asn1_read_value(3)						     libtasn1							asn1_read_value(3)

NAME

       asn1_read_value - Returns the value of one element inside a structure

SYNOPSIS

       #include <libtasn1.h>

       asn1_retCode asn1_read_value(ASN1_TYPE root, const char * name, void * ivalue, int * len);

ARGUMENTS

       ASN1_TYPE 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.

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

DESCRIPTION

       Returns the value of one element inside a structure.

       If  an  element	is OPTIONAL and the function "read_value" 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.

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
       Set value OK.

ASN1_ELEMENT_NOT_FOUND
       NAME is not a valid element.

ASN1_VALUE_NOT_FOUND
       There isn't any value for the element selected.

ASN1_MEM_ERROR
       The value vector isn't big enough to store the result.  In this case LEN will contain the number of bytes needed.

COPYRIGHT

       Copyright (C) 2006, 2007, 2008, 2009 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.

libtasn1								2.2							asn1_read_value(3)