--- /dev/null
+/*
+ * Copyright (c) 2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef OER_DECODER_H
+#define OER_DECODER_H
+
+#include <asn_application.h>
+#include <oer_support.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct asn_TYPE_descriptor_s; /* Forward declaration */
+struct asn_codec_ctx_s; /* Forward declaration */
+
+/*
+ * The Octet Encoding Rules (OER, X.696 08/2015) decoder for any given type.
+ * This function may be invoked directly by the application.
+ * Parses CANONICAL-OER and BASIC-OER.
+ */
+asn_dec_rval_t oer_decode(const struct asn_codec_ctx_s *opt_codec_ctx,
+ const struct asn_TYPE_descriptor_s *type_descriptor,
+ void **struct_ptr, /* Pointer to a target structure's pointer */
+ const void *buffer, /* Data to be decoded */
+ size_t size /* Size of that buffer */
+ );
+
+/*
+ * Type of generic function which decodes the byte stream into the structure.
+ */
+typedef asn_dec_rval_t(oer_type_decoder_f)(
+ const struct asn_codec_ctx_s *opt_codec_ctx,
+ const struct asn_TYPE_descriptor_s *type_descriptor,
+ const asn_oer_constraints_t *constraints,
+ void **struct_ptr,
+ const void *buf_ptr,
+ size_t size);
+
+/*
+ * Swallow the Open Type (X.696 (08/2015), #30) into /dev/null.
+ * RETURN VALUES:
+ * -1: Fatal error deciphering length.
+ * 0: More data expected than bufptr contains.
+ * >0: Number of bytes used from bufptr.
+ */
+ssize_t oer_open_type_skip(const void *bufptr, size_t size);
+
+/*
+ * Read the Open Type (X.696 (08/2015), #30).
+ * RETURN VALUES:
+ * 0: More data expected than bufptr contains.
+ * -1: Fatal error deciphering length.
+ * >0: Number of bytes used from bufptr.
+ */
+ssize_t oer_open_type_get(const asn_codec_ctx_t *opt_codec_ctx,
+ const struct asn_TYPE_descriptor_s *td,
+ const asn_oer_constraints_t *constraints,
+ void **struct_ptr, const void *bufptr, size_t size);
+
+/*
+ * Length-prefixed buffer decoding for primitive types.
+ */
+oer_type_decoder_f oer_decode_primitive;
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* OER_DECODER_H */