bit_ops 0.2.3

/*
MIT License

Copyright (c) 2025 Philipp Schuster

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
//! The function-oriented API of this crate, which is also the main
//! functionality. For every relevant primitive type (`u8`, `u16`, `u32`, `u64`,
//! `u128`, `usize`), there is a module with typical bit operations as dedicated
//! functions.
//!
//! This enables a smooth manual and direct approach to several bit-oriented
//! operations without the need for sophisticated high-level types with specific
//! bitfields.
//!
//! - [`bitops_u8`]
//! - [`bitops_u16`]
//! - [`bitops_u32`]
//! - [`bitops_u64`]
//! - [`bitops_u128`]
//! - [`bitops_usize`]

#[macro_use]
mod macros;

impl_mod!(u8);
impl_mod!(u16);
impl_mod!(u32);
impl_mod!(u64);
impl_mod!(u128);
impl_mod!(usize);

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn set_bit() {
        assert_eq!(bitops_u8::set_bit(0, 0), 1);
        assert_eq!(bitops_u8::set_bit(1, 1), 3);
        assert_eq!(bitops_u8::set_bit(1, 0), 1);
        assert_eq!(bitops_u8::set_bit(1 << 7, 6), 0b1100_0000);
        assert_eq!(bitops_u8::set_bit(u8::MAX - 1, 0), u8::MAX);

        assert_eq!(bitops_u64::set_bit(0, 0), 1);
        assert_eq!(bitops_u64::set_bit(1, 1), 3);
        assert_eq!(bitops_u64::set_bit(1, 0), 1);
        assert_eq!(bitops_u64::set_bit(1 << 7, 6), 0b1100_0000);
        assert_eq!(bitops_u64::set_bit(u64::MAX - 1, 0), u64::MAX);
    }

    #[test]
    fn set_bit_exact() {
        assert_eq!(bitops_u8::set_bit_exact(0, 0, true), 1);
        assert_eq!(bitops_u8::set_bit_exact(0, 0, false), 0);
        assert_eq!(bitops_u8::set_bit_exact(1, 1, true), 3);
        assert_eq!(bitops_u8::set_bit_exact(1, 0, true), 1);
        assert_eq!(bitops_u8::set_bit_exact(1, 0, false), 0);

        assert_eq!(bitops_u64::set_bit_exact(0, 0, true), 1);
        assert_eq!(bitops_u64::set_bit_exact(0, 0, false), 0);
        assert_eq!(bitops_u64::set_bit_exact(1, 1, true), 3);
        assert_eq!(bitops_u64::set_bit_exact(1, 0, true), 1);
        assert_eq!(bitops_u64::set_bit_exact(1, 0, false), 0);
    }

    #[test]
    fn clear_bit() {
        assert_eq!(bitops_u8::clear_bit(1, 0), 0);
        assert_eq!(bitops_u8::clear_bit(3, 1), 1);
        assert_eq!(bitops_u8::clear_bit(1, 0), 0);
        assert_eq!(bitops_u8::clear_bit(1 << 7, 7), 0);
        assert_eq!(bitops_u8::clear_bit(u8::MAX, 7), u8::MAX / 2);

        assert_eq!(bitops_u64::clear_bit(1, 0), 0);
        assert_eq!(bitops_u64::clear_bit(3, 1), 1);
        assert_eq!(bitops_u64::clear_bit(1, 0), 0);
        assert_eq!(bitops_u64::clear_bit(1 << 7, 7), 0);
        assert_eq!(bitops_u64::clear_bit(u64::MAX, 63), u64::MAX / 2);
    }

    #[test]
    fn is_set() {
        assert!(!bitops_u8::is_set(0, 0));
        assert!(bitops_u8::is_set(1, 0));
        assert!(bitops_u8::is_set(u8::MAX, 0));
        assert!(bitops_u8::is_set(u8::MAX, 7));
        assert!(!bitops_u8::is_set(1 << 6, 7));

        assert!(!bitops_u64::is_set(0, 0));
        assert!(bitops_u64::is_set(1, 0));
        assert!(bitops_u64::is_set(u64::MAX, 0));
        assert!(bitops_u64::is_set(u64::MAX, 7));
    }

    #[test]
    fn get_bit() {
        assert_eq!(bitops_u8::get_bit(0, 0), 0);
        assert_eq!(bitops_u8::get_bit(1, 0), 1);
        assert_eq!(bitops_u8::get_bit(u8::MAX, 0), 1);
        assert_eq!(bitops_u8::get_bit(u8::MAX, 7), 1);
        assert_eq!(bitops_u8::get_bit(1 << 6, 7), 0);

        assert_eq!(bitops_u64::get_bit(0, 0), 0);
        assert_eq!(bitops_u64::get_bit(1, 0), 1);
        assert_eq!(bitops_u64::get_bit(u64::MAX, 0), 1);
        assert_eq!(bitops_u64::get_bit(u64::MAX, 7), 1);
    }

    #[test]
    fn toggle_bit() {
        assert!(bitops_u8::is_set(bitops_u8::toggle_bit(0, 0), 0));
        assert!(!bitops_u8::is_set(bitops_u8::toggle_bit(1, 0), 0));
        assert_eq!(bitops_u8::toggle_bit(3, 0), 0b10);
        assert_eq!(bitops_u8::toggle_bit(u8::MAX, 7), u8::MAX / 2);

        assert!(bitops_u64::is_set(bitops_u64::toggle_bit(0, 0), 0));
        assert!(!bitops_u64::is_set(bitops_u64::toggle_bit(1, 0), 0));
        assert_eq!(bitops_u64::toggle_bit(3, 0), 0b10);
        assert_eq!(bitops_u64::toggle_bit(u64::MAX, 63), u64::MAX / 2);
    }

    #[test]
    fn toggle_bits() {
        assert_eq!(bitops_u8::toggle_bits(0, 0, 0), 0);
        assert_eq!(bitops_u8::toggle_bits(1, 0, 0), 1);
        assert_eq!(bitops_u8::toggle_bits(0b111, 2, 1), 1);
        assert_eq!(bitops_u8::toggle_bits(0, 2, 1), 0b110);

        assert_eq!(bitops_u64::toggle_bits(0, 0, 0), 0);
        assert_eq!(bitops_u64::toggle_bits(1, 0, 0), 1);
        assert_eq!(bitops_u64::toggle_bits(0b111, 2, 1), 1);
        assert_eq!(bitops_u64::toggle_bits(u64::MAX, 62, 2), 0b11);
    }

    #[test]
    fn set_bits() {
        assert_eq!(bitops_u8::set_bits(0, 0, 0, 0), 0);
        assert_eq!(bitops_u8::set_bits(5, 0, 0, 0), 5);
        assert_eq!(bitops_u8::set_bits(0b100, 0b11, 2, 0), 0b111);
        assert_eq!(bitops_u8::set_bits(0b100, 0b11, 2, 2), 0b1100);
        assert_eq!(bitops_u8::set_bits(0b100, 0b11, 1, 0), 0b101);
        assert_eq!(bitops_u8::set_bits(0b100, 0b11, 0, 0), 0b100);
        assert_eq!(bitops_u8::set_bits(0, u8::MAX, 8, 0), u8::MAX);
        assert_eq!(bitops_u8::set_bits(0, u8::MAX, 1, 7), 0b1000_0000);

        assert_eq!(bitops_u64::set_bits(0, 0, 0, 0), 0);
        assert_eq!(bitops_u64::set_bits(5, 0, 0, 0), 5);
        assert_eq!(bitops_u64::set_bits(0b100, 0b11, 2, 0), 0b111);
        assert_eq!(bitops_u64::set_bits(0b100, 0b11, 2, 2), 0b1100);
        assert_eq!(bitops_u64::set_bits(0b100, 0b11, 1, 0), 0b101);
        assert_eq!(bitops_u64::set_bits(0b100, 0b11, 0, 0), 0b100);
        assert_eq!(bitops_u64::set_bits(0, u64::MAX, 64, 0), u64::MAX);
    }

    #[test]
    fn set_bits_exact() {
        assert_eq!(bitops_u8::set_bits_exact(0, 0, 0, 0), 0);
        assert_eq!(
            bitops_u8::set_bits_exact(0b1000_1100, 0b010, 3, 0),
            0b1000_1010
        );
        assert_eq!(
            bitops_u8::set_bits_exact(0b11111111, 0b10101, 5, 3),
            0b10101111
        );

        assert_eq!(bitops_u64::set_bits_exact(0, 0, 0, 0), 0);
        assert_eq!(
            bitops_u64::set_bits_exact(0b1000_1100, 0b010, 3, 0),
            0b1000_1010
        );
        assert_eq!(
            bitops_u64::set_bits_exact(0b11111111, 0b10101, 5, 3),
            0b10101111
        );
    }

    #[test]
    fn clear_bits() {
        assert_eq!(bitops_u8::clear_bits(0, 0), 0);
        assert_eq!(bitops_u8::clear_bits(0b11111111, 0), 0b11111111);
        assert_eq!(bitops_u8::clear_bits(0b11111111, 0b01111110), 0b10000001);

        assert_eq!(bitops_u64::clear_bits(0, 0), 0);
        assert_eq!(bitops_u64::clear_bits(0b11111111, 0), 0b11111111);
        assert_eq!(bitops_u64::clear_bits(0b11111111, 0b01111110), 0b10000001);
        assert_eq!(bitops_u64::clear_bits(u64::MAX, u64::MAX), 0);
    }

    #[test]
    fn highest_bit() {
        assert_eq!(bitops_u8::highest_bit(0), None);
        assert_eq!(bitops_u8::highest_bit(1), Some(0));
        assert_eq!(bitops_u8::highest_bit(0b10), Some(1));
        assert_eq!(bitops_u8::highest_bit(0b11), Some(1));
        assert_eq!(bitops_u8::highest_bit(u8::MAX), Some(7));

        assert_eq!(bitops_u64::highest_bit(0), None);
        assert_eq!(bitops_u64::highest_bit(1), Some(0));
        assert_eq!(bitops_u64::highest_bit(0b10), Some(1));
        assert_eq!(bitops_u64::highest_bit(0b11), Some(1));
        assert_eq!(bitops_u64::highest_bit(u64::MAX), Some(63));
    }

    #[test]
    fn lowest_bit() {
        assert_eq!(bitops_u8::lowest_bit(0), None);
        assert_eq!(bitops_u8::lowest_bit(1), Some(0));
        assert_eq!(bitops_u8::lowest_bit(0b1000_0001), Some(0));
        assert_eq!(bitops_u8::lowest_bit(0b1000_0010), Some(1));
        assert_eq!(bitops_u8::lowest_bit(u8::MAX), Some(0));

        assert_eq!(bitops_u64::lowest_bit(0), None);
        assert_eq!(bitops_u64::lowest_bit(1), Some(0));
        assert_eq!(bitops_u64::lowest_bit(0b1000_0001), Some(0));
        assert_eq!(bitops_u64::lowest_bit(0b1000_0010), Some(1));
        assert_eq!(bitops_u64::lowest_bit(u64::MAX), Some(0));
    }

    #[test]
    fn create_mask() {
        assert_eq!(bitops_u8::create_mask(0), 0);
        assert_eq!(bitops_u8::create_mask(1), 0b1);
        assert_eq!(bitops_u8::create_mask(2), 0b11);
        assert_eq!(bitops_u8::create_mask(3), 0b111);
        assert_eq!(bitops_u8::create_mask(8), 0xff);

        assert_eq!(bitops_u64::create_mask(0), 0);
        assert_eq!(bitops_u64::create_mask(64), u64::MAX);
    }

    /// This tests various functions in combination using a real-world scenario.
    #[test]
    fn combined() {
        use x86_ioapic::*;

        mod x86_ioapic {
            pub const VECTOR_BITS: u64 = 8;
            pub const VECTOR_SHIFT: u64 = 0;
            pub const DELIVERY_MODE_BITS: u64 = 3;
            pub const DELIVERY_MODE_SHIFT: u64 = 8;
            pub const DESTINATION_MODE_BITS: u64 = 1;
            pub const DESTINATION_MODE_SHIFT: u64 = 11;
            pub const PIN_POLARITY_BITS: u64 = 1;
            pub const PIN_POLARITY_SHIFT: u64 = 13;
            pub const TRIGGER_MODE_BITS: u64 = 1;
            pub const TRIGGER_MODE_SHIFT: u64 = 15;
            pub const MASKED_BITS: u64 = 1;
            pub const MASKED_SHIFT: u64 = 16;
            pub const DESTINATION_BITS: u64 = 8;
            pub const DESTINATION_SHIFT: u64 = 56;
        }

        let vector = 7;
        let delivery_mode = 0b111; // ExtInt
        let destination_mode = 0; // physical
        let pin_polarity = 1; // low-active
        let trigger_mode = 1; // level-triggered
        let masked = 1;
        let destination = 13;

        let redirection_entry = bitops_u64::set_bits_exact_n(
            0,
            &[
                (vector, VECTOR_BITS, VECTOR_SHIFT),
                (delivery_mode, DELIVERY_MODE_BITS, DELIVERY_MODE_SHIFT),
                (
                    destination_mode,
                    DESTINATION_MODE_BITS,
                    DESTINATION_MODE_SHIFT,
                ),
                (pin_polarity, PIN_POLARITY_BITS, PIN_POLARITY_SHIFT),
                (trigger_mode, TRIGGER_MODE_BITS, TRIGGER_MODE_SHIFT),
                (masked, MASKED_BITS, MASKED_SHIFT),
                (destination, DESTINATION_BITS, DESTINATION_SHIFT),
            ],
        );
        assert_eq!(redirection_entry, 0xd0000000001a707);

        // Now check the other direction: get those bits again

        assert_eq!(
            bitops_u64::get_bits(redirection_entry, VECTOR_BITS, VECTOR_SHIFT),
            vector
        );
        assert_eq!(
            bitops_u64::get_bits(redirection_entry, DELIVERY_MODE_BITS, DELIVERY_MODE_SHIFT),
            delivery_mode
        );
        assert_eq!(
            bitops_u64::get_bits(
                redirection_entry,
                DESTINATION_MODE_BITS,
                DESTINATION_MODE_SHIFT
            ),
            destination_mode
        );
        assert_eq!(
            bitops_u64::get_bits(redirection_entry, PIN_POLARITY_BITS, PIN_POLARITY_SHIFT),
            pin_polarity
        );
        assert_eq!(
            bitops_u64::get_bits(redirection_entry, TRIGGER_MODE_BITS, TRIGGER_MODE_SHIFT),
            trigger_mode
        );
        assert_eq!(
            bitops_u64::get_bits(redirection_entry, MASKED_BITS, MASKED_SHIFT),
            masked
        );
        assert_eq!(
            bitops_u64::get_bits(redirection_entry, DESTINATION_BITS, DESTINATION_SHIFT),
            destination
        );
    }
}