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License Information

Dual Licensing

Hayasen is dual-licensed under the MIT License and Apache License 2.0. You may choose to use, modify, and distribute this software under the terms of either license.

Why Dual Licensing?

The dual licensing approach provides maximum flexibility for different use cases:

  • MIT License: Simple, permissive license ideal for proprietary applications and commercial use
  • Apache License 2.0: More comprehensive license with explicit patent grants and trademark protections

You can choose the license that best fits your project's requirements.

License Texts

MIT License

MIT License

Copyright (c) [YEAR] [COPYRIGHT_HOLDER]

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.

Apache License 2.0

Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/

TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

1. Definitions.

   "License" shall mean the terms and conditions for use, reproduction,
   and distribution as defined by Sections 1 through 9 of this document.

   "Licensor" shall mean the copyright owner or entity granting the License.

   "Legal Entity" shall mean the union of the acting entity and all
   other entities that control, are controlled by, or are under common
   control with that entity. For the purposes of this definition,
   "control" means (i) the power, direct or indirect, to cause the
   direction or management of such entity, whether by contract or
   otherwise, or (ii) ownership of fifty percent (50%) or more of the
   outstanding shares, or (iii) beneficial ownership of such entity.

   "You" (or "Your") shall mean an individual or Legal Entity
   exercising permissions granted by this License.

   "Source" form shall mean the preferred form for making modifications,
   including but not limited to software source code, documentation
   source, and configuration files.

   "Object" form shall mean any form resulting from mechanical
   transformation or translation of a Source form, including but
   not limited to compiled object code, generated documentation,
   and conversions to other media types.

   "Work" shall mean the work of authorship, whether in Source or
   Object form, made available under the License, as indicated by a
   copyright notice that is included in or attached to the work
   (which shall not include communications that are clearly marked or
   otherwise designated in writing by the copyright owner as "Not a Contribution").

   "Derivative Works" shall mean any work, whether in Source or Object
   form, that is based upon (or derived from) the Work and for which the
   editorial revisions, annotations, elaborations, or other modifications
   represent, as a whole, an original work of authorship. For the purposes
   of this License, Derivative Works shall not include works that remain
   separable from, or merely link (or bind by name) to the interfaces of,
   the Work and derivative works thereof.

   "Contribution" shall mean any work of authorship, including
   the original version of the Work and any modifications or additions
   to that Work or Derivative Works thereof, that is intentionally
   submitted to Licensor for inclusion in the Work by the copyright
   owner or by an individual or Legal Entity authorized to submit on
   behalf of the copyright owner. For the purposes of this definition,
   "submitted" means any form of electronic, verbal, or written
   communication sent to the Licensor or its representatives, including
   but not limited to communication on electronic mailing lists, source
   code control systems, and issue tracking systems that are managed by,
   or on behalf of, the Licensor for the purpose of discussing and
   improving the Work, but excluding communication that is conspicuously
   marked or otherwise designated in writing by the copyright owner as
   "Not a Contribution."

2. Grant of Copyright License. Subject to the terms and conditions of
   this License, each Contributor hereby grants to You a perpetual,
   worldwide, non-exclusive, no-charge, royalty-free, irrevocable
   copyright license to use, reproduce, modify, publicly display,
   publicly perform, sublicense, and distribute the Work and such Derivative
   Works in Source or Object form.

3. Grant of Patent License. Subject to the terms and conditions of
   this License, each Contributor hereby grants to You a perpetual,
   worldwide, non-exclusive, no-charge, royalty-free, irrevocable
   (except as stated in this section) patent license to make, have made,
   use, offer to sell, sell, import, and otherwise transfer the Work,
   where such license applies only to those patent claims licensable
   by such Contributor that are necessarily infringed by their
   Contribution(s) alone or by combination of their Contribution(s)
   with the Work to which such Contribution(s) was submitted. If You
   institute patent litigation against any entity (including a
   cross-claim or counterclaim in a lawsuit) alleging that the Work
   or a Contribution incorporated within the Work constitutes direct
   or contributory patent infringement, then any patent licenses
   granted to You under this License for that Work shall terminate
   as of the date such litigation is filed.

4. Redistribution. You may reproduce and distribute copies of the
   Work or Derivative Works thereof in any medium, with or without
   modifications, and in Source or Object form, provided that You
   meet the following conditions:

   (a) You must give any other recipients of the Work or
       Derivative Works a copy of this License; and

   (b) You must cause any modified files to carry prominent notices
       stating that You changed the files; and

   (c) You must retain, in the Source form of any Derivative Works
       that You distribute, all copyright, trademark, patent,
       attribution notices from the Source form of the Work,
       excluding those notices that do not pertain to any part of
       the Derivative Works; and

   (d) If the Work includes a "NOTICE" text file as part of its
       distribution, then any Derivative Works that You distribute must
       include a readable copy of the attribution notices contained
       within such NOTICE file, excluding those notices that do not
       pertain to any part of the Derivative Works, in at least one
       of the following places: within a NOTICE text file distributed
       as part of the Derivative Works; within the Source form or
       documentation, if provided along with the Derivative Works; or,
       within a display generated by the Derivative Works, if and
       wherever such third-party notices normally appear. The contents
       of the NOTICE file are for informational purposes only and
       do not modify the License. You may add Your own attribution
       notices within Derivative Works that You distribute, alongside
       or as an addendum to the NOTICE text from the Work, provided
       that such additional attribution notices cannot be construed
       as modifying the License.

   You may add Your own copyright notice to Your modifications and
   may provide additional or different license terms and conditions
   for use, reproduction, or distribution of Your modifications, or
   for any such Derivative Works as a whole, provided Your use,
   reproduction, and distribution of the Work otherwise complies with
   the conditions stated in this License.

5. Submission of Contributions. Unless You explicitly state otherwise,
   any Contribution intentionally submitted for inclusion in the Work
   by You to the Licensor shall be under the terms and conditions of
   this License, without any additional terms or conditions.
   Notwithstanding the above, nothing herein shall supersede or modify
   the terms of any separate contributor license agreement you may have
   executed with Licensor regarding such Contributions.

6. Trademarks. This License does not grant permission to use the trade
   names, trademarks, service marks, or product names of the Licensor,
   except as required for reasonable and customary use in describing the
   origin of the Work and reproducing the content of the NOTICE file.

7. Disclaimer of Warranty. Unless required by applicable law or
   agreed to in writing, Licensor provides the Work (and each
   Contributor provides its Contributions) on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
   implied, including, without limitation, any warranties or conditions
   of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
   PARTICULAR PURPOSE. You are solely responsible for determining the
   appropriateness of using or redistributing the Work and assume any
   risks associated with Your exercise of permissions under this License.

8. Limitation of Liability. In no event and under no legal theory,
   whether in tort (including negligence), contract, or otherwise,
   unless required by applicable law (such as deliberate and grossly
   negligent acts) or agreed to in writing, shall any Contributor be
   liable to You for damages, including any direct, indirect, special,
   incidental, or consequential damages of any character arising as a
   result of this License or out of the use or inability to use the
   Work (including but not limited to damages for loss of goodwill,
   work stoppage, computer failure or malfunction, or any and all
   other commercial damages or losses), even if such Contributor
   has been advised of the possibility of such damages.

9. Accepting Warranty or Additional Support. When redistributing
   the Work or Derivative Works thereof, You may choose to offer,
   and charge a fee for, acceptance of support, warranty, indemnity,
   or other liability obligations and/or rights consistent with this
   License. However, in accepting such obligations, You may act only
   on Your own behalf and on Your sole responsibility, not on behalf
   of any other Contributor, and only if You agree to indemnify,
   defend, and hold each Contributor harmless for any liability
   incurred by, or claims asserted against, such Contributor by reason
   of your accepting any such warranty or support.

END OF TERMS AND CONDITIONS

License Selection Guide

Choose MIT License If:

  • ✅ You want maximum simplicity and permissiveness
  • ✅ Your project is proprietary or closed-source
  • ✅ You prefer minimal legal complexity
  • ✅ You don't need explicit patent protection
  • ✅ You want broad compatibility with other projects

Choose Apache 2.0 License If:

  • ✅ You want explicit patent grant protection
  • ✅ Your project involves potential patent considerations
  • ✅ You need trademark protection provisions
  • ✅ You prefer more detailed legal terms
  • ✅ You're contributing to Apache ecosystem projects

Compliance Requirements

For MIT License

When using Hayasen under the MIT License:

  1. Include Copyright Notice: Include the MIT license text with copyright notice in your distribution
  2. Attribution: Maintain attribution to the original authors
  3. License Propagation: Include the license file with any redistribution

For Apache 2.0 License

When using Hayasen under the Apache 2.0 License:

  1. Include License: Include the Apache 2.0 license text
  2. Copyright Notices: Preserve all copyright notices from the source
  3. NOTICE File: If a NOTICE file exists, include it in redistributions
  4. Modification Notices: Mark any files you modify
  5. Patent Grant: Benefit from explicit patent grant provisions

Cargo.toml Configuration

Include both licenses in your Cargo.toml:

[package]
name = "hayasen"
version = "x.x.x"
license = "MIT OR Apache-2.0"
authors = ["Your Name <your.email@example.com>"]
description = "Embedded sensor driver library for motion tracking devices"
repository = "https://github.com/yourusername/hayasen"
documentation = "https://docs.rs/hayasen"
keywords = ["embedded", "sensor", "mpu9250", "imu", "no-std"]
categories = ["embedded", "hardware-support", "no-std"]

File Structure

Ensure these license files are present in your repository root:

hayasen/
├── LICENSE-MIT         # Full MIT license text
├── LICENSE-APACHE      # Full Apache 2.0 license text
├── Cargo.toml         # With license = "MIT OR Apache-2.0"
├── README.md          # License section referencing both
└── src/
    └── lib.rs         # With license headers

Source Code Headers

Include license headers in your source files:

#![allow(unused)]
fn main() {
// Licensed under the MIT License or Apache License, Version 2.0
// at your option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Hayasen - Embedded sensor driver library
//! 
//! Copyright (c) [YEAR] [COPYRIGHT_HOLDER]
//! 
//! Licensed under either:
//! - MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
//! - Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
//! 
//! at your option.
}

Third-Party Dependencies

When adding dependencies, ensure license compatibility:

  • ✅ MIT: Compatible with both MIT and Apache 2.0
  • ✅ Apache 2.0: Compatible with both licenses
  • ✅ BSD-2-Clause/BSD-3-Clause: Compatible with both
  • ⚠️ GPL variants: May require careful consideration
  • ❌ Copyleft licenses: May not be compatible with permissive dual licensing

Attribution

When using Hayasen in your projects, attribution can be provided as:

This project uses Hayasen (https://github.com/yourusername/hayasen),
licensed under MIT OR Apache-2.0.

Or in a more formal NOTICE file:

Hayasen Embedded Sensor Library
Copyright (c) [YEAR] [COPYRIGHT_HOLDER]
Licensed under MIT OR Apache-2.0

This product includes software developed by [Your Name/Organization].

Commercial Use

Both licenses explicitly permit commercial use:

  • No royalties or licensing fees required
  • Modification rights for proprietary applications
  • Distribution rights in commercial products
  • Sublicensing permitted under both licenses

Contributing

By contributing to Hayasen, you agree that your contributions will be licensed under the same dual MIT/Apache-2.0 license terms. This ensures consistency across the entire codebase and maintains the dual licensing benefits for all users.

Contributor License Agreement

Contributors should be aware that:

  1. Contributions are licensed under both MIT and Apache 2.0
  2. You retain copyright to your contributions
  3. You grant broad rights to use, modify, and distribute your contributions
  4. Patent rights are handled according to Apache 2.0 terms

Frequently Asked Questions

Q: Can I use Hayasen in my commercial product?

A: Yes, both licenses explicitly permit commercial use without restrictions.

Q: Do I need to open-source my modifications?

A: No, both licenses are permissive and do not require you to open-source derivative works.

Q: Which license should I choose for my project?

A: Choose based on your needs:

  • MIT for simplicity and broad compatibility
  • Apache 2.0 for explicit patent protection

Q: Can I relicense Hayasen under a different license?

A: You can license your derivative work under different terms, but you must maintain attribution and comply with the original license terms.

Q: What if I only want to use one of the licenses?

A: You can choose to use Hayasen under either license exclusively. Simply follow the terms of your chosen license.

Disclaimer: This license information is provided for informational purposes. For legal advice regarding license compliance, consult with a qualified attorney.