px4-ulog-rs's Introduction

PX4 Ulog file parser for Rust

NOTE: Before 1.0 we will not follow semantic versioning.

A ULog file parser for Rust written with a small memory footprint. Reading the file is implemented in a streaming manner, where possible.

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Design goals

The API should be streaming, meaning:

Store minimum possible amount of data in memory
Everything should be implemented as iterators
Data should be read directly from file, where possible

Other goals are:

Don't panic
Don't use unsafe

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px4-ulog-rs's Issues

Failed to read vector of floats

For the data chunk

data = [217, 135, 153, 12, 0, 0, 0, 0, 
        251, 133, 153, 12, 0, 0, 0, 0, 
        231, 207, 50, 49, 
        64, 131, 213, 36, 
        215, 182, 109, 50, 
        247, 152, 146, 50, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0, 192, 127, 
        0, 0]

and field description

[('uint64_t', 1, 'timestamp'),
 ('uint64_t', 1, 'timestamp_sample'),
 ('float', 12, 'control'),
 ('uint16_t', 1, 'reversible_flags'),
 ('uint8_t', 6, '_padding0')]

This library only outputs the first two items from the field description in

px4-ulog-rs/examples/gps-position.rs

Line 24 in 41b5b61

println!("{} at {}: {:?}", item.name(), item.index(), item.data());

The extracted format from this library is

["uint64_t timestamp", "uint64_t timestamp_sample", "float[12] control", "uint16_t reversible_flags", "uint8_t[6] _padding0", ""]

Here is how I correctly parse them

import struct

timestamp = struct.unpack('<Q', bytes([217, 135, 153, 12, 0, 0, 0, 0]))[0]
timestamp_sample = struct.unpack('<Q', bytes([251, 133, 153, 12, 0, 0, 0, 0]))[0]
control_0 = struct.unpack('<f', bytes([231, 207, 50, 49]))
control_1 = struct.unpack('<f', bytes([64, 131, 213, 36]))
control_2 = struct.unpack('<f', bytes([215, 182, 109, 50]))
control_3 = struct.unpack('<f', bytes([247, 152, 146, 50]))
control_4 = np.nan 
# ...
control_11 = np.nan

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