zrip-core 0.5.0

Shared types and codecs for zrip (internal crate)
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
148
149
150

#[cfg(feature = "alloc")]
use alloc::vec::Vec;

#[cfg(all(target_arch = "x86_64", not(feature = "paranoid")))]
use super::CpuTier;

#[inline]
pub fn append_literals(dst: &mut Vec<u8>, src: &[u8]) {
    if src.is_empty() {
        return;
    }

    #[cfg(not(feature = "paranoid"))]
    {
        let len = src.len();
        dst.reserve(len + 32);
        let dst_offset = dst.len();

        #[cfg(target_arch = "x86_64")]
        {
            let tier = super::cpu_tier();
            if tier >= CpuTier::Avx2 && len >= 32 {
                unsafe {
                    let dst_ptr = dst.as_mut_ptr().add(dst_offset);
                    super::x86_64::avx2::wildcopy_avx2(src.as_ptr(), dst_ptr, len);
                    dst.set_len(dst_offset + len);
                }
                return;
            }
            if tier >= CpuTier::Sse2 && len >= 16 {
                unsafe {
                    let dst_ptr = dst.as_mut_ptr().add(dst_offset);
                    super::x86_64::sse2::wildcopy_sse2(src.as_ptr(), dst_ptr, len);
                    dst.set_len(dst_offset + len);
                }
                return;
            }
        }

        #[cfg(target_arch = "aarch64")]
        {
            if len >= 16 {
                unsafe {
                    let dst_ptr = dst.as_mut_ptr().add(dst_offset);
                    super::aarch64::neon::wildcopy_neon(src.as_ptr(), dst_ptr, len);
                    dst.set_len(dst_offset + len);
                }
                return;
            }
        }

        if len >= 8 {
            unsafe {
                let dst_ptr = dst.as_mut_ptr().add(dst_offset);
                super::scalar::wildcopy_nonoverlap(src.as_ptr(), dst_ptr, len);
                dst.set_len(dst_offset + len);
            }
        } else {
            dst.extend_from_slice(src);
        }
    }

    #[cfg(feature = "paranoid")]
    dst.extend_from_slice(src);
}

#[inline]
pub fn append_match(dst: &mut Vec<u8>, offset: usize, match_length: usize) {
    if match_length == 0 {
        return;
    }

    debug_assert!(offset <= dst.len());
    debug_assert!(offset > 0);

    #[cfg(not(feature = "paranoid"))]
    {
        dst.reserve(match_length + 32);
        let dst_len = dst.len();
        unsafe {
            let base = dst.as_mut_ptr();
            let write_ptr = base.add(dst_len);
            super::scalar::copy_match(write_ptr, offset, match_length);
            dst.set_len(dst_len + match_length);
        }
    }

    #[cfg(feature = "paranoid")]
    {
        dst.reserve(match_length);
        let start = dst.len() - offset;
        if offset >= match_length {
            let len = dst.len();
            dst.resize(len + match_length, 0);
            dst.copy_within(start..start + match_length, len);
        } else {
            for i in 0..match_length {
                let b = dst[start + i % offset];
                dst.push(b);
            }
        }
    }
}

#[inline]
pub fn common_prefix_len(a: &[u8], b: &[u8]) -> usize {
    #[cfg(all(target_arch = "x86_64", not(feature = "paranoid")))]
    {
        let tier = super::cpu_tier();
        if tier >= CpuTier::Avx2 && a.len() >= 32 && b.len() >= 32 {
            return unsafe { super::x86_64::avx2::common_prefix_len_avx2(a, b) };
        }
    }
    #[cfg(all(target_arch = "aarch64", not(feature = "paranoid")))]
    {
        if a.len() >= 16 && b.len() >= 16 {
            return unsafe { super::aarch64::neon::common_prefix_len_neon(a, b) };
        }
    }
    super::scalar::common_prefix_len(a, b)
}

#[inline]
pub fn append_match_with_history(
    dst: &mut Vec<u8>,
    history: &[u8],
    offset: usize,
    match_length: usize,
) {
    if match_length == 0 {
        return;
    }

    let out_len = dst.len();

    if offset <= out_len {
        append_match(dst, offset, match_length);
    } else {
        let history_reach = offset - out_len;
        let history_start = history.len() - history_reach;
        let from_history = history_reach.min(match_length);

        dst.extend_from_slice(&history[history_start..history_start + from_history]);

        let remaining = match_length - from_history;
        if remaining > 0 {
            append_match(dst, offset, remaining);
        }
    }
}