brie-tree 0.1.2

A fast B+ Tree implementation that uses integer keys
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147

use super::{SimdSearch, exact_div_unchecked};
#[cfg(target_arch = "x86")]
use core::arch::x86::*;
#[cfg(target_arch = "x86_64")]
use core::arch::x86_64::*;

#[inline]
#[target_feature(enable = "avx2")]
unsafe fn search8(keys: *const i8, search: i8) -> usize {
    let search = _mm256_set1_epi8(search);
    let cmp = |offset: usize| {
        let vec = unsafe { _mm256_load_si256(keys.cast::<__m256i>().add(offset)) };
        _mm256_cmpgt_epi8(search, vec)
    };
    let a = cmp(0);
    let b = cmp(1);
    let c = cmp(2);
    let d = cmp(3);
    let mask1 = _mm256_movemask_epi8(a);
    let mask2 = _mm256_movemask_epi8(b);
    let mask3 = _mm256_movemask_epi8(c);
    let mask4 = _mm256_movemask_epi8(d);
    mask1.count_ones() as usize
        + mask2.count_ones() as usize
        + mask3.count_ones() as usize
        + mask4.count_ones() as usize
}

#[inline]
#[target_feature(enable = "avx2")]
unsafe fn search16(keys: *const i16, search: i16) -> usize {
    let search = _mm256_set1_epi16(search);
    let cmp = |offset: usize| {
        let vec = unsafe { _mm256_load_si256(keys.cast::<__m256i>().add(offset)) };
        _mm256_cmpgt_epi16(search, vec)
    };
    let a = cmp(0);
    let b = cmp(1);
    let c = cmp(2);
    let d = cmp(3);
    let ab = _mm256_packs_epi16(a, b);
    let cd = _mm256_packs_epi16(c, d);
    let mask1 = _mm256_movemask_epi8(ab);
    let mask2 = _mm256_movemask_epi8(cd);
    mask1.count_ones() as usize + mask2.count_ones() as usize
}

#[inline]
#[target_feature(enable = "avx2")]
unsafe fn search32(keys: *const i32, search: i32) -> usize {
    let search = _mm256_set1_epi32(search);
    let cmp = |offset: usize| {
        let vec = unsafe { _mm256_load_si256(keys.cast::<__m256i>().add(offset)) };
        _mm256_cmpgt_epi32(search, vec)
    };
    let a = cmp(0);
    let b = cmp(1);
    let c = cmp(2);
    let d = cmp(3);
    let ab = _mm256_blend_epi16(a, b, 0b01010101);
    let cd = _mm256_blend_epi16(c, d, 0b01010101);
    let abcd = _mm256_packs_epi16(ab, cd);
    let mask = _mm256_movemask_epi8(abcd);
    mask.count_ones() as usize
}

#[inline]
#[target_feature(enable = "avx2")]
unsafe fn search64(keys: *const i64, search: i64) -> usize {
    let search = _mm256_set1_epi64x(search);
    let cmp = |offset: usize| {
        let vec = unsafe { _mm256_load_si256(keys.cast::<__m256i>().add(offset)) };
        _mm256_cmpgt_epi64(search, vec)
    };
    let a = cmp(0);
    let b = cmp(1);
    let c = cmp(2);
    let d = cmp(3);
    let ab = _mm256_blend_epi32(a, b, 0b01010101);
    let cd = _mm256_blend_epi32(c, d, 0b01010101);
    let abcd = _mm256_blend_epi16(ab, cd, 0b01010101);
    let mask = _mm256_movemask_epi8(abcd);
    unsafe { exact_div_unchecked(mask.count_ones() as usize, 2) }
}

impl SimdSearch for u8 {
    const SIMD_WIDTH: usize = 128;
    const BIAS: Self = i8::MIN as Self;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search8(keys.cast(), search as i8) }
    }
}
impl SimdSearch for u16 {
    const SIMD_WIDTH: usize = 64;
    const BIAS: Self = i16::MIN as Self;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search16(keys.cast(), search as i16) }
    }
}
impl SimdSearch for u32 {
    const SIMD_WIDTH: usize = 32;
    const BIAS: Self = i32::MIN as Self;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search32(keys.cast(), search as i32) }
    }
}
impl SimdSearch for u64 {
    const SIMD_WIDTH: usize = 16;
    const BIAS: Self = i64::MIN as Self;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search64(keys.cast(), search as i64) }
    }
}
impl SimdSearch for u128 {}
impl SimdSearch for i8 {
    const SIMD_WIDTH: usize = 128;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search8(keys, search) }
    }
}
impl SimdSearch for i16 {
    const SIMD_WIDTH: usize = 64;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search16(keys, search) }
    }
}
impl SimdSearch for i32 {
    const SIMD_WIDTH: usize = 32;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search32(keys, search) }
    }
}
impl SimdSearch for i64 {
    const SIMD_WIDTH: usize = 16;
    #[inline]
    unsafe fn simd_search(keys: *const Self, search: Self) -> usize {
        unsafe { search64(keys, search) }
    }
}
impl SimdSearch for i128 {}