NAME

       asn1_read_value_type - API function

SYNOPSIS

       #include <libtasn1.h>

       int  asn1_read_value_type(asn1_node_const  root,  const  char * name, void * ivalue, int *
       len, unsigned int * etype);

ARGUMENTS

       asn1_node_const root
                   pointer to a structure.

       const char * name
                   the name of the element inside a structure that you want to read.

       void * ivalue
                   vector that will contain the element's content, must be a  pointer  to  memory
                   cells already allocated (may be NULL).

       int * len   number  of  bytes of *value: value[0]..value[len-1]. Initialy holds the sizeof
                   value.

       unsigned int * etype
                   The type of the value read (ASN1_ETYPE)

DESCRIPTION

       Returns the type and value of one element inside a structure.  If an element  is  OPTIONAL
       and  this returns ASN1_ELEMENT_NOT_FOUND, it means that this element wasn't present in the
       der encoding that created the structure.  The first element of a SEQUENCE_OF or SET_OF  is
       named  "?1".  The  second  one "?2" and so on. If the  root provided is a node to specific
       sequence element, then the keyword "?CURRENT" is also acceptable and indicates the current
       sequence element of this node.

       Note  that  there  can  be valid values with length zero. In these case this function will
       succeed and  len will be zero.

INTEGER

       VALUE will contain a two's complement form integer.

       integer=-1  -> value[0]=0xFF , len=1.  integer=1   -> value[0]=0x01 , len=1.

ENUMERATED

       As INTEGER (but only with not negative numbers).

BOOLEAN

       VALUE will be the null terminated string "TRUE" or "FALSE" and LEN=5 or LEN=6.

       OBJECT IDENTIFIER: VALUE will be a null terminated string with each number separated by  a
       dot (i.e. "1.2.3.543.1").

       LEN = strlen(VALUE)+1

UTCTIME

       VALUE  will  be a null terminated string in one of these formats: "YYMMDDhhmmss+hh'mm'" or
       "YYMMDDhhmmss-hh'mm'".  LEN=strlen(VALUE)+1.

GENERALIZEDTIME

       VALUE will be a null terminated string in the same format used to set the value.

       OCTET STRING: VALUE will contain the octet string and LEN will be the number of octets.

GENERALSTRING

       VALUE will contain the generalstring and LEN will be the number of octets.

       BIT STRING: VALUE will contain the bit string organized by  bytes  and  LEN  will  be  the
       number of bits.

CHOICE

       If NAME indicates a choice type, VALUE will specify the alternative selected.

ANY

       If  NAME  indicates  an  any  type,  VALUE will indicate the DER encoding of the structure
       actually used.

RETURNS

       ASN1_SUCCESS if value is returned, ASN1_ELEMENT_NOT_FOUND if  name is not a valid element,
       ASN1_VALUE_NOT_FOUND if there isn't any value for the element selected, and ASN1_MEM_ERROR
       if The value vector isn't big enough to store the result,  and  in  this  case   len  will
       contain  the  number  of  bytes  needed.  On  the  occasion  that  the  stored data are of
       zero-length this function may return ASN1_SUCCESS even if the provided  len is zero.

COPYRIGHT

       Copyright © 2006-2022 Free Software Foundation, Inc..
       Copying and distribution of this file, with or without modification, are permitted in  any
       medium without royalty provided the copyright notice and this notice are preserved.

SEE ALSO

       The  full  documentation  for libtasn1 is maintained as a Texinfo manual.  If the info and
       libtasn1 programs are properly installed at your site, the command

              info libtasn1

       should give you access to the complete manual.  As  an  alternative  you  may  obtain  the
       manual from:

              https://www.gnu.org/software/libtasn1/manual/