injective_math/fp_decimal/
from_str.rs

1use crate::fp_decimal::{FPDecimal, U256};
2use cosmwasm_std::StdError;
3use std::str::FromStr;
4
5impl FromStr for FPDecimal {
6    type Err = StdError;
7
8    /// Converts the decimal string to a FPDecimal
9    /// Possible inputs: "1.23", "1", "000012", "1.123000000"
10    /// Disallowed: "", ".23"
11    ///
12    /// This never performs any kind of rounding.
13    /// More than 18 fractional digits, even zeros, result in an error.
14    fn from_str(input: &str) -> Result<Self, Self::Err> {
15        let mut sign = if input.starts_with('-') { 0 } else { 1 };
16        let parts = input.trim_start_matches('-').split('.').collect::<Vec<&str>>();
17        match parts.len() {
18            1 => {
19                let integer = U256::from_dec_str(parts[0]).map_err(|_| StdError::generic_err("Error parsing integer"))?;
20                if integer == U256([0, 0, 0, 0]) {
21                    sign = 1;
22                }
23                Ok(FPDecimal {
24                    num: integer * FPDecimal::ONE.num,
25                    sign,
26                })
27            }
28            2 => {
29                let integer = U256::from_dec_str(parts[0]).map_err(|_| StdError::generic_err("Error parsing integer"))?;
30                let fraction = U256::from_dec_str(parts[1]).map_err(|_| StdError::generic_err("Error parsing fraction"))?;
31                let exp = FPDecimal::DIGITS
32                    .checked_sub(parts[1].len())
33                    .ok_or_else(|| StdError::generic_err(format!("Cannot parse more than {} fractional digits", FPDecimal::DIGITS)))?;
34
35                Ok(FPDecimal {
36                    num: integer * FPDecimal::ONE.num + fraction * U256::exp10(exp),
37                    sign,
38                })
39            }
40            _ => Err(StdError::generic_err("Unexpected number of dots")),
41        }
42    }
43}
44
45impl FPDecimal {
46    pub fn must_from_str(input: &str) -> Self {
47        Self::from_str(input).unwrap()
48    }
49}
50
51#[cfg(test)]
52mod tests {
53    use crate::FPDecimal;
54    use primitive_types::U256;
55    use std::str::FromStr;
56
57    #[test]
58    fn test_from_str_neg() {
59        //-0.69314718055994530943
60        assert_eq!((FPDecimal::ONE / FPDecimal::TWO).ln(), FPDecimal::must_from_str("-0.693147180435828445"));
61        assert_eq!(
62            (FPDecimal::ONE / FPDecimal::must_from_str("1.9")).ln(),
63            FPDecimal::must_from_str("-0.641853885737462182")
64        );
65        assert_eq!(
66            (FPDecimal::ONE / FPDecimal::THREE).ln(),
67            FPDecimal::must_from_str("-1.098612288365102671")
68        );
69    }
70
71    #[test]
72    fn test_from_str_zero() {
73        let zero = FPDecimal::from_str("0").unwrap();
74        let neg_zero = FPDecimal::from_str("-0").unwrap();
75        let zero_zero = FPDecimal::from_str("00").unwrap();
76        let neg_zero_zero = FPDecimal::from_str("-00").unwrap();
77        assert_eq!(zero, FPDecimal::ZERO);
78        assert_eq!(zero_zero, FPDecimal::ZERO);
79        assert_eq!(neg_zero, FPDecimal::ZERO);
80        assert_eq!(neg_zero_zero, FPDecimal::ZERO);
81    }
82
83    #[test]
84    fn test_from_str() {
85        let val = FPDecimal::from_str("-1.23");
86        assert_eq!(
87            val.unwrap(),
88            FPDecimal {
89                num: U256([123, 0, 0, 0]) * FPDecimal::ONE.num / U256::from(100),
90                sign: 0
91            }
92        );
93    }
94
95    #[test]
96    fn test_from_str_one() {
97        let val = FPDecimal::from_str("1");
98        assert_eq!(val.unwrap(), FPDecimal::ONE);
99    }
100}
injective_math/fp_decimal/from_str.rs

injective_math/fp_decimal/
from_str.rs
