ber_tlv_length.h

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/*-
 * Copyright (c) 2003-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#ifndef _BER_TLV_LENGTH_H_
#define _BER_TLV_LENGTH_H_
 
#ifdef __cplusplus
extern "C" {
#endif
 
typedef ssize_t ber_tlv_len_t;
 
/*
 * This function tries to fetch the length of the BER TLV value and place it
 * in *len_r.
 * RETURN VALUES:
 *       0:     More data expected than bufptr contains.
 *      -1:     Fatal error deciphering length.
 *      >0:     Number of bytes used from bufptr.
 * On return with >0, len_r is constrained as -1..MAX, where -1 mean
 * that the value is of indefinite length.
 */
ssize_t ber_fetch_length(int _is_constructed, const void *bufptr, size_t size,
        ber_tlv_len_t *len_r);
 
/*
 * This function expects bufptr to be positioned over L in TLV.
 * It returns number of bytes occupied by L and V together, suitable
 * for skipping. The function properly handles indefinite length.
 * RETURN VALUES:
 *      Standard {-1,0,>0} convention.
 */
ssize_t ber_skip_length(
        const struct asn_codec_ctx_s *opt_codec_ctx,    /* optional context */
        int _is_constructed, const void *bufptr, size_t size);
 
/*
 * This function serializes the length (L from TLV) in DER format.
 * It always returns number of bytes necessary to represent the length,
 * it is a caller's responsibility to check the return value
 * against the supplied buffer's size.
 */
size_t der_tlv_length_serialize(ber_tlv_len_t len, void *bufptr, size_t size);
 
#ifdef __cplusplus
}
#endif
 
#endif  /* _BER_TLV_LENGTH_H_ */