rasterizeddb_core 0.0.8

A schemaless, high-performance database written in Rust, designed for speed and scalability.
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

use std::{
    arch::{asm, x86_64::*},
    mem::ManuallyDrop,
    ptr,
};

#[inline]
pub(crate) fn compare_vecs_eq(vec1: &[u8], vec2: &[u8]) -> bool {
    // If lengths differ, the vectors can't be equal.
    if vec1.len() != vec2.len() {
        return false;
    }

    return vec1.eq(vec2);
}

#[inline]
pub(crate) fn compare_vecs_ne(vec1: &[u8], vec2: &[u8]) -> bool {
    // If lengths differ, the vectors can't be equal.
    if vec1.len() != vec2.len() {
        return true;
    }

    return vec1.ne(vec2);
}

/// Check if `haystack` contains `needle`
#[inline(always)]
pub(crate) fn contains_subsequence(haystack: &[u8], needle: &[u8]) -> bool {
    if needle.is_empty() || needle.len() > haystack.len() {
        return false;
    }

    // Get the lengths
    let needle_len = needle.len();
    let haystack_len = haystack.len();

    unsafe {
        // If x86_64 is used
        #[cfg(target_arch = "x86_64")]
        {
            let needle_first_byte = _mm_set1_epi8(needle[0] as i8);
            let mut i = 0;

            while i <= haystack_len - needle_len {
                // Load 16 bytes from haystack using SSE2
                let chunk = _mm_loadu_si128(haystack[i..].as_ptr() as *const __m128i);

                // Compare with first byte of needle
                let cmp_mask = _mm_movemask_epi8(_mm_cmpeq_epi8(chunk, needle_first_byte));

                // Process matching positions
                for offset in 0..16 {
                    if cmp_mask & (1 << offset) != 0 {
                        // Check for full needle match
                        if haystack[i + offset..].starts_with(needle) {
                            return true;
                        }
                    }
                }

                i += 16;
            }

            return false;
        }
    }

    #[cfg(not(target_arch = "x86_64"))]
    {
        // Fallback: Naive search if SIMD is unavailable
        haystack.windows(needle_len).any(|window| window == needle)
    }
}

#[inline]
pub(crate) fn compare_vecs_starts_with(vec1: &[u8], vec2: &[u8]) -> bool {
    return vec1.starts_with(vec2);
}

#[inline]
pub(crate) fn compare_vecs_ends_with(vec1: &[u8], vec2: &[u8]) -> bool {
    return vec1.ends_with(vec2);
}

#[inline(always)]
pub unsafe fn compare_raw_vecs(
    vec_a: *mut u8,
    vec_b: *mut u8,
    vec_a_len: u32,
    vec_b_len: u32,
) -> bool {
    let mut result: u8;

    if vec_a_len != vec_b_len {
        return false;
    }

    asm!(
        "repe cmpsb",
        inout("rsi") vec_a => _,
        inout("rdi") vec_b => _,
        inout("rcx") vec_a_len => _,
        out("al") result
    );

    result == 0
}

#[allow(unused)]
pub fn copy_vec_to_ptr(vec: &[u8], dst: *mut u8) {
    unsafe {
        ptr::copy_nonoverlapping(vec.as_ptr(), dst, vec.len());
    }
}

pub fn copy_ptr_to_vec(src: *const u8, vec: &mut Vec<u8>, len: usize) {
    unsafe {
        vec[..len].copy_from_slice(std::slice::from_raw_parts(src, len));
    }
}

pub fn vec_from_ptr_safe(ptr: *mut u8, len: usize) -> Vec<u8> {
    let mut vec = vec![0_u8; len];
    copy_ptr_to_vec(ptr, &mut vec, len);
    vec
}

pub unsafe fn ref_vec(ptr: *mut u8, len: usize) -> ManuallyDrop<Vec<u8>> {
    unsafe {
        let vec = Vec::from_raw_parts(ptr, len, len);
        let manual = ManuallyDrop::new(vec);
        manual
    }
}