malachite_nz/integer/conversion/string/
from_string.rs

1// Copyright © 2025 Mikhail Hogrefe
2//
3// This file is part of Malachite.
4//
5// Malachite is free software: you can redistribute it and/or modify it under the terms of the GNU
6// Lesser General Public License (LGPL) as published by the Free Software Foundation; either version
7// 3 of the License, or (at your option) any later version. See <https://www.gnu.org/licenses/>.
8
9use crate::integer::Integer;
10use crate::natural::Natural;
11use core::ops::Neg;
12use core::str::FromStr;
13use malachite_base::num::conversion::traits::FromStringBase;
14
15impl FromStr for Integer {
16    type Err = ();
17
18    /// Converts an string to an [`Integer`].
19    ///
20    /// If the string does not represent a valid [`Integer`], an `Err` is returned. To be valid, the
21    /// string must be nonempty and only contain the [`char`]s `'0'` through `'9'`, with an optional
22    /// leading `'-'`. Leading zeros are allowed, as is the string `"-0"`. The string `"-"` is not.
23    ///
24    /// # Worst-case complexity
25    /// $T(n) = O(n (\log n)^2 \log\log n)$
26    ///
27    /// $M(n) = O(n \log n)$
28    ///
29    /// where $T$ is time, $M$ is additional memory, and $n$ is `s.len()`.
30    ///
31    /// # Examples
32    /// ```
33    /// use core::str::FromStr;
34    /// use malachite_nz::integer::Integer;
35    ///
36    /// assert_eq!(Integer::from_str("123456").unwrap(), 123456);
37    /// assert_eq!(Integer::from_str("00123456").unwrap(), 123456);
38    /// assert_eq!(Integer::from_str("0").unwrap(), 0);
39    /// assert_eq!(Integer::from_str("-123456").unwrap(), -123456);
40    /// assert_eq!(Integer::from_str("-00123456").unwrap(), -123456);
41    /// assert_eq!(Integer::from_str("-0").unwrap(), 0);
42    ///
43    /// assert!(Integer::from_str("").is_err());
44    /// assert!(Integer::from_str("a").is_err());
45    /// ```
46    #[inline]
47    fn from_str(s: &str) -> Result<Integer, ()> {
48        Integer::from_string_base(10, s).ok_or(())
49    }
50}
51
52impl FromStringBase for Integer {
53    /// Converts an string, in a specified base, to an [`Integer`].
54    ///
55    /// If the string does not represent a valid [`Integer`], an `Err` is returned. To be valid, the
56    /// string must be nonempty and only contain the [`char`]s `'0'` through `'9'`, `'a'` through
57    /// `'z'`, and `'A'` through `'Z'`, with an optional single leading `'-'` or `'+'`; and only
58    /// characters that represent digits smaller than the base are allowed. Leading zeros are
59    /// allowed, as is the string `"-0"`. The string `"-"` is not.
60    ///
61    /// # Worst-case complexity
62    /// $T(n) = O(n (\log n)^2 \log\log n)$
63    ///
64    /// $M(n) = O(n \log n)$
65    ///
66    /// where $T$ is time, $M$ is additional memory, and $n$ is `s.len()`.
67    ///
68    /// # Panics
69    /// Panics if `base` is less than 2 or greater than 36.
70    ///
71    /// # Examples
72    /// ```
73    /// use malachite_base::num::conversion::traits::FromStringBase;
74    /// use malachite_nz::integer::Integer;
75    ///
76    /// assert_eq!(Integer::from_string_base(10, "123456").unwrap(), 123456);
77    /// assert_eq!(Integer::from_string_base(10, "00123456").unwrap(), 123456);
78    /// assert_eq!(Integer::from_string_base(16, "0").unwrap(), 0);
79    /// assert_eq!(
80    ///     Integer::from_string_base(16, "deadbeef").unwrap(),
81    ///     3735928559i64
82    /// );
83    /// assert_eq!(
84    ///     Integer::from_string_base(16, "deAdBeEf").unwrap(),
85    ///     3735928559i64
86    /// );
87    /// assert_eq!(Integer::from_string_base(10, "-123456").unwrap(), -123456);
88    /// assert_eq!(Integer::from_string_base(10, "-00123456").unwrap(), -123456);
89    /// assert_eq!(Integer::from_string_base(16, "-0").unwrap(), 0);
90    /// assert_eq!(
91    ///     Integer::from_string_base(16, "-deadbeef").unwrap(),
92    ///     -3735928559i64
93    /// );
94    /// assert_eq!(
95    ///     Integer::from_string_base(16, "-deAdBeEf").unwrap(),
96    ///     -3735928559i64
97    /// );
98    ///
99    /// assert!(Integer::from_string_base(10, "").is_none());
100    /// assert!(Integer::from_string_base(10, "a").is_none());
101    /// assert!(Integer::from_string_base(2, "2").is_none());
102    /// assert!(Integer::from_string_base(2, "-2").is_none());
103    /// ```
104    #[inline]
105    fn from_string_base(base: u8, s: &str) -> Option<Integer> {
106        if let Some(abs_string) = s.strip_prefix('-') {
107            if abs_string.starts_with('+') {
108                None
109            } else {
110                Natural::from_string_base(base, abs_string).map(Neg::neg)
111            }
112        } else {
113            Natural::from_string_base(base, s).map(Integer::from)
114        }
115    }
116}
malachite_nz/integer/conversion/string/from_string.rs

malachite_nz/integer/conversion/string/
from_string.rs
