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https://github.com/frozolotl/noak
A java bytecode decoding and encoding library written in rust. Mirror of https://gitlab.com/frozo/noak
https://github.com/frozolotl/noak
bytecode bytecode-manipulation bytecode-parser bytecode-reading java rust
Last synced: about 2 months ago
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A java bytecode decoding and encoding library written in rust. Mirror of https://gitlab.com/frozo/noak
- Host: GitHub
- URL: https://github.com/frozolotl/noak
- Owner: frozolotl
- License: apache-2.0
- Created: 2019-09-15T19:05:29.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2024-06-14T18:06:50.000Z (6 months ago)
- Last Synced: 2024-10-10T23:32:55.823Z (2 months ago)
- Topics: bytecode, bytecode-manipulation, bytecode-parser, bytecode-reading, java, rust
- Language: Rust
- Size: 780 KB
- Stars: 32
- Watchers: 1
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE-APACHE
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README
# Noak
A library for reading and writing java class files.
## Example
```rust
use noak::reader::Class;
let mut class = Class::new(&bytes)?;
println!("Major Version: {}", class.version().major);
println!(" Access Flags: {:?}", class.access_flags()?);
println!(" Class Name: {}", class.this_class_name()?.display()?);
```
## Why should you use noak?
- Reading:
- You want to parse class files without losing information.
- You don't want to parse the entire class file.
- Any valid class file is accepted by noak. Many invalid class files are accepted as well (this can be useful for reading heavily obfuscated code).
- Writing:
- You want to write your own class files (limitations apply; see below).
## Why wouldn't you use noak?
Many of these issues are in the process of being resolved, but that may take some time.
- You want more than just a low-level class file reader and writer.
- Noak makes heavy use of the type system and macros. This can cause problems with your IDE or make some aspects hard to understand.
- Documentation is virtually non-existent.
- The API is very unstable.
- The code is not heavily tested.
- Reading:
- Some code may be repetitive (e.g. retrieving values from the constant pool).
- Writing:
- Modifying existing class files can be very tedious.
- Not every attribute can be written at the moment ([related issue](https://gitlab.com/frozo/noak/-/issues/4))
- Jumps above 65535 bytes may fail to be written.
- The builder API isn't flexible enough for your use case.
- Custom errors are quite restricted.
- Stack Map Frames are not automatically generated.
## Alternatives
This is not an exhaustive list. The statements below may not accurately reflect reality.
Libraries written in Rust:
- [cafebabe](https://github.com/staktrace/cafebabe)
- Parses the entire file at once.
- Accesses the constant pool during parsing. No explicit retrieval from the user side required.
- [classreader-rs](https://github.com/Alfriadox/classreader-rs)
- Parses the entire file at once.
- Only supports parsing.
- Does not support any attributes from version 53.0 and above.
- Does not parse strings containing unpaired surrogates.
- [jbcrs](https://github.com/orasunis/jbcrs)
- Parses the entire file at once.
- Only supports parsing.
- Does not support any attributes from version 53.0 and above.
- Does not parse files containing UTF-8 constants with unpaired surrogates.
- [frappe/classfile](https://github.com/tjdetwiler/frappe)
- Parses the entire file at once.
- Only supports parsing.
- Does not support any attributes from version 53.0 and above.
- Does not parse files containing UTF-8 constants with surrogates.
- [classfile-rs](https://github.com/x4e/classfile-rs)
- Seems to be very incomplete.
- Supports writing as well as parsing.
- Parses the entire file at once.
- Reads UTF-8 constants lossily.
- [classfile-parser](https://github.com/palmr/classfile-parser)
- Seems to be very incomplete.
- Parses the entire file at once.
- Only supports parsing.
- [classfmt](https://github.com/chickenbreeder/classfmt)
- Seems to be very incomplete.
- Parses the entire file at once.
- Only supports parsing.
- [javabc](https://github.com/dylanmckay/javabc)
- Seems to be very incomplete.
- Parses the entire file at once.
- Only supports parsing.
A small fraction of libraries written in languages that are not Rust:
- [ASM](https://asm.ow2.io/) (Java)
- The most comprehensive and best supported class file manipulation and analysis framework.
- Use this if noak does not suit your requirements and probably even if it does suit them.
- [javassist](https://github.com/jboss-javassist/javassist) (Java)
- A high-level bytecode library.
- [BCEL](https://commons.apache.org/proper/commons-bcel/) (Java)
## License
This project is licensed under the [MIT](https://gitlab.com/frozo/noak/-/blob/master/LICENSE) license.