len2 = 2*c->space+1 | c->space+len+1;
if (len2 > SSIZE_MAX/4) return 0;
newbuf = realloc(c->buf, len2*4);
if (!newbuf) return 0;
*c->bufp = c->buf = newbuf;
len2 = 2*c->space+1 | c->space+len+1;
if (len2 > SSIZE_MAX/4) return 0;
newbuf = realloc(c->buf, len2*4);
if (!newbuf) return 0;
*c->bufp = c->buf = newbuf;