sqjson 0.1.3

[![Crates.io](https://img.shields.io/crates/v/sqjson.svg)](https://crates.io/crates/sqjson)
[![Documentation](https://docs.rs/sqjson/badge.svg)](https://docs.rs/sqjson)


# sqjson

**sqjson** is a simple, embedded, file-based key-value database using JSON values and memory-mapped files (like SQLite, but for JSON). It's written in pure Rust and has zero dependencies beyond `serde`, `memmap2`, and `thiserror`.

## 🚀 Features

- Lightweight and fast
- File-based — stores data in a single `.db` file
- JSON values for flexibility
- Key-based storage and retrieval
- Backed by memory-mapped I/O
- Easy to embed in any Rust project

---

## 📦 Installation

Add to your Rust project:

```sh
cargo add sqjson
```

Or add manually to your `Cargo.toml`:

```toml
[dependencies]
sqjson = "0.1"
```

---

## 🛠 Usage

```rust
use sqjson::{YourDb, DbError};
use serde_json::json;

fn main() -> Result<(), DbError> {
    let mut db = YourDb::open("mydata.db")?;

    db.put("user:1", &json!({ "name": "Alice", "age": 30 }))?;
    db.put("user:2", &json!({ "name": "Bob", "age": 25 }))?;

    db.flush()?; // Persist to disk

    if let Some(user) = db.get("user:1")? {
        println!("Got user: {}", user);
    }

    Ok(())
}
```

---

## 🔧 API Overview

| Method           | Description                             |
|------------------|-----------------------------------------|
| `YourDb::open()` | Open or create a database file          |
| `put()`          | Insert or update a key with a JSON value |
| `get()`          | Retrieve a JSON value by key            |
| `flush()`        | Write index and pages to disk           |
| `show_all()`     | Print all key-value pairs (debug tool)  |

---

## 📁 File Format

- Page 0: Stores the index (key → page ID)
- Page 1+: Stores actual JSON-encoded data
- Each page is fixed-size (`4096` bytes default)

---

## 📃 License

MIT OR Apache-2.0

---

## 👤 Author

Made with ❤️ by Hafiz Ali Raza