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

//! ASN.1 `TeletexString` support.

use crate::{
    asn1::AnyRef, ord::OrdIsValueOrd, ByteSlice, DecodeValue, EncodeValue, Error, FixedTag, Header,
    Length, Reader, Result, StrSlice, Tag, Writer,
};
use core::{fmt, ops::Deref, str};

/// ASN.1 `TeletexString` type.
///
/// Supports a subset the ASCII character set (described below).
///
/// For UTF-8, use [`Utf8StringRef`][`crate::asn1::Utf8StringRef`] instead.
/// For the full ASCII character set, use
/// [`Ia5StringRef`][`crate::asn1::Ia5StringRef`].
///
/// This is a zero-copy reference type which borrows from the input data.
///
/// # Supported characters
///
/// The standard defines a complex character set allowed in this type. However, quoting the ASN.1
/// mailing list, "a sizable volume of software in the world treats TeletexString (T61String) as a
/// simple 8-bit string with mostly Windows Latin 1 (superset of iso-8859-1) encoding".
///
#[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord)]
pub struct TeletexStringRef<'a> {
    /// Inner value
    inner: StrSlice<'a>,
}

impl<'a> TeletexStringRef<'a> {
    /// Create a new ASN.1 `TeletexString`.
    pub fn new<T>(input: &'a T) -> Result<Self>
    where
        T: AsRef<[u8]> + ?Sized,
    {
        let input = input.as_ref();

        // FIXME: support higher part of the charset
        if input.iter().any(|&c| c > 0x7F) {
            return Err(Self::TAG.value_error());
        }

        StrSlice::from_bytes(input)
            .map(|inner| Self { inner })
            .map_err(|_| Self::TAG.value_error())
    }
}

impl<'a> Deref for TeletexStringRef<'a> {
    type Target = StrSlice<'a>;

    fn deref(&self) -> &Self::Target {
        &self.inner
    }
}

impl AsRef<str> for TeletexStringRef<'_> {
    fn as_ref(&self) -> &str {
        self.as_str()
    }
}

impl AsRef<[u8]> for TeletexStringRef<'_> {
    fn as_ref(&self) -> &[u8] {
        self.as_bytes()
    }
}

impl<'a> DecodeValue<'a> for TeletexStringRef<'a> {
    fn decode_value<R: Reader<'a>>(reader: &mut R, header: Header) -> Result<Self> {
        Self::new(ByteSlice::decode_value(reader, header)?.as_slice())
    }
}

impl<'a> EncodeValue for TeletexStringRef<'a> {
    fn value_len(&self) -> Result<Length> {
        self.inner.value_len()
    }

    fn encode_value(&self, writer: &mut dyn Writer) -> Result<()> {
        self.inner.encode_value(writer)
    }
}

impl FixedTag for TeletexStringRef<'_> {
    const TAG: Tag = Tag::TeletexString;
}

impl OrdIsValueOrd for TeletexStringRef<'_> {}

impl<'a> From<&TeletexStringRef<'a>> for TeletexStringRef<'a> {
    fn from(value: &TeletexStringRef<'a>) -> TeletexStringRef<'a> {
        *value
    }
}

impl<'a> TryFrom<AnyRef<'a>> for TeletexStringRef<'a> {
    type Error = Error;

    fn try_from(any: AnyRef<'a>) -> Result<TeletexStringRef<'a>> {
        any.decode_into()
    }
}

impl<'a> From<TeletexStringRef<'a>> for AnyRef<'a> {
    fn from(teletex_string: TeletexStringRef<'a>) -> AnyRef<'a> {
        AnyRef::from_tag_and_value(Tag::TeletexString, teletex_string.inner.into())
    }
}

impl<'a> fmt::Display for TeletexStringRef<'a> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.write_str(self.as_str())
    }
}

impl<'a> fmt::Debug for TeletexStringRef<'a> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "TeletexString({:?})", self.as_str())
    }
}

#[cfg(test)]
mod tests {
    use super::TeletexStringRef;
    use crate::Decode;
    use crate::SliceWriter;

    #[test]
    fn parse_bytes() {
        let example_bytes = &[
            0x14, 0x0b, 0x54, 0x65, 0x73, 0x74, 0x20, 0x55, 0x73, 0x65, 0x72, 0x20, 0x31,
        ];

        let teletex_string = TeletexStringRef::from_der(example_bytes).unwrap();
        assert_eq!(teletex_string.as_str(), "Test User 1");
        let mut out = [0_u8; 30];
        let mut writer = SliceWriter::new(&mut out);
        writer.encode(&teletex_string).unwrap();
        let encoded = writer.finish().unwrap();
        assert_eq!(encoded, example_bytes);
    }
}