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

// do not use the `asn1_string` macro, since types are not the same
// X.680 section 37.15

use crate::*;
use alloc::borrow::Cow;
#[cfg(not(feature = "std"))]
use alloc::string::{String, ToString};
#[cfg(not(feature = "std"))]
use alloc::vec::Vec;

/// ASN.1 `BMPSTRING` type
///
/// Note: parsing a `BmpString` allocates memory since the UTF-16 to UTF-8 conversion requires a memory allocation.
/// (see `String::from_utf16` method).
#[derive(Debug, PartialEq, Eq)]
pub struct BmpString<'a> {
    pub(crate) data: Cow<'a, str>,
}

impl<'a> BmpString<'a> {
    pub const fn new(s: &'a str) -> Self {
        BmpString {
            data: Cow::Borrowed(s),
        }
    }

    pub fn string(&self) -> String {
        self.data.to_string()
    }
}

impl<'a> AsRef<str> for BmpString<'a> {
    fn as_ref(&self) -> &str {
        &self.data
    }
}

impl<'a> From<&'a str> for BmpString<'a> {
    fn from(s: &'a str) -> Self {
        Self::new(s)
    }
}

impl From<String> for BmpString<'_> {
    fn from(s: String) -> Self {
        Self {
            data: Cow::Owned(s),
        }
    }
}

impl<'a, 'r> core::convert::TryFrom<&'r Any<'a>> for BmpString<'a> {
    type Error = Error;

    fn try_from(any: &'r Any<'a>) -> Result<BmpString<'a>> {
        any.tag().assert_eq(Self::TAG)?;

        // read slice as big-endian UTF-16 string
        let v = &any
            .data
            .chunks(2)
            .map(|s| match s {
                [a, b] => ((*a as u16) << 8) | (*b as u16),
                [a] => *a as u16,
                _ => unreachable!(),
            })
            .collect::<Vec<_>>();

        let s = String::from_utf16(v)?;
        let data = Cow::Owned(s);

        Ok(BmpString { data })
    }
}

impl<'a> core::convert::TryFrom<Any<'a>> for BmpString<'a> {
    type Error = Error;

    #[inline]
    fn try_from(any: Any<'a>) -> Result<BmpString<'a>> {
        BmpString::try_from(&any)
    }
}

impl<'a> CheckDerConstraints for BmpString<'a> {
    fn check_constraints(any: &Any) -> Result<()> {
        any.header.assert_primitive()?;
        Ok(())
    }
}

impl DerAutoDerive for BmpString<'_> {}

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

impl<'a> TestValidCharset for BmpString<'a> {
    fn test_valid_charset(i: &[u8]) -> Result<()> {
        if i.len() % 2 != 0 {
            return Err(Error::StringInvalidCharset);
        }
        let iter = i.chunks(2).map(|s| ((s[0] as u16) << 8) | (s[1] as u16));
        for c in char::decode_utf16(iter) {
            if c.is_err() {
                return Err(Error::StringInvalidCharset);
            }
        }
        Ok(())
    }
}

#[cfg(feature = "std")]
impl ToDer for BmpString<'_> {
    fn to_der_len(&self) -> Result<usize> {
        // compute the UTF-16 length
        let sz = self.data.encode_utf16().count() * 2;
        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> {
        // compute the UTF-16 length
        let l = self.data.encode_utf16().count() * 2;
        let header = Header::new(Class::Universal, false, Self::TAG, Length::Definite(l));
        header.write_der_header(writer).map_err(Into::into)
    }

    fn write_der_content(&self, writer: &mut dyn std::io::Write) -> SerializeResult<usize> {
        let mut v = Vec::new();
        for u in self.data.encode_utf16() {
            v.push((u >> 8) as u8);
            v.push((u & 0xff) as u8);
        }
        writer.write(&v).map_err(Into::into)
    }
}