typedef T CharType;
wxCharTypeBuffer(const CharType *str = NULL)
- : m_str(str ? wxStrdup(str) : NULL),
- m_owned(true)
{
+ if ( str )
+ m_data = new Data(wxStrdup(str));
+ else
+ m_data = &NullData;
}
wxCharTypeBuffer(size_t len)
- : m_str((CharType *)malloc((len + 1)*sizeof(CharType))),
- m_owned(true)
{
- m_str[len] = (CharType)0;
+ m_data = new Data((CharType *)malloc((len + 1)*sizeof(CharType)));
+ m_data->m_str[len] = (CharType)0;
}
static const wxCharTypeBuffer CreateNonOwned(const CharType *str)
{
wxCharTypeBuffer buf;
- buf.m_str = wx_const_cast(CharType*, str);
- buf.m_owned = false;
+ if ( str )
+ buf.m_data = new Data(wx_const_cast(CharType*, str), Data::NonOwned);
return buf;
}
- /* no need to check for NULL, free() does it */
~wxCharTypeBuffer()
{
- if ( m_owned)
- free(m_str);
+ DecRef();
}
- /*
- WARNING:
+ // NB: this method is only const for backward compatibility. It used to
+ // be needed for auto_ptr-like semantics of the copy ctor, but now
+ // that ref-counting is used, it's not really needed.
+ CharType *release() const
+ {
+ if ( m_data == &NullData )
+ return NULL;
- the copy ctor and assignment operators change the passed in object
- even although it is declared as "const", so:
+ wxASSERT_MSG( m_data->m_owned, _T("can't release non-owned buffer") );
+ wxASSERT_MSG( m_data->m_ref == 1, _T("can't release shared buffer") );
- a) it shouldn't be really const
- b) you shouldn't use it afterwards (or know that it was reset)
+ CharType *p = m_data->m_str;
- This is very ugly but is unfortunately needed to make the normal use
- of wxCharTypeBuffer buffer objects possible and is very similar to what
- std::auto_ptr<> does (as if it were an excuse...)
- */
+ wxCharTypeBuffer *self = wx_const_cast(wxCharTypeBuffer*, this);
+ self->m_data->m_str = NULL;
+ self->DecRef();
- /*
- because of the remark above, release() is declared const even if it
- isn't really const
- */
- CharType *release() const
- {
- wxASSERT_MSG( m_owned, _T("can't release non-owned buffer") );
- return DoRelease();
+ return p;
}
void reset()
{
- if ( m_owned )
- free(m_str);
- m_str = NULL;
+ DecRef();
}
wxCharTypeBuffer(const wxCharTypeBuffer& src)
{
- CopyFrom(src);
+ m_data = src.m_data;
+ IncRef();
}
wxCharTypeBuffer& operator=(const CharType *str)
{
- if ( m_owned )
- free(m_str);
- m_str = str ? wxStrdup(str) : NULL;
- m_owned = true;
+ DecRef();
+
+ if ( str )
+ m_data = new Data(wxStrdup(str));
return *this;
}
wxCharTypeBuffer& operator=(const wxCharTypeBuffer& src)
{
- if (&src != this)
- {
- if ( m_owned )
- free(m_str);
- CopyFrom(src);
- }
+ if ( &src == this )
+ return *this;
+
+ DecRef();
+ m_data = src.m_data;
+ IncRef();
+
return *this;
}
bool extend(size_t len)
{
- wxASSERT_MSG( m_owned, _T("cannot extend non-owned buffer") );
+ wxASSERT_MSG( m_data->m_owned, _T("cannot extend non-owned buffer") );
+ wxASSERT_MSG( m_data->m_ref == 1, _T("can't extend shared buffer") );
- CharType *
- str = (CharType *)realloc(m_str, (len + 1)*sizeof(CharType));
+ CharType *str =
+ (CharType *)realloc(data(), (len + 1) * sizeof(CharType));
if ( !str )
return false;
- m_str = str;
+ if ( m_data == &NullData )
+ {
+ m_data = new Data(str);
+ }
+ else
+ {
+ m_data->m_str = str;
+ m_data->m_owned = true;
+ }
return true;
}
- CharType *data() { return m_str; }
- const CharType *data() const { return m_str; }
- operator const CharType *() const { return m_str; }
- CharType operator[](size_t n) const { return m_str[n]; }
-
+ CharType *data() { return m_data->m_str; }
+ const CharType *data() const { return m_data->m_str; }
+ operator const CharType *() const { return data(); }
+ CharType operator[](size_t n) const { return data()[n]; }
private:
- CharType *DoRelease() const
+ // reference-counted data
+ struct Data
{
- CharType *p = m_str;
- ((wxCharTypeBuffer *)this)->m_str = NULL;
- return p;
+ enum Kind
+ {
+ Owned,
+ NonOwned
+ };
+
+ Data(CharType *str, Kind kind = Owned)
+ : m_str(str), m_ref(1), m_owned(kind == Owned) {}
+
+ ~Data()
+ {
+ if ( m_owned )
+ free(m_str);
+ }
+
+ CharType *m_str;
+
+ // "short" to have sizeof(Data)=8 on 32bit archs
+ unsigned short m_ref;
+
+ bool m_owned;
+ };
+
+ // placeholder for NULL string, to simplify this code
+ // NB: this is defined in string.cpp, not (non-existent) buffer.cpp
+#ifdef __MINGW32__
+ // MinGW requires explicit WXDLLIMPEXP_DATA_BASE to avoid compilation
+ // errors
+ static WXDLLIMPEXP_DATA_BASE(Data) NullData;
+#else
+ // but Visual C++ doesn't like it
+ static Data NullData;
+#endif
+
+ void IncRef()
+ {
+ if ( m_data == &NullData ) // exception, not ref-counted
+ return;
+ m_data->m_ref++;
}
- void CopyFrom(const wxCharTypeBuffer& src)
+ void DecRef()
{
- m_owned = src.m_owned;
- m_str = src.DoRelease();
+ if ( m_data == &NullData ) // exception, not ref-counted
+ return;
+ if ( --m_data->m_ref == 0 )
+ delete m_data;
+ m_data = &NullData;
}
private:
- CharType *m_str;
- bool m_owned;
+ Data *m_data;
};
WXDLLIMPEXP_TEMPLATE_INSTANCE_BASE( wxCharTypeBuffer<char> )
projects / wxWidgets.git / blobdiff