68 lines
1.9 KiB
Zig
68 lines
1.9 KiB
Zig
const std = @import("std");
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const builtin = @import("builtin");
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const symbol = @import("../c.zig").symbol;
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comptime {
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if (builtin.target.isMuslLibC() or builtin.target.isWasiLibC()) {
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symbol(&insque, "insque");
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symbol(&remque, "remque");
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}
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}
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const Node = extern struct {
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next: ?*Node,
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prev: ?*Node,
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};
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fn insque(element: *anyopaque, pred: ?*anyopaque) callconv(.c) void {
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const e: *Node = @ptrCast(@alignCast(element));
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if (pred) |p_ptr| {
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const p: *Node = @ptrCast(@alignCast(p_ptr));
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e.next = p.next;
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e.prev = p;
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p.next = e;
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if (e.next) |next| {
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next.prev = e;
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}
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} else {
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e.next = null;
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e.prev = null;
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}
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}
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fn remque(element: *anyopaque) callconv(.c) void {
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const e: *Node = @ptrCast(@alignCast(element));
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if (e.next) |next| next.prev = e.prev;
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if (e.prev) |prev| prev.next = e.next;
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}
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test "insque and remque" {
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var first = Node{ .next = null, .prev = null };
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var second = Node{ .next = null, .prev = null };
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var third = Node{ .next = null, .prev = null };
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insque(&first, null);
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try std.testing.expectEqual(@as(?*Node, null), first.next);
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try std.testing.expectEqual(@as(?*Node, null), first.prev);
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insque(&second, &first);
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try std.testing.expectEqual(@as(?*Node, &second), first.next);
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try std.testing.expectEqual(@as(?*Node, &first), second.prev);
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insque(&third, &first);
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try std.testing.expectEqual(@as(?*Node, &third), first.next);
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try std.testing.expectEqual(@as(?*Node, &second), third.next);
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try std.testing.expectEqual(@as(?*Node, &first), third.prev);
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try std.testing.expectEqual(@as(?*Node, &third), second.prev);
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remque(&third);
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try std.testing.expectEqual(@as(?*Node, &second), first.next);
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try std.testing.expectEqual(@as(?*Node, &first), second.prev);
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remque(&second);
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try std.testing.expectEqual(@as(?*Node, null), first.next);
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}
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