--- /dev/null
+/*
+ * Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
+ * Redistribution and modifications are permitted subject to BSD license.
+ */
+#ifndef _APER_SUPPORT_H_
+#define _APER_SUPPORT_H_
+
+#include <asn_system.h> /* Platform-specific types */
+#include <per_support.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * X.691 (08/2015) #11.9 "General rules for encoding a length determinant"
+ * Get the length "n" from the Aligned PER stream.
+ */
+ssize_t aper_get_length(asn_per_data_t *pd, ssize_t lb, ssize_t ub,
+ int effective_bound_bits, int *repeat);
+
+/*
+ * Get the normally small length "n".
+ */
+ssize_t aper_get_nslength(asn_per_data_t *pd);
+
+/*
+ * Get the normally small non-negative whole number.
+ */
+ssize_t aper_get_nsnnwn(asn_per_data_t *pd, int range);
+
+/*
+ * X.691 (08/2015) #11.9 "General rules for encoding a length determinant"
+ * Put the length "n" to the Aligned PER stream.
+ * If (opt_need_eom) is given, it will be set to 1 if final 0-n is needed.
+ * In that case, invoke aper_put_length(po, -1, -1, 0, NULL) after encoding the
+ * last block.
+ * This function returns the number of units which may be flushed
+ * in the next units saving iteration.
+ */
+ssize_t aper_put_length(asn_per_outp_t *po, ssize_t lb, ssize_t ub, size_t n,
+ int *opt_need_eom);
+
+/* Align the current bit position to octet bundary */
+int aper_put_align(asn_per_outp_t *po);
+int32_t aper_get_align(asn_per_data_t *pd);
+
+/*
+ * Put the normally small length "n" to the Unaligned PER stream.
+ * Returns 0 or -1.
+ */
+int aper_put_nslength(asn_per_outp_t *po, size_t length);
+
+/*
+ * Put the normally small non-negative whole number.
+ */
+int aper_put_nsnnwn(asn_per_outp_t *po, int range, int number);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _APER_SUPPORT_H_ */