mask.go

// MIT License
//
// Copyright (c) 2021 Wojciech Franczyk
//
// 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.

package ento

type mask []uint64

func makeMask(size int) mask {
	return make(mask, 1+((size-1)/64))
}

func (m mask) Get(index int) bool {
	return m[index/64]&(1<<(index%64)) != 0
}

func (m mask) Set(index int) {
	m[index/64] |= 1 << (index % 64)
}

func (m mask) Clear(index int) {
	m[index/64] &^= 1 << (index % 64)
}

func (m mask) Contains(mask mask) bool {
	for i, bits := range m {
		if bits&mask[i] != mask[i] {
			return false
		}
	}
	return true
}