Method SetBitAtIndex

postgres/parser/utils/bitarray.go:574–589

SetBitAtIndex returns the BitArray with an updated bit at a given index.

(index, toSet int)

// SetBitAtIndex returns the BitArray with an updated bit at a given index.
func (d BitArray) SetBitAtIndex(index, toSet int) (BitArray, error) {
	res := d.Clone()
	// Check whether index asked is inside BitArray.
	if index < 0 || uint(index) >= res.BitLen() {
		err := fmt.Errorf("SetBitAtIndex: bit index %d out of valid range (0..%d)", index, int(res.BitLen())-1)
		return BitArray{}, pgerror.WithCandidateCode(err, pgcode.ArraySubscript)
	}
	// To update bit at the given index, we have to determine the
	// position within words array, i.e. index/numBitsPerWord after
	// that updated the bit at residual index.
	// Forcefully making bit at the index to 0.
	res.words[index/numBitsPerWord] &= ^(word(1) << (numBitsPerWord - 1 - uint(index)%numBitsPerWord))
	// Updating value at the index to toSet.
	res.words[index/numBitsPerWord] |= word(toSet) << (numBitsPerWord - 1 - uint(index)%numBitsPerWord)
	return res, nil
}