https://github.com/huonw/rust-malloc

A pure Rust memory allocator
https://github.com/huonw/rust-malloc

Last synced: 8 days ago
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A pure Rust memory allocator

• Host: GitHub
• URL: https://github.com/huonw/rust-malloc
• Owner: huonw
• License: other
• Created: 2013-07-15T03:02:43.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2013-09-07T23:11:02.000Z (about 11 years ago)
• Last Synced: 2024-10-31T13:50:15.959Z (15 days ago)
• Language: Rust
• Size: 109 KB
• Stars: 49
• Watchers: 5
• Forks: 5
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: COPYING

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README

        
# Rust malloc

A pure-Rust proof-of-concept implementation of `malloc`/`free` for

x86-64 Linux. It is very, very basic: a linked list of allocations

(traversed on every `malloc` call!), first-fit strategy and all

allocations come directly from the `brk` syscall. As such, it is very

slow, not-threadsafe and generally bad. There is little-to-no error

checking.

Uses a modified version of

[zero.rs](https://github.com/pcwalton/zero.rs) and a

[tiny syscall](https://gist.github.com/Aatch/5894562)

wrapper. Requires a recent `rustc` from master.

There is an example of a custom version of `~T` using this allocator

at the bottom of `malloc.rs`.

Test with:

    make

    ./malloc

To enable the debugging `assert`s:

    make debug

    ./malloc-debug

Code map:

- `malloc.rs` contains `malloc`, `free`, etc, as well as `main` and some tests/examples.

- `types.rs` contains the allocation header (`Header`, surprisingly)

  as well some newtype structs around raw pointers (`Box` and `Data`;

  in theory these have no runtime cost over using `*mut Header` and

  `*mut u8` directly) which make the implementation relatively

  type-safe.

- `util.rs` & `diag.rs` contain utilities and tools for printing

  diagnostics about the current allocation state.

**Only useful for segfaulting and generally making programs incorrect.**

## TODO

- Use `mmap`.

- Return memory to the OS.

- Merge adjacent free cells better.

### Wishlist

- Make it fast.

- Support other platforms/operating systems.