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Fix RandomPCG::random(int, int) overflow bug

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- Use int64_t for subtraction before converting to uint32_t
- Don't add one to uint32_t max value for rand() bounds
This commit is contained in:
aaronp64
2024-12-05 14:31:05 -05:00
parent 6a6a1168a5
commit 1089f61868
1 changed files with 11 additions and 1 deletions
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12
core/math/random_pcg.cpp
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@@ -80,5 +80,15 @@ int RandomPCG::random(int p_from, int p_to) {
if (p_from == p_to) {
return p_from;
}
return int(rand(uint32_t(Math::abs(p_from - p_to)) + 1U)) + MIN(p_from, p_to);
int64_t min = MIN(p_from, p_to);
int64_t max = MAX(p_from, p_to);
uint32_t diff = static_cast<uint32_t>(max - min);
if (diff == UINT32_MAX) {
// Can't add 1 to max uint32_t value for inclusive range, so call rand without passing bounds.
return static_cast<int64_t>(rand()) + min;
}
return static_cast<int64_t>(rand(diff + 1U)) + min;
}