+ struct cookie *c = f->cookie;
+ size_t k = MIN(c->n, f->wpos - f->wbase);
+ if (k) {
+ memcpy(c->s, f->wbase, k);
+ c->s += k;
+ c->n -= k;
+ }
+ k = MIN(c->n, l);
+ if (k) {
+ memcpy(c->s, s, k);
+ c->s += k;
+ c->n -= k;
+ }
+ *c->s = 0;
+ f->wpos = f->wbase = f->buf;
+ /* pretend to succeed, even if we discarded extra data */