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Working with C strings in HD 1.2

Back in October I posted a message with the following problem:

    let buffer  = c-type-cast(<c-unsigned-char*>, pointer);
    let request-string = "Some request data";
    let index = 100;
    for(char in request-string)
      buffer[index] := as(<integer>, char);
      index := index + 1;
    end for;
    buffer[index] := 0;

I wanted a quicker/better way of doing the above when transfering
strings to/from a C memory buffer. I've revisited this and I now do
the following:


    let request-string = "Some request data";
    let dest = make(<c-string>, address: \%+(pointer, 100));
    with-c-string( source = request-string )
      copy-bytes!(dest, source, source.size + 1);
    end with-c-string;

This is an order of magnitude faster in the circumstances where I was
using it (copying strings to and from <string>'s and a rich text
editor buffer using the Windows API.


The other problem I asked about:

  The result I need to get out of the buffer is also a zero terminated
  string. I don't know the length of it, I only know the starting
  location. How best to get the information out of the buffer and into
  a <byte-string> or <c-string>? At the moment I'm doing the rather
  slow:

    let index = 100;
    let count = 0;
    while(buffer[index] ~= 0)
      count := count + 1;
      index := index + 1;
    end while;
    let result = make(<byte-string>, size: count);
    for(index2 from 0 below count)
      result[index2] := $char-map[buffer[index2 + 100]];
    end for;

can be solved as follows:

    make(<c-string>, address: \%+(buffer.pointer-address, 100));

I got no replies when I posted the problem so I thought I'd post my
solution in case anyone else comes across a similar problem.

Chris.
-- 
http://www.double.co.nz/dylan