So, playing around with the sal string classes I see that... rtl_string_new_WithLength/rtl_uString_new_WithLength create an rtl/String/rtl_uString of the given length, but set the full buffer contents to 0s[1]
meanwhile I see that we have x_rtl_uString_new_WithLength in inc/i18nutil/x_rtl_ustring.h which is a non-zeroed out variant of rtl_uString_new_WithLength so there's an uninitialized buffer available to play with. We can assign ownership of the rtl_uString to an OUString with OUString( rtl_uString * str, __sal_NoAcquire ) and skip calling acquire, i.e. OUString has *two* methods to take ownership of a rtl_uString without calling acquire. the public OUString( rtl_uString * str, __sal_NoAcquire ) the private OUString( rtl_uString * value, DO_NOT_ACQUIRE * ) as well as the usual add-add-refcount version of OUString( rtl_uString * str ) While OString has only the private OString( rtl_String * value, DO_NOT_ACQUIRE * ) as well as the usual add-add-refcount version of OString( rtl_String * str ), so the same hack isn't available. I'm vaguely thinking of moving that i18nutil x_rtl stuff into comphelper/string or something, hard-coding its refcount argument to 0 or 1 and fixing up its uses to consistently use one or the other public OUString acquire/noacquire ctors and add a OString variant so that either of the belows is possible to skip copying buffers around the place. #if thinko-one rtl_String *pStr = foo_rtl_string_new_WithLength(nLen/*, refCount=0*/); //call acquire, refCount of 1, OString::dtor destroys buffer rtl::OString aRet(pStr); pStr->length = rStrm.Read(pStr->buffer, nLen); #else rtl_String *pStr = foo_rtl_string_new_WithLength(nLen/*, refCount=1*/); //don't call acquire, refCount stays 1, OString::dtor destroys buffer rtl::OString aRet(pStr, SAL_NO_ACQUIRE); pStr->length = rStrm.Read(pStr->buffer, nLen); #endif //if unlikely length != nLen make deep copy of string to release excess //mem, nobody seems to worry about excess for rtl::O[U]String buffers, //but much less opportunity to have a large chunk of unused //buffer there. C. [1] with a loop, I suppose its no real optimization there to use memset or rtl_allocateMemory for that case ? _______________________________________________ LibreOffice mailing list LibreOffice@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/libreoffice
