alloc &__a, std::forward_iterator_tag)

## Protected Types

typedef __gnu_cxx::__normal_iterator < const_pointer, __gnu_cxx::__versa_string < _CharT, _Traits, _Alloc, __rc_string_base > > | __const_rc_iterator
typedef __gnu_cxx::__normal_iterator < const_pointer, __gnu_cxx::__versa_string < _CharT, _Traits, _Alloc, __sso_string_base > > | __const_sso_iterator
typedef __gnu_cxx::__normal_iterator < pointer, __gnu_cxx::__versa_string < _CharT, _Traits, _Alloc, __rc_string_base > > | __rc_iterator
typedef __gnu_cxx::__normal_iterator < pointer, __gnu_cxx::__versa_string < _CharT, _Traits, _Alloc, __sso_string_base > > | __sso_iterator
typedef _CharT_alloc_type::const_pointer | const_pointer
typedef _CharT_alloc_type::difference_type | difference_type
typedef _CharT_alloc_type::pointer | pointer

## Static Protected Member Functions

static void | _S_assign (_CharT *__d, size_type __n, _CharT __c)
static int | _S_compare (size_type __n1, size_type __n2)
static void | _S_copy (_CharT *__d, const _CharT *__s, size_type __n)
template<typename _Iterator >
static void | _S_copy_chars (_CharT *__p, _Iterator __k1, _Iterator __k2)
static void | _S_copy_chars (_CharT *__p, __sso_iterator __k1, __sso_iterator __k2)
static void | _S_copy_chars (_CharT *__p, __const_sso_iterator __k1, __const_sso_iterator __k2)
static void | _S_copy_chars (_CharT *__p, __rc_iterator __k1, __rc_iterator __k2)
static void | _S_copy_chars (_CharT *__p, __const_rc_iterator __k1, __const_rc_iterator __k2)
static void | _S_copy_chars (_CharT *__p, _CharT *__k1, _CharT *__k2)
static void | _S_copy_chars (_CharT *__p, const _CharT *__k1, const _CharT *__k2)
static void | _S_move (_CharT *__d, const _CharT *__s, size_type __n)

## Detailed Description

### template<typename _CharT, typename _Traits, typename _Alloc>
class __gnu_cxx::__rc_string_base< _CharT, _Traits, _Alloc >

Documentation? What's that? Nathan Myers ncm@c.nosp@m.antr.nosp@m.ip.or.nosp@m.g.

A string looks like this:

[_Rep]
_M_length
[__rc_string_base<char_type>] _M_capacity
_M_dataplus _M_refcount
_M_p ----------------> unnamed array of char_type

Where the _M_p points to the first character in the string, and you cast it to a pointer-to-_Rep and subtract 1 to get a pointer to the header.

This approach has the enormous advantage that a string object requires only one allocation. All the ugliness is confined within a single pair of inline functions, which each compile to a single add instruction: _Rep::_M_refdata(), and __rc_string_base::_M_rep(); and the allocation function which gets a block of raw bytes and with room enough and constructs a _Rep object at the front.

The reason you want _M_data pointing to the character array and not the _Rep is so that the debugger can see the string contents. (Probably we should add a non-inline member to get the _Rep for the debugger to use, so users can check the actual string length.)

Note that the _Rep object is a POD so that you can have a static empty string _Rep object already constructed before static constructors have run. The reference-count encoding is chosen so that a 0 indicates one reference, so you never try to destroy the empty-string _Rep object.

All but the last paragraph is considered pretty conventional for a C++ string implementation.

Definition at line 82 of file rc_string_base.h.

The documentation for this class was generated from the following file:

- rc_string_base.h