fit_file

FIT file parser written in Rust. FIT (Flexible and Interoperable Data Transfer) is a binary file format that is commonly used to exchange fitness data, such as that from a sports watch or bike computer.

This implementation uses a callback, as shown in the example below. The callback is an effient method for dealing with large files as it allows us to avoid returning a large array containing each of the records that was processed.

Example

```rust extern crate fit;

use std::io::BufReader; use std::fs::File;

/// Called for each record message as it is processed. fn callback(timestamp: u32, globalmessagenum: u16, localmsgtype: u8, messageindex: u16, fields: Vec, context: *mut c_void) { let data: &mut Context = unsafe { &mut *(context as *mut Context) };

if global_message_num == crate::fit::GLOBAL_MSG_NUM_SESSION {
    let msg = crate::fit::FitSessionMsg::new(fields);
    let sport_names = crate::fit::init_sport_name_map();
    let sport_id = msg.sport.unwrap();

    println!("Sport: {}", sport_names.get(&sport_id).unwrap());
}
else if global_message_num == crate::fit::GLOBAL_MSG_NUM_RECORD {
    let msg = crate::fit::FitRecordMsg::new(fields);

    println!("Timestamp: {} Latitude: {} Longitude: {}", timestamp, crate::fit::semicircles_to_degrees(msg.position_lat.unwrap()), crate::fit::semicircles_to_degrees(msg.position_long.unwrap()));
}

}

/// Context structure. An instance of this will be passed to the parser and ultimately to the callback function so we can use it for whatever. struct Context { numrecordsprocessed: u16, }

impl Context { pub fn new() -> Self { let context = Context{ numrecordsprocessed: 0 }; context } }

fn main() { let file = std::fs::File::open("tests/20210218zwift.fit").unwrap(); let mut reader = std::io::BufReader::new(file); let mut context = Context::new(); let contextptr: *mut cvoid = &mut context as *mut _ as *mut cvoid; let fit = crate::fit::read(&mut reader, callback, context_ptr); } ```

Current Status

Work in progress.

Revision History

• 0.3.0 - Fixed numerous issues interpreting the specification. Now passing with several Garmin test files, instead of just the original Wahoo test file.
• 0.2.0 - Updated critical message structures by implementing a code generator that is just barely good enough.
• 0.1.0 - Basic functionality, can extract position and timestamp data for run and cycling activities.

License

This project is licensed under the MIT license.