Function reverseIterator [src]

Iterates over a slice in reverse.

Prototype

pub fn reverseIterator(slice: anytype) ReverseIterator(@TypeOf(slice))

Example

 test reverseIterator {
    {
        var it = reverseIterator("abc");
        try testing.expectEqual(@as(?u8, 'c'), it.next());
        try testing.expectEqual(@as(?u8, 'b'), it.next());
        try testing.expectEqual(@as(?u8, 'a'), it.next());
        try testing.expectEqual(@as(?u8, null), it.next());
    }
    {
        var array = [2]i32{ 3, 7 };
        const slice: []const i32 = &array;
        var it = reverseIterator(slice);
        try testing.expectEqual(@as(?i32, 7), it.next());
        try testing.expectEqual(@as(?i32, 3), it.next());
        try testing.expectEqual(@as(?i32, null), it.next());

        it = reverseIterator(slice);
        try testing.expect(*const i32 == @TypeOf(it.nextPtr().?));
        try testing.expectEqual(@as(?i32, 7), it.nextPtr().?.*);
        try testing.expectEqual(@as(?i32, 3), it.nextPtr().?.*);
        try testing.expectEqual(@as(?*const i32, null), it.nextPtr());

        const mut_slice: []i32 = &array;
        var mut_it = reverseIterator(mut_slice);
        mut_it.nextPtr().?.* += 1;
        mut_it.nextPtr().?.* += 2;
        try testing.expectEqual([2]i32{ 5, 8 }, array);
    }
    {
        var array = [2]i32{ 3, 7 };
        const ptr_to_array: *const [2]i32 = &array;
        var it = reverseIterator(ptr_to_array);
        try testing.expectEqual(@as(?i32, 7), it.next());
        try testing.expectEqual(@as(?i32, 3), it.next());
        try testing.expectEqual(@as(?i32, null), it.next());

        it = reverseIterator(ptr_to_array);
        try testing.expect(*const i32 == @TypeOf(it.nextPtr().?));
        try testing.expectEqual(@as(?i32, 7), it.nextPtr().?.*);
        try testing.expectEqual(@as(?i32, 3), it.nextPtr().?.*);
        try testing.expectEqual(@as(?*const i32, null), it.nextPtr());

        const mut_ptr_to_array: *[2]i32 = &array;
        var mut_it = reverseIterator(mut_ptr_to_array);
        mut_it.nextPtr().?.* += 1;
        mut_it.nextPtr().?.* += 2;
        try testing.expectEqual([2]i32{ 5, 8 }, array);
    }
}

Source

  pub fn reverseIterator(slice: anytype) ReverseIterator(@TypeOf(slice)) {
    return .{ .ptr = slice.ptr, .index = slice.len };
}  