an efficient binary archive format
cleanup padding calculations
+35
-16
+6
-3
build.rs
+6
-3
build.rs
···
7
7
// Instead of using .generate(), use the Builder for more control
8
8
let config = cbindgen::Config::from_file("cbindgen.toml").unwrap_or_default();
9
9
10
-
cbindgen::Builder::new()
10
+
if let Ok(b) = cbindgen::Builder::new()
11
11
.with_crate(&crate_dir)
12
12
.with_config(config)
13
13
.generate()
14
-
.expect("Unable to generate bindings")
15
-
.write_to_file(PathBuf::from(crate_dir).join("include/bindle.h"));
14
+
{
15
+
b.write_to_file(PathBuf::from(crate_dir).join("include/bindle.h"));
16
+
} else {
17
+
eprintln!("WARNING: bindle.h not updated");
18
+
}
16
19
}
+29
-13
src/lib.rs
+29
-13
src/lib.rs
···
13
13
const BNDL_ALIGN: usize = 8;
14
14
const ENTRY_SIZE: usize = std::mem::size_of::<Entry>();
15
15
const FOOTER_SIZE: usize = std::mem::size_of::<Footer>();
16
-
const HEADER_SIZE: u64 = 8;
16
+
const HEADER_SIZE: usize = 8;
17
+
18
+
fn pad<
19
+
const SIZE: usize,
20
+
T: Copy + TryFrom<usize> + std::ops::Sub<T, Output = T> + std::ops::Rem<T, Output = T>,
21
+
>(
22
+
n: T,
23
+
) -> T
24
+
where
25
+
<T as std::ops::Sub>::Output: std::ops::Rem<T>,
26
+
{
27
+
if let Ok(size) = T::try_from(SIZE) {
28
+
return (size - (n % size)) % size;
29
+
}
30
+
31
+
unreachable!()
32
+
}
17
33
18
34
#[repr(C)]
19
35
#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
···
26
42
#[repr(C, packed)]
27
43
#[derive(FromBytes, Unaligned, IntoBytes, Immutable, Clone, Copy, Debug, Default)]
28
44
pub struct Entry {
29
-
pub offset: [u8; 8], // Use [u8; 8] for disk stability
30
-
pub compressed_size: [u8; 8],
31
-
pub uncompressed_size: [u8; 8],
32
-
pub crc32: [u8; 4],
33
-
pub name_len: [u8; 2],
45
+
pub offset: [u8; std::mem::size_of::<u64>()], // Use [u8; 8] for disk stability
46
+
pub compressed_size: [u8; std::mem::size_of::<u64>()],
47
+
pub uncompressed_size: [u8; std::mem::size_of::<u64>()],
48
+
pub crc32: [u8; std::mem::size_of::<u32>()],
49
+
pub name_len: [u8; std::mem::size_of::<u16>()],
34
50
pub compression_type: u8,
35
51
pub _reserved: u8,
36
52
}
···
120
136
file,
121
137
mmap: None,
122
138
index: BTreeMap::new(),
123
-
data_end: HEADER_SIZE,
139
+
data_end: HEADER_SIZE as u64,
124
140
});
125
141
}
126
142
···
170
186
171
187
let offset = self.data_end;
172
188
let c_size = processed.len() as u64;
173
-
let pad = (8 - (c_size % 8)) % 8;
189
+
let pad = pad::<8, u64>(c_size);
174
190
if pad > 0 {
175
191
self.file.write_all(&vec![0u8; pad as usize])?;
176
192
}
···
198
214
for (name, entry) in &self.index {
199
215
self.file.write_all(entry.as_bytes())?;
200
216
self.file.write_all(name.as_bytes())?;
201
-
let pad = (BNDL_ALIGN - ((ENTRY_SIZE + name.len()) % BNDL_ALIGN)) % BNDL_ALIGN;
217
+
let pad = pad::<BNDL_ALIGN, usize>(ENTRY_SIZE + name.len()); // (BNDL_ALIGN - ((ENTRY_SIZE + name.len()) % BNDL_ALIGN)) % BNDL_ALIGN;
202
218
if pad > 0 {
203
219
self.file.write_all(&vec![0u8; pad])?;
204
220
}
···
227
243
.open(&tmp_path)?;
228
244
229
245
new_file.write_all(BNDL_MAGIC)?;
230
-
let mut current_offset = HEADER_SIZE;
246
+
let mut current_offset = HEADER_SIZE as u64;
231
247
232
248
// Copy only live entries to the new file
233
249
for entry in self.index.values_mut() {
···
235
251
self.file.seek(SeekFrom::Start(entry.offset()))?;
236
252
self.file.read_exact(&mut buf)?;
237
253
238
-
new_file.seek(SeekFrom::Start(current_offset))?;
254
+
new_file.seek(SeekFrom::Start(current_offset as u64))?;
239
255
new_file.write_all(&buf)?;
240
256
241
257
entry.offset = current_offset.to_le_bytes();
242
-
let pad = (8 - (entry.compressed_size() % 8)) % 8;
258
+
let pad = pad::<8, u64>(entry.compressed_size());
243
259
if pad > 0 {
244
260
new_file.write_all(&vec![0u8; pad as usize])?;
245
261
}
···
251
267
for (name, entry) in &self.index {
252
268
new_file.write_all(entry.as_bytes())?;
253
269
new_file.write_all(name.as_bytes())?;
254
-
let pad = (BNDL_ALIGN - ((ENTRY_SIZE + name.len()) % BNDL_ALIGN)) % BNDL_ALIGN;
270
+
let pad = pad::<BNDL_ALIGN, usize>(ENTRY_SIZE + name.len());
255
271
if pad > 0 {
256
272
new_file.write_all(&vec![0u8; pad])?;
257
273
}