refactor: Replace handwritten Ord and PartialOrd for DateTime

[sorairolake]

Use the derive macro to implement these.

In #267, I changed these to handwritten implementations. However, given the structure of MS-DOS date and time, I don't think this change was necessary.

This change improves the performance when comparing the order of DateTime.

[gemini-code-assist]

Summary of Changes

Hello @sorairolake, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refactors the DateTime struct by replacing its handwritten Ord and PartialOrd trait implementations with derived versions. The primary goal is to simplify the codebase and enhance the performance of DateTime comparisons by utilizing Rust's built-in derive capabilities for these traits.

Highlights

• Refactoring DateTime Comparison: Replaced the manual implementations of the Ord and PartialOrd traits for the DateTime struct with #[derive(Ord, PartialOrd)]. This simplifies the code by leveraging Rust's automatic trait derivation.
• Performance Improvement: This change is expected to improve the performance of DateTime comparisons, as derived trait implementations are often optimized by the compiler.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[gemini-code-assist]

Code Review

This pull request refactors the DateTime struct to use derived implementations for Ord and PartialOrd, replacing the previous handwritten ones. This is a solid improvement, leveraging the lexicographical ordering of the MS-DOS date and time formats when packed into integers. This change correctly simplifies the code and improves comparison performance by replacing a sequence of expensive field extractions and comparisons with two simple integer comparisons. The logic is sound and the implementation is clean. I have no issues to report.