int asn1_read_value_type(asn1_node root, const char * name, void * ivalue, int * len, unsigned int * etype);
- 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..value[len-1]. Initialy holds the sizeof value.
- unsigned int * etype
- The type of the value read (ASN1_ETYPE)
DESCRIPTIONReturns 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.
INTEGERVALUE will contain a two's complement form integer.
integer=-1 -> value=0xFF , len=1. integer=1 -> value=0x01 , len=1.
ENUMERATEDAs INTEGER (but only with not negative numbers).
BOOLEANVALUE 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. "126.96.36.1993.1").
LEN = strlen(VALUE)+1
UTCTIMEVALUE will be a null terminated string in one of these formats: "YYMMDDhhmmss+hh'mm'" or "YYMMDDhhmmss-hh'mm'". LEN=strlen(VALUE)+1.
GENERALIZEDTIMEVALUE 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.
GENERALSTRINGVALUE 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.
CHOICEIf NAME indicates a choice type, VALUE will specify the alternative selected.
ANYIf NAME indicates an any type, VALUE will indicate the DER encoding of the structure actually used.
RETURNSASN1_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.
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