X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/53c75dc2f27fb1679f47a4a297f36d5066d354da..b27679518606c4739f1821fbb600687b17497dbf:/include/wx/buffer.h diff --git a/include/wx/buffer.h b/include/wx/buffer.h index 81a445afe5..3244323737 100644 --- a/include/wx/buffer.h +++ b/include/wx/buffer.h @@ -15,7 +15,9 @@ #include "wx/chartype.h" #include "wx/wxcrtbase.h" +#ifndef __WXPALMOS5__ #include // malloc() and free() +#endif // ! __WXPALMOS5__ class WXDLLIMPEXP_FWD_BASE wxCStrData; @@ -31,123 +33,168 @@ public: 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 ( 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 ) @@ -317,9 +364,12 @@ public: wxMemoryBuffer& operator=(const wxMemoryBuffer& src) { - m_bufdata->DecRef(); - m_bufdata = src.m_bufdata; - m_bufdata->IncRef(); + if (&src != this) + { + m_bufdata->DecRef(); + m_bufdata = src.m_bufdata; + m_bufdata->IncRef(); + } return *this; }