add README and LICENSE

Author: deminy

LICENSE

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+MIT License
+
+Copyright (c) <2022> Demin Yin <deminy@deminy.net>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+Developer’s Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.

README.md

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+# php-bsdiff
+
+`bsdiff` is a PHP extension to build and apply patches to binary files.
+
+This PHP extension is based on [the bsdiff and bspatch libraries][1] maintained by Matthew Endsley. The original algorithm
+and implementation was developed by Colin Percival. The algorithm is detailed in Colin's paper, [Naïve Differences of Executable Code][1].
+For more information, visit his website at <http://www.daemonology.net/bsdiff/>.
+
+---
+
+## Requirements
+
+* PHP 8.x
+
+## Installation
+
+```bash
+phpize
+./configure
+make
+make test # optional
+make install
+```
+
+Once done, add the following line to your `php.ini` file:
+
+```ini
+extension=bsdiff.so
+```
+
+## Functions
+
+There are two PHP functions added by the extension:
+
+```php
+/**
+  * @throws \BsdiffException If there is any error happens.
+  */
+function bsdiff_diff(string $old_file, string $new_file, string $diff_file): void {}
+
+/**
+  * @throws \BsdiffException If there is any error happens.
+  */
+function bsdiff_patch(string $old_file, string $new_file, string $diff_file): void {}
+```
+
+---
+
+## License
+
+MIT license.
+
+[1]: https://github.com/mendsley/bsdiff
+[2]: http://www.daemonology.net/papers/bsdiff.pdf