v2 / vlib / v / tests / pointers / offsetof_test.v
43 lines · 38 sloc · 998 bytes · 6488041a749df9762348d019c4223908c476f2e2
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1import math.complex


2


3struct Cat {


4    name  string


5    breed string


6    age   int


7}


8


9type Feline = Cat


10


11fn test_offsetof() {


12    cat := Cat{


13        name:  'Cthulhu'


14        breed: 'Great Old One'


15        age:   2147483647


16    }


17    unsafe {


18        assert *(&string(&u8(&cat) + __offsetof(Cat, name))) == 'Cthulhu'


19        assert *(&string(&u8(&cat) + __offsetof(Cat, breed))) == 'Great Old One'


20        assert *(&int(&u8(&cat) + __offsetof(Cat, age))) == 2147483647


21    }


22}


23


24fn test_offsetof_struct_from_another_module() {


25    num := complex.Complex{1.0, 1.0}


26    unsafe {


27        assert *(&f64(&u8(&num) + __offsetof(complex.Complex, re))) == 1.0


28        assert *(&f64(&u8(&num) + __offsetof(complex.Complex, im))) == 1.0


29    }


30}


31


32fn test_offsetof_alias() {


33    fel := Feline{


34        name:  'Cthulhu'


35        breed: 'Great Old One'


36        age:   2147483647


37    }


38    unsafe {


39        assert *(&string(&u8(&fel) + __offsetof(Feline, name))) == 'Cthulhu'


40        assert *(&string(&u8(&fel) + __offsetof(Feline, breed))) == 'Great Old One'


41        assert *(&int(&u8(&fel) + __offsetof(Feline, age))) == 2147483647


42    }


43}


44