const_hex/
serde.rs

1//! Hex encoding with [`serde`](serde_core).
2//!
3//! # Examples
4//!
5//! ```
6//! # #[cfg(feature = "alloc")] {
7//! use serde::{Serialize, Deserialize};
8//!
9//! #[derive(Serialize, Deserialize)]
10//! struct Foo {
11//!     #[serde(with = "const_hex")]
12//!     bar: Vec<u8>,
13//! }
14//! # }
15//! ```
16
17use crate::FromHex;
18use core::fmt;
19use core::marker::PhantomData;
20use serde_core::de::{Error, Visitor};
21use serde_core::Deserializer;
22
23#[cfg(feature = "alloc")]
24mod serialize {
25    use serde_core::Serializer;
26
27    /// Serializes `data` as hex string using lowercase characters.
28    ///
29    /// Lowercase characters are used (e.g. `f9b4ca`). The resulting string's length
30    /// is always even, each byte in data is always encoded using two hex digits.
31    /// Thus, the resulting string contains exactly twice as many bytes as the input
32    /// data.
33    #[inline]
34    pub fn serialize<S, T>(data: T, serializer: S) -> Result<S::Ok, S::Error>
35    where
36        S: Serializer,
37        T: AsRef<[u8]>,
38    {
39        serializer.serialize_str(&crate::encode_prefixed(data.as_ref()))
40    }
41
42    /// Serializes `data` as hex string using uppercase characters.
43    ///
44    /// Apart from the characters' casing, this works exactly like [`serialize`].
45    #[inline]
46    pub fn serialize_upper<S, T>(data: T, serializer: S) -> Result<S::Ok, S::Error>
47    where
48        S: Serializer,
49        T: AsRef<[u8]>,
50    {
51        serializer.serialize_str(&crate::encode_upper_prefixed(data.as_ref()))
52    }
53}
54
55#[cfg(feature = "alloc")]
56pub use serialize::{serialize, serialize_upper};
57
58/// Deserializes a hex string into raw bytes.
59///
60/// Both, upper and lower case characters are valid in the input string and can
61/// even be mixed (e.g. `f9b4ca`, `F9B4CA` and `f9B4Ca` are all valid strings).
62#[inline]
63pub fn deserialize<'de, D, T>(deserializer: D) -> Result<T, D::Error>
64where
65    D: Deserializer<'de>,
66    T: FromHex,
67    <T as FromHex>::Error: fmt::Display,
68{
69    struct HexStrVisitor<T>(PhantomData<T>);
70
71    impl<T> Visitor<'_> for HexStrVisitor<T>
72    where
73        T: FromHex,
74        <T as FromHex>::Error: fmt::Display,
75    {
76        type Value = T;
77
78        fn expecting(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
79            f.write_str("a hex encoded string")
80        }
81
82        fn visit_bytes<E: Error>(self, data: &[u8]) -> Result<Self::Value, E> {
83            FromHex::from_hex(data).map_err(Error::custom)
84        }
85
86        fn visit_str<E: Error>(self, data: &str) -> Result<Self::Value, E> {
87            FromHex::from_hex(data.as_bytes()).map_err(Error::custom)
88        }
89    }
90
91    deserializer.deserialize_str(HexStrVisitor(PhantomData))
92}
const_hex/serde.rs

const_hex/
serde.rs
