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bitfield.go
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bitfield.go
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package util
import (
"github.com/filecoin-project/go-bitfield"
rlepluslazy "github.com/filecoin-project/go-bitfield/rle"
)
type BitField = bitfield.BitField
func isEmpty(iter rlepluslazy.RunIterator) (bool, error) {
// Look for the first non-zero bit.
for iter.HasNext() {
r, err := iter.NextRun()
if err != nil {
return false, err
}
if r.Val {
return false, nil
}
}
return true, nil
}
// Checks whether bitfield `a` contains any bit that is set in bitfield `b`.
func BitFieldContainsAny(a, b BitField) (bool, error) {
aruns, err := a.RunIterator()
if err != nil {
return false, err
}
bruns, err := b.RunIterator()
if err != nil {
return false, err
}
// Take the intersection of the two bitfields.
combined, err := rlepluslazy.And(aruns, bruns)
if err != nil {
return false, err
}
// Look for the first non-zero bit.
empty, err := isEmpty(combined)
if err != nil {
return false, err
}
return !empty, nil
}
// Checks whether bitfield `a` contains all bits set in bitfield `b`.
func BitFieldContainsAll(a, b BitField) (bool, error) {
aruns, err := a.RunIterator()
if err != nil {
return false, err
}
bruns, err := b.RunIterator()
if err != nil {
return false, err
}
// Remove any elements in a from b. If b contains bits not in a, some
// bits will remain.
combined, err := rlepluslazy.Subtract(bruns, aruns)
if err != nil {
return false, err
}
return isEmpty(combined)
}