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COMMON: Fix divide by zero in getRandomNumber()

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Calling RandomSource::getRandomNumber() results in divide by zero
exception when called with max = 4294967295 as max + 1 overflows to zero
and the subsequent modulus operation causes the exception.

Certain game saves in Bladerunner trigger this.
This commit is contained in:
Aapo Vienamo 2021-08-02 00:32:36 +03:00 committed by Antoniou Athanasios
parent 9cda2f54d6
commit de1338787f
1 changed files with 5 additions and 0 deletions
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5
common/random.cpp
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@ -20,6 +20,8 @@
*
*/
#include <climits>
#include "common/random.h"
#include "common/system.h"
#include "gui/EventRecorder.h"
@ -46,6 +48,9 @@ void RandomSource::setSeed(uint32 seed) {
uint RandomSource::getRandomNumber(uint max) {
_randSeed = 0xDEADBF03 * (_randSeed + 1);
_randSeed = (_randSeed >> 13) | (_randSeed << 19);
if (max == UINT_MAX)
return _randSeed;
return _randSeed % (max + 1);
}