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OR logic si AND logic - never say never

Mi-am adus aminte de o experienta nefericita pe care am avuto la începutului anului cu operatorii logici.
Era nevoie să fac debug pe un OR logic intre un ulong si un int.
int sursa1;
ulong sursa2;
Init(sursa1,sursa2);
ulong stare=sursa2 | sursa1;
Din pacate nu puteam sa folosesc enum. Era o aplicație vechie, care a fost portata de cineva in C# si era plina de erori de compilare. Nimeni nu cunoștea exact care sunt stariile in care se poate ajunge variabila stare si ce înseamnă fiecare stare.
Prima problema pe care o aveam era ca linia de cod care facea OR logic, codul nu compila deloc din cauza ca cele doua date( sursa1 si sursa2) erau de tipuri diferite. Eroarea pe care o primeam era "Operator | cannot be applied to operands of type int and ulong.". Era normal sa avem aceasta eroare, deoarece sursa2 era strict pozitiva, in comparație cu sursa1 care era o variabila cu semn(+/-).
Nici o problema am zis:
ulong stare= sursa2 | (ulong) sursa1;
Codul a compilat, aveam un warning legat de modul in care se face casting-ul dar am zis ca e okay si am trecut mai departe. Dupa o zi sau doua am ajuns sa rulez aplicatia si surpriza, valoriile pe care le optineam in urma OR logic erau eronate. Obtineam niste valori care nu aveau nici o legatura cu valoriile pe care le asteptam.
Am stat cîteva ore bune pana să îmi dau seama ce se întîmpla. Problema apărea din modul in care se face CAST. Noi vrem să obținem un ulong din int. Dar conversia care se face nu este directa, de la int la ulong, asa cum poate ne-am astepta. Pășii pe care ii face .NET sunt:
int -> long -> ulong
Prima data int este convertit in long iar apoi in ulong. In momentul in care se face conversia la long valoarea pe care noi am asteptao se pierde in totalitate.
Solutia pe care am gasito, desi pare ciudata este:
ulong rezultat = sursa 2 | (ulong)(long) sursa1;
Ciudat nu? Eu zic ca e destul de ciudat. Cand lucrati cu OR logic sau AND logic, incercati sa evitati sa lucrati cu tipuri diferite de date. Recomandarea mea este sa evitati OR logic. Puteți folosii cu succes, enum-ul in acest caz, unde fiecare stare sa aibe o anumita valorea binara(FLAG).
Exemplu:
    [Flags]
enum FileType
{
None = 0x0,
Exe = 0x1,
Zip = 0x2,
Video = 0x4,
Sound = 0x8,
D3 = 0x10
}




Problema era ca rezultatul care era obtinut in urma acestui OR logic nu era cel asteptat.

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