1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
use crate::*;
use alloc::borrow::Cow;
#[cfg(not(feature = "std"))]
use alloc::vec::Vec;
use core::convert::TryFrom;

mod btreeset;
mod hashset;
mod iterator;
mod set_of;

pub use iterator::*;
pub use set_of::*;

/// The `SET` object is an unordered list of heteregeneous types.
///
/// Sets can usually be of 2 types:
/// - a list of different objects (`SET`, usually parsed as a `struct`)
/// - a list of similar objects (`SET OF`, usually parsed as a `BTreeSet<T>` or `HashSet<T>`)
///
/// The current object covers the former. For the latter, see the [`SetOf`] documentation.
///
/// The `Set` object contains the (*unparsed*) encoded representation of its content. It provides
/// methods to parse and iterate contained objects, or convert the sequence to other types.
///
/// # Building a Set
///
/// To build a DER set:
/// - if the set is composed of objects of the same type, the [`Set::from_iter_to_der`] method can be used
/// - otherwise, the [`ToDer`] trait can be used to create content incrementally
///
/// ```
/// use asn1_rs::{Integer, Set, SerializeResult, ToDer};
///
/// fn build_set<'a>() -> SerializeResult<Set<'a>> {
///     let mut v = Vec::new();
///     // add an Integer object (construct type):
///     let i = Integer::from_u32(4);
///     let _ = i.write_der(&mut v)?;
///     // some primitive objects also implement `ToDer`. A string will be mapped as `Utf8String`:
///     let _ = "abcd".write_der(&mut v)?;
///     // return the set built from the DER content
///     Ok(Set::new(v.into()))
/// }
///
/// let seq = build_set().unwrap();
///
/// ```
///
/// # Examples
///
/// ```
/// use asn1_rs::{Error, Set};
///
/// // build set
/// let it = [2, 3, 4].iter();
/// let set = Set::from_iter_to_der(it).unwrap();
///
/// // `set` now contains the serialized DER representation of the array
///
/// // iterate objects
/// let mut sum = 0;
/// for item in set.der_iter::<u32, Error>() {
///     // item has type `Result<u32>`, since parsing the serialized bytes could fail
///     sum += item.expect("parsing list item failed");
/// }
/// assert_eq!(sum, 9);
///
/// ```
///
/// Note: the above example encodes a `SET OF INTEGER` object, the [`SetOf`] object could
/// be used to provide a simpler API.
///
#[derive(Clone, Debug)]
pub struct Set<'a> {
    /// Serialized DER representation of the set content
    pub content: Cow<'a, [u8]>,
}

impl<'a> Set<'a> {
    /// Build a set, given the provided content
    pub const fn new(content: Cow<'a, [u8]>) -> Self {
        Set { content }
    }

    /// Consume the set and return the content
    #[inline]
    pub fn into_content(self) -> Cow<'a, [u8]> {
        self.content
    }

    /// Apply the parsing function to the set content, consuming the set
    ///
    /// Note: this function expects the caller to take ownership of content.
    /// In some cases, handling the lifetime of objects is not easy (when keeping only references on
    /// data). Other methods are provided (depending on the use case):
    /// - [`Set::parse`] takes a reference on the set data, but does not consume it,
    /// - [`Set::from_der_and_then`] does the parsing of the set and applying the function
    ///   in one step, ensuring there are only references (and dropping the temporary set).
    pub fn and_then<U, F, E>(self, op: F) -> ParseResult<'a, U, E>
    where
        F: FnOnce(Cow<'a, [u8]>) -> ParseResult<U, E>,
    {
        op(self.content)
    }

    /// Same as [`Set::from_der_and_then`], but using BER encoding (no constraints).
    pub fn from_ber_and_then<U, F, E>(bytes: &'a [u8], op: F) -> ParseResult<'a, U, E>
    where
        F: FnOnce(&'a [u8]) -> ParseResult<U, E>,
        E: From<Error>,
    {
        let (rem, seq) = Set::from_ber(bytes).map_err(Err::convert)?;
        let data = match seq.content {
            Cow::Borrowed(b) => b,
            // Since 'any' is built from 'bytes', it is borrowed by construction
            Cow::Owned(_) => unreachable!(),
        };
        let (_, res) = op(data)?;
        Ok((rem, res))
    }

    /// Parse a DER set and apply the provided parsing function to content
    ///
    /// After parsing, the set object and header are discarded.
    ///
    /// ```
    /// use asn1_rs::{FromDer, ParseResult, Set};
    ///
    /// // Parse a SET {
    /// //      a INTEGER (0..255),
    /// //      b INTEGER (0..4294967296)
    /// // }
    /// // and return only `(a,b)
    /// fn parser(i: &[u8]) -> ParseResult<(u8, u32)> {
    ///     Set::from_der_and_then(i, |i| {
    ///             let (i, a) = u8::from_der(i)?;
    ///             let (i, b) = u32::from_der(i)?;
    ///             Ok((i, (a, b)))
    ///         }
    ///     )
    /// }
    /// ```
    pub fn from_der_and_then<U, F, E>(bytes: &'a [u8], op: F) -> ParseResult<'a, U, E>
    where
        F: FnOnce(&'a [u8]) -> ParseResult<U, E>,
        E: From<Error>,
    {
        let (rem, seq) = Set::from_der(bytes).map_err(Err::convert)?;
        let data = match seq.content {
            Cow::Borrowed(b) => b,
            // Since 'any' is built from 'bytes', it is borrowed by construction
            Cow::Owned(_) => unreachable!(),
        };
        let (_, res) = op(data)?;
        Ok((rem, res))
    }

    /// Apply the parsing function to the set content (non-consuming version)
    pub fn parse<F, T, E>(&'a self, mut f: F) -> ParseResult<'a, T, E>
    where
        F: FnMut(&'a [u8]) -> ParseResult<'a, T, E>,
    {
        let input: &[u8] = &self.content;
        f(input)
    }

    /// Apply the parsing function to the set content (consuming version)
    ///
    /// Note: to parse and apply a parsing function in one step, use the
    /// [`Set::from_der_and_then`] method.
    ///
    /// # Limitations
    ///
    /// This function fails if the set contains `Owned` data, because the parsing function
    /// takes a reference on data (which is dropped).
    pub fn parse_into<F, T, E>(self, mut f: F) -> ParseResult<'a, T, E>
    where
        F: FnMut(&'a [u8]) -> ParseResult<'a, T, E>,
        E: From<Error>,
    {
        match self.content {
            Cow::Borrowed(b) => f(b),
            _ => Err(Err::Error(Error::LifetimeError.into())),
        }
    }

    /// Return an iterator over the set content, attempting to decode objects as BER
    ///
    /// This method can be used when all objects from the set have the same type.
    pub fn ber_iter<T, E>(&'a self) -> SetIterator<'a, T, BerParser, E>
    where
        T: FromBer<'a, E>,
    {
        SetIterator::new(&self.content)
    }

    /// Return an iterator over the set content, attempting to decode objects as DER
    ///
    /// This method can be used when all objects from the set have the same type.
    pub fn der_iter<T, E>(&'a self) -> SetIterator<'a, T, DerParser, E>
    where
        T: FromDer<'a, E>,
    {
        SetIterator::new(&self.content)
    }

    /// Attempt to parse the set as a `SET OF` items (BER), and return the parsed items as a `Vec`.
    pub fn ber_set_of<T, E>(&'a self) -> Result<Vec<T>, E>
    where
        T: FromBer<'a, E>,
        E: From<Error>,
    {
        self.ber_iter().collect()
    }

    /// Attempt to parse the set as a `SET OF` items (DER), and return the parsed items as a `Vec`.
    pub fn der_set_of<T, E>(&'a self) -> Result<Vec<T>, E>
    where
        T: FromDer<'a, E>,
        E: From<Error>,
    {
        self.der_iter().collect()
    }

    /// Attempt to parse the set as a `SET OF` items (BER) (consuming input),
    /// and return the parsed items as a `Vec`.
    ///
    /// Note: if `Self` is an `Owned` object, the data will be duplicated (causing allocations) into separate objects.
    pub fn into_ber_set_of<T, E>(self) -> Result<Vec<T>, E>
    where
        for<'b> T: FromBer<'b, E>,
        E: From<Error>,
        T: ToStatic<Owned = T>,
    {
        match self.content {
            Cow::Borrowed(bytes) => SetIterator::<T, BerParser, E>::new(bytes).collect(),
            Cow::Owned(data) => {
                let v1 =
                    SetIterator::<T, BerParser, E>::new(&data).collect::<Result<Vec<T>, E>>()?;
                let v2 = v1.iter().map(|t| t.to_static()).collect::<Vec<_>>();
                Ok(v2)
            }
        }
    }

    /// Attempt to parse the set as a `SET OF` items (DER) (consuming input),
    /// and return the parsed items as a `Vec`.
    ///
    /// Note: if `Self` is an `Owned` object, the data will be duplicated (causing allocations) into separate objects.
    pub fn into_der_set_of<T, E>(self) -> Result<Vec<T>, E>
    where
        for<'b> T: FromDer<'b, E>,
        E: From<Error>,
        T: ToStatic<Owned = T>,
    {
        match self.content {
            Cow::Borrowed(bytes) => SetIterator::<T, DerParser, E>::new(bytes).collect(),
            Cow::Owned(data) => {
                let v1 =
                    SetIterator::<T, DerParser, E>::new(&data).collect::<Result<Vec<T>, E>>()?;
                let v2 = v1.iter().map(|t| t.to_static()).collect::<Vec<_>>();
                Ok(v2)
            }
        }
    }

    pub fn into_der_set_of_ref<T, E>(self) -> Result<Vec<T>, E>
    where
        T: FromDer<'a, E>,
        E: From<Error>,
    {
        match self.content {
            Cow::Borrowed(bytes) => SetIterator::<T, DerParser, E>::new(bytes).collect(),
            Cow::Owned(_) => Err(Error::LifetimeError.into()),
        }
    }
}

impl<'a> ToStatic for Set<'a> {
    type Owned = Set<'static>;

    fn to_static(&self) -> Self::Owned {
        Set {
            content: Cow::Owned(self.content.to_vec()),
        }
    }
}

impl<'a> AsRef<[u8]> for Set<'a> {
    fn as_ref(&self) -> &[u8] {
        &self.content
    }
}

impl<'a> TryFrom<Any<'a>> for Set<'a> {
    type Error = Error;

    fn try_from(any: Any<'a>) -> Result<Set<'a>> {
        TryFrom::try_from(&any)
    }
}

impl<'a, 'b> TryFrom<&'b Any<'a>> for Set<'a> {
    type Error = Error;

    fn try_from(any: &'b Any<'a>) -> Result<Set<'a>> {
        any.tag().assert_eq(Self::TAG)?;
        any.header.assert_constructed()?;
        Ok(Set {
            content: Cow::Borrowed(any.data),
        })
    }
}

impl<'a> CheckDerConstraints for Set<'a> {
    fn check_constraints(_any: &Any) -> Result<()> {
        Ok(())
    }
}

impl<'a> DerAutoDerive for Set<'a> {}

impl<'a> Tagged for Set<'a> {
    const TAG: Tag = Tag::Set;
}

#[cfg(feature = "std")]
impl ToDer for Set<'_> {
    fn to_der_len(&self) -> Result<usize> {
        let sz = self.content.len();
        if sz < 127 {
            // 1 (class+tag) + 1 (length) + len
            Ok(2 + sz)
        } else {
            // 1 (class+tag) + n (length) + len
            let n = Length::Definite(sz).to_der_len()?;
            Ok(1 + n + sz)
        }
    }

    fn write_der_header(&self, writer: &mut dyn std::io::Write) -> SerializeResult<usize> {
        let header = Header::new(
            Class::Universal,
            true,
            Self::TAG,
            Length::Definite(self.content.len()),
        );
        header.write_der_header(writer).map_err(Into::into)
    }

    fn write_der_content(&self, writer: &mut dyn std::io::Write) -> SerializeResult<usize> {
        writer.write(&self.content).map_err(Into::into)
    }
}

#[cfg(feature = "std")]
impl<'a> Set<'a> {
    /// Attempt to create a `Set` from an iterator over serializable objects (to DER)
    ///
    /// # Examples
    ///
    /// ```
    /// use asn1_rs::Set;
    ///
    /// // build set
    /// let it = [2, 3, 4].iter();
    /// let seq = Set::from_iter_to_der(it).unwrap();
    /// ```
    pub fn from_iter_to_der<T, IT>(it: IT) -> SerializeResult<Self>
    where
        IT: Iterator<Item = T>,
        T: ToDer,
        T: Tagged,
    {
        let mut v = Vec::new();
        for item in it {
            let item_v = <T as ToDer>::to_der_vec(&item)?;
            v.extend_from_slice(&item_v);
        }
        Ok(Set {
            content: Cow::Owned(v),
        })
    }
}