Add pgpPubKeyCertLen() to get the length of the pub key certificate.

rpmio/rpmpgp.c

@@ -1238,6 +1238,29 @@ pgpArmor pgpParsePkts(const char *armor, uint8_t ** pkt, size_t * pktlen)
     return ec;
 }
 
+int pgpPubKeyCertLen(const uint8_t *pkts, size_t pktslen, size_t *certlen)
+{
+    const uint8_t *p = pkts;
+    const uint8_t *pend = pkts + pktslen;
+    struct pgpPkt pkt;
+
+    while (p < pend) {
+	if (decodePkt(p, (pend - p), &pkt))
+	    return -1;
+
+	if (pkt.tag == PGPTAG_PUBLIC_KEY && pkts != p) {
+	    *certlen = p - pkts;
+	    return 0;
+	}
+
+	p += (pkt.body - pkt.head) + pkt.blen;
+    }
+
+    *certlen = pktslen;
+
+    return 0;
+}
+
 char * pgpArmorWrap(int atype, const unsigned char * s, size_t ns)
 {
     char *buf = NULL, *val = NULL;

rpmio/rpmpgp.h

@@ -1027,6 +1027,20 @@ pgpArmor pgpReadPkts(const char * fn, uint8_t ** pkt, size_t * pktlen);
  */
 pgpArmor pgpParsePkts(const char *armor, uint8_t ** pkt, size_t * pktlen);
 
+/** \ingroup rpmpgp
+ * Return a length of the first public key certificate in a buffer given
+ * by pkts that contains one or more certificates. A public key certificate
+ * consits of packets like Public key packet, User ID packet and so on.
+ * In a buffer every certificate starts with Public key packet and it ends
+ * with the start of the next certificate or with the end of the buffer.
+ *
+ * @param pkts		pointer to a buffer with certificates
+ * @param pktslen	length of the buffer with certificates
+ * @param certlen	length of the first certificate in the buffer
+ * @return		0 on success
+ */
+int pgpPubKeyCertLen(const uint8_t *pkts, size_t pktslen, size_t *certlen);
+
 /** \ingroup rpmpgp
  * Wrap a OpenPGP packets in ascii armor for transport.
  * @param atype		type of armor