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#descDescription libtasn1
libtasn1 — 
Synopsis
#define     
gnutls-libtasn1.html#LIBTASN1-VERSION:CAPSLIBTASN1_VERSION #define     
gnutls-libtasn1.html#MAX-NAME-SIZE:CAPSMAX_NAME_SIZE #define     
gnutls-libtasn1.html#MAX-ERROR-DESCRIPTION-SIZE:CAPSMAX_ERROR_DESCRIPTION_SIZE typedef     
gnutls-libtasn1.html#asn1-retCodeasn1_retCode ;
#define     
gnutls-libtasn1.html#ASN1-SUCCESS:CAPSASN1_SUCCESS #define     
gnutls-libtasn1.html#ASN1-FILE-NOT-FOUND:CAPSASN1_FILE_NOT_FOUND #define     
gnutls-libtasn1.html#ASN1-ELEMENT-NOT-FOUND:CAPSASN1_ELEMENT_NOT_FOUND #define     
gnutls-libtasn1.html#ASN1-IDENTIFIER-NOT-FOUND:CAPSASN1_IDENTIFIER_NOT_FOUND #define     
gnutls-libtasn1.html#ASN1-DER-ERROR:CAPSASN1_DER_ERROR #define     
gnutls-libtasn1.html#ASN1-VALUE-NOT-FOUND:CAPSASN1_VALUE_NOT_FOUND #define     
gnutls-libtasn1.html#ASN1-GENERIC-ERROR:CAPSASN1_GENERIC_ERROR #define     
gnutls-libtasn1.html#ASN1-VALUE-NOT-VALID:CAPSASN1_VALUE_NOT_VALID #define     
gnutls-libtasn1.html#ASN1-TAG-ERROR:CAPSASN1_TAG_ERROR #define     
gnutls-libtasn1.html#ASN1-TAG-IMPLICIT:CAPSASN1_TAG_IMPLICIT #define     
gnutls-libtasn1.html#ASN1-ERROR-TYPE-ANY:CAPSASN1_ERROR_TYPE_ANY #define     
gnutls-libtasn1.html#ASN1-SYNTAX-ERROR:CAPSASN1_SYNTAX_ERROR #define     
gnutls-libtasn1.html#ASN1-MEM-ERROR:CAPSASN1_MEM_ERROR #define     
gnutls-libtasn1.html#ASN1-MEM-ALLOC-ERROR:CAPSASN1_MEM_ALLOC_ERROR #define     
gnutls-libtasn1.html#ASN1-DER-OVERFLOW:CAPSASN1_DER_OVERFLOW #define     
gnutls-libtasn1.html#ASN1-NAME-TOO-LONG:CAPSASN1_NAME_TOO_LONG #define     
gnutls-libtasn1.html#ASN1-ARRAY-ERROR:CAPSASN1_ARRAY_ERROR #define     
gnutls-libtasn1.html#ASN1-ELEMENT-NOT-EMPTY:CAPSASN1_ELEMENT_NOT_EMPTY #define     
gnutls-libtasn1.html#ASN1-PRINT-NAME:CAPSASN1_PRINT_NAME #define     
gnutls-libtasn1.html#ASN1-PRINT-NAME-TYPE:CAPSASN1_PRINT_NAME_TYPE #define     
gnutls-libtasn1.html#ASN1-PRINT-NAME-TYPE-VALUE:CAPSASN1_PRINT_NAME_TYPE_VALUE #define     
gnutls-libtasn1.html#ASN1-PRINT-ALL:CAPSASN1_PRINT_ALL #define     
gnutls-libtasn1.html#ASN1-CLASS-UNIVERSAL:CAPSASN1_CLASS_UNIVERSAL #define     
gnutls-libtasn1.html#ASN1-CLASS-APPLICATION:CAPSASN1_CLASS_APPLICATION #define     
gnutls-libtasn1.html#ASN1-CLASS-CONTEXT-SPECIFIC:CAPSASN1_CLASS_CONTEXT_SPECIFIC #define     
gnutls-libtasn1.html#ASN1-CLASS-PRIVATE:CAPSASN1_CLASS_PRIVATE #define     
gnutls-libtasn1.html#ASN1-TAG-BOOLEAN:CAPSASN1_TAG_BOOLEAN #define     
gnutls-libtasn1.html#ASN1-TAG-INTEGER:CAPSASN1_TAG_INTEGER #define     
gnutls-libtasn1.html#ASN1-TAG-SEQUENCE:CAPSASN1_TAG_SEQUENCE #define     
gnutls-libtasn1.html#ASN1-TAG-SET:CAPSASN1_TAG_SET #define     
gnutls-libtasn1.html#ASN1-TAG-OCTET-STRING:CAPSASN1_TAG_OCTET_STRING #define     
gnutls-libtasn1.html#ASN1-TAG-BIT-STRING:CAPSASN1_TAG_BIT_STRING #define     
gnutls-libtasn1.html#ASN1-TAG-UTCTimeASN1_TAG_UTCTime #define     
gnutls-libtasn1.html#ASN1-TAG-GENERALIZEDTimeASN1_TAG_GENERALIZEDTime #define     
gnutls-libtasn1.html#ASN1-TAG-OBJECT-ID:CAPSASN1_TAG_OBJECT_ID #define     
gnutls-libtasn1.html#ASN1-TAG-ENUMERATED:CAPSASN1_TAG_ENUMERATED #define     
gnutls-libtasn1.html#ASN1-TAG-NULL:CAPSASN1_TAG_NULL #define     
gnutls-libtasn1.html#ASN1-TAG-GENERALSTRING:CAPSASN1_TAG_GENERALSTRING             
gnutls-libtasn1.html#node-asnnode_asn ;
typedef     
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE ;
#define     
gnutls-libtasn1.html#ASN1-TYPE-EMPTY:CAPSASN1_TYPE_EMPTY struct      
gnutls-libtasn1.html#static-struct-asnstatic_struct_asn ;
typedef     
gnutls-libtasn1.html#ASN1-ARRAY-TYPE:CAPSASN1_ARRAY_TYPE ;
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-parser2treeasn1_parser2tree                (const char *file_name,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *definitions,
                                             char *errorDescription);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-parser2arrayasn1_parser2array               (const char *inputFileName,
                                             const char *outputFileName,
                                             const char *vectorName,
                                             char *errorDescription);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-array2treeasn1_array2tree                 (const gnutls-libtasn1.html#ASN1-ARRAY-TYPE:CAPSASN1_ARRAY_TYPE  *array,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *definitions,
                                             char *errorDescription);
../gss/gss-ext.html#voidvoid         gnutls-libtasn1.html#asn1-print-structureasn1_print_structure             (FILE *out,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  structure,
                                             const char *name,
                                             int mode);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-create-elementasn1_create_element             ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             const char *source_name,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-delete-structureasn1_delete_structure           ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *structure);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-delete-elementasn1_delete_element             ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  structure,
                                             const char *element_name);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-write-valueasn1_write_value                ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  node_root,
                                             const char *name,
                                             const 
../gss/gss-ext.html#voidvoid  *ivalue,
                                             int len);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-read-valueasn1_read_value                 ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  root,
                                             const char *name,
                                             
../gss/gss-ext.html#voidvoid  *ivalue,
                                             int *len);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-number-of-elementsasn1_number_of_elements         ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  element,
                                             const char *name,
                                             int *num);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-der-codingasn1_der_coding                 ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  element,
                                             const char *name,
                                             
../gss/gss-ext.html#voidvoid  *ider,
                                             int *len,
                                             char *ErrorDescription);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-der-decodingasn1_der_decoding               ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element,
                                             const 
../gss/gss-ext.html#voidvoid  *ider,
                                             int len,
                                             char *errorDescription);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-der-decoding-elementasn1_der_decoding_element       ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *structure,
                                             const char *elementName,
                                             const 
../gss/gss-ext.html#voidvoid  *ider,
                                             int len,
                                             char *errorDescription);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-der-decoding-startEndasn1_der_decoding_startEnd      ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  element,
                                             const 
../gss/gss-ext.html#voidvoid  *ider,
                                             int len,
                                             const char *name_element,
                                             int *start,
                                             int *end);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-expand-any-defined-byasn1_expand_any_defined_by      ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-expand-octet-stringasn1_expand_octet_string        ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element,
                                             const char *octetName,
                                             const char *objectName);
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  gnutls-libtasn1.html#asn1-read-tagasn1_read_tag                   ( gnutls-libtasn1.html#node-asnnode_asn  *root,
                                             const char *name,
                                             int *tagValue,
                                             int *classValue);
const char* 
gnutls-libtasn1.html#asn1-find-structure-from-oidasn1_find_structure_from_oid     ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             const char *oidValue);
const char* 
gnutls-libtasn1.html#asn1-check-versionasn1_check_version               (const char *req_version);
const char* 
gnutls-libtasn1.html#libtasn1-strerrorlibtasn1_strerror                ( gnutls-libtasn1.html#asn1-retCodeasn1_retCode  error);
../gss/gss-ext.html#voidvoid         gnutls-libtasn1.html#libtasn1-perrorlibtasn1_perror                  ( gnutls-libtasn1.html#asn1-retCodeasn1_retCode  error);
Description
Details
LIBTASN1_VERSION
#define LIBTASN1_VERSION "0.2.18"
MAX_NAME_SIZE
#define MAX_NAME_SIZE 128 /* maximum number of characters of a name */ 
MAX_ERROR_DESCRIPTION_SIZE
#define MAX_ERROR_DESCRIPTION_SIZE 128 /* maximum number of characters */ 
asn1_retCode
typedef int asn1_retCode;  /* type returned by libtasn1 functions */
ASN1_SUCCESS
#define ASN1_SUCCESS               0
ASN1_FILE_NOT_FOUND
#define ASN1_FILE_NOT_FOUND        1
ASN1_ELEMENT_NOT_FOUND
#define ASN1_ELEMENT_NOT_FOUND     2
ASN1_IDENTIFIER_NOT_FOUND
#define ASN1_IDENTIFIER_NOT_FOUND  3
ASN1_DER_ERROR
#define ASN1_DER_ERROR             4
ASN1_VALUE_NOT_FOUND
#define ASN1_VALUE_NOT_FOUND       5
ASN1_GENERIC_ERROR
#define ASN1_GENERIC_ERROR         6
ASN1_VALUE_NOT_VALID
#define ASN1_VALUE_NOT_VALID       7
ASN1_TAG_ERROR
#define ASN1_TAG_ERROR             8
ASN1_TAG_IMPLICIT
#define ASN1_TAG_IMPLICIT          9
ASN1_ERROR_TYPE_ANY
#define ASN1_ERROR_TYPE_ANY        10
ASN1_SYNTAX_ERROR
#define ASN1_SYNTAX_ERROR          11
ASN1_MEM_ERROR
#define ASN1_MEM_ERROR		   12
ASN1_MEM_ALLOC_ERROR
#define ASN1_MEM_ALLOC_ERROR	   13
ASN1_DER_OVERFLOW
#define ASN1_DER_OVERFLOW          14
ASN1_NAME_TOO_LONG
#define ASN1_NAME_TOO_LONG         15
ASN1_ARRAY_ERROR
#define ASN1_ARRAY_ERROR           16
ASN1_ELEMENT_NOT_EMPTY
#define ASN1_ELEMENT_NOT_EMPTY     17
ASN1_PRINT_NAME
#define ASN1_PRINT_NAME             1
ASN1_PRINT_NAME_TYPE
#define ASN1_PRINT_NAME_TYPE        2
ASN1_PRINT_NAME_TYPE_VALUE
#define ASN1_PRINT_NAME_TYPE_VALUE  3
ASN1_PRINT_ALL
#define ASN1_PRINT_ALL              4
ASN1_CLASS_UNIVERSAL
#define ASN1_CLASS_UNIVERSAL        1
ASN1_CLASS_APPLICATION
#define ASN1_CLASS_APPLICATION      2
ASN1_CLASS_CONTEXT_SPECIFIC
#define ASN1_CLASS_CONTEXT_SPECIFIC 3
ASN1_CLASS_PRIVATE
#define ASN1_CLASS_PRIVATE          4
ASN1_TAG_BOOLEAN
#define ASN1_TAG_BOOLEAN          0x01
ASN1_TAG_INTEGER
#define ASN1_TAG_INTEGER          0x02
ASN1_TAG_SEQUENCE
#define ASN1_TAG_SEQUENCE         0x10
ASN1_TAG_SET
#define ASN1_TAG_SET              0x11
ASN1_TAG_OCTET_STRING
#define ASN1_TAG_OCTET_STRING     0x04
ASN1_TAG_BIT_STRING
#define ASN1_TAG_BIT_STRING       0x03
ASN1_TAG_UTCTime
#define ASN1_TAG_UTCTime          0x17
ASN1_TAG_GENERALIZEDTime
#define ASN1_TAG_GENERALIZEDTime  0x18
ASN1_TAG_OBJECT_ID
#define ASN1_TAG_OBJECT_ID        0x06
ASN1_TAG_ENUMERATED
#define ASN1_TAG_ENUMERATED       0x0A
ASN1_TAG_NULL
#define ASN1_TAG_NULL             0x05
ASN1_TAG_GENERALSTRING
#define ASN1_TAG_GENERALSTRING    0x1B
node_asn
typedef struct {
  char *name;                    /* Node name */
  unsigned int type;             /* Node type */
  unsigned char *value;          /* Node value */
  int value_len;
  struct node_asn_struct *down;  /* Pointer to the son node */
  struct node_asn_struct *right; /* Pointer to the brother node */
  struct node_asn_struct *left;  /* Pointer to the next list element */ 
} node_asn;
ASN1_TYPE
typedef node_asn* ASN1_TYPE;
ASN1_TYPE_EMPTY
#define ASN1_TYPE_EMPTY  NULL
struct static_struct_asn
struct static_struct_asn {
  char *name;                    /* Node name */
  unsigned int type;             /* Node type */
  unsigned char *value;          /* Node value */
};
ASN1_ARRAY_TYPE
typedef struct static_struct_asn ASN1_ARRAY_TYPE;
asn1_parser2tree ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_parser2tree               (const char *file_name,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *definitions,
                                             char *errorDescription);
file_name : definitions : errorDescription : Returns : asn1_parser2array ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_parser2array              (const char *inputFileName,
                                             const char *outputFileName,
                                             const char *vectorName,
                                             char *errorDescription);
inputFileName : outputFileName : vectorName : errorDescription : Returns : asn1_array2tree ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_array2tree                (const gnutls-libtasn1.html#ASN1-ARRAY-TYPE:CAPSASN1_ARRAY_TYPE  *array,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *definitions,
                                             char *errorDescription);
Creates the structures needed to manage the ASN.1 definitions.
array is a vector created by gnutls-libtasn1.html#asn1-parser2arrayasn1_parser2array() .
array :  specify the array that contains ASN.1 declarations
definitions :  return the pointer to the structure created by
  *ARRAY ASN.1 declarations
errorDescription :  return the error description.
Returns : ASN1_SUCCESS: Structure created correctly.
ASN1_ELEMENT_NOT_EMPTY: *
definitions not ASN1_TYPE_EMPTY.
ASN1_IDENTIFIER_NOT_FOUND: In the file there is an identifier that
  is not defined (see 
errorDescription for more information).
ASN1_ARRAY_ERROR: The array pointed by 
array is wrong.
asn1_print_structure ()
../gss/gss-ext.html#voidvoid         asn1_print_structure            (FILE *out,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  structure,
                                             const char *name,
                                             int mode);
Prints on the 
out file descriptor the structure's tree starting
from the 
name element inside the structure structure.
out :  pointer to the output file (e.g. stdout).
structure :  pointer to the structure that you want to visit.
name :  an element of the structure
mode :  specify how much of the structure to print, can be
  
ASN1_PRINT_NAME, ASN1_PRINT_NAME_TYPE,
  
ASN1_PRINT_NAME_TYPE_VALUE, or ASN1_PRINT_ALL.
asn1_create_element ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_create_element            ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             const char *source_name,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element);Creates a structure of type 
source_name.  Example using
 "pkix.asn":
rc = asn1_create_structure(cert_def, "PKIX1.Certificate",
certptr);
definitions :  pointer to the structure returned by "parser_asn1" function
source_name :  the name of the type of the new structure (must be
  inside p_structure).
element :  pointer to the structure created.
Returns : ASN1_SUCCESS: Creation OK.
ASN1_ELEMENT_NOT_FOUND: SOURCE_NAME isn't known
asn1_delete_structure ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_delete_structure          ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *structure);Deletes the structure *
structure.  At the end, *structure is set
to ASN1_TYPE_EMPTY.
structure :  pointer to the structure that you want to delete.
Returns : ASN1_SUCCESS: Everything OK.
ASN1_ELEMENT_NOT_FOUND: *
structure was ASN1_TYPE_EMPTY.
asn1_delete_element ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_delete_element            ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  structure,
                                             const char *element_name);
Deletes the element named *
element_name inside *structure.
structure :  pointer to the structure that contains the element you
  want to delete.
element_name :  element's name you want to delete.
Returns : ASN1_SUCCESS: Everything OK.
ASN1_ELEMENT_NOT_FOUND: The name element was not found.
asn1_write_value ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_write_value               ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  node_root,
                                             const char *name,
                                             const 
../gss/gss-ext.html#voidvoid  *ivalue,
                                             int len);
Set the value of one element inside a structure.
If an element is OPTIONAL and you want to delete it, you must use
the value=NULL and len=0.  Using "pkix.asn":
result=asn1_write_value(cert, "tbsCertificate.issuerUniqueID",
NULL, 0);
Description for each type:
INTEGER: VALUE must contain a two's complement form integer.
           value[0]=0xFF ,               len=1 -> integer=-1.
           value[0]=0xFF value[1]=0xFF , len=2 -> integer=-1.
           value[0]=0x01 ,               len=1 -> integer= 1.
           value[0]=0x00 value[1]=0x01 , len=2 -> integer= 1.
           value="123"                 , len=0 -> integer= 123.
ENUMERATED: As INTEGER (but only with not negative numbers).
BOOLEAN: VALUE must be the null terminated string "TRUE" or
  "FALSE" and LEN != 0.
           value="TRUE" , len=1 -> boolean=TRUE.
           value="FALSE" , len=1 -> boolean=FALSE.
OBJECT IDENTIFIER: VALUE must be a null terminated string with
  each number separated by a dot (e.g. "1.2.3.543.1").  LEN != 0.
           value="1 2 840 10040 4 3" , len=1 -> OID=dsa-with-sha.
UTCTime: VALUE must be a null terminated string in one of these
  formats: "YYMMDDhhmmssZ", "YYMMDDhhmmssZ",
  "YYMMDDhhmmss+hh'mm'", "YYMMDDhhmmss-hh'mm'",
  "YYMMDDhhmm+hh'mm'", or "YYMMDDhhmm-hh'mm'".  LEN != 0.
           value="9801011200Z" , len=1 -> time=Jannuary 1st, 1998
           at 12h 00m Greenwich Mean Time
GeneralizedTime: VALUE must be in one of this format:
  "YYYYMMDDhhmmss.sZ", "YYYYMMDDhhmmss.sZ",
  "YYYYMMDDhhmmss.s+hh'mm'", "YYYYMMDDhhmmss.s-hh'mm'",
  "YYYYMMDDhhmm+hh'mm'", or "YYYYMMDDhhmm-hh'mm'" where ss.s
  indicates the seconds with any precision like "10.1" or "01.02".
  LEN != 0
           value="2001010112001.12-0700" , len=1 -> time=Jannuary
           1st, 2001 at 12h 00m 01.12s Pacific Daylight Time
OCTET STRING: VALUE contains the octet string and LEN is the
  number of octets.
           value="$\backslash$x01$\backslash$x02$\backslash$x03" ,
           len=3 -> three bytes octet string
GeneralString: VALUE contains the generalstring and LEN is the
  number of octets.
           value="$\backslash$x01$\backslash$x02$\backslash$x03" ,
           len=3 -> three bytes generalstring
BIT STRING: VALUE contains the bit string organized by bytes and
  LEN is the number of bits.
  value="$\backslash$xCF" , len=6 -> bit string="110011" (six
  bits)
CHOICE: if NAME indicates a choice type, VALUE must specify one of
  the alternatives with a null terminated string. LEN != 0. Using
  "pkix.asn"\:
          result=asn1_write_value(cert,
          "certificate1.tbsCertificate.subject", "rdnSequence",
          1);
ANY: VALUE indicates the der encoding of a structure.  LEN != 0.
SEQUENCE OF: VALUE must be the null terminated string "NEW" and
  LEN != 0. With this instruction another element is appended in
  the sequence. The name of this element will be "?1" if it's the
  first one, "?2" for the second and so on.
  Using "pkix.asn"\:
  result=asn1_write_value(cert,
  "certificate1.tbsCertificate.subject.rdnSequence", "NEW", 1);
SET OF: the same as SEQUENCE OF.  Using "pkix.asn":
          result=asn1_write_value(cert,
          "tbsCertificate.subject.rdnSequence.?LAST", "NEW", 1);
node_root :  pointer to a structure
name :  the name of the element inside the structure that you want to set.
ivalue :  vector used to specify the value to set. If len is >0,
  VALUE must be a two's complement form integer.  if len=0 *VALUE
  must be a null terminated string with an integer value.
len :  number of bytes of *value to use to set the value:
  value[0]..value[len-1] or 0 if value is a null terminated string
Returns :   ASN1_SUCCESS: Set value OK.
  ASN1_ELEMENT_NOT_FOUND: NAME is not a valid element.
  ASN1_VALUE_NOT_VALID: VALUE has a wrong format.
asn1_read_value ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_read_value                ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  root,
                                             const char *name,
                                             
../gss/gss-ext.html#voidvoid  *ivalue,
                                             int *len);
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.
root :  pointer to a structure.
name :  the name of the element inside a structure that you want to read.
ivalue :  vector that will contain the element's content, must be a
  pointer to memory cells already allocated.
len :  number of bytes of *value: value[0]..value[len-1]. Initialy
  holds the sizeof value.
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.
asn1_number_of_elements ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_number_of_elements        ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  element,
                                             const char *name,
                                             int *num);
Counts the number of elements of a sub-structure called NAME with
names equal to "?1","?2", ...
element :  pointer to the root of an ASN1 structure.
name :  the name of a sub-structure of ROOT.
num :  pointer to an integer where the result will be stored
Returns :  ASN1_SUCCESS: Creation OK.
 ASN1_ELEMENT_NOT_FOUND: NAME isn't known.
 ASN1_GENERIC_ERROR: Pointer num equal to NULL.
asn1_der_coding ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_der_coding                ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  element,
                                             const char *name,
                                             
../gss/gss-ext.html#voidvoid  *ider,
                                             int *len,
                                             char *ErrorDescription);
Creates the DER encoding for the NAME structure (inside *POINTER
structure).
element :  pointer to an ASN1 element
name :  the name of the structure you want to encode (it must be
  inside *POINTER).
ider :  vector that will contain the DER encoding. DER must be a
  pointer to memory cells already allocated.
len :  number of bytes of *ider: ider[0]..ider[len-1], Initialy
  holds the sizeof of der vector.
ErrorDescription :  return the error description or an empty
  string if success.
Returns :   ASN1_SUCCESS: DER encoding OK.
  ASN1_ELEMENT_NOT_FOUND: NAME is not a valid element.
  ASN1_VALUE_NOT_FOUND: There is an element without a value.
  ASN1_MEM_ERROR: 
ider vector isn't big enough. Also in this case
    LEN will contain the length needed.
asn1_der_decoding ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_der_decoding              ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element,
                                             const 
../gss/gss-ext.html#voidvoid  *ider,
                                             int len,
                                             char *errorDescription);
Fill the structure *ELEMENT with values of a DER encoding
string. The sructure must just be created with function
'create_stucture'.  If an error occurs during the decoding
procedure, the *ELEMENT is deleted and set equal to
ASN1_TYPE_EMPTY.
element :  pointer to an ASN1 structure.
ider :  vector that contains the DER encoding.
len :  number of bytes of *ider: ider[0]..ider[len-1].
errorDescription :  null-terminated string contains details when an
  error occurred.
Returns :   ASN1_SUCCESS: DER encoding OK.
  ASN1_ELEMENT_NOT_FOUND: ELEMENT is ASN1_TYPE_EMPTY.
  ASN1_TAG_ERROR,ASN1_DER_ERROR: The der encoding doesn't match
    the structure NAME. *ELEMENT deleted.
asn1_der_decoding_element ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_der_decoding_element      ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *structure,
                                             const char *elementName,
                                             const 
../gss/gss-ext.html#voidvoid  *ider,
                                             int len,
                                             char *errorDescription);
Fill the element named ELEMENTNAME with values of a DER encoding
string.  The sructure must just be created with function
'create_stucture'.  The DER vector must contain the encoding
string of the whole STRUCTURE.  If an error occurs during the
decoding procedure, the *STRUCTURE is deleted and set equal to
ASN1_TYPE_EMPTY.
structure :  pointer to an ASN1 structure
elementName :  name of the element to fill
ider :  vector that contains the DER encoding of the whole structure.
len :  number of bytes of *der: der[0]..der[len-1]
errorDescription :  null-terminated string contains details when an
  error occurred.
Returns :   ASN1_SUCCESS: DER encoding OK.
  ASN1_ELEMENT_NOT_FOUND: ELEMENT is ASN1_TYPE_EMPTY or
    elementName == NULL.
  ASN1_TAG_ERROR,ASN1_DER_ERROR: The der encoding doesn't match
  the structure STRUCTURE. *ELEMENT deleted.
asn1_der_decoding_startEnd ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_der_decoding_startEnd     ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  element,
                                             const 
../gss/gss-ext.html#voidvoid  *ider,
                                             int len,
                                             const char *name_element,
                                             int *start,
                                             int *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.
Example: the sequence "tbsCertificate" inside an X509 certificate.
element :  pointer to an ASN1 element
ider :  vector that contains the DER encoding.
len :  number of bytes of *ider: ider[0]..ider[len-1]
name_element :  an element of NAME structure.
start :  the position of the first byte of NAME_ELEMENT decoding
  (
ider[*start])
end :  the position of the last byte of NAME_ELEMENT decoding
 (
ider[*end])
Returns :   ASN1_SUCCESS: DER encoding OK.
  ASN1_ELEMENT_NOT_FOUND: ELEMENT is ASN1_TYPE EMPTY or
  NAME_ELEMENT is not a valid element.
  ASN1_TAG_ERROR,ASN1_DER_ERROR: the der encoding doesn't match
  the structure ELEMENT.
asn1_expand_any_defined_by ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_expand_any_defined_by     ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element);Expands every "ANY DEFINED BY" element of a structure created from
a DER decoding process (asn1_der_decoding function). The element ANY
must be defined by an OBJECT IDENTIFIER. The type used to expand
the element ANY is the first one following the definition of
the actual value of the OBJECT IDENTIFIER.
definitions :  ASN1 definitions
element :  pointer to an ASN1 structure
Returns :   ASN1_SUCCESS: Substitution OK.
  ASN1_ERROR_TYPE_ANY: Some "ANY DEFINED BY" element couldn't be
  expanded due to a problem in OBJECT_ID -> TYPE association.
  other errors: Result of der decoding process.
asn1_expand_octet_string ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_expand_octet_string       ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             
gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  *element,
                                             const char *octetName,
                                             const char *objectName);
Expands an "OCTET STRING" element of a structure created from a
DER decoding process (asn1_der_decoding function). The type used
for expansion is the first one following the definition of the
actual value of the OBJECT IDENTIFIER indicated by OBJECTNAME.
definitions :  ASN1 definitions
element :  pointer to an ASN1 structure
octetName :  name of the OCTECT STRING field to expand.
objectName :  name of the OBJECT IDENTIFIER field to use to define
   the type for expansion.
Returns :   ASN1_SUCCESS: Substitution OK.
  ASN1_ELEMENT_NOT_FOUND: OBJECTNAME or OCTETNAME are not correct.
  ASN1_VALUE_NOT_VALID: Wasn't possible to find the type to use
      for expansion.
  other errors: result of der decoding process.
asn1_read_tag ()
gnutls-libtasn1.html#asn1-retCodeasn1_retCode  asn1_read_tag                  ( gnutls-libtasn1.html#node-asnnode_asn  *root,
                                             const char *name,
                                             int *tagValue,
                                             int *classValue);
Returns the TAG and the CLASS of one element inside a structure.
CLASS can have one of these constants: 
ASN1_CLASS_APPLICATION,
ASN1_CLASS_UNIVERSAL, ASN1_CLASS_PRIVATE or
ASN1_CLASS_CONTEXT_SPECIFIC.
root :  pointer to a structure
name :  the name of the element inside a structure.
tagValue :   variable that will contain the TAG value.
classValue :  variable that will specify the TAG type.
Returns :   ASN1_SUCCESS: Set value OK.
  ASN1_ELEMENT_NOT_FOUND: NAME is not a valid element.
asn1_find_structure_from_oid ()
const char* asn1_find_structure_from_oid    ( gnutls-libtasn1.html#ASN1-TYPE:CAPSASN1_TYPE  definitions,
                                             const char *oidValue);
Search the structure that is defined just after an OID definition.
definitions :  ASN1 definitions
oidValue :  value of the OID to search (e.g. "1.2.3.4").
Returns :  NULL when OIDVALUE not found, otherwise the pointer to a
  constant string that contains the element name defined just
  after the OID.
asn1_check_version ()
const char* asn1_check_version              (const char *req_version);Check that the the version of the library is at minimum the
requested one and return the version string; return 
NULL if the
condition is not satisfied.  If a 
NULL is passed to this function,
no check is done, but the version string is simply returned.
See 
LIBTASN1_VERSION for a suitable req_version string.
req_version :  Required version number, or NULL.
Returns :  Version string of run-time library, or NULL if the
  run-time library does not meet the required version number.
libtasn1_strerror ()
const char* libtasn1_strerror               ( gnutls-libtasn1.html#asn1-retCodeasn1_retCode  error);This function is similar to 
strerror(). The only difference is
that it accepts an error (number) returned by a libtasn1 function.
error :  is an error returned by a libtasn1 function.
Returns :  Pointer to static zero-terminated string describing error
  code.
libtasn1_perror ()
../gss/gss-ext.html#voidvoid         libtasn1_perror                 ( gnutls-libtasn1.html#asn1-retCodeasn1_retCode  error);This function is like 
perror(). The only difference is that it
accepts an error returned by a libtasn1 function.
error :  is an error returned by a libtasn1 function.
