+
+struct encode_info {
+ int sysno;
+ int seqno;
+ char buf[512];
+};
+
+void encode_key_init (struct encode_info *i)
+{
+ i->sysno = 0;
+ i->seqno = 0;
+}
+
+char *encode_key_int (int d, char *bp)
+{
+ if (d <= 63)
+ *bp++ = d;
+ else if (d <= 16383)
+ {
+ *bp++ = 64 + (d>>8);
+ *bp++ = d & 255;
+ }
+ else if (d <= 4194303)
+ {
+ *bp++ = 128 + (d>>16);
+ *bp++ = (d>>8) & 255;
+ *bp++ = d & 255;
+ }
+ else
+ {
+ *bp++ = 192 + (d>>24);
+ *bp++ = (d>>16) & 255;
+ *bp++ = (d>>8) & 255;
+ *bp++ = d & 255;
+ }
+ return bp;
+}
+
+void encode_key_write (char *k, struct encode_info *i, FILE *outf)
+{
+ struct it_key key;
+ char *bp = i->buf;
+
+ while ((*bp++ = *k++))
+ ;
+ memcpy (&key, k+1, sizeof(struct it_key));
+ bp = encode_key_int ( (key.sysno - i->sysno) * 2 + *k, bp);
+ if (i->sysno != key.sysno)
+ {
+ i->sysno = key.sysno;
+ i->seqno = 0;
+ }
+ bp = encode_key_int (key.seqno - i->seqno, bp);
+ i->seqno = key.seqno;
+ if (fwrite (i->buf, bp - i->buf, 1, outf) != 1)
+ {
+ logf (LOG_FATAL|LOG_ERRNO, "fwrite");
+ exit (1);
+ }
+}
+