binary-layout 4.0.2

The binary-layout library allows type-safe, inplace, zero-copy access to structured binary data. You define a custom data layout and give it a slice of binary data, and it will allow you to read and write the fields defined in the layout from the binary data without having to copy any of the data. It's similar to transmuting to/from a `#[repr(packed)]` struct, but much safer.
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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299

use binary_layout::prelude::*;
use core::any::{Any, TypeId};
use std::convert::TryInto;
use std::num::NonZeroI32;

mod common;
use common::data_region;

binary_layout!(withslice, LittleEndian, {
    first: i8,
    second: i64,
    third: [u8; 5],
    fourth: u16,
    fifth: NonZeroI32,
    sixth: [u8],
});

#[test]
fn metadata() {
    assert_eq!(0, withslice::first::OFFSET);
    assert_eq!(Some(1), withslice::first::SIZE);
    assert_eq!(1, withslice::second::OFFSET);
    assert_eq!(Some(8), withslice::second::SIZE);
    assert_eq!(9, withslice::third::OFFSET);
    assert_eq!(Some(5), withslice::third::SIZE);
    assert_eq!(14, withslice::fourth::OFFSET);
    assert_eq!(Some(2), withslice::fourth::SIZE);
    assert_eq!(16, withslice::fifth::OFFSET);
    assert_eq!(Some(4), withslice::fifth::SIZE);
    assert_eq!(20, withslice::sixth::OFFSET);
    assert_eq!(None, withslice::sixth::SIZE);
}

#[test]
fn types() {
    let storage = data_region(1024, 5);
    let view = withslice::View::new(&storage);

    assert_eq!(
        TypeId::of::<i8>(),
        withslice::first::read(&storage).type_id()
    );
    assert_eq!(
        TypeId::of::<i64>(),
        withslice::second::read(&storage).type_id()
    );
    assert_eq!(
        TypeId::of::<[u8; 5]>(),
        withslice::third::data(&storage).type_id()
    );
    assert_eq!(
        TypeId::of::<u16>(),
        withslice::fourth::read(&storage).type_id()
    );
    assert_eq!(
        TypeId::of::<NonZeroI32>(),
        withslice::fifth::try_read(&storage).unwrap().type_id(),
    );
    assert_eq!(
        TypeId::of::<[u8]>(),
        withslice::sixth::data(&storage).type_id()
    );

    assert_eq!(TypeId::of::<i8>(), view.first().read().type_id());
    assert_eq!(TypeId::of::<i64>(), view.second().read().type_id());
    assert_eq!(TypeId::of::<[u8; 5]>(), view.third().type_id());
    assert_eq!(TypeId::of::<u16>(), view.fourth().read().type_id());
    assert_eq!(
        TypeId::of::<NonZeroI32>(),
        view.fifth().try_read().unwrap().type_id()
    );
    assert_eq!(TypeId::of::<[u8]>(), view.sixth().type_id());
}

#[test]
fn fields() {
    let mut storage = data_region(1024, 5);

    // Test initial data is read correctly
    assert_eq!(5, withslice::third::data(&storage).len());
    assert_eq!(5, withslice::third::data_mut(&mut storage).len());
    assert_eq!(1024 - 20, withslice::sixth::data(&storage).len());
    assert_eq!(1024 - 20, withslice::sixth::data_mut(&mut storage).len());

    // Test data can be written
    withslice::first::write(&mut storage, 60);
    withslice::second::write(&mut storage, -100_000_000_000);
    withslice::third::data_mut(&mut storage).copy_from_slice(&[10, 20, 30, 40, 50]);
    withslice::fourth::write(&mut storage, 1_000);
    withslice::fifth::write(&mut storage, NonZeroI32::new(10i32.pow(8)).unwrap());
    withslice::sixth::data_mut(&mut storage).copy_from_slice(&data_region(1024 - 20, 6));

    // Test reading will return changed data
    assert_eq!(60, withslice::first::read(&storage));
    assert_eq!(-100_000_000_000, withslice::second::read(&storage));
    assert_eq!(&[10, 20, 30, 40, 50], withslice::third::data(&storage));
    assert_eq!(1_000, withslice::fourth::read(&storage));
    assert_eq!(
        NonZeroI32::new(10i32.pow(8)).unwrap(),
        withslice::fifth::try_read(&storage).unwrap()
    );
    assert_eq!(&data_region(1024 - 20, 6), withslice::sixth::data(&storage));
}

#[test]
fn view_readonly() {
    let storage = data_region(1024, 5);
    let view = withslice::View::new(&storage);

    // Test initial data is read correctly
    assert_eq!(
        i8::from_le_bytes((&data_region(1024, 5)[0..1]).try_into().unwrap()),
        view.first().read()
    );
    assert_eq!(
        i64::from_le_bytes((&data_region(1024, 5)[1..9]).try_into().unwrap()),
        view.second().read()
    );
    assert_eq!(&data_region(1024, 5)[9..14], view.third(),);
    assert_eq!(
        u16::from_le_bytes((&data_region(1024, 5)[14..16]).try_into().unwrap()),
        view.fourth().read()
    );
    assert_eq!(
        i32::from_le_bytes((&data_region(1024, 5)[16..20]).try_into().unwrap()),
        view.fifth().try_read().unwrap().get()
    );
    assert_eq!(&data_region(1024, 5)[20..], view.sixth());

    // Test into_storage will return correct data
    let extracted_storage: &Vec<u8> = view.into_storage();
    assert_eq!(storage, *extracted_storage);
}

#[test]
fn view_readwrite() {
    let mut storage = data_region(1024, 5);
    let mut view = withslice::View::new(&mut storage);

    // Test initial data is read correctly
    assert_eq!(
        i8::from_le_bytes((&data_region(1024, 5)[0..1]).try_into().unwrap()),
        view.first().read()
    );
    assert_eq!(
        i64::from_le_bytes((&data_region(1024, 5)[1..9]).try_into().unwrap()),
        view.second().read()
    );
    assert_eq!(&data_region(1024, 5)[9..14], view.third(),);
    assert_eq!(
        u16::from_le_bytes((&data_region(1024, 5)[14..16]).try_into().unwrap()),
        view.fourth().read()
    );
    assert_eq!(
        i32::from_le_bytes((&data_region(1024, 5)[16..20]).try_into().unwrap()),
        view.fifth().try_read().unwrap().get(),
    );
    assert_eq!(&data_region(1024, 5)[20..], view.sixth());

    // Test data can be written
    view.first_mut().write(50);
    view.second_mut().write(10i64.pow(15));
    view.third_mut().copy_from_slice(&[10, 20, 30, 40, 50]);
    view.fourth_mut().write(1000);
    view.fifth_mut()
        .write(NonZeroI32::new(10i32.pow(8)).unwrap());
    view.sixth_mut()
        .copy_from_slice(&data_region(1024, 6)[20..]);

    // Test reading will return changed data
    assert_eq!(50, view.first().read());
    assert_eq!(10i64.pow(15), view.second().read());
    assert_eq!(&[10, 20, 30, 40, 50], view.third());
    assert_eq!(1000, view.fourth().read());
    assert_eq!(
        NonZeroI32::new(10i32.pow(8)).unwrap(),
        view.fifth().try_read().unwrap()
    );
    assert_eq!(&data_region(1024, 6)[20..], view.sixth());

    // Test into_storage will return correct data
    let extracted_storage = view.into_storage().to_vec();
    assert_eq!(&storage, &extracted_storage);

    // Test storage is actually changed
    assert_eq!(50, i8::from_le_bytes((&storage[0..1]).try_into().unwrap()));
    assert_eq!(
        10i64.pow(15),
        i64::from_le_bytes((&storage[1..9]).try_into().unwrap())
    );
    assert_eq!(&[10, 20, 30, 40, 50], &storage[9..14]);
    assert_eq!(
        1000,
        u16::from_le_bytes((&storage[14..16]).try_into().unwrap())
    );
    assert_eq!(
        10i32.pow(8),
        i32::from_le_bytes((&storage[16..20]).try_into().unwrap()),
    );
    assert_eq!(&data_region(1024, 6)[20..], &storage[20..]);
}

#[test]
fn view_vec_readonly() {
    let view = withslice::View::new(data_region(1024, 5));

    // Test initial data is read correctly
    assert_eq!(
        i8::from_le_bytes((&data_region(1024, 5)[0..1]).try_into().unwrap()),
        view.first().read()
    );
    assert_eq!(
        i64::from_le_bytes((&data_region(1024, 5)[1..9]).try_into().unwrap()),
        view.second().read()
    );
    assert_eq!(&data_region(1024, 5)[9..14], view.third(),);
    assert_eq!(
        u16::from_le_bytes((&data_region(1024, 5)[14..16]).try_into().unwrap()),
        view.fourth().read()
    );
    assert_eq!(
        i32::from_le_bytes((&data_region(1024, 5)[16..20]).try_into().unwrap()),
        view.fifth().try_read().unwrap().get(),
    );
    assert_eq!(&data_region(1024, 5)[20..], view.sixth());

    // Test into_storage will return correct data
    let extracted_storage: Vec<u8> = view.into_storage();
    assert_eq!(&data_region(1024, 5), &*extracted_storage);
}

#[test]
fn view_vec_readwrite() {
    let mut view = withslice::View::new(data_region(1024, 5));

    // Test initial data is read correctly
    assert_eq!(
        i8::from_le_bytes((&data_region(1024, 5)[0..1]).try_into().unwrap()),
        view.first().read()
    );
    assert_eq!(
        i64::from_le_bytes((&data_region(1024, 5)[1..9]).try_into().unwrap()),
        view.second().read()
    );
    assert_eq!(&data_region(1024, 5)[9..14], view.third(),);
    assert_eq!(
        u16::from_le_bytes((&data_region(1024, 5)[14..16]).try_into().unwrap()),
        view.fourth().read()
    );
    assert_eq!(
        i32::from_le_bytes((&data_region(1024, 5)[16..20]).try_into().unwrap()),
        view.fifth().try_read().unwrap().get(),
    );
    assert_eq!(&data_region(1024, 5)[20..], view.sixth());

    // Test data can be written
    view.first_mut().write(50);
    view.second_mut().write(10i64.pow(15));
    view.third_mut().copy_from_slice(&[10, 20, 30, 40, 50]);
    view.fourth_mut().write(1000);
    view.fifth_mut()
        .write(NonZeroI32::new(10i32.pow(8)).unwrap());
    view.sixth_mut()
        .copy_from_slice(&data_region(1024, 6)[20..]);

    // Test reading will return changed data
    assert_eq!(50, view.first().read());
    assert_eq!(10i64.pow(15), view.second().read());
    assert_eq!(&[10, 20, 30, 40, 50], view.third());
    assert_eq!(1000, view.fourth().read());
    assert_eq!(
        NonZeroI32::new(10i32.pow(8)).unwrap(),
        view.fifth().try_read().unwrap()
    );
    assert_eq!(&data_region(1024, 6)[20..], view.sixth());

    // Test into_storage will return correct data
    let extracted_storage = view.into_storage();
    assert_eq!(
        50,
        i8::from_le_bytes((&extracted_storage[0..1]).try_into().unwrap())
    );
    assert_eq!(
        10i64.pow(15),
        i64::from_le_bytes((&extracted_storage[1..9]).try_into().unwrap())
    );
    assert_eq!(&[10, 20, 30, 40, 50], &extracted_storage[9..14]);
    assert_eq!(
        1000,
        u16::from_le_bytes((&extracted_storage[14..16]).try_into().unwrap())
    );
    assert_eq!(
        10i32.pow(8),
        i32::from_le_bytes((&extracted_storage[16..20]).try_into().unwrap())
    );
    assert_eq!(&data_region(1024, 6)[20..], &extracted_storage[20..]);
}

// TODO Here and in other tests, add an array-based alternative to the _vec_ views