core/convert/
num.rs

1use crate::num::TryFromIntError;
2
3mod private {
4    /// This trait being unreachable from outside the crate
5    /// prevents other implementations of the `FloatToInt` trait,
6    /// which allows potentially adding more trait methods after the trait is `#[stable]`.
7    #[unstable(feature = "convert_float_to_int", issue = "67057")]
8    pub trait Sealed {}
9}
10
11/// Supporting trait for inherent methods of `f32` and `f64` such as `to_int_unchecked`.
12/// Typically doesn’t need to be used directly.
13#[unstable(feature = "convert_float_to_int", issue = "67057")]
14pub trait FloatToInt<Int>: private::Sealed + Sized {
15    #[unstable(feature = "convert_float_to_int", issue = "67057")]
16    #[doc(hidden)]
17    unsafe fn to_int_unchecked(self) -> Int;
18}
19
20macro_rules! impl_float_to_int {
21    ($Float:ty => $($Int:ty),+) => {
22        #[unstable(feature = "convert_float_to_int", issue = "67057")]
23        impl private::Sealed for $Float {}
24        $(
25            #[unstable(feature = "convert_float_to_int", issue = "67057")]
26            impl FloatToInt<$Int> for $Float {
27                #[inline]
28                unsafe fn to_int_unchecked(self) -> $Int {
29                    // SAFETY: the safety contract must be upheld by the caller.
30                    unsafe { crate::intrinsics::float_to_int_unchecked(self) }
31                }
32            }
33        )+
34    }
35}
36
37impl_float_to_int!(f16 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
38impl_float_to_int!(f32 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
39impl_float_to_int!(f64 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
40impl_float_to_int!(f128 => u8, u16, u32, u64, u128, usize, i8, i16, i32, i64, i128, isize);
41
42/// Implement `From<bool>` for integers
43macro_rules! impl_from_bool {
44    ($($int:ty)*) => {$(
45        #[stable(feature = "from_bool", since = "1.28.0")]
46        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
47        impl const From<bool> for $int {
48            /// Converts from [`bool`] to
49            #[doc = concat!("[`", stringify!($int), "`]")]
50            /// , by turning `false` into `0` and `true` into `1`.
51            ///
52            /// # Examples
53            ///
54            /// ```
55            #[doc = concat!("assert_eq!(", stringify!($int), "::from(false), 0);")]
56            ///
57            #[doc = concat!("assert_eq!(", stringify!($int), "::from(true), 1);")]
58            /// ```
59            #[inline(always)]
60            #[ferrocene::prevalidated]
61            fn from(b: bool) -> Self {
62                b as Self
63            }
64        }
65    )*}
66}
67
68// boolean -> integer
69impl_from_bool!(u8 u16 u32 u64 u128 usize);
70impl_from_bool!(i8 i16 i32 i64 i128 isize);
71
72/// Implement `From<$small>` for `$large`
73macro_rules! impl_from {
74    ($small:ty => $large:ty, $(#[$attrs:meta]),+) => {
75        $(#[$attrs])+
76        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
77        impl const From<$small> for $large {
78            #[doc = concat!("Converts from [`", stringify!($small), "`] to [`", stringify!($large), "`] losslessly.")]
79            #[inline(always)]
80            #[ferrocene::prevalidated]
81            fn from(small: $small) -> Self {
82                debug_assert!(<$large>::MIN as i128 <= <$small>::MIN as i128);
83                debug_assert!(<$small>::MAX as u128 <= <$large>::MAX as u128);
84                small as Self
85            }
86        }
87    }
88}
89
90// unsigned integer -> unsigned integer
91impl_from!(u8 => u16, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
92impl_from!(u8 => u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
93impl_from!(u8 => u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
94impl_from!(u8 => u128, #[stable(feature = "i128", since = "1.26.0")]);
95impl_from!(u8 => usize, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
96impl_from!(u16 => u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
97impl_from!(u16 => u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
98impl_from!(u16 => u128, #[stable(feature = "i128", since = "1.26.0")]);
99impl_from!(u32 => u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
100impl_from!(u32 => u128, #[stable(feature = "i128", since = "1.26.0")]);
101impl_from!(u64 => u128, #[stable(feature = "i128", since = "1.26.0")]);
102
103// signed integer -> signed integer
104impl_from!(i8 => i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
105impl_from!(i8 => i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
106impl_from!(i8 => i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
107impl_from!(i8 => i128, #[stable(feature = "i128", since = "1.26.0")]);
108impl_from!(i8 => isize, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
109impl_from!(i16 => i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
110impl_from!(i16 => i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
111impl_from!(i16 => i128, #[stable(feature = "i128", since = "1.26.0")]);
112impl_from!(i32 => i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
113impl_from!(i32 => i128, #[stable(feature = "i128", since = "1.26.0")]);
114impl_from!(i64 => i128, #[stable(feature = "i128", since = "1.26.0")]);
115
116// unsigned integer -> signed integer
117impl_from!(u8 => i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
118impl_from!(u8 => i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
119impl_from!(u8 => i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
120impl_from!(u8 => i128, #[stable(feature = "i128", since = "1.26.0")]);
121impl_from!(u16 => i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
122impl_from!(u16 => i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
123impl_from!(u16 => i128, #[stable(feature = "i128", since = "1.26.0")]);
124impl_from!(u32 => i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")]);
125impl_from!(u32 => i128, #[stable(feature = "i128", since = "1.26.0")]);
126impl_from!(u64 => i128, #[stable(feature = "i128", since = "1.26.0")]);
127
128// The C99 standard defines bounds on INTPTR_MIN, INTPTR_MAX, and UINTPTR_MAX
129// which imply that pointer-sized integers must be at least 16 bits:
130// https://port70.net/~nsz/c/c99/n1256.html#7.18.2.4
131impl_from!(u16 => usize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")]);
132impl_from!(u8 => isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")]);
133impl_from!(i16 => isize, #[stable(feature = "lossless_iusize_conv", since = "1.26.0")]);
134
135// RISC-V defines the possibility of a 128-bit address space (RV128).
136
137// CHERI proposes 128-bit “capabilities”. Unclear if this would be relevant to usize/isize.
138// https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/20171017a-cheri-poster.pdf
139// https://www.cl.cam.ac.uk/techreports/UCAM-CL-TR-951.pdf
140
141// Note: integers can only be represented with full precision in a float if
142// they fit in the significand, which is:
143// * 11 bits in f16
144// * 24 bits in f32
145// * 53 bits in f64
146// * 113 bits in f128
147// Lossy float conversions are not implemented at this time.
148// FIXME(f16,f128): The `f16`/`f128` impls `#[stable]` attributes should be changed to reference
149// `f16`/`f128` when they are stabilised (trait impls have to have a `#[stable]` attribute, but none
150// of the `f16`/`f128` impls can be used on stable as the `f16` and `f128` types are unstable).
151
152// signed integer -> float
153impl_from!(i8 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
154impl_from!(i8 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
155impl_from!(i8 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
156impl_from!(i8 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
157impl_from!(i16 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
158impl_from!(i16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
159impl_from!(i16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
160impl_from!(i32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
161impl_from!(i32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
162impl_from!(i64 => f128, #[unstable(feature = "f128", issue = "116909")], #[unstable_feature_bound(f128)]);
163
164// unsigned integer -> float
165impl_from!(u8 => f16, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
166impl_from!(u8 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
167impl_from!(u8 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
168impl_from!(u8 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
169impl_from!(u16 => f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
170impl_from!(u16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
171impl_from!(u16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
172impl_from!(u32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
173impl_from!(u32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
174impl_from!(u64 => f128, #[unstable(feature = "f128", issue = "116909")], #[unstable_feature_bound(f128)]);
175
176// float -> float
177// FIXME(f16,f128): adding additional `From<{float}>` impls to `f32` breaks inference. See
178// <https://github.com/rust-lang/rust/issues/123831>
179impl_from!(f16 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
180impl_from!(f16 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
181impl_from!(f32 => f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
182impl_from!(f32 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
183impl_from!(f64 => f128, #[stable(feature = "lossless_float_conv", since = "1.6.0")]);
184
185macro_rules! impl_float_from_bool {
186    (
187        $float:ty $(;
188            doctest_prefix: $(#[doc = $doctest_prefix:literal])*
189            doctest_suffix: $(#[doc = $doctest_suffix:literal])*
190        )?
191    ) => {
192        #[stable(feature = "float_from_bool", since = "1.68.0")]
193        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
194            impl const From<bool> for $float {
195            #[doc = concat!("Converts a [`bool`] to [`", stringify!($float),"`] losslessly.")]
196            /// The resulting value is positive `0.0` for `false` and `1.0` for `true` values.
197            ///
198            /// # Examples
199            /// ```
200            $($(#[doc = $doctest_prefix])*)?
201            #[doc = concat!("let x = ", stringify!($float), "::from(false);")]
202            /// assert_eq!(x, 0.0);
203            /// assert!(x.is_sign_positive());
204            ///
205            #[doc = concat!("let y = ", stringify!($float), "::from(true);")]
206            /// assert_eq!(y, 1.0);
207            $($(#[doc = $doctest_suffix])*)?
208            /// ```
209            #[inline]
210            fn from(small: bool) -> Self {
211                small as u8 as Self
212            }
213        }
214    };
215}
216
217// boolean -> float
218impl_float_from_bool!(
219    f16;
220    doctest_prefix:
221    // rustdoc doesn't remove the conventional space after the `///`
222    ///# #![allow(unused_features)]
223    ///#![feature(f16)]
224    ///# #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
225    ///
226    doctest_suffix:
227    ///# }
228);
229impl_float_from_bool!(f32);
230impl_float_from_bool!(f64);
231impl_float_from_bool!(
232    f128;
233    doctest_prefix:
234    ///# #![allow(unused_features)]
235    ///#![feature(f128)]
236    ///# #[cfg(all(target_arch = "x86_64", target_os = "linux"))] {
237    ///
238    doctest_suffix:
239    ///# }
240);
241
242// no possible bounds violation
243macro_rules! impl_try_from_unbounded {
244    ($source:ty => $($target:ty),+) => {$(
245        #[stable(feature = "try_from", since = "1.34.0")]
246        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
247        impl const TryFrom<$source> for $target {
248            type Error = TryFromIntError;
249
250            /// Tries to create the target number type from a source
251            /// number type. This returns an error if the source value
252            /// is outside of the range of the target type.
253            #[inline]
254            #[ferrocene::prevalidated]
255            fn try_from(value: $source) -> Result<Self, Self::Error> {
256                Ok(value as Self)
257            }
258        }
259    )*}
260}
261
262// only negative bounds
263macro_rules! impl_try_from_lower_bounded {
264    ($source:ty => $($target:ty),+) => {$(
265        #[stable(feature = "try_from", since = "1.34.0")]
266        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
267        impl const TryFrom<$source> for $target {
268            type Error = TryFromIntError;
269
270            /// Tries to create the target number type from a source
271            /// number type. This returns an error if the source value
272            /// is outside of the range of the target type.
273            #[inline]
274            #[ferrocene::prevalidated]
275            fn try_from(u: $source) -> Result<Self, Self::Error> {
276                if u >= 0 {
277                    Ok(u as Self)
278                } else {
279                    Err(TryFromIntError(()))
280                }
281            }
282        }
283    )*}
284}
285
286// unsigned to signed (only positive bound)
287macro_rules! impl_try_from_upper_bounded {
288    ($source:ty => $($target:ty),+) => {$(
289        #[stable(feature = "try_from", since = "1.34.0")]
290        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
291        impl const TryFrom<$source> for $target {
292            type Error = TryFromIntError;
293
294            /// Tries to create the target number type from a source
295            /// number type. This returns an error if the source value
296            /// is outside of the range of the target type.
297            #[inline]
298            #[ferrocene::prevalidated]
299            fn try_from(u: $source) -> Result<Self, Self::Error> {
300                if u > (Self::MAX as $source) {
301                    Err(TryFromIntError(()))
302                } else {
303                    Ok(u as Self)
304                }
305            }
306        }
307    )*}
308}
309
310// all other cases
311macro_rules! impl_try_from_both_bounded {
312    ($source:ty => $($target:ty),+) => {$(
313        #[stable(feature = "try_from", since = "1.34.0")]
314        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
315        impl const TryFrom<$source> for $target {
316            type Error = TryFromIntError;
317
318            /// Tries to create the target number type from a source
319            /// number type. This returns an error if the source value
320            /// is outside of the range of the target type.
321            #[inline]
322            #[ferrocene::prevalidated]
323            fn try_from(u: $source) -> Result<Self, Self::Error> {
324                let min = Self::MIN as $source;
325                let max = Self::MAX as $source;
326                if u < min || u > max {
327                    Err(TryFromIntError(()))
328                } else {
329                    Ok(u as Self)
330                }
331            }
332        }
333    )*}
334}
335
336/// Implement `TryFrom<integer>` for `bool`
337macro_rules! impl_try_from_integer_for_bool {
338    ($($int:ty)+) => {$(
339        #[stable(feature = "try_from", since = "1.34.0")]
340        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
341        impl const TryFrom<$int> for bool {
342            type Error = TryFromIntError;
343
344            /// Tries to create a bool from an integer type.
345            /// Returns an error if the integer is not 0 or 1.
346            ///
347            /// # Examples
348            ///
349            /// ```
350            #[doc = concat!("assert_eq!(bool::try_from(0_", stringify!($int), "), Ok(false));")]
351            ///
352            #[doc = concat!("assert_eq!(bool::try_from(1_", stringify!($int), "), Ok(true));")]
353            ///
354            #[doc = concat!("assert!(bool::try_from(2_", stringify!($int), ").is_err());")]
355            /// ```
356            #[inline]
357            #[ferrocene::prevalidated]
358            fn try_from(i: $int) -> Result<Self, Self::Error> {
359                match i {
360                    0 => Ok(false),
361                    1 => Ok(true),
362                    _ => Err(TryFromIntError(())),
363                }
364            }
365        }
366    )*}
367}
368
369macro_rules! rev {
370    ($mac:ident, $source:ty => $($target:ty),+) => {$(
371        $mac!($target => $source);
372    )*}
373}
374
375// integer -> bool
376impl_try_from_integer_for_bool!(u128 u64 u32 u16 u8);
377impl_try_from_integer_for_bool!(i128 i64 i32 i16 i8);
378
379// unsigned integer -> unsigned integer
380impl_try_from_upper_bounded!(u16 => u8);
381impl_try_from_upper_bounded!(u32 => u8, u16);
382impl_try_from_upper_bounded!(u64 => u8, u16, u32);
383impl_try_from_upper_bounded!(u128 => u8, u16, u32, u64);
384
385// signed integer -> signed integer
386impl_try_from_both_bounded!(i16 => i8);
387impl_try_from_both_bounded!(i32 => i8, i16);
388impl_try_from_both_bounded!(i64 => i8, i16, i32);
389impl_try_from_both_bounded!(i128 => i8, i16, i32, i64);
390
391// unsigned integer -> signed integer
392impl_try_from_upper_bounded!(u8 => i8);
393impl_try_from_upper_bounded!(u16 => i8, i16);
394impl_try_from_upper_bounded!(u32 => i8, i16, i32);
395impl_try_from_upper_bounded!(u64 => i8, i16, i32, i64);
396impl_try_from_upper_bounded!(u128 => i8, i16, i32, i64, i128);
397
398// signed integer -> unsigned integer
399impl_try_from_lower_bounded!(i8 => u8, u16, u32, u64, u128);
400impl_try_from_both_bounded!(i16 => u8);
401impl_try_from_lower_bounded!(i16 => u16, u32, u64, u128);
402impl_try_from_both_bounded!(i32 => u8, u16);
403impl_try_from_lower_bounded!(i32 => u32, u64, u128);
404impl_try_from_both_bounded!(i64 => u8, u16, u32);
405impl_try_from_lower_bounded!(i64 => u64, u128);
406impl_try_from_both_bounded!(i128 => u8, u16, u32, u64);
407impl_try_from_lower_bounded!(i128 => u128);
408
409// usize/isize
410impl_try_from_upper_bounded!(usize => isize);
411impl_try_from_lower_bounded!(isize => usize);
412
413#[cfg(target_pointer_width = "16")]
414mod ptr_try_from_impls {
415    use super::TryFromIntError;
416
417    impl_try_from_upper_bounded!(usize => u8);
418    impl_try_from_unbounded!(usize => u16, u32, u64, u128);
419    impl_try_from_upper_bounded!(usize => i8, i16);
420    impl_try_from_unbounded!(usize => i32, i64, i128);
421
422    impl_try_from_both_bounded!(isize => u8);
423    impl_try_from_lower_bounded!(isize => u16, u32, u64, u128);
424    impl_try_from_both_bounded!(isize => i8);
425    impl_try_from_unbounded!(isize => i16, i32, i64, i128);
426
427    rev!(impl_try_from_upper_bounded, usize => u32, u64, u128);
428    rev!(impl_try_from_lower_bounded, usize => i8, i16);
429    rev!(impl_try_from_both_bounded, usize => i32, i64, i128);
430
431    rev!(impl_try_from_upper_bounded, isize => u16, u32, u64, u128);
432    rev!(impl_try_from_both_bounded, isize => i32, i64, i128);
433}
434
435#[cfg(target_pointer_width = "32")]
436mod ptr_try_from_impls {
437    use super::TryFromIntError;
438
439    impl_try_from_upper_bounded!(usize => u8, u16);
440    impl_try_from_unbounded!(usize => u32, u64, u128);
441    impl_try_from_upper_bounded!(usize => i8, i16, i32);
442    impl_try_from_unbounded!(usize => i64, i128);
443
444    impl_try_from_both_bounded!(isize => u8, u16);
445    impl_try_from_lower_bounded!(isize => u32, u64, u128);
446    impl_try_from_both_bounded!(isize => i8, i16);
447    impl_try_from_unbounded!(isize => i32, i64, i128);
448
449    rev!(impl_try_from_unbounded, usize => u32);
450    rev!(impl_try_from_upper_bounded, usize => u64, u128);
451    rev!(impl_try_from_lower_bounded, usize => i8, i16, i32);
452    rev!(impl_try_from_both_bounded, usize => i64, i128);
453
454    rev!(impl_try_from_unbounded, isize => u16);
455    rev!(impl_try_from_upper_bounded, isize => u32, u64, u128);
456    rev!(impl_try_from_unbounded, isize => i32);
457    rev!(impl_try_from_both_bounded, isize => i64, i128);
458}
459
460#[cfg(target_pointer_width = "64")]
461mod ptr_try_from_impls {
462    use super::TryFromIntError;
463
464    impl_try_from_upper_bounded!(usize => u8, u16, u32);
465    impl_try_from_unbounded!(usize => u64, u128);
466    impl_try_from_upper_bounded!(usize => i8, i16, i32, i64);
467    impl_try_from_unbounded!(usize => i128);
468
469    impl_try_from_both_bounded!(isize => u8, u16, u32);
470    impl_try_from_lower_bounded!(isize => u64, u128);
471    impl_try_from_both_bounded!(isize => i8, i16, i32);
472    impl_try_from_unbounded!(isize => i64, i128);
473
474    rev!(impl_try_from_unbounded, usize => u32, u64);
475    rev!(impl_try_from_upper_bounded, usize => u128);
476    rev!(impl_try_from_lower_bounded, usize => i8, i16, i32, i64);
477    rev!(impl_try_from_both_bounded, usize => i128);
478
479    rev!(impl_try_from_unbounded, isize => u16, u32);
480    rev!(impl_try_from_upper_bounded, isize => u64, u128);
481    rev!(impl_try_from_unbounded, isize => i32, i64);
482    rev!(impl_try_from_both_bounded, isize => i128);
483}
484
485// Conversion traits for non-zero integer types
486use crate::num::NonZero;
487
488macro_rules! impl_nonzero_int_from_nonzero_int {
489    ($Small:ty => $Large:ty) => {
490        #[stable(feature = "nz_int_conv", since = "1.41.0")]
491        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
492        impl const From<NonZero<$Small>> for NonZero<$Large> {
493            // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
494            // Rustdocs on functions do not.
495            #[doc = concat!("Converts <code>[NonZero]\\<[", stringify!($Small), "]></code> ")]
496            #[doc = concat!("to <code>[NonZero]\\<[", stringify!($Large), "]></code> losslessly.")]
497            #[inline]
498            fn from(small: NonZero<$Small>) -> Self {
499                // SAFETY: input type guarantees the value is non-zero
500                unsafe { Self::new_unchecked(From::from(small.get())) }
501            }
502        }
503    };
504}
505
506// non-zero unsigned integer -> non-zero unsigned integer
507impl_nonzero_int_from_nonzero_int!(u8 => u16);
508impl_nonzero_int_from_nonzero_int!(u8 => u32);
509impl_nonzero_int_from_nonzero_int!(u8 => u64);
510impl_nonzero_int_from_nonzero_int!(u8 => u128);
511impl_nonzero_int_from_nonzero_int!(u8 => usize);
512impl_nonzero_int_from_nonzero_int!(u16 => u32);
513impl_nonzero_int_from_nonzero_int!(u16 => u64);
514impl_nonzero_int_from_nonzero_int!(u16 => u128);
515impl_nonzero_int_from_nonzero_int!(u16 => usize);
516impl_nonzero_int_from_nonzero_int!(u32 => u64);
517impl_nonzero_int_from_nonzero_int!(u32 => u128);
518impl_nonzero_int_from_nonzero_int!(u64 => u128);
519
520// non-zero signed integer -> non-zero signed integer
521impl_nonzero_int_from_nonzero_int!(i8 => i16);
522impl_nonzero_int_from_nonzero_int!(i8 => i32);
523impl_nonzero_int_from_nonzero_int!(i8 => i64);
524impl_nonzero_int_from_nonzero_int!(i8 => i128);
525impl_nonzero_int_from_nonzero_int!(i8 => isize);
526impl_nonzero_int_from_nonzero_int!(i16 => i32);
527impl_nonzero_int_from_nonzero_int!(i16 => i64);
528impl_nonzero_int_from_nonzero_int!(i16 => i128);
529impl_nonzero_int_from_nonzero_int!(i16 => isize);
530impl_nonzero_int_from_nonzero_int!(i32 => i64);
531impl_nonzero_int_from_nonzero_int!(i32 => i128);
532impl_nonzero_int_from_nonzero_int!(i64 => i128);
533
534// non-zero unsigned -> non-zero signed integer
535impl_nonzero_int_from_nonzero_int!(u8 => i16);
536impl_nonzero_int_from_nonzero_int!(u8 => i32);
537impl_nonzero_int_from_nonzero_int!(u8 => i64);
538impl_nonzero_int_from_nonzero_int!(u8 => i128);
539impl_nonzero_int_from_nonzero_int!(u8 => isize);
540impl_nonzero_int_from_nonzero_int!(u16 => i32);
541impl_nonzero_int_from_nonzero_int!(u16 => i64);
542impl_nonzero_int_from_nonzero_int!(u16 => i128);
543impl_nonzero_int_from_nonzero_int!(u32 => i64);
544impl_nonzero_int_from_nonzero_int!(u32 => i128);
545impl_nonzero_int_from_nonzero_int!(u64 => i128);
546
547macro_rules! impl_nonzero_int_try_from_int {
548    ($Int:ty) => {
549        #[stable(feature = "nzint_try_from_int_conv", since = "1.46.0")]
550        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
551        impl const TryFrom<$Int> for NonZero<$Int> {
552            type Error = TryFromIntError;
553
554            // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
555            // Rustdocs on functions do not.
556            #[doc = concat!("Attempts to convert [`", stringify!($Int), "`] ")]
557            #[doc = concat!("to <code>[NonZero]\\<[", stringify!($Int), "]></code>.")]
558            #[inline]
559            fn try_from(value: $Int) -> Result<Self, Self::Error> {
560                Self::new(value).ok_or(TryFromIntError(()))
561            }
562        }
563    };
564}
565
566// integer -> non-zero integer
567impl_nonzero_int_try_from_int!(u8);
568impl_nonzero_int_try_from_int!(u16);
569impl_nonzero_int_try_from_int!(u32);
570impl_nonzero_int_try_from_int!(u64);
571impl_nonzero_int_try_from_int!(u128);
572impl_nonzero_int_try_from_int!(usize);
573impl_nonzero_int_try_from_int!(i8);
574impl_nonzero_int_try_from_int!(i16);
575impl_nonzero_int_try_from_int!(i32);
576impl_nonzero_int_try_from_int!(i64);
577impl_nonzero_int_try_from_int!(i128);
578impl_nonzero_int_try_from_int!(isize);
579
580macro_rules! impl_nonzero_int_try_from_nonzero_int {
581    ($source:ty => $($target:ty),+) => {$(
582        #[stable(feature = "nzint_try_from_nzint_conv", since = "1.49.0")]
583        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
584        impl const TryFrom<NonZero<$source>> for NonZero<$target> {
585            type Error = TryFromIntError;
586
587            // Rustdocs on the impl block show a "[+] show undocumented items" toggle.
588            // Rustdocs on functions do not.
589            #[doc = concat!("Attempts to convert <code>[NonZero]\\<[", stringify!($source), "]></code> ")]
590            #[doc = concat!("to <code>[NonZero]\\<[", stringify!($target), "]></code>.")]
591            #[inline]
592            fn try_from(value: NonZero<$source>) -> Result<Self, Self::Error> {
593                // SAFETY: Input is guaranteed to be non-zero.
594                Ok(unsafe { Self::new_unchecked(<$target>::try_from(value.get())?) })
595            }
596        }
597    )*};
598}
599
600// unsigned non-zero integer -> unsigned non-zero integer
601impl_nonzero_int_try_from_nonzero_int!(u16 => u8);
602impl_nonzero_int_try_from_nonzero_int!(u32 => u8, u16, usize);
603impl_nonzero_int_try_from_nonzero_int!(u64 => u8, u16, u32, usize);
604impl_nonzero_int_try_from_nonzero_int!(u128 => u8, u16, u32, u64, usize);
605impl_nonzero_int_try_from_nonzero_int!(usize => u8, u16, u32, u64, u128);
606
607// signed non-zero integer -> signed non-zero integer
608impl_nonzero_int_try_from_nonzero_int!(i16 => i8);
609impl_nonzero_int_try_from_nonzero_int!(i32 => i8, i16, isize);
610impl_nonzero_int_try_from_nonzero_int!(i64 => i8, i16, i32, isize);
611impl_nonzero_int_try_from_nonzero_int!(i128 => i8, i16, i32, i64, isize);
612impl_nonzero_int_try_from_nonzero_int!(isize => i8, i16, i32, i64, i128);
613
614// unsigned non-zero integer -> signed non-zero integer
615impl_nonzero_int_try_from_nonzero_int!(u8 => i8);
616impl_nonzero_int_try_from_nonzero_int!(u16 => i8, i16, isize);
617impl_nonzero_int_try_from_nonzero_int!(u32 => i8, i16, i32, isize);
618impl_nonzero_int_try_from_nonzero_int!(u64 => i8, i16, i32, i64, isize);
619impl_nonzero_int_try_from_nonzero_int!(u128 => i8, i16, i32, i64, i128, isize);
620impl_nonzero_int_try_from_nonzero_int!(usize => i8, i16, i32, i64, i128, isize);
621
622// signed non-zero integer -> unsigned non-zero integer
623impl_nonzero_int_try_from_nonzero_int!(i8 => u8, u16, u32, u64, u128, usize);
624impl_nonzero_int_try_from_nonzero_int!(i16 => u8, u16, u32, u64, u128, usize);
625impl_nonzero_int_try_from_nonzero_int!(i32 => u8, u16, u32, u64, u128, usize);
626impl_nonzero_int_try_from_nonzero_int!(i64 => u8, u16, u32, u64, u128, usize);
627impl_nonzero_int_try_from_nonzero_int!(i128 => u8, u16, u32, u64, u128, usize);
628impl_nonzero_int_try_from_nonzero_int!(isize => u8, u16, u32, u64, u128, usize);
core/convert/num.rs

core/convert/
num.rs
