76 lines
1.8 KiB
Dart
76 lines
1.8 KiB
Dart
// ignore_for_file: avoid-unsafe-collection-methods
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import 'dart:async';
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class CollectionUtil {
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const CollectionUtil();
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static int compareToNullable<T extends Comparable>(T? a, T? b) {
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if (a == null) {
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return 1;
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}
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if (b == null) {
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return -1;
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}
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return a.compareTo(b);
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}
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/// Find the difference between the two lists [first] and [second]
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/// Results are passed as callbacks back to the caller during the comparison
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static FutureOr<bool> diffLists<T>(
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List<T> first,
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List<T> second, {
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required int Function(T a, T b) compare,
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required FutureOr<bool> Function(T a, T b) both,
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required FutureOr<void> Function(T a) onlyFirst,
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required FutureOr<void> Function(T b) onlySecond,
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}) async {
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first.sort(compare);
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first.uniqueConsecutive(compare);
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second.sort(compare);
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second.uniqueConsecutive(compare);
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bool diff = false;
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int i = 0, j = 0;
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for (; i < first.length && j < second.length;) {
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final int order = compare(first[i], second[j]);
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if (order == 0) {
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diff |= await both(first[i++], second[j++]);
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} else if (order < 0) {
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await onlyFirst(first[i++]);
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diff = true;
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} else if (order > 0) {
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await onlySecond(second[j++]);
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diff = true;
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}
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}
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diff |= i < first.length || j < second.length;
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for (; i < first.length; i++) {
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onlyFirst(first[i]);
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}
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for (; j < second.length; j++) {
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onlySecond(second[j]);
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}
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return diff;
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}
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}
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extension _ListExtension<T> on List<T> {
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List<T> uniqueConsecutive(int Function(T a, T b) compare) {
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int i = 1, j = 1;
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for (; i < length; i++) {
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if (compare(this[i - 1], this[i]) != 0) {
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if (i != j) {
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this[j] = this[i];
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}
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j++;
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}
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}
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length = length == 0 ? 0 : j;
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return this;
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}
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}
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