core/num/
int_log10.rs
1#[inline]
6pub(super) const fn u8(val: u8) -> u32 {
7 let val = val as u32;
8
9 const C1: u32 = 0b11_00000000 - 10; const C2: u32 = 0b10_00000000 - 100; ((val + C1) & (val + C2)) >> 8
23}
24
25#[inline]
27const fn less_than_5(val: u32) -> u32 {
28 const C1: u32 = 0b011_00000000000000000 - 10; const C2: u32 = 0b100_00000000000000000 - 100; const C3: u32 = 0b111_00000000000000000 - 1000; const C4: u32 = 0b100_00000000000000000 - 10000; (((val + C1) & (val + C2)) ^ ((val + C3) & (val + C4))) >> 17
44}
45
46#[inline]
48pub(super) const fn u16(val: u16) -> u32 {
49 less_than_5(val as u32)
50}
51
52#[inline]
54pub(super) const fn u32(mut val: u32) -> u32 {
55 let mut log = 0;
56 if val >= 100_000 {
57 val /= 100_000;
58 log += 5;
59 }
60 log + less_than_5(val)
61}
62
63#[inline]
65pub(super) const fn u64(mut val: u64) -> u32 {
66 let mut log = 0;
67 if val >= 10_000_000_000 {
68 val /= 10_000_000_000;
69 log += 10;
70 }
71 if val >= 100_000 {
72 val /= 100_000;
73 log += 5;
74 }
75 log + less_than_5(val as u32)
76}
77
78#[inline]
80pub(super) const fn u128(mut val: u128) -> u32 {
81 let mut log = 0;
82 if val >= 100_000_000_000_000_000_000_000_000_000_000 {
83 val /= 100_000_000_000_000_000_000_000_000_000_000;
84 log += 32;
85 return log + u32(val as u32);
86 }
87 if val >= 10_000_000_000_000_000 {
88 val /= 10_000_000_000_000_000;
89 log += 16;
90 }
91 log + u64(val as u64)
92}
93
94#[cfg(target_pointer_width = "16")]
95#[inline]
96pub(super) const fn usize(val: usize) -> u32 {
97 u16(val as _)
98}
99
100#[cfg(target_pointer_width = "32")]
101#[inline]
102pub(super) const fn usize(val: usize) -> u32 {
103 u32(val as _)
104}
105
106#[cfg(target_pointer_width = "64")]
107#[inline]
108pub(super) const fn usize(val: usize) -> u32 {
109 u64(val as _)
110}
111
112#[inline]
114pub(super) const fn i8(val: i8) -> u32 {
115 u8(val as u8)
116}
117
118#[inline]
120pub(super) const fn i16(val: i16) -> u32 {
121 u16(val as u16)
122}
123
124#[inline]
126pub(super) const fn i32(val: i32) -> u32 {
127 u32(val as u32)
128}
129
130#[inline]
132pub(super) const fn i64(val: i64) -> u32 {
133 u64(val as u64)
134}
135
136#[inline]
138pub(super) const fn i128(val: i128) -> u32 {
139 u128(val as u128)
140}
141
142#[cold]
145#[track_caller]
146pub(super) const fn panic_for_nonpositive_argument() -> ! {
147 panic!("argument of integer logarithm must be positive")
148}