Below is a professional and detailed README.md file for your Rust crate. It includes an overview of the functionality, installation instructions, usage examples, and additional notes.

Search Crate

A flexible and efficient Rust library for searching text within files. Supports multiple search modes (substring and regex), optional case-insensitive searches, and writing results to an output file or printing them to the console.

Features

• Substring Search: Perform simple substring searches in a file.
• Regex Search: Use regular expressions for advanced pattern matching.
• Case-Insensitive Searches: Optionally ignore case during searches.
• Output Flexibility: Write results to an output file or print them to the console.
• Efficient File Handling: Reads large files line by line using buffered I/O for optimal performance.

Installation

Prerequisites

• Rust 1.60 or higher.
• Cargo package manager.

Add as a Dependency

If you want to use this crate in your project, add it to your Cargo.toml:

[dependencies]
search = { path = "path_to_search_crate" }

Alternatively, if the crate is published to crates.io, you can include it as:

[dependencies]
search = "0.2.0"

Usage

Command-Line Interface

The crate provides a command-line interface for performing searches. Below are examples of how to use it.

Substring Search

Perform a case-sensitive substring search and print results to the console:

cargo run -- search "Error" "./large_log_file.txt"

Case-Insensitive Regex Search

Perform a case-insensitive regex search and write results to an output file:

cargo run -- regex "error\d+" "./large_log_file.txt" "./output.txt" --ignore-case

Help Message

If insufficient arguments are provided, the program will display a usage message:

Usage: cargo run -- <mode> <search_string> <file_path> [output_file] [--ignore-case]

Programmatic Usage

You can also use the crate programmatically in your Rust code. Here's an example:

use search::search_in_file;

fn main() -> std::io::Result<()> {
    // Perform a case-insensitive regex search and print results to the console
    search_in_file(
        "./large_log_file.txt", // File path
        "error\\d+",           // Query (regex pattern)
        None,                  // Output file (None means print to console)
        true,                  // Ignore case
        true                   // Treat query as regex
    )
}

Arguments

The program accepts the following arguments:

Examples

Example 1: Substring Search

Search for the word "Error" in large_log_file.txt and print results to the console:

cargo run -- search "Error" "./large_log_file.txt"

Example 2: Case-Insensitive Regex Search

Search for lines matching the regex pattern "error\d+" in large_log_file.txt, ignoring case, and write results to output.txt:

cargo run -- regex "error\d+" "./large_log_file.txt" "./output.txt" --ignore-case

Example 3: Invalid Regex Pattern

If the regex pattern is invalid, the program will notify you:

cargo run -- regex "[" "./large_log_file.txt"
Invalid regex pattern '['

Error Handling

The program gracefully handles errors such as:

• Missing or invalid arguments.
• File opening or reading errors.
• Invalid regex patterns.

Example error messages:

Error: No such file or directory (os error 2)
Invalid regex pattern '['

Notes

1. Performance: The crate reads files line by line using buffered I/O, making it suitable for large files.
2. Dependencies: The crate uses the regex crate for regex support.
3. Extensibility: Additional search modes or features can be added in the future.

Contributing

Contributions are welcome! To contribute:

1. Fork the repository.
2. Create a new branch (git checkout -b feature/your-feature).
3. Commit your changes (git commit -am 'Add feature').
4. Push to the branch (git push origin feature/your-feature).
5. Open a pull request.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Authors

• zero

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