1 //! This tests the `Integer::{ilog,log2,log10}` methods. These tests are in a
2 //! separate file because there's both a large number of them, and not all tests
3 //! can be run on Android. This is because in Android `ilog2` uses an imprecise
4 //! approximation:https://github.com/rust-lang/rust/blob/4825e12fc9c79954aa0fe18f5521efa6c19c7539/src/libstd/sys/unix/android.rs#L27-L53
8 assert_eq!(999u32.checked_ilog(10), Some(2));
9 assert_eq!(1000u32.checked_ilog(10), Some(3));
10 assert_eq!(555u32.checked_ilog(13), Some(2));
11 assert_eq!(63u32.checked_ilog(4), Some(2));
12 assert_eq!(64u32.checked_ilog(4), Some(3));
13 assert_eq!(10460353203u64.checked_ilog(3), Some(21));
14 assert_eq!(10460353202u64.checked_ilog(3), Some(20));
15 assert_eq!(147808829414345923316083210206383297601u128.checked_ilog(3), Some(80));
16 assert_eq!(147808829414345923316083210206383297600u128.checked_ilog(3), Some(79));
17 assert_eq!(22528399544939174411840147874772641u128.checked_ilog(19683), Some(8));
18 assert_eq!(22528399544939174411840147874772631i128.checked_ilog(19683), Some(7));
20 assert_eq!(0u8.checked_ilog(4), None);
21 assert_eq!(0u16.checked_ilog(4), None);
22 assert_eq!(0i8.checked_ilog(4), None);
23 assert_eq!(0i16.checked_ilog(4), None);
25 #[cfg(not(miri))] // Miri is too slow
26 for i in i16::MIN..=0 {
27 assert_eq!(i.checked_ilog(4), None);
29 #[cfg(not(miri))] // Miri is too slow
30 for i in 1..=i16::MAX {
31 assert_eq!(i.checked_ilog(13), Some((i as f32).log(13.0) as u32));
33 #[cfg(not(miri))] // Miri is too slow
34 for i in 1..=u16::MAX {
35 assert_eq!(i.checked_ilog(13), Some((i as f32).log(13.0) as u32));
41 assert_eq!(5u32.checked_ilog2(), Some(2));
42 assert_eq!(0u64.checked_ilog2(), None);
43 assert_eq!(128i32.checked_ilog2(), Some(7));
44 assert_eq!((-55i16).checked_ilog2(), None);
46 assert_eq!(0u8.checked_ilog2(), None);
47 assert_eq!(0u16.checked_ilog2(), None);
48 assert_eq!(0i8.checked_ilog2(), None);
49 assert_eq!(0i16.checked_ilog2(), None);
51 for i in 1..=u8::MAX {
52 assert_eq!(i.checked_ilog2(), Some((i as f32).log2() as u32));
54 #[cfg(not(miri))] // Miri is too slow
55 for i in 1..=u16::MAX {
56 // Guard against Android's imprecise f32::ilog2 implementation.
57 if i != 8192 && i != 32768 {
58 assert_eq!(i.checked_ilog2(), Some((i as f32).log2() as u32));
61 for i in i8::MIN..=0 {
62 assert_eq!(i.checked_ilog2(), None);
64 for i in 1..=i8::MAX {
65 assert_eq!(i.checked_ilog2(), Some((i as f32).log2() as u32));
67 #[cfg(not(miri))] // Miri is too slow
68 for i in i16::MIN..=0 {
69 assert_eq!(i.checked_ilog2(), None);
71 #[cfg(not(miri))] // Miri is too slow
72 for i in 1..=i16::MAX {
73 // Guard against Android's imprecise f32::ilog2 implementation.
75 assert_eq!(i.checked_ilog2(), Some((i as f32).log2() as u32));
80 // Validate cases that fail on Android's imprecise float ilog2 implementation.
82 #[cfg(not(target_os = "android"))]
83 fn checked_ilog2_not_android() {
84 assert_eq!(8192u16.checked_ilog2(), Some((8192f32).log2() as u32));
85 assert_eq!(32768u16.checked_ilog2(), Some((32768f32).log2() as u32));
86 assert_eq!(8192i16.checked_ilog2(), Some((8192f32).log2() as u32));
91 assert_eq!(0u8.checked_ilog10(), None);
92 assert_eq!(0u16.checked_ilog10(), None);
93 assert_eq!(0i8.checked_ilog10(), None);
94 assert_eq!(0i16.checked_ilog10(), None);
96 #[cfg(not(miri))] // Miri is too slow
97 for i in i16::MIN..=0 {
98 assert_eq!(i.checked_ilog10(), None);
100 #[cfg(not(miri))] // Miri is too slow
101 for i in 1..=i16::MAX {
102 assert_eq!(i.checked_ilog10(), Some((i as f32).log10() as u32));
104 #[cfg(not(miri))] // Miri is too slow
105 for i in 1..=u16::MAX {
106 assert_eq!(i.checked_ilog10(), Some((i as f32).log10() as u32));
108 #[cfg(not(miri))] // Miri is too slow
109 for i in 1..=100_000u32 {
110 assert_eq!(i.checked_ilog10(), Some((i as f32).log10() as u32));
114 macro_rules! ilog10_loop {
115 ($T:ty, $ilog10_max:expr) => {
116 assert_eq!(<$T>::MAX.ilog10(), $ilog10_max);
117 for i in 0..=$ilog10_max {
118 let p = (10 as $T).pow(i as u32);
120 assert_eq!((p - 9).ilog10(), i - 1);
121 assert_eq!((p - 1).ilog10(), i - 1);
123 assert_eq!(p.ilog10(), i);
124 assert_eq!((p + 1).ilog10(), i);
126 assert_eq!((p + 9).ilog10(), i);
129 // also check `x.ilog(10)`
131 assert_eq!((p - 9).ilog(10), i - 1);
132 assert_eq!((p - 1).ilog(10), i - 1);
134 assert_eq!(p.ilog(10), i);
135 assert_eq!((p + 1).ilog(10), i);
137 assert_eq!((p + 9).ilog(10), i);
145 ilog10_loop! { u8, 2 }
150 ilog10_loop! { u16, 4 }
155 ilog10_loop! { u32, 9 }
160 ilog10_loop! { u64, 19 }
165 ilog10_loop! { u128, 38 }
169 #[should_panic(expected = "argument of integer logarithm must be positive")]
170 fn ilog2_of_0_panic() {
171 let _ = 0u32.ilog2();
175 #[should_panic(expected = "argument of integer logarithm must be positive")]
176 fn ilog10_of_0_panic() {
177 let _ = 0u32.ilog10();
181 #[should_panic(expected = "argument of integer logarithm must be positive")]
182 fn ilog3_of_0_panic() {
183 let _ = 0u32.ilog(3);
187 #[should_panic(expected = "base of integer logarithm must be at least 2")]
188 fn ilog0_of_1_panic() {
189 let _ = 1u32.ilog(0);
193 #[should_panic(expected = "base of integer logarithm must be at least 2")]
194 fn ilog1_of_1_panic() {
195 let _ = 1u32.ilog(1);