flatarray 1.1.0

Implementation of a flattened iterator, that acts as if it still was an iterator of iterator
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
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167

use std::marker::PhantomData;
use std::ops::Range;
use std::ops::{Deref, DerefMut};

use crate::str::FlatStr;

pub trait FlattenedCollection<T> {
    fn indices_len(&self) -> usize;
    /// # Safety
    /// The index must be inside the bounds of the indices.
    unsafe fn get_indices(&self, index: usize) -> usize;
    /// # Safety
    /// The range must be inside the bounds of the indices.
    unsafe fn get_content(&self, range: Range<usize>) -> &[T];
    /// # Safety
    /// The range must be inside the bounds of the indices.
    unsafe fn get_mut_content(&mut self, range: Range<usize>) -> &mut [T];
    fn indices_empty(&self) -> bool {
        self.indices_len() == 0
    }
}

impl<T> FlattenedCollection<T> for Box<dyn FlattenedCollection<T>> {
    fn indices_len(&self) -> usize {
        self.deref().indices_len()
    }
    unsafe fn get_indices(&self, index: usize) -> usize {
        unsafe { self.deref().get_indices(index) }
    }
    unsafe fn get_content(&self, range: Range<usize>) -> &[T] {
        unsafe { self.deref().get_content(range) }
    }
    unsafe fn get_mut_content(&mut self, range: Range<usize>) -> &mut [T] {
        unsafe { self.deref_mut().get_mut_content(range) }
    }
}

impl<T, Flat: FlattenedCollection<T>> FlattenedCollection<T> for Box<Flat> {
    fn indices_len(&self) -> usize {
        self.deref().indices_len()
    }
    unsafe fn get_indices(&self, index: usize) -> usize {
        unsafe { self.deref().get_indices(index) }
    }
    unsafe fn get_content(&self, range: Range<usize>) -> &[T] {
        unsafe { self.deref().get_content(range) }
    }
    unsafe fn get_mut_content(&mut self, range: Range<usize>) -> &mut [T] {
        unsafe { self.deref_mut().get_mut_content(range) }
    }
}

#[derive(Debug)]
pub struct Iter<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
    T: 'a,
{
    indice_index: usize,
    token_vecs: &'a Flat,
    counter: usize,
    phantom_data: PhantomData<T>,
}

impl<'a, Flat, T> Clone for Iter<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
    T: 'a,
{
    fn clone(&self) -> Self {
        Self {
            indice_index: self.indice_index,
            token_vecs: self.token_vecs,
            counter: self.counter,
            phantom_data: PhantomData,
        }
    }
}

impl<'a, Flat, T> Iter<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
{
    pub(crate) fn new(token_vecs: &'a Flat) -> Self {
        Self {
            indice_index: 0,
            token_vecs,
            counter: 0,
            phantom_data: PhantomData,
        }
    }
}
impl<'a, Flat, T> Iterator for Iter<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
{
    type Item = &'a [T];
    // NOTE: Inlining this function seems to _reduce_ the performance
    // #[inline(always)]
    fn next(&mut self) -> Option<Self::Item> {
        if self.token_vecs.indices_empty() || self.counter >= self.token_vecs.indices_len() - 1 {
            return None;
        }
        let start = unsafe { self.token_vecs.get_indices(self.indice_index) };
        let end = unsafe { self.token_vecs.get_indices(self.indice_index + 1) };
        self.counter += 1;
        self.indice_index += 1;
        unsafe { Some(self.token_vecs.get_content(start..end)) }
    }
}

#[derive(Debug)]
pub struct IterMut<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
{
    indice_index: usize,
    token_vecs: &'a mut Flat,
    counter: usize,
    phantom_data: PhantomData<&'a T>,
}

impl<'a, Flat, T> IterMut<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
{
    pub(crate) fn new(token_vecs: &'a mut Flat) -> Self {
        Self {
            indice_index: 0,
            token_vecs,
            counter: 0,
            phantom_data: PhantomData,
        }
    }
}

impl<'a, Flat, T> Iterator for IterMut<'a, Flat, T>
where
    Flat: FlattenedCollection<T>,
{
    type Item = &'a mut [T];
    // NOTE: Inlining this function seems to reduce the performance
    // #[inline(always)]
    fn next(&mut self) -> Option<Self::Item> {
        if self.counter >= self.token_vecs.indices_len() - 1 {
            return None;
        }
        let start = unsafe { self.token_vecs.get_indices(self.indice_index) };
        let end = unsafe { self.token_vecs.get_indices(self.indice_index + 1) };
        self.counter += 1;
        self.indice_index += 1;
        unsafe { Some(&mut *(self.token_vecs.get_mut_content(start..end) as *mut _)) }
    }
}

pub struct StrIter<'a>(pub(crate) Iter<'a, FlatStr, u8>);

impl<'a> Iterator for StrIter<'a> {
    type Item = &'a str;

    fn next(&mut self) -> Option<Self::Item> {
        match self.0.next() {
            None => None,
            Some(bytes) => unsafe { Some(str::from_utf8_unchecked(bytes)) },
        }
    }
}