# ranked-semaphore
> **A priority-aware semaphore for async Rust.**
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## Features
- **Priority scheduling**: Configurable priority-based task ordering
- **No runtime dependency**: Works with any async runtime (Tokio, async-std, smol, etc.)
- **Flexible queue strategies**: FIFO/LIFO and custom rules per priority
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## Quick Start
```rust
use ranked_semaphore::RankedSemaphore;
#[tokio::main]
async fn main() {
// Create a semaphore with 3 permits, FIFO strategy
let sem = RankedSemaphore::new_fifo(3);
// Acquire a permit (default priority)
let permit = sem.acquire().await.unwrap();
// Acquire with custom priority
let high = sem.acquire_with_priority(10).await.unwrap();
// Release permits automatically on drop
drop(permit);
drop(high);
}
```
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## Advanced Usage
### Priority-based API Rate Limiting
```rust
use ranked_semaphore::{RankedSemaphore, PriorityConfig, QueueStrategy};
use std::sync::Arc;
let config = PriorityConfig::new()
.default_strategy(QueueStrategy::Fifo)
.exact(10, QueueStrategy::Lifo);
let limiter = Arc::new(RankedSemaphore::new_with_config(2, config));
let _admin = limiter.acquire_with_priority(10).await.unwrap();
let _guest = limiter.acquire_with_priority(0).await.unwrap();
```
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## Examples
- [Tokio example](examples/tokio-example)
- [Async-std example](examples/async-std-example)
- [Smol example](examples/smol-example)
- [Futures example](examples/futures-example)
運行：
```sh
cargo run -p tokio-example
cargo run -p async-std-example
cargo run -p smol-example
cargo run -p futures-example
```
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## License
MIT
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## Links
- [API Documentation (docs.rs)](https://docs.rs/ranked-semaphore)
- [Crates.io](https://crates.io/crates/ranked-semaphore)
- [docs.rs](https://docs.rs/ranked-semaphore)。
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