ber_tlv_tag.h

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/*-
 * Copyright (c) 2003, 2004 Lev Walkin <vlm@lionet.info>. All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#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 buflen);
ssize_t ber_tlv_tag_fwrite(ber_tlv_tag_t tag, FILE *);
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_ */