From mboxrd@z Thu Jan  1 00:00:00 1970
From: richard@inf.ed.ac.uk (Richard Tobin)
Date: Tue,  5 Sep 2017 15:41:55 +0100 (BST)
Subject: [TUHS] Future Languages
In-Reply-To: Larry McVoy's message of Mon, 4 Sep 2017 14:59:24 -0700
Message-ID: <20170905144155.4A625150E352@macaroni.inf.ed.ac.uk>

> So we have some source (that you can have as well, Apache license)
> that handles not strings but vectors of strings (or structs or whatever).
> 
> I need to write up how it works, it's sort of clever.  It stores both
> the size of the vector (always a power of 2) in part of the bits of the
> first entry and the actual length in the other part.  Because we can
> express powers of two in very little space we can support both values
> in a 32 bit unsigned with a max length of used space of around 134M.

I have something similar.  It allocates space for two ints (number
allocated and used) at ((int *)array)[-1] and [-2].

Typical use is

    LTVectorAndInit(char *, names);

    while(...)
      LTVectorPush(names, s);

    for(i=0; i<LTVectorCount(names); i++)
      ... names[i] ...;

    LTVectorFree(names);

-- Richard

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