# Module Netasn1.Value

    module Value: sig .. end

    type pc =

`|` | `Primitive`
`|` | `Constructed`

    type value =

`|` | `Bool of `bool`` | `(*` | Boolean (primitive) | `*)`
`|` | `Integer of `int_value`` | `(*` | Integer (primitive) | `*)`
`|` | `Enum of `int_value`` | `(*` | Enumeration (primitive) | `*)`
`|` | `Real of `real_value`` | `(*` | Floating-point number, using either base 2 or base 10 (primitive) | `*)`
`|` | `Bitstring of `bitstring_value`` | `(*` | Bit strings (primitive or constructed) | `*)`
`|` | `Octetstring of `string`` | `(*` | Octet strings (primitive or constructed) | `*)`
`|` | `Null` | `(*` | Null (primitive) | `*)`
`|` | `Seq of `value list`` | `(*` | Sequences (records or arrays) (constructed) | `*)`
`|` | `Set of `value list`` | `(*` | Sets (constructed) | `*)`
`|` | `Tagptr of `tag_class * int * pc * Netstring_tstring.tstring_polybox * int * int`` | `(*` | Pointer to an undecoded value that was implicitly tagged. The `tag_class` can be `Application`, `Context`, or `Private`. | `*)`
`|` | `Tag of `tag_class * int * pc * value`` | `(*` | Explicit tag (primitive or constructed depending on inner value) | `*)`
`|` | `ITag of `tag_class * int * value`` | `(*` | Implicit tag (never returned by the decoder, but needed for encoding such tags) | `*)`
`|` | `OID of `int array``
`|` | `ROID of `int array``
`|` | `ObjectDescriptor of `string`` | `(*` | A placeholder with a comment (primitive) | `*)`
`|` | `External of `value list`` | `(*` | Something complex I don't understand (constructed) | `*)`
`|` | `Embedded_PDV of `value list`` | `(*` | Something complex I don't understand (constructed) | `*)`
`|` | `NumericString of `string`` | `(*` | String made of digits and spaces (primitive or constructed) | `*)`
`|` | `PrintableString of `string`` | `(*` | A small subset of ASCII (primitive or constructed) | `*)`
`|` | `TeletexString of `string``
`|` | `VideotexString of `string``
`|` | `VisibleString of `string`` | `(*` | 7 bit ASCII w/o control characters (primitive or constructed) | `*)`
`|` | `IA5String of `string`` | `(*` | 7 bit ASCII (primitive or constructed) | `*)`
`|` | `GraphicString of `string`` | `(*` | ISO-2022-encoded string w/o control characters | `*)`
`|` | `GeneralString of `string`` | `(*` | ISO-2022-encoded string | `*)`
`|` | `UniversalString of `string`` | `(*` | Any ISO-10646-1 character string represented as UTF-32-BE (primitive or constructed). Roughly, ISO-10646-1 equals to Unicode. | `*)`
`|` | `BMPString of `string`` | `(*` | Any ISO-10646-1 character string from only the basic multilingual plane, i.e. with code points <= 65535, represented as UTF-16-BE (primitive or constructed) | `*)`
`|` | `UTF8String of `string`` | `(*` | Any ISO-10646-1 character string represented as UTF-8 (primitive or constructed) | `*)`
`|` | `CharString of `string`` | `(*` | A complicated description of an arbitrary charset encoding (primitive or constructed) | `*)`
`|` | `UTCTime of `time_value`` | `(*` | Like GeneralizedTime but less precise, and with 2-digit year | `*)`
`|` | `GeneralizedTime of `time_value`` | `(*` | Calendar date with time of day, including timezone (primitive) | `*)`

    type tag_class =

`|` | `Universal`
`|` | `Application`
`|` | `Context`
`|` | `Private`

    type int_value

    type real_value

    type bitstring_value

    type time_value

    type time_subtype = [ `G | `U ]

    val type_of_value : value -> Netasn1.Type_name.type_name option

Returns the type, or `None` for `Tag`, `ITag` and `Tagptr`

#### Integer

    val get_int_repr : int_value -> string

Get an integer as bytes

    val get_int_b256 : int_value -> int array

Get an integer in base 256 notation, big endian. Negative values are represented using two's complement (i.e. the first array element is >= 128). The empty array means 0.

    val get_int : int_value -> int

Get an integer as `int` if representable, or raise `Out_of_range`

    val get_int32 : int_value -> int32

Get an integer as `int32` if representable, or raise `Out_of_range`

    val get_int64 : int_value -> int64

Get an integer as `int64` if representable, or raise `Out_of_range`

    val int : int -> int_value

Create an int

    val int32 : int32 -> int_value

Create an int

    val int64 : int64 -> int_value

Create an int

    val int_b256 : int array -> int_value

Create an int from a base 256 number, big endian, signed

#### Real

Reals are not really supported ;-(

    val get_real_repr : real_value -> string

Get the byte representation of the real

#### Bitstring

In some contexts it is usual that trailing zero bits are truncated.

    val get_bitstring_size : bitstring_value -> int

Get the number of bits

    val get_bitstring_data : bitstring_value -> string

Get the data. The last byte may be partial. The order of the bits in every byte: bit 7 (MSB) contains the first bit

    val get_bitstring_bits : ?size:int -> bitstring_value -> bool array

Get the bitstring as bool array. If `size` is specified the array will have exactly this number of bits (by dropping exceeding data, or by adding `false` at the end)

    val get_bitstring_repr : bitstring_value -> string

Get the representation

    val bitstring_of_bits : bool array -> bitstring_value

Get the bitstring from a bool array

    val bitstring_of_string : string -> int -> bitstring_value

Get the bitstring from a string and the total number of bits. The bits are taken from the beginning of the string (MSB first). If the string is shorter than the number of bits suggests, the remaining bits are assumed to be zero. If the string is longer than the number of bits suggests, the exceeding data is ignored.

    val truncate_trailing_zero_bits : bitstring_value -> bitstring_value

Truncates the biggest trailing part that only consist of 0 bits

#### Time

Time values referring to the local time zone are not supported

    val get_time_subtype : time_value -> time_subtype

Whether this is for UTCTime (``U`) or GeneralizedTime (``G`)

    val get_time_repr : time_value -> string

Get the raw time string

    val get_time : time_value -> Netdate.t

Get the time. Notes:

- UTCTime years are two-digit years, and interpreted so that 0-49 is understood as 2000-2049, and 50-99 is understood as 1950-1999 (as required by X.509).
- This function is restricted to the time formats occurring in DER (string terminates with "Z", i.e. UTC time zone)

    val utctime : Netdate.t -> time_value

Create a time value for UTCTime. This function is restricted to years between 1950 and 2049.

    val gentime : digits:int -> Netdate.t -> time_value

Create a time value for GeneralizedTime. `digits` is the number of fractional (subsecond) digits

#### Equality

    val equal : value -> value -> bool

Checks for equality. Notes:

- `Tag` and `Tagptr` are considered different
- `Tagptr` is checked by comparing the equality of the substring
- `Set` is so far not compared as set, but as sequence (i.e. order matters)