NAME

       asn1_read_value_type - API function

SYNOPSIS

       #include <libtasn1.h>

       int  asn1_read_value_type(asn1_node  root,  const  char  * name, void * ivalue, int * len,
       unsigned int * etype);

ARGUMENTS

       asn1_node 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 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.

       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.

COPYRIGHT

       Copyright © 2006-2013 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:

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