import * as v6 from './constants';
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export function groupPossibilities(possibilities: string[]): string {
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return `(${possibilities.join('|')})`;
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}
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export function padGroup(group: string): string {
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if (group.length < 4) {
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return `0{0,${4 - group.length}}${group}`;
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}
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return group;
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}
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export const ADDRESS_BOUNDARY = '[^A-Fa-f0-9:]';
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export function simpleRegularExpression(groups: string[]) {
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const zeroIndexes: number[] = [];
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groups.forEach((group, i) => {
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const groupInteger = parseInt(group, 16);
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if (groupInteger === 0) {
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zeroIndexes.push(i);
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}
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});
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// You can technically elide a single 0, this creates the regular expressions
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// to match that eventuality
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const possibilities = zeroIndexes.map((zeroIndex) =>
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groups
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.map((group, i) => {
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if (i === zeroIndex) {
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const elision = i === 0 || i === v6.GROUPS - 1 ? ':' : '';
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return groupPossibilities([padGroup(group), elision]);
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}
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return padGroup(group);
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})
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.join(':'),
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);
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// The simplest case
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possibilities.push(groups.map(padGroup).join(':'));
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return groupPossibilities(possibilities);
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}
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export function possibleElisions(
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elidedGroups: number,
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moreLeft?: boolean,
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moreRight?: boolean,
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): string {
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const left = moreLeft ? '' : ':';
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const right = moreRight ? '' : ':';
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const possibilities = [];
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// 1. elision of everything (::)
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if (!moreLeft && !moreRight) {
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possibilities.push('::');
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}
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// 2. complete elision of the middle
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if (moreLeft && moreRight) {
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possibilities.push('');
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}
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if ((moreRight && !moreLeft) || (!moreRight && moreLeft)) {
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// 3. complete elision of one side
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possibilities.push(':');
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}
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// 4. elision from the left side
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possibilities.push(`${left}(:0{1,4}){1,${elidedGroups - 1}}`);
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// 5. elision from the right side
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possibilities.push(`(0{1,4}:){1,${elidedGroups - 1}}${right}`);
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// 6. no elision
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possibilities.push(`(0{1,4}:){${elidedGroups - 1}}0{1,4}`);
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// 7. elision (including sloppy elision) from the middle
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for (let groups = 1; groups < elidedGroups - 1; groups++) {
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for (let position = 1; position < elidedGroups - groups; position++) {
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possibilities.push(
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`(0{1,4}:){${position}}:(0{1,4}:){${elidedGroups - position - groups - 1}}0{1,4}`,
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);
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}
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}
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return groupPossibilities(possibilities);
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}
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