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asn1_read_value(3) [debian man page]

asn1_read_value(3)						     libtasn1							asn1_read_value(3)

NAME

       asn1_read_value - API function

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 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 (C) 2006-2011 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							       2.13							asn1_read_value(3)

Check Out this Related Man Page

asn1_der_decoding_startEnd(3)					     libtasn1					     asn1_der_decoding_startEnd(3)

NAME

       asn1_der_decoding_startEnd - API function

SYNOPSIS

       #include <libtasn1.h>

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

ARGUMENTS

       asn1_node element
		   pointer to an ASN1 element

       const void * ider
		   vector that contains the DER encoding.

       int 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])

DESCRIPTION

       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.

RETURNS

       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.

COPYRIGHT

       Copyright (C) 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.

libtasn1								3.3					     asn1_der_decoding_startEnd(3)
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