# relox
[](https://crates.io/crates/relox)
[](https://docs.rs/relox/)
[](https://github.com/tamaspetz/relox/releases/latest)
[](https://travis-ci.com/tamaspetz/relox)
[](https://codecov.io/gh/tamaspetz/relox)
# Compress and decompress ELF32 relocation sections
This crate can be used to compress ELF32 relocation sections post-link time.
It also provides a decompressing method which can be used during relocation.
The approach might be useful for embedded system if a relocation section
uses too much static storage.
Decompressing relocations is a trade-off between used static storage and
CPU time required to process relocations during initialization.
## Compressed section layout for ELF32
```rust
/// ELF32 relocations grouped by relocation type.
struct Elf32CRelGroup {
// Type of the relocation.
relocation_type: u8,
// Number of relocations encoded as ULEB128.
count: u32,
// Offsets are encoded as ULEB128.
// First offset is relative to `base_address`,
// otherwise offset[i+1] is relative to offset[i].
offsets: [u32; count],
}
/// A compressed ELF32 relocation section.
struct Elf32CRel {
// Base address of all the relocations.
base_address: u32,
// Number of relocation groups.
count: u8,
// Relocation groups.
groups: [Elf32CRelGroup; count],
}
```
## Recommended usage
On host machines, during post-link time processing,
use `host` feature group.
When targeting embedded devices use either `embedded` or `embedded_minimal`
feature group. The latter one enables `no_bounds_check` and
`no_sanity_check` features to further reduce memory footprint.
### List of optional features
* `compress`: include methods and structures related to compressing.
* `decompress`: include methods and structures related to decompressing.
* `no-std`: do not use standard library.
* `no_bounds_check`: use `unsafe` code instead of bounds-checking variants.
* `no_sanity_check`: do not perform extra sanity checks when processing LEB128
encodings.
## License
Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in `relox` by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.