port/merge Eurecom APER support from OPENAIRMME

Eurecom has developed APER support for asn1c as part of the OPENAIRMME
softare (a LTE MME).  This is too important to let it bit-rout out
of asn1c.  Let's forward-port and merge it.
diff --git a/skeletons/per_decoder.h b/skeletons/per_decoder.h
index 8397a54..5541bae 100644
--- a/skeletons/per_decoder.h
+++ b/skeletons/per_decoder.h
@@ -38,8 +38,30 @@
 	int unused_bits		/* Number of unused tailing bits, 0..7 */
 	);
 
+/*
+ * Aligned PER decoder of a "complete encoding" as per X.691#10.1.
+ * On success, this call always returns (.consumed >= 1), as per X.691#10.1.3.
+ */
+asn_dec_rval_t aper_decode_complete(struct asn_codec_ctx_s *opt_codec_ctx,
+									struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+									void **struct_ptr,	/* Pointer to a target structure's pointer */
+									const void *buffer,	/* Data to be decoded */
+									size_t size		/* Size of data buffer */
+									);
 
 /*
+ * Aligned PER decoder of any ASN.1 type. May be invoked by the application.
+ * WARNING: This call returns the number of BITS read from the stream. Beware.
+ */
+asn_dec_rval_t aper_decode(struct asn_codec_ctx_s *opt_codec_ctx,
+						   struct asn_TYPE_descriptor_s *type_descriptor,	/* Type to decode */
+						   void **struct_ptr,	/* Pointer to a target structure's pointer */
+						   const void *buffer,	/* Data to be decoded */
+						   size_t size,		/* Size of data buffer */
+						   int skip_bits,		/* Number of unused leading bits, 0..7 */
+						   int unused_bits		/* Number of unused tailing bits, 0..7 */
+					       );
+/*
  * Type of the type-specific PER decoder function.
  */
 typedef asn_dec_rval_t (per_type_decoder_f)(asn_codec_ctx_t *opt_codec_ctx,