miden_client/
utils.rs

1//! Provides various utilities that are commonly used throughout the Miden
2//! client library.
3
4use alloc::string::{String, ToString};
5use alloc::vec::Vec;
6use core::num::ParseIntError;
7
8use miden_standards::account::faucets::BasicFungibleFaucet;
9pub use miden_tx::utils::sync::{LazyLock, RwLock, RwLockReadGuard, RwLockWriteGuard};
10pub use miden_tx::utils::{
11    ByteReader,
12    ByteWriter,
13    Deserializable,
14    DeserializationError,
15    Serializable,
16    ToHex,
17    bytes_to_hex_string,
18    hex_to_bytes,
19};
20
21use crate::alloc::borrow::ToOwned;
22
23/// Converts an amount in the faucet base units to the token's decimals.
24///
25/// This is meant for display purposes only.
26pub fn base_units_to_tokens(units: u64, decimals: u8) -> String {
27    let units_str = units.to_string();
28    let len = units_str.len();
29
30    if decimals == 0 {
31        return units_str;
32    }
33
34    if decimals as usize >= len {
35        // Handle cases where the number of decimals is greater than the length of units
36        "0.".to_owned() + &"0".repeat(decimals as usize - len) + &units_str
37    } else {
38        // Insert the decimal point at the correct position
39        let integer_part = &units_str[..len - decimals as usize];
40        let fractional_part = &units_str[len - decimals as usize..];
41        format!("{integer_part}.{fractional_part}")
42    }
43}
44
45/// Errors that can occur when parsing a token represented as a decimal number in
46/// a string into base units.
47#[derive(thiserror::Error, Debug)]
48pub enum TokenParseError {
49    #[error("Number of decimals {0} must be less than or equal to {max_decimals}", max_decimals = BasicFungibleFaucet::MAX_DECIMALS)]
50    MaxDecimals(u8),
51    #[error("More than one decimal point")]
52    MultipleDecimalPoints,
53    #[error("Failed to parse u64")]
54    ParseU64(#[source] ParseIntError),
55    #[error("Amount has more than {0} decimal places")]
56    TooManyDecimals(u8),
57}
58
59/// Converts a decimal number, represented as a string, into an integer by shifting
60/// the decimal point to the right by a specified number of decimal places.
61pub fn tokens_to_base_units(decimal_str: &str, n_decimals: u8) -> Result<u64, TokenParseError> {
62    if n_decimals > BasicFungibleFaucet::MAX_DECIMALS {
63        return Err(TokenParseError::MaxDecimals(n_decimals));
64    }
65
66    // Split the string on the decimal point
67    let parts: Vec<&str> = decimal_str.split('.').collect();
68
69    if parts.len() > 2 {
70        return Err(TokenParseError::MultipleDecimalPoints);
71    }
72
73    // Validate that the parts are valid numbers
74    for part in &parts {
75        part.parse::<u64>().map_err(TokenParseError::ParseU64)?;
76    }
77
78    // Get the integer part
79    let integer_part = parts[0];
80
81    // Get the fractional part; remove trailing zeros
82    let mut fractional_part = if parts.len() > 1 {
83        parts[1].trim_end_matches('0').to_string()
84    } else {
85        String::new()
86    };
87
88    // Check if the fractional part has more than N decimals
89    if fractional_part.len() > n_decimals.into() {
90        return Err(TokenParseError::TooManyDecimals(n_decimals));
91    }
92
93    // Add extra zeros if the fractional part is shorter than N decimals
94    while fractional_part.len() < n_decimals.into() {
95        fractional_part.push('0');
96    }
97
98    // Combine the integer and padded fractional part
99    let combined = format!("{}{}", integer_part, &fractional_part[0..n_decimals.into()]);
100
101    // Convert the combined string to an integer
102    combined.parse::<u64>().map_err(TokenParseError::ParseU64)
103}
104
105// TESTS
106// ================================================================================================
107
108#[cfg(test)]
109mod tests {
110    use crate::utils::{TokenParseError, base_units_to_tokens, tokens_to_base_units};
111
112    #[test]
113    fn convert_tokens_to_base_units() {
114        assert_eq!(tokens_to_base_units("18446744.073709551615", 12).unwrap(), u64::MAX);
115        assert_eq!(tokens_to_base_units("7531.2468", 8).unwrap(), 753_124_680_000);
116        assert_eq!(tokens_to_base_units("7531.2468", 4).unwrap(), 75_312_468);
117        assert_eq!(tokens_to_base_units("0", 3).unwrap(), 0);
118        assert_eq!(tokens_to_base_units("0", 3).unwrap(), 0);
119        assert_eq!(tokens_to_base_units("0", 3).unwrap(), 0);
120        assert_eq!(tokens_to_base_units("1234", 8).unwrap(), 123_400_000_000);
121        assert_eq!(tokens_to_base_units("1", 0).unwrap(), 1);
122        assert!(matches!(
123            tokens_to_base_units("1.1", 0),
124            Err(TokenParseError::TooManyDecimals(0))
125        ),);
126        assert!(matches!(
127            tokens_to_base_units("18446744.073709551615", 11),
128            Err(TokenParseError::TooManyDecimals(11))
129        ),);
130        assert!(matches!(tokens_to_base_units("123u3.23", 4), Err(TokenParseError::ParseU64(_))),);
131        assert!(matches!(tokens_to_base_units("2.k3", 4), Err(TokenParseError::ParseU64(_))),);
132        assert_eq!(tokens_to_base_units("12.345000", 4).unwrap(), 123_450);
133        assert!(tokens_to_base_units("0.0001.00000001", 12).is_err());
134    }
135
136    #[test]
137    fn convert_base_units_to_tokens() {
138        assert_eq!(base_units_to_tokens(u64::MAX, 12), "18446744.073709551615");
139        assert_eq!(base_units_to_tokens(753_124_680_000, 8), "7531.24680000");
140        assert_eq!(base_units_to_tokens(75_312_468, 4), "7531.2468");
141        assert_eq!(base_units_to_tokens(75_312_468, 0), "75312468");
142    }
143}
miden_client/utils.rs

miden_client/
utils.rs
