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
148
149
150
151
152
153
154
155
156
157
|
use core::arch::aarch64::{
uint8x16_t, uint8x16x4_t, vaddlvq_u8, vandq_u8, vceqq_u8, vdupq_n_u8, vld1q_u8, vld1q_u8_x4,
vmvnq_u8, vsubq_u8,
};
const MASK: [u8; 32] = [
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 255, 255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255,
];
#[target_feature(enable = "neon")]
unsafe fn u8x16_from_offset(slice: &[u8], offset: usize) -> uint8x16_t {
debug_assert!(
offset + 16 <= slice.len(),
"{} + 16 ≥ {}",
offset,
slice.len()
);
vld1q_u8(slice.as_ptr().add(offset) as *const _) // TODO: does this need to be aligned?
}
#[target_feature(enable = "neon")]
unsafe fn u8x16_x4_from_offset(slice: &[u8], offset: usize) -> uint8x16x4_t {
debug_assert!(
offset + 64 <= slice.len(),
"{} + 64 ≥ {}",
offset,
slice.len()
);
vld1q_u8_x4(slice.as_ptr().add(offset) as *const _)
}
#[target_feature(enable = "neon")]
unsafe fn sum(u8s: uint8x16_t) -> usize {
vaddlvq_u8(u8s) as usize
}
#[target_feature(enable = "neon")]
pub unsafe fn chunk_count(haystack: &[u8], needle: u8) -> usize {
assert!(haystack.len() >= 16);
let mut offset = 0;
let mut count = 0;
let needles = vdupq_n_u8(needle);
// 16320
while haystack.len() >= offset + 64 * 255 {
let (mut count1, mut count2, mut count3, mut count4) =
(vdupq_n_u8(0), vdupq_n_u8(0), vdupq_n_u8(0), vdupq_n_u8(0));
for _ in 0..255 {
let uint8x16x4_t(h1, h2, h3, h4) = u8x16_x4_from_offset(haystack, offset);
count1 = vsubq_u8(count1, vceqq_u8(h1, needles));
count2 = vsubq_u8(count2, vceqq_u8(h2, needles));
count3 = vsubq_u8(count3, vceqq_u8(h3, needles));
count4 = vsubq_u8(count4, vceqq_u8(h4, needles));
offset += 64;
}
count += sum(count1) + sum(count2) + sum(count3) + sum(count4);
}
// 64
let (mut count1, mut count2, mut count3, mut count4) =
(vdupq_n_u8(0), vdupq_n_u8(0), vdupq_n_u8(0), vdupq_n_u8(0));
for _ in 0..(haystack.len() - offset) / 64 {
let uint8x16x4_t(h1, h2, h3, h4) = u8x16_x4_from_offset(haystack, offset);
count1 = vsubq_u8(count1, vceqq_u8(h1, needles));
count2 = vsubq_u8(count2, vceqq_u8(h2, needles));
count3 = vsubq_u8(count3, vceqq_u8(h3, needles));
count4 = vsubq_u8(count4, vceqq_u8(h4, needles));
offset += 64;
}
count += sum(count1) + sum(count2) + sum(count3) + sum(count4);
let mut counts = vdupq_n_u8(0);
// 16
for i in 0..(haystack.len() - offset) / 16 {
counts = vsubq_u8(
counts,
vceqq_u8(u8x16_from_offset(haystack, offset + i * 16), needles),
);
}
if haystack.len() % 16 != 0 {
counts = vsubq_u8(
counts,
vandq_u8(
vceqq_u8(u8x16_from_offset(haystack, haystack.len() - 16), needles),
u8x16_from_offset(&MASK, haystack.len() % 16),
),
);
}
count + sum(counts)
}
#[target_feature(enable = "neon")]
unsafe fn is_leading_utf8_byte(u8s: uint8x16_t) -> uint8x16_t {
vmvnq_u8(vceqq_u8(
vandq_u8(u8s, vdupq_n_u8(0b1100_0000)),
vdupq_n_u8(0b1000_0000),
))
}
#[target_feature(enable = "neon")]
pub unsafe fn chunk_num_chars(utf8_chars: &[u8]) -> usize {
assert!(utf8_chars.len() >= 16);
let mut offset = 0;
let mut count = 0;
// 4080
while utf8_chars.len() >= offset + 16 * 255 {
let mut counts = vdupq_n_u8(0);
for _ in 0..255 {
counts = vsubq_u8(
counts,
is_leading_utf8_byte(u8x16_from_offset(utf8_chars, offset)),
);
offset += 16;
}
count += sum(counts);
}
// 2048
if utf8_chars.len() >= offset + 16 * 128 {
let mut counts = vdupq_n_u8(0);
for _ in 0..128 {
counts = vsubq_u8(
counts,
is_leading_utf8_byte(u8x16_from_offset(utf8_chars, offset)),
);
offset += 16;
}
count += sum(counts);
}
// 16
let mut counts = vdupq_n_u8(0);
for i in 0..(utf8_chars.len() - offset) / 16 {
counts = vsubq_u8(
counts,
is_leading_utf8_byte(u8x16_from_offset(utf8_chars, offset + i * 16)),
);
}
if utf8_chars.len() % 16 != 0 {
counts = vsubq_u8(
counts,
vandq_u8(
is_leading_utf8_byte(u8x16_from_offset(utf8_chars, utf8_chars.len() - 16)),
u8x16_from_offset(&MASK, utf8_chars.len() % 16),
),
);
}
count += sum(counts);
count
}
|
