Manpages - asn1_der_decoding_startEnd.3

asn1_der_decoding_startEnd - API function

#include <libtasn1.h>

int asn1_der_decoding_startEnd(asn1_node */element/, const void * ider, int ider_len, const char * name_element, int * start, int * end);*

asn1_node element

pointer to an ASN1 element

const void * ider

vector that contains the DER encoding.

int ider_len

number of bytes of * ider : ider [0].. ider [len-1]

const char * name_element

an element of NAME structure.

int * start

the position of the first byte of NAME_ELEMENT decoding ( ider [*start])

int * end

the position of the last byte of NAME_ELEMENT decoding ( ider [*end])

Find the start and end point of an element in a DER encoding string. I mean that if you have a der encoding and you have already used the function asn1_der_decoding() to fill a structure, it may happen that you want to find the piece of string concerning an element of the structure.

One example is the sequence “tbsCertificate” inside an X509 certificate.

Note that since libtasn1 3.7 the ider and ider_len parameters can be omitted, if the element is already decoded using asn1_der_decoding().

ASN1_SUCCESS if DER encoding OK, ASN1_ELEMENT_NOT_FOUND if ELEMENT is asn1_node EMPTY or name_element is not a valid element, ASN1_TAG_ERROR or ASN1_DER_ERROR if the der encoding doesn’t match the structure ELEMENT.

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