lazycsv

Vectorized, lazy-decoding, zero-copy CSV parser.

Primary Focuses

• Vectorized: The parser utilizes SIMD operations, therefore is very performant.
• Minimal hidden costs: Every API doesn't bring any invisible overheads, and each operation only does what it needs to do.
• Zero copy, zero allocation by default: The parser doesn't allocate any memory during parsing and only performs allocation when dequoting each cell.
• Lazy Decoding: Input is not copied or unquoted until requested. This is useful when you only need to access a few cells in a large CSV file.
• #![no_std] eligible: The crate is #![no_std] compatible, and it can be used in systems without an allocator.

Supported Features

lazycsv primarily supports a subset of RFC 4180 with minor extensions.

According to RFC 4180:

• No escape mechanisms other than quoting are supported.
• Padding cells with whitespace is not allowed.
• Using double quotes without quoting is not allowed.
• Quotes must always appear at the very beginning of a cell.

Additional Restrictions:

• Only ASCII and UTF-8 encodings are supported.

Additional Supports:

• Using LF (\n) instead of CRLF (\r\n) as the newline is permitted.
• Customizing the separator character is possible.

Examples

use lazycsv::{Csv, CsvIterItem};

// Iterating over rows
let csv = Csv::new(b"a,b,c\n1,2,3");
for [first, second, third] in csv.into_rows() {
    println!(
        "{}, {}, {}",
        first.try_as_str()?,
        second.try_as_str()?,
        third.try_as_str()?,
    );
}

// Or if you want to avoid buffering:
let csv2 = Csv::new(b"a,b,c\n1,2,3");
for item in csv2 {
    if let CsvIterItem::Cell(cell) = item {
        println!("{}", cell.try_as_str()?);
    }
}

 

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lazycsv is primarily distributed under the terms of both the Apache License (Version 2.0) and the MIT license. See COPYRIGHT for details.