/*-
 * SPDX-FileCopyrightText: (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
 * SPDX-License-Identifier: BSD-1-Clause
 */
#ifndef _BER_TLV_TAG_H
#define _BER_TLV_TAG_H

#ifdef __cplusplus
extern "C"
{
#endif

    enum asn_tag_class
    {
        ASN_TAG_CLASS_UNIVERSAL = 0,   /* 0b00 */
        ASN_TAG_CLASS_APPLICATION = 1, /* 0b01 */
        ASN_TAG_CLASS_CONTEXT = 2,     /* 0b10 */
        ASN_TAG_CLASS_PRIVATE = 3      /* 0b11 */
    };
    typedef unsigned ber_tlv_tag_t; /* BER TAG from Tag-Length-Value */

/*
 * Tag class is encoded together with tag value for optimization purposes.
 */
#define BER_TAG_CLASS(tag) ((tag) & 0x3)
#define BER_TAG_VALUE(tag) ((tag) >> 2)
#define BER_TLV_CONSTRUCTED(tagptr) \
    (((*(const uint8_t *)tagptr) & 0x20) ? 1 : 0)

#define BER_TAGS_EQUAL(tag1, tag2) ((tag1) == (tag2))

    /*
     * Several functions for printing the TAG in the canonical form
     * (i.e. "[PRIVATE 0]").
     * Return values correspond to their libc counterparts (if any).
     */
    ssize_t ber_tlv_tag_snprint(ber_tlv_tag_t tag, char *buf, size_t size);
    ssize_t ber_tlv_tag_fwrite(ber_tlv_tag_t tag, FILE * /*f*/);
    char *ber_tlv_tag_string(ber_tlv_tag_t tag);

    /*
     * This function tries to fetch the tag from the input stream.
     * RETURN VALUES:
     *      0:    More data expected than bufptr contains.
     *     -1:    Fatal error deciphering tag.
     *     >0:    Number of bytes used from bufptr. tag_r will contain the tag.
     */
    ssize_t ber_fetch_tag(const void *bufptr, size_t size,
        ber_tlv_tag_t *tag_r);

    /*
     * This function serializes the tag (T from TLV) in BER format.
     * It always returns number of bytes necessary to represent the tag,
     * it is a caller's responsibility to check the return value
     * against the supplied buffer's size.
     */
    size_t ber_tlv_tag_serialize(ber_tlv_tag_t tag, void *bufptr, size_t size);

#ifdef __cplusplus
}
#endif

#endif /* _BER_TLV_TAG_H_ */
