Add project README

Signed-off-by: Keshav Priyadarshi <[email protected]>

Author: keshav-space

README.md

@@ -1 +1,76 @@
-# purl-validator
+# purl-validator
+
+[![License](https://img.shields.io/badge/License-Apache--2.0-blue.svg?style=for-the-badge)](https://opensource.org/licenses/Apache-2.0)
+[![Version](https://img.shields.io/github/v/release/aboutcode-org/purl-validator-rust?style=for-the-badge)](https://github.com/aboutcode-org/purl-validator-rust/releases)
+[![Test](https://img.shields.io/github/actions/workflow/status/aboutcode-org/purl-validator-rust/run-test.yml?style=for-the-badge&logo=github)](https://github.com/aboutcode-org/purl-validator-rust/actions)
+
+**purl-validator** is a Rust library for validating [Package URLs (PURLs)](https://github.com/package-url/purl-spec). It works fully offline, including in **air-gapped** or **restricted environments**, and answers one key question: **Does the package this PURL represents actually exist?**
+
+## How It Works?
+
+**purl-validator** is shipped with a pre-built FST (Finite State Transducer), a set of compact automata containing latest Package URLs mined by the MineCode[^1]. Library uses this FST to perform lookups and confirm whether the **base PURL**[^2] exists.
+
+## Currently Supported Ecosystems
+
+- **nuget**: [https://www.nuget.org/](https://www.nuget.org/)
+
+## Usage
+
+Add `purl-validator` to your Rust dependency
+
+```bash
+cargo add purl-validator
+```
+
+Use it in your code like this
+
+```rust
+use purl_validator::validate;
+
+let result: bool = validate("pkg:nuget/FluentValidation");
+```
+
+## Contribution
+
+We welcome contributions from the community! If you find a bug or have an idea for a new feature, please open an issue on the GitHub repository. If you want to contribute code, you can fork the repository, make your changes, and submit a pull request.
+
+* Please try to write a good commit message, see [good commit message wiki](https://aboutcode.readthedocs.io/en/latest/contributing/writing_good_commit_messages.html).
+* Add DCO `Sign Off` to your commits.
+
+## Development Setup
+
+Run these commands, starting from a git clone of [https://github.com/aboutcode-org/purl-validator-rust.git](https://github.com/aboutcode-org/purl-validator-rust.git)
+
+Generate FST:
+
+```bash
+make build-fst
+```
+
+Run tests:
+
+```bash
+make test
+```
+
+## License
+
+SPDX-License-Identifier: Apache-2.0
+
+purl-validator is licensed under Apache License version 2.0.
+
+```text
+You may not use this software except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+```
+
+[^1]: MineCode continuously collects package metadata from various package ecosystems to maintain an up-to-date catalog of known packages.
+[^2]: A Base Package URL is a Package URL without a version or subpath.