| Clem Clarke 2007-04-13, 3:57 am |
| Some 20 years ago, it became clear that C strings were not as safe, nor
as fast, as strings in PL/I, Assembler or Pascal.
The primary reasons are that one needs to find the current length of a
string before or during a copy process - this is very time consuming.
Secondly, there is no way of determining the maximum length of a string,
and therefore when copying to a string, it is easy to over-write
adjacent storage with often disastrous consequences, including the
deliberate introduction of viruses.
Decades have passed and the C string problem continues. Buffer
over-runs are just part of the story, and the bugs that can be
introduced - the safety problem is still with us all and it has come
back to bite all of us on the lower part of our anatomy, over and over
again.
I have spent some years studying this problem and have developed some
User friendly C macros that solve the problem.
These solutions do enhance the speed and safety aspects of all "C"
programs - these benefits of speed and safety can be passed on to your
users.
The main benefits are:
* Increased speed (up to 20 times for some string handling)
* More reliability (strings cannot overwrite adjacent storage)
* Easier coding and debugging (consistent set of macros)
* Easier external variables
Here is a very short example:
dcl (op,charvar,253," ",ext); // Variable 'op' is defined
// as an External variable - Max length of 253 characters.
dcl (symbolic,charfixed,8," ",ext); // Fixed length of 8
cpylit(op, "This is a 30 character string ");
cat(op,op); /* Concatenate variable op with it self. Now 60
characters */
cpy(symbolic,op); /* Truncates it to 8 characters */
cpy(op,symbolic); /* Copy it back. */
I invite you download the macros and code at
http://members.ozemail.com.au/~osca...d/fastsafe.html where a fuller
discussion can be found.
Clement Clarke
,-._|\ Clement V. Clarke - Author Jol, EASYPANEL, OSCAR, 370TO486
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