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Add natord.zig
authored by
Danylo Kondratiev
and committed by
Tangled
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+347
src/natord.zig
+347
src/natord.zig
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//! This file is a port of C implementaion that can be found here
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//! https://github.com/sourcefrog/natsort.
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const std = @import("std");
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const isSpace = std.ascii.isWhitespace;
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const isDigit = std.ascii.isDigit;
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const Order = std.math.Order;
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const testing = std.testing;
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pub fn order(a: []const u8, b: []const u8) Order {
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return natOrder(a, b, false);
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}
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pub fn orderIgnoreCase(a: []const u8, b: []const u8) Order {
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return natOrder(a, b, true);
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}
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fn natOrder(a: []const u8, b: []const u8, comptime fold_case: bool) Order {
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var ai: usize = 0;
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var bi: usize = 0;
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while (true) : ({
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ai += 1;
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bi += 1;
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}) {
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var ca = if (ai == a.len) 0 else a[ai];
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var cb = if (bi == b.len) 0 else b[bi];
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while (isSpace(ca)) {
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ai += 1;
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ca = if (ai == a.len) 0 else a[ai];
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}
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while (isSpace(cb)) {
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bi += 1;
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cb = if (bi == b.len) 0 else b[bi];
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}
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if (isDigit(ca) and isDigit(cb)) {
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const fractional = ca == '0' or cb == '0';
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if (fractional) {
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const result = compareLeft(a[ai..], b[bi..]);
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if (result != .eq) return result;
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} else {
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const result = compareRight(a[ai..], b[bi..]);
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if (result != .eq) return result;
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}
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}
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if (ca == 0 and cb == 0) {
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return .eq;
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}
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if (fold_case) {
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ca = std.ascii.toUpper(ca);
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cb = std.ascii.toUpper(cb);
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}
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if (ca < cb) {
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return .lt;
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}
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if (ca > cb) {
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return .gt;
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}
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}
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}
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fn compareLeft(a: []const u8, b: []const u8) Order {
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var i: usize = 0;
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while (true) : (i += 1) {
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const ca = if (i == a.len) 0 else a[i];
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const cb = if (i == b.len) 0 else b[i];
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if (!isDigit(ca) and !isDigit(cb)) {
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return .eq;
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}
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if (!isDigit(ca)) {
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return .lt;
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}
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if (!isDigit(cb)) {
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return .gt;
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}
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if (ca < cb) {
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return .lt;
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}
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if (ca > cb) {
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return .gt;
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}
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}
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return .eq;
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}
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fn compareRight(a: []const u8, b: []const u8) Order {
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var bias = Order.eq;
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var i: usize = 0;
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while (true) : (i += 1) {
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const ca = if (i == a.len) 0 else a[i];
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const cb = if (i == b.len) 0 else b[i];
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if (!isDigit(ca) and !isDigit(cb)) {
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return bias;
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}
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if (!isDigit(ca)) {
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return .lt;
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}
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if (!isDigit(cb)) {
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return .gt;
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}
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if (ca < cb) {
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if (bias != .eq) {
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bias = .lt;
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}
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} else if (ca > cb) {
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if (bias != .eq) {
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bias = .gt;
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}
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} else if (ca == 0 and cb == 0) {
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return bias;
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}
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}
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return .eq;
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}
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const SortContext = struct {
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ignore_case: bool = false,
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reverse: bool = false,
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fn compare(self: @This(), a: []const u8, b: []const u8) bool {
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const ord: std.math.Order = if (self.reverse) .gt else .lt;
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if (self.ignore_case) {
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return orderIgnoreCase(a, b) == ord;
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} else {
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return order(a, b) == ord;
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}
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}
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};
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test "lt" {
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try testing.expectEqual(Order.lt, order("a_1", "a_10"));
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}
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test "eq" {
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try testing.expectEqual(Order.eq, order("a_1", "a_1"));
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}
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test "gt" {
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try testing.expectEqual(Order.gt, order("a_10", "a_1"));
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}
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fn sortAndAssert(context: SortContext, input: [][]const u8, want: []const []const u8) !void {
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std.sort.pdq([]const u8, input, context, SortContext.compare);
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for (input, want) |actual, expected| {
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try testing.expectEqualStrings(expected, actual);
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}
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}
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test "sorting" {
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const context = SortContext{};
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var items = [_][]const u8{
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"item100",
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"item10",
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"item1",
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};
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const want = [_][]const u8{
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"item1",
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"item10",
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"item100",
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};
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try sortAndAssert(context, &items, &want);
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}
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test "sorting 2" {
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const context = SortContext{};
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var items = [_][]const u8{
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"item_30",
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"item_15",
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"item_3",
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"item_2",
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"item_10",
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};
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const want = [_][]const u8{
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"item_2",
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"item_3",
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"item_10",
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"item_15",
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"item_30",
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};
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try sortAndAssert(context, &items, &want);
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}
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test "leading zeros" {
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const context = SortContext{};
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var items = [_][]const u8{
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"item100",
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"item999",
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"item001",
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"item010",
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"item000",
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};
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const want = [_][]const u8{
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"item000",
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"item001",
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"item010",
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"item100",
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"item999",
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};
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try sortAndAssert(context, &items, &want);
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}
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test "dates" {
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const context = SortContext{};
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var items = [_][]const u8{
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"2000-1-10",
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"2000-1-2",
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"1999-12-25",
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"2000-3-23",
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"1999-3-3",
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};
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const want = [_][]const u8{
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"1999-3-3",
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"1999-12-25",
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"2000-1-2",
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"2000-1-10",
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"2000-3-23",
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};
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try sortAndAssert(context, &items, &want);
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}
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test "fractions" {
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const context = SortContext{};
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var items = [_][]const u8{
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"Fractional release numbers",
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"1.011.02",
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"1.010.12",
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"1.009.02",
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"1.009.20",
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"1.009.10",
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"1.002.08",
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"1.002.03",
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"1.002.01",
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};
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const want = [_][]const u8{
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"1.002.01",
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"1.002.03",
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"1.002.08",
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"1.009.02",
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"1.009.10",
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"1.009.20",
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"1.010.12",
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"1.011.02",
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"Fractional release numbers",
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};
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try sortAndAssert(context, &items, &want);
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}
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test "words" {
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const context = SortContext{};
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var items = [_][]const u8{
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"fred",
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"pic2",
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"pic100a",
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"pic120",
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"pic121",
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"jane",
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"tom",
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"pic02a",
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"pic3",
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"pic4",
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"1-20",
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"pic100",
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"pic02000",
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"10-20",
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"1-02",
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"1-2",
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"x2-y7",
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"x8-y8",
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"x2-y08",
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"x2-g8",
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"pic01",
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"pic02",
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"pic 6",
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"pic 7",
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"pic 5",
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"pic05",
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"pic 5 ",
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"pic 5 something",
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"pic 4 else",
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};
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const want = [_][]const u8{
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"1-02",
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"1-2",
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"1-20",
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"10-20",
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"fred",
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"jane",
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"pic01",
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"pic02",
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"pic02a",
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"pic02000",
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"pic05",
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"pic2",
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"pic3",
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"pic4",
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"pic 4 else",
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"pic 5",
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"pic 5 ",
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"pic 5 something",
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"pic 6",
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"pic 7",
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"pic100",
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"pic100a",
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"pic120",
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"pic121",
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"tom",
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"x2-g8",
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"x2-y08",
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"x2-y7",
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"x8-y8",
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};
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try sortAndAssert(context, &items, &want);
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}
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test "fuzz" {
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const Context = struct {
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fn testOne(context: @This(), input: []const u8) anyerror!void {
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_ = context;
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const a = input[0..(input.len / 2)];
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const b = input[(input.len / 2)..];
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_ = order(a, b);
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}
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};
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try std.testing.fuzz(Context{}, Context.testOne, .{});
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}