Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!decwrl!Angelo!lindy!news
From: GQ.RLG@forsythe.stanford.edu (Dick Guertin)
Newsgroups: comp.arch
Subject: Re: String length
Message-ID: <1944@lindy.Stanford.EDU>
Date: 6 Feb 89 21:15:35 GMT
Sender: news@lindy.Stanford.EDU
Lines: 27

In article <28200268@mcdurb>,
aglew@mcdurb.Urbana.Gould.COM writes:
->
->Abstract from: comp.arch 8281,  6 Feb 89,  56 lines.
->
->May I encourage people implementing string libraries to use an extra
->level of indirection? Instead of length immediately preceding the string,
->let length be associated with a pointer to the string. Makes
->substringing operations much easier, and has the ability to reduce
->unnecessary copies (at the risk of increased aliasing).
->
->       +------+---+
->       |length|ptr|
->       +------+---+
->                |
->         +------+
->         |
->         V
->       +---+---+---+---+---+---+---+---+---+---+---+---+---+
->       | H | E | L | L | O | , |   | W | O | R | L | D | \n|
->       +---+---+---+---+---+---+---+---+---+---+---+---+---+

Such an implementation has adverse effects when the string is sent
to/from an external device, such as a file.  The 'length' must be
with the string, or the string needs a terminator character.
Furthermore, when a 'ptr' is changed to point to a new string,
what happens to the 'length' information for the old string?