At 11:11 AM -0700 5/21/02, Steve Fink wrote:
>On Tue, May 21, 2002 at 01:38:45PM -0400, Dan Sugalski wrote:
>> At 5:27 PM +0000 5/21/02, "Peter Gibbs" (via RT) wrote:
>> > > I think I'd like these differently. STRING is a subclass of Buffer,
>> >> and the bufstart and buflen fields in Buffers point to the actual
>> >> start of memory and length of allocated data. I'd rather keep it that
>> >> way, and have the 'real' string length and string start be extra
>> >> fields in the STRING part.
>> >
>> >Quote from
>> >http://www.mail-archive.com/perl6-internals@perl.org/msg09497.html:
>> >>The COWing of substrings requires a major interface change:
>> >>*** All references to the data in a STRING must use the new strstart
>> >pointer
>> >>instead of bufstart ***
>> >
>> >Actually, we don't. (Sez the man catching up on altogether too much
>> >mail) Since we're putting the COW stuff at the tail end, substrings
>> >of COW strings are fine. You set the bufstart to where the substring
>> >starts, buflen set so it goes to the end of the original buffer, and
>> >the string length bit holds the real string length. That way you
>> >start where you need to, but you can still find the COW marker off
>> >the end of the original buffer.
>> >[End quote]
>>
>> Either I was thinking of something else, or being rather stupid
>> there. Either way, it seems inappropriate for what you're
>> doing.Leaving the Buffer bits to point to the real buffered data and
>> leaving the string bits to do all the magic twiddly substring bits
>> seems more appropriate at the moment.
>> --
>
><ouch> That's exactly what Peter's original COW patch did. It was
>called strstart.
Yeah, I wasn't happy about having an extra field in each string for
the real start of string data (as opposed to the start of the buffer)
so I was thinking we'd only do COW for a subset of strings. At this
point I've given in--it's an extra pointer per string, but we're
chewing up gobs of memory anyway so I'll cope. :)
--
Dan
--------------------------------------"it's like this"-------------------
Dan Sugalski even samurai
[EMAIL PROTECTED] have teddy bears and even
teddy bears get drunk
