sizefilter

Human-readable size string parsing, formatting, arithmetic, and filtering with comparison operators — ">=1GB", "<500KB", "=0".

Installation

cargo add sizefilter

Features

• Parse: "1GB", "500KB", "1024", "1.5MB" → i64 bytes
• Format: 1073741824 → "1.0GB", -1024 → "-1.0KB"
• Filter: SizeFilter::ge(1_073_741_824) or ">=1GB".parse::<SizeFilter>()
• Arithmetic: +, -, *, /, Neg on [Size] — all byte-level
• Serde (optional): serialize/deserialize [Size] & [SizeFilter] as strings
• i64 (not u64) — negative sizes supported
• Zero heap allocation in parsing and error paths — SizeError is a ZST in .rodata
• Binary units (1 KB = 1024 B), matching filesystem convention
• #[must_use] annotations throughout — no silently ignored results

Testing

cargo test

58 tests (47 unit + 11 doc-tests) covering parsing, formatting, filtering, arithmetic, edge cases (whitespace, case sensitivity, negative values, sub-byte decimals, extreme ranges, invalid inputs), round-trip consistency, and serde round-trip.

Quick example

use sizefilter::prelude::*;

// Parse a human-readable size to bytes
let bytes = parse_size("1.5GB").unwrap();
assert_eq!(bytes, 1_610_612_736);

// Using the Size newtype
let s: Size = "2GB".parse().unwrap();
assert_eq!(s.bytes(), 2_147_483_648);
assert_eq!(s.to_string(), "2.0GB");

// Parse a filter expression
let f: SizeFilter = ">=500MB".parse().unwrap();
assert!(f.matches(bytes));
assert!(!f.matches(100_000));

// Use convenience constructors
let f = SizeFilter::lt(GB);
assert!(f.matches(500 * MB));

// Arithmetic
assert_eq!(Size::from_mb(2) + Size::from_kb(512), Size::from_bytes(2_097_152 + 524_288));

Modules

src/
├── lib.rs    — Crate root, prelude module
└── size.rs   — Size, SizeOp, SizeFilter, SizeError, constants, all ops

Prelude

use sizefilter::prelude::* brings in the most common types and functions:

use sizefilter::prelude::*;
// Now available:
//   Size, SizeFilter, SizeOp, SizeError, SizeResult
//   KB, MB, GB, TB, PB, EB
//   parse_size(), format_size(), parse_size_filter()

Error handling

All fallible operations return Result<T, SizeError>. The SizeError enum is #[non_exhaustive] — new variants may be added in minor releases.

use sizefilter::{parse_size, SizeError};

match parse_size("1XB") {
    Err(SizeError::UnknownUnit) => println!("unknown unit"),
    Err(SizeError::InvalidNumber) => println!("bad number"),
    Err(SizeError::EmptyInput) => println!("empty"),
    _ => {}
}

License

MIT License