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'use strict';
function getCIDRSuffix(mask, protocol = 'ipv4') {
const isV6 = protocol === 'ipv6';
const bitsString = mask
.split(isV6 ? ':' : '.')
.filter((v) => !!v)
.map((v) => pad(parseInt(v, isV6 ? 16 : 10).toString(2), isV6))
.join('');
if (isValidMask(bitsString)) {
return countOnes(bitsString);
} else {
return null;
}
}
function pad(binaryString, isV6) {
const groupLength = isV6 ? 16 : 8;
const binLen = binaryString.length;
return binLen < groupLength ?
`${'0'.repeat(groupLength - binLen)}${binaryString}` : binaryString;
}
function isValidMask(bitsString) {
const firstIndexOfZero = bitsString.indexOf(0);
const lastIndexOfOne = bitsString.lastIndexOf(1);
return firstIndexOfZero < 0 || firstIndexOfZero > lastIndexOfOne;
}
function countOnes(bitsString) {
return bitsString
.split('')
.reduce((acc, bit) => acc += parseInt(bit, 10), 0);
}
module.exports = {
getCIDRSuffix
};