# cj_bitmask_vec

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BitmaskVec is a vec that pairs bitmasks with T. Bitmasks u8 through u128 are supported.<br>

Items can be added with or without supplying bitmasks. Bitmask will default to zero if not supplied.

Filtering iterator using bitmasks

```rust
// filtering by bitmask
fn main() {
    use cj_bitmask_vec::prelude::*;

    let mut v = BitmaskVec::<u8, i32>::new();
    // bitmasks hold whatever meaning the developer gives them.
    // In this example any u8 is a valid bitmask.
    //                (bitmask)  (T)      
    v.push_with_mask(0b00000000, 100);
    v.push_with_mask(0b00000010, 101);
    v.push_with_mask(0b00000011, 102);
    v.push_with_mask(0b00000100, 103);
    v.push_with_mask(0b00000110, 104);
    v.push(105);  // <- bitmask will default to zero
    // or an easier way to add items   
    v += (0b00000000, 106);
    v += (0b00010000, 107);
    v += (0b00100000, 108);
    v += (0b00000100, 109);
    v += (0b10000001, 110);
    v += (0b00000001, 111);
    v += (0b00000000, 112);
    v += 113; // <- bitmask will default to zero

    assert_eq!(v[6], 106);

    // here we're going to iterate all items that have bitmask bit 1 set
    let mut count = 0;
    let mut iter = v.iter_with_mask();
    //                                (mask with bit 1 set)
    //                                               V
    while let Some(pair) = iter.filter_mask(&0b00000010) {
        // only T 101, 102 and 104 in the Vec above have
        // bitmask bit one set.
        assert!([101, 102, 104].contains(&pair.item));
        count += 1;
    }
    assert_eq!(count, 3);
}
```

Iterating over T

```rust
fn main() {
    use cj_bitmask_vec::prelude::*;

    let mut v = BitmaskVec::<u8, i32>::new();
    v.push_with_mask(0b00000000, 100);
    v.push_with_mask(0b00000010, 101);
    v.push_with_mask(0b00000010, 102);
    v.push_with_mask(0b00000110, 103);
    v.push_with_mask(0b00000001, 104);
    v.push_with_mask(0b00000001, 105);
    v.push_with_mask(0b00000000, 106);

    let mut total = 0;
    // iter excludes the bitmask
    for x in v.iter() {
        total += x;
    }
    assert_eq!(total, 721);
}
```

Iterating over T and bitmask.

```rust
fn main() {
    use cj_bitmask_vec::prelude::*;
    use cj_common::prelude::CjMatchesMask;

    let mut v = BitmaskVec::<u8, i32>::new();
    v.push_with_mask(0b00000000, 100);
    v.push_with_mask(0b00000010, 101);
    v.push_with_mask(0b00000010, 102);
    v.push_with_mask(0b00000110, 103);
    v.push_with_mask(0b00000001, 104);
    v.push_with_mask(0b00000001, 105);
    v.push_with_mask(0b00000000, 106);

    let mut total = 0;
    for x in v.iter_with_mask() {
        if x.matches_mask(&0b00000010) {
            total += x.item;
        }
    }
    assert_eq!(total, 306);
}
```

Mutably iterating over T

```rust
fn main() {
    use cj_bitmask_vec::prelude::*;

    let mut v = BitmaskVec::<u8, i32>::new();
    v.push_with_mask(0b00000000, 100);
    v.push_with_mask(0b00000010, 101);
    v.push_with_mask(0b00000010, 102);
    v.push_with_mask(0b00000100, 103);
    v.push_with_mask(0b00000011, 104);
    v.push_with_mask(0b00000001, 105);
    v.push_with_mask(0b00000000, 106);

    let mut total = 0;
    // iter_mut exludes the bitmask
    let x = v.iter_mut();
    for z in x {
        // here we modify T
        total += *z;
        *z *= 2;
    }

    // verify the changes from above
    let mut total_2 = 0;
    let x = v.iter();
    for z in x {
        total_2 += *z;
    }

    assert_eq!(total_2, total * 2);
}
```

Mutably iterating over T and bitmask

```rust
fn main() {
    use cj_bitmask_vec::prelude::*;
    use cj_common::prelude::{Bitflag, CjMatchesMask};

    let mut v = BitmaskVec::<u8, i32>::new();
    v.push_with_mask(0b00000000, 100);
    v.push_with_mask(0b00000010, 101);
    v.push_with_mask(0b00000010, 102);
    v.push_with_mask(0b00000100, 103);
    v.push_with_mask(0b00000011, 104);
    v.push_with_mask(0b00000001, 105);
    v.push_with_mask(0b00000000, 106);

    let mut total = 0;
    let x = v.iter_with_mask_mut();
    for z in x {
        total += z.item;
        // here we modify T
        z.item *= 2;

        // here we modify the 8th bit of the bitmask.
        // - note that set_bit() only modifies a single bit,
        //   leaving the rest of bitmask unchanged.
        z.bitmask.set_bit(7, true);
    }

    // verify the changes from above
    let mut total_2 = 0;
    let x = v.iter_with_mask();
    for z in x {
        total_2 += z.item;
        // test that the 8th bit is now set.
        assert!(z.matches_mask(&0b10000000));
    }
    // test that T was modified
    assert_eq!(total_2, total * 2);
}
```