ciborium_ll/
enc.rs

1use super::*;
2
3use ciborium_io::Write;
4
5/// An encoder for serializing CBOR items
6///
7/// This structure wraps a writer and provides convenience functions for
8/// writing `Header` objects to the wire.
9pub struct Encoder<W: Write>(W);
10
11impl<W: Write> From<W> for Encoder<W> {
12    #[inline]
13    fn from(value: W) -> Self {
14        Self(value)
15    }
16}
17
18impl<W: Write> Write for Encoder<W> {
19    type Error = W::Error;
20
21    fn write_all(&mut self, data: &[u8]) -> Result<(), Self::Error> {
22        self.0.write_all(data)
23    }
24
25    fn flush(&mut self) -> Result<(), Self::Error> {
26        self.0.flush()
27    }
28}
29
30impl<W: Write> Encoder<W> {
31    /// Push a `Header` to the wire
32    #[inline]
33    pub fn push(&mut self, header: Header) -> Result<(), W::Error> {
34        let title = Title::from(header);
35
36        let major = match title.0 {
37            Major::Positive => 0,
38            Major::Negative => 1,
39            Major::Bytes => 2,
40            Major::Text => 3,
41            Major::Array => 4,
42            Major::Map => 5,
43            Major::Tag => 6,
44            Major::Other => 7,
45        };
46
47        let minor = match title.1 {
48            Minor::This(x) => x,
49            Minor::Next1(..) => 24,
50            Minor::Next2(..) => 25,
51            Minor::Next4(..) => 26,
52            Minor::Next8(..) => 27,
53            Minor::More => 31,
54        };
55
56        self.0.write_all(&[major << 5 | minor])?;
57        self.0.write_all(title.1.as_ref())
58    }
59
60    /// Serialize a byte slice as CBOR
61    ///
62    /// Optionally, segment the output into `segment` size segments. Note that
63    /// if `segment == Some(0)` it will be silently upgraded to `Some(1)`. This
64    /// minimum value is highly inefficient and should not be relied upon.
65    #[inline]
66    pub fn bytes(
67        &mut self,
68        value: &[u8],
69        segment: impl Into<Option<usize>>,
70    ) -> Result<(), W::Error> {
71        let max = segment.into().unwrap_or(value.len());
72        let max = core::cmp::max(max, 1);
73
74        if max >= value.len() {
75            self.push(Header::Bytes(Some(value.len())))?;
76            self.write_all(value)?;
77        } else {
78            self.push(Header::Bytes(None))?;
79
80            for chunk in value.chunks(max) {
81                self.push(Header::Bytes(Some(chunk.len())))?;
82                self.write_all(chunk)?;
83            }
84
85            self.push(Header::Break)?;
86        }
87
88        Ok(())
89    }
90
91    /// Serialize a string slice as CBOR
92    ///
93    /// Optionally, segment the output into `segment` size segments. Note that
94    /// since care is taken to ensure that each segment is itself a valid UTF-8
95    /// string, if `segment` contains a value of less than 4, it will be
96    /// silently upgraded to 4. This minimum value is highly inefficient and
97    /// should not be relied upon.
98    #[inline]
99    pub fn text(&mut self, value: &str, segment: impl Into<Option<usize>>) -> Result<(), W::Error> {
100        let max = segment.into().unwrap_or(value.len());
101        let max = core::cmp::max(max, 4);
102
103        if max >= value.len() {
104            self.push(Header::Text(Some(value.len())))?;
105            self.write_all(value.as_bytes())?;
106        } else {
107            self.push(Header::Text(None))?;
108
109            let mut bytes = value.as_bytes();
110            while !bytes.is_empty() {
111                let mut len = core::cmp::min(bytes.len(), max);
112                while len > 0 && core::str::from_utf8(&bytes[..len]).is_err() {
113                    len -= 1
114                }
115
116                let (prefix, suffix) = bytes.split_at(len);
117                self.push(Header::Text(Some(prefix.len())))?;
118                self.write_all(prefix)?;
119                bytes = suffix;
120            }
121
122            self.push(Header::Break)?;
123        }
124
125        Ok(())
126    }
127}
ciborium_ll/enc.rs

ciborium_ll/
enc.rs
