dashu_int/third_party/
serde.rs

1//! Implement serde traits.
2
3use crate::{convert::words_to_le_bytes, ibig::IBig, ubig::UBig, Sign};
4use core::fmt::{self, Formatter};
5use serde::{
6    de::{self, Deserialize, Deserializer, Visitor},
7    ser::{Serialize, Serializer},
8};
9
10impl Serialize for UBig {
11    #[inline]
12    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
13        if serializer.is_human_readable() {
14            serializer.collect_str(self)
15        } else if self.is_zero() {
16            serializer.serialize_bytes(&[])
17        } else {
18            let bytes = words_to_le_bytes(self.as_words());
19            serializer.serialize_bytes(&bytes)
20        }
21    }
22}
23
24impl<'de> Deserialize<'de> for UBig {
25    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
26        if deserializer.is_human_readable() {
27            deserializer.deserialize_str(UBigVisitor)
28        } else {
29            deserializer.deserialize_bytes(UBigVisitor)
30        }
31    }
32}
33
34/// UBig is serialized as little-endian bytes.
35struct UBigVisitor;
36
37impl<'de> Visitor<'de> for UBigVisitor {
38    type Value = UBig;
39
40    fn expecting(&self, f: &mut Formatter) -> fmt::Result {
41        write!(f, "a string or a sequence of bytes")
42    }
43
44    fn visit_str<E: de::Error>(self, v: &str) -> Result<Self::Value, E> {
45        match UBig::from_str_with_radix_prefix(v) {
46            Ok((n, _)) => Ok(n),
47            Err(e) => Err(de::Error::custom(e)),
48        }
49    }
50
51    fn visit_bytes<E: de::Error>(self, v: &[u8]) -> Result<Self::Value, E> {
52        Ok(UBig::from_le_bytes(v))
53    }
54}
55
56impl Serialize for IBig {
57    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
58        if serializer.is_human_readable() {
59            serializer.collect_str(self)
60        } else if self.is_zero() {
61            serializer.serialize_bytes(&[])
62        } else {
63            let (sign, words) = self.as_sign_words();
64            let mut bytes = words_to_le_bytes(words);
65
66            // use the length to encode the sign, postive <=> even, negative <=> odd.
67            // pad zeros when necessary
68            if (sign == Sign::Positive && bytes.len() & 1 == 1)
69                || (sign == Sign::Negative && bytes.len() & 1 == 0)
70            {
71                bytes.push(0);
72            }
73            serializer.serialize_bytes(&bytes)
74        }
75    }
76}
77
78impl<'de> Deserialize<'de> for IBig {
79    fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error> {
80        if deserializer.is_human_readable() {
81            deserializer.deserialize_str(IBigVisitor)
82        } else {
83            deserializer.deserialize_bytes(IBigVisitor)
84        }
85    }
86}
87
88/// IBig is serialized as little-endian bytes, where the sign is encoded in the byte length
89struct IBigVisitor;
90
91impl<'de> Visitor<'de> for IBigVisitor {
92    type Value = IBig;
93
94    fn expecting(&self, f: &mut Formatter) -> fmt::Result {
95        write!(f, "a string or a sequence of 64-bit words")
96    }
97
98    fn visit_str<E: de::Error>(self, v: &str) -> Result<Self::Value, E> {
99        match IBig::from_str_with_radix_prefix(v) {
100            Ok((n, _)) => Ok(n),
101            Err(e) => Err(de::Error::custom(e)),
102        }
103    }
104
105    fn visit_bytes<E: de::Error>(self, v: &[u8]) -> Result<Self::Value, E> {
106        let sign = Sign::from(v.len() & 1 == 1);
107        Ok(IBig::from_parts(sign, UBig::from_le_bytes(v)))
108    }
109}
dashu_int/third_party/serde.rs

dashu_int/third_party/
serde.rs
