newline-normalizer

Convert between newline formats (\n, \r, \r\n) safely and efficiently.

Features

• Adds extension traits to str — call .to_unix_newlines() and .to_dos_newlines() naturally.
• Preserves input with Cow<str> — avoids allocating when input is already normalized.
• Converts all common newline formats (\n, \r, \r\n) including classic Mac line endings.
• Unicode-safe — preserves emojis, RTL, combining marks, and other sequences.
• Fast scanning using memchr utilizing SIMD for efficient large text processing.

Benchmark

Benchmarks are located under the /benches folder.

Run them using:

cargo bench --bench to_unix
cargo bench --bench to_dos

Examples

use newline_normalizer::{ToUnixNewlines, ToDosNewlines};

let unix = "line1\r\nline2\rline3".to_unix_newlines();
assert_eq!(unix, "line1\nline2\nline3");

let dos = "line1\nline2\nline3".to_dos_newlines();
assert_eq!(dos, "line1\r\nline2\r\nline3");

Unicode behavior

This crate does not alter Unicode content. It only rewrites newline boundaries.

All valid UTF-8 sequences are preserved, including:

• Combining characters stay attached
• Emoji and multi-codepoint sequences remain valid
• Right-to-left (RTL) markers are unaffected

Limitations

This crate does not currently normalize U+2028 (LINE SEPARATOR) or U+2029 (PARA SEP). Only ASCII newline formats are converted.