spacecell

A lightweight, zero-dependency datetime library for Rust. Provides ISO8601/RFC3339 parsing and formatting, proleptic Gregorian calendar calculations, and business day operations.

Features

• Zero dependencies - No external crates required
• Proleptic Gregorian calendar - Correct handling of dates before 1582
• ISO 8601 / RFC 3339 - Parse and format standard datetime strings
• Precision support - Seconds, milliseconds, microseconds, and nanoseconds
• Calendar arithmetic - Add/subtract days, weeks, months, years
• Business day calculations - Weekend and holiday-aware date arithmetic
• ISO week numbering - Week-based year calculations
• Fiscal calendar support - Quarters, half-years, fiscal years

Installation

Add to your Cargo.toml:

[dependencies]
spacecell = "0.1"

Usage

Parsing and Formatting

use spacecell::{parse_iso8601, format_iso8601};

// Parse ISO8601 datetime
let (timestamp, unit) = parse_iso8601("2024-06-15T14:30:00.123Z").unwrap();

// Format back to string
let formatted = format_iso8601(timestamp, unit);
assert_eq!(formatted, "2024-06-15T14:30:00.123Z");

Calendar Operations

use spacecell::{ymd_to_days, days_to_ymd, is_leap_year, days_in_month};

// Convert date to days since Unix epoch
let days = ymd_to_days(2024, 6, 15);

// Convert back to year/month/day
let (year, month, day) = days_to_ymd(days);
assert_eq!((year, month, day), (2024, 6, 15));

// Leap year detection
assert!(is_leap_year(2024));
assert!(!is_leap_year(2023));

// Days in a month
assert_eq!(days_in_month(2024, 2), 29); // Leap year
assert_eq!(days_in_month(2023, 2), 28);

Business Day Calculations

use spacecell::{
    CalendarConfig, add_business_days, count_business_days,
    next_business_day, is_business_day,
};

// Create a calendar with holidays
let config = CalendarConfig::new()
    .add_holiday(2024, 12, 25)  // Christmas
    .add_holiday(2024, 12, 26); // Boxing Day

// Add business days (skips weekends and holidays)
let (y, m, d) = add_business_days(2024, 12, 23, 3, &config);
// Skips Sat 24, Sun 25 (also holiday), Thu 26 (holiday)

// Count business days in a range
let count = count_business_days(2024, 12, 1, 2024, 12, 31, &config);

// Find next business day
let (y, m, d) = next_business_day(2024, 12, 24, &config);

Time Deltas

use spacecell::TimeDelta;

let delta = TimeDelta::hours(25);
assert_eq!(delta.total_seconds(), 90_000);

let d1 = TimeDelta::days(3);
let d2 = TimeDelta::hours(12);
let sum = d1 + d2;

Algorithms

Date calculations use Howard Hinnant's public domain algorithms for efficient, loop-free conversions between calendar dates and day counts.

Licence

Licensed under either of:

• Apache Licence, Version 2.0 (LICENCE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT licence (LICENCE-MIT or http://opensource.org/licenses/MIT)

at your option.