However, still I don't see any reason why this function increments its
second argument ? And why to the first byte after the DER-encoded INTEGER
(it's out of preallocated memory) ?
The usual reason for building library routines that bump an output
pointer is to be able to use them in a chained fashion to build
a composite output object:
char thingbuffer[256], *cp = thingbuffer;
...
makeafoo(stuff,&cp);
makeabar(other,&cp);
{
char *bp = baz; /* pointer to a null-terminated baz */
while ( *cp++ = *bp++ );
}
makeabletch(params,&cp);
*cp = 0; /* null terminate it OR */
len = cp - thingbuffer; /* compute length made */
If the make routines bump their second argument, it all
strings out nicely in memory. Compare this to:
char thingbuffer[256], *cp = thingbuffer;
int len;
...
makeafoo(stuff,cp); /* fixed length item */
cp += sizeof(foo);
len = makeabar(other,cp); /* variable length item */
cp += len;
...
makeabletch(params,cp);
cp += computelengthofbletchat(cp);
The only real negative is remembering to put in the ampersand,
(I guess "references" removes even this, but am I correct in
remembering that "references" are really C++ and one should
not count on them being in plain vanilla C? Or did references
get added to C in the ANSI standardization process???)
--
Charles B (Ben) Cranston
mailto: [EMAIL PROTECTED]
http://www.wam.umd.edu/~zben
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