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
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

// Copyright (c) 2021 Anatoly Ikorsky
//
// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. All files in the project carrying such notice may not be copied,
// modified, or distributed except according to those terms.

//! Various parsing/serialization primitives.

use std::io;

use ::bytes::BufMut;
use smallvec::{Array, SmallVec};

use crate::{
    io::ParseBuf,
    proto::{MyDeserialize, MySerialize},
};

use self::bytes::LenEnc;
pub use self::{
    _const::{Const, RawConst},
    bytes::RawBytes,
    flags::RawFlags,
    int::RawInt,
    seq::RawSeq,
};

use super::unexpected_buf_eof;

pub mod _const;
pub mod bytes;
pub mod flags;
pub mod int;
pub mod seq;

impl<'de> MyDeserialize<'de> for &'de [u8] {
    const SIZE: Option<usize> = None;
    type Ctx = usize;

    fn deserialize(len: Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        buf.checked_eat(len).ok_or_else(unexpected_buf_eof)
    }
}

impl MySerialize for [u8] {
    fn serialize(&self, buf: &mut Vec<u8>) {
        buf.put_slice(self);
    }
}

impl<'de, const LEN: usize> MyDeserialize<'de> for [u8; LEN] {
    const SIZE: Option<usize> = Some(LEN);
    type Ctx = ();

    fn deserialize((): Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        let value = buf.eat(LEN);
        let mut this = [0_u8; LEN];
        this.copy_from_slice(value);
        Ok(this)
    }
}

impl<const LEN: usize> MySerialize for [u8; LEN] {
    fn serialize(&self, buf: &mut Vec<u8>) {
        buf.put_slice(&self[..]);
    }
}

#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct Skip<const LEN: usize>;

impl<'de, const LEN: usize> MyDeserialize<'de> for Skip<LEN> {
    const SIZE: Option<usize> = Some(LEN);
    type Ctx = ();

    fn deserialize((): Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        buf.skip(LEN);
        Ok(Self)
    }
}

impl<const LEN: usize> MySerialize for Skip<LEN> {
    fn serialize(&self, buf: &mut Vec<u8>) {
        buf.put_slice(&[0_u8; LEN]);
    }
}

impl<'de> MyDeserialize<'de> for ParseBuf<'de> {
    const SIZE: Option<usize> = None;
    type Ctx = usize;

    fn deserialize(len: Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        buf.checked_eat_buf(len).ok_or_else(unexpected_buf_eof)
    }
}

/// This ad-hock impl parses length-encoded string into a `SmallVec`.
impl<'de, const LEN: usize> MyDeserialize<'de> for SmallVec<[u8; LEN]>
where
    [u8; LEN]: Array<Item = u8>,
{
    const SIZE: Option<usize> = None;
    type Ctx = ();

    fn deserialize((): Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        let mut small_vec = SmallVec::new();
        let s: RawBytes<'de, LenEnc> = buf.parse(())?;
        small_vec.extend_from_slice(s.as_bytes());
        Ok(small_vec)
    }
}

impl<const LEN: usize> MySerialize for SmallVec<[u8; LEN]>
where
    [u8; LEN]: Array<Item = u8>,
{
    fn serialize(&self, buf: &mut Vec<u8>) {
        buf.put_slice(&*self)
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
pub enum Either<T, U> {
    Left(T),
    Right(U),
}

impl<'de, T, U> MyDeserialize<'de> for Either<T, U>
where
    T: MyDeserialize<'de>,
    U: MyDeserialize<'de>,
{
    const SIZE: Option<usize> = None; // TODO: maybe later
    /// Which one to deserialize.
    type Ctx = Either<T::Ctx, U::Ctx>;

    fn deserialize(ctx: Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        match ctx {
            Either::Left(ctx) => T::deserialize(ctx, buf).map(Either::Left),
            Either::Right(ctx) => U::deserialize(ctx, buf).map(Either::Right),
        }
    }
}

impl<T, U> MySerialize for Either<T, U>
where
    T: MySerialize,
    U: MySerialize,
{
    fn serialize(&self, buf: &mut Vec<u8>) {
        match self {
            Either::Left(x) => x.serialize(buf),
            Either::Right(x) => x.serialize(buf),
        }
    }
}

impl<'de> MyDeserialize<'de> for f64 {
    const SIZE: Option<usize> = Some(8);
    type Ctx = ();

    fn deserialize((): Self::Ctx, buf: &mut ParseBuf<'de>) -> io::Result<Self> {
        Ok(buf.eat_f64_le())
    }
}

impl MySerialize for f64 {
    fn serialize(&self, buf: &mut Vec<u8>) {
        buf.put_f64_le(*self);
    }
}