lambdaworks_math/field/test_fields/
u32_test_field.rs

1use crate::{
2    errors::CreationError,
3    field::errors::FieldError,
4    field::traits::{IsFFTField, IsField, IsPrimeField},
5};
6
7use crate::traits::ByteConversion;
8
9#[derive(Debug, Clone, PartialEq, Eq)]
10
11pub struct U32Field<const MODULUS: u32>;
12
13impl ByteConversion for u32 {
14    #[cfg(feature = "alloc")]
15    fn to_bytes_be(&self) -> alloc::vec::Vec<u8> {
16        unimplemented!()
17    }
18
19    #[cfg(feature = "alloc")]
20    fn to_bytes_le(&self) -> alloc::vec::Vec<u8> {
21        unimplemented!()
22    }
23
24    fn from_bytes_be(_bytes: &[u8]) -> Result<Self, crate::errors::ByteConversionError>
25    where
26        Self: Sized,
27    {
28        unimplemented!()
29    }
30
31    fn from_bytes_le(_bytes: &[u8]) -> Result<Self, crate::errors::ByteConversionError>
32    where
33        Self: Sized,
34    {
35        unimplemented!()
36    }
37}
38
39impl<const MODULUS: u32> IsField for U32Field<MODULUS> {
40    type BaseType = u32;
41
42    fn add(a: &u32, b: &u32) -> u32 {
43        ((*a as u128 + *b as u128) % MODULUS as u128) as u32
44    }
45
46    fn sub(a: &u32, b: &u32) -> u32 {
47        (((*a as u128 + MODULUS as u128) - *b as u128) % MODULUS as u128) as u32
48    }
49
50    fn neg(a: &u32) -> u32 {
51        MODULUS - a
52    }
53
54    fn mul(a: &u32, b: &u32) -> u32 {
55        ((*a as u128 * *b as u128) % MODULUS as u128) as u32
56    }
57
58    fn div(a: &u32, b: &u32) -> Result<u32, FieldError> {
59        let b_inv = &Self::inv(b)?;
60        Ok(Self::mul(a, b_inv))
61    }
62
63    fn inv(a: &u32) -> Result<u32, FieldError> {
64        if *a == 0 {
65            return Err(FieldError::InvZeroError);
66        }
67        Ok(Self::pow(a, MODULUS - 2))
68    }
69
70    fn eq(a: &u32, b: &u32) -> bool {
71        Self::from_base_type(*a) == Self::from_base_type(*b)
72    }
73
74    fn zero() -> u32 {
75        0
76    }
77
78    fn one() -> u32 {
79        1
80    }
81
82    fn from_u64(x: u64) -> u32 {
83        (x % MODULUS as u64) as u32
84    }
85
86    fn from_base_type(x: u32) -> u32 {
87        x % MODULUS
88    }
89}
90
91impl<const MODULUS: u32> IsPrimeField for U32Field<MODULUS> {
92    type RepresentativeType = u32;
93
94    fn representative(a: &Self::BaseType) -> u32 {
95        *a
96    }
97
98    /// Returns how many bits do you need to represent the biggest field element
99    /// It expects the MODULUS to be a Prime
100    fn field_bit_size() -> usize {
101        ((MODULUS - 1).ilog2() + 1) as usize
102    }
103
104    /// Unimplemented for test fields
105    fn from_hex(hex_string: &str) -> Result<Self::BaseType, crate::errors::CreationError> {
106        let mut hex_string = hex_string;
107        // Remove 0x if it's on the string
108        let mut char_iterator = hex_string.chars();
109        if hex_string.len() > 2
110            && char_iterator.next().unwrap() == '0'
111            && char_iterator.next().unwrap() == 'x'
112        {
113            hex_string = &hex_string[2..];
114        }
115
116        u32::from_str_radix(hex_string, 16).map_err(|_| CreationError::InvalidHexString)
117    }
118
119    #[cfg(feature = "std")]
120    fn to_hex(x: &u32) -> String {
121        format!("{x:X}")
122    }
123}
124
125// 15 * 2^27 + 1;
126pub type U32TestField = U32Field<2013265921>;
127
128// These params correspond to the 2013265921 modulus.
129impl IsFFTField for U32TestField {
130    const TWO_ADICITY: u64 = 27;
131    const TWO_ADIC_PRIMITVE_ROOT_OF_UNITY: u32 = 440532289;
132}
133
134#[cfg(test)]
135mod tests_u32_test_field {
136    use crate::field::{test_fields::u32_test_field::U32TestField, traits::IsPrimeField};
137
138    #[test]
139    fn from_hex_for_b_is_11() {
140        assert_eq!(U32TestField::from_hex("B").unwrap(), 11);
141    }
142
143    #[cfg(feature = "std")]
144    #[test]
145    fn to_hex_test() {
146        let num = U32TestField::from_hex("B").unwrap();
147        assert_eq!(U32TestField::to_hex(&num), "B");
148    }
149
150    #[test]
151    fn bit_size_of_test_field_is_31() {
152        assert_eq!(
153            <U32TestField as crate::field::traits::IsPrimeField>::field_bit_size(),
154            31
155        );
156    }
157}
lambdaworks_math/field/test_fields/u32_test_field.rs

lambdaworks_math/field/test_fields/
u32_test_field.rs
