icydb_schema/
nat_big.rs

1//! Canonical arbitrary-precision unsigned-integer atom.
2
3use crate::{Decimal, NumericValue};
4use candid::{CandidType, Nat as WrappedNat};
5use derive_more::{Add, AddAssign, Sub, SubAssign};
6use num_bigint::BigUint;
7use serde::{Deserialize, Serialize};
8use std::{
9    fmt,
10    iter::{Product, Sum},
11    ops::{Div, DivAssign, Mul, MulAssign},
12    str::FromStr,
13};
14
15//
16// NatBig
17//
18
19#[derive(
20    Add,
21    AddAssign,
22    CandidType,
23    Clone,
24    Debug,
25    Default,
26    Eq,
27    PartialEq,
28    Hash,
29    Ord,
30    PartialOrd,
31    Serialize,
32    Deserialize,
33    Sub,
34    SubAssign,
35)]
36/// Arbitrary-precision unsigned integer used by schema and typed values.
37pub struct NatBig(WrappedNat);
38
39impl NatBig {
40    /// Construct from the canonical Candid natural-number representation.
41    #[must_use]
42    pub const fn from_candid(value: WrappedNat) -> Self {
43        Self(value)
44    }
45
46    /// Construct from a `num_bigint` unsigned integer.
47    #[must_use]
48    pub fn from_biguint(value: BigUint) -> Self {
49        Self::from_candid(WrappedNat::from(value))
50    }
51
52    /// Return base-2^32 limbs for decimal key encoding.
53    ///
54    /// This allocates for the returned limb vector.
55    #[must_use]
56    pub fn u32_digits(&self) -> Vec<u32> {
57        self.0.0.to_u32_digits()
58    }
59
60    /// Convert to `u128` when the value is in range.
61    #[must_use]
62    pub fn to_u128(&self) -> Option<u128> {
63        let big = &self.0.0;
64
65        u128::try_from(big).ok()
66    }
67
68    /// Convert to `u64` when the value is in range.
69    #[must_use]
70    pub fn to_u64(&self) -> Option<u64> {
71        let big = &self.0.0;
72
73        u64::try_from(big).ok()
74    }
75
76    /// Serialize this arbitrary-precision natural for internal hash and sort-key framing.
77    #[must_use]
78    pub fn to_leb128(&self) -> Vec<u8> {
79        let mut out = Vec::new();
80        let encoded = self.0.encode(&mut out);
81        debug_assert!(
82            encoded.is_ok(),
83            "Vec-backed unsigned LEB128 encoding failed"
84        );
85
86        out
87    }
88
89    pub(crate) fn to_magnitude_bytes(&self) -> Vec<u8> {
90        self.0.0.to_bytes_be()
91    }
92
93    pub(crate) fn from_magnitude_bytes(magnitude: &[u8]) -> Self {
94        Self::from_biguint(BigUint::from_bytes_be(magnitude))
95    }
96
97    /// Saturating addition (unbounded; equivalent to normal addition).
98    #[must_use]
99    pub fn saturating_add(self, rhs: Self) -> Self {
100        Self(self.0 + rhs.0)
101    }
102
103    /// Saturating subtraction; clamps at zero on underflow.
104    #[must_use]
105    pub fn saturating_sub(self, rhs: Self) -> Self {
106        if rhs > self {
107            return Self::default();
108        }
109
110        Self(self.0 - rhs.0)
111    }
112}
113
114impl fmt::Display for NatBig {
115    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
116        self.0.fmt(f)
117    }
118}
119
120impl FromStr for NatBig {
121    type Err = <WrappedNat as FromStr>::Err;
122
123    fn from_str(s: &str) -> Result<Self, Self::Err> {
124        WrappedNat::from_str(s).map(Self::from_candid)
125    }
126}
127
128impl Div for NatBig {
129    type Output = Self;
130
131    fn div(self, other: Self) -> Self::Output {
132        Self(self.0 / other.0)
133    }
134}
135
136impl DivAssign for NatBig {
137    fn div_assign(&mut self, other: Self) {
138        self.0 /= other.0;
139    }
140}
141
142impl From<u64> for NatBig {
143    fn from(n: u64) -> Self {
144        Self::from_candid(WrappedNat::from(n))
145    }
146}
147
148impl From<u32> for NatBig {
149    fn from(n: u32) -> Self {
150        Self::from_candid(WrappedNat::from(n))
151    }
152}
153
154impl Mul for NatBig {
155    type Output = Self;
156
157    fn mul(self, other: Self) -> Self::Output {
158        Self(self.0 * other.0)
159    }
160}
161
162impl MulAssign for NatBig {
163    fn mul_assign(&mut self, other: Self) {
164        self.0 *= other.0;
165    }
166}
167
168impl NumericValue for NatBig {
169    fn try_to_decimal(&self) -> Option<Decimal> {
170        self.to_u128().and_then(Decimal::from_u128)
171    }
172
173    fn try_from_decimal(value: Decimal) -> Option<Self> {
174        value.to_u128().map(WrappedNat::from).map(Self::from_candid)
175    }
176}
177
178impl Product for NatBig {
179    fn product<I: Iterator<Item = Self>>(iter: I) -> Self {
180        iter.fold(Self::from(1_u32), |acc, value| acc * value)
181    }
182}
183
184impl Sum for NatBig {
185    fn sum<I: Iterator<Item = Self>>(iter: I) -> Self {
186        iter.fold(Self::default(), |acc, x| acc + x)
187    }
188}
189
190impl TryFrom<i32> for NatBig {
191    type Error = std::num::TryFromIntError;
192
193    fn try_from(n: i32) -> Result<Self, Self::Error> {
194        let v = Self::from_candid(WrappedNat::from(u32::try_from(n)?));
195        Ok(v)
196    }
197}
icydb_schema/nat_big.rs

icydb_schema/
nat_big.rs
