mirror of https://github.com/libsdl-org/SDL
Added check for n<0 in SDL_rand_n()
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@ -67,6 +67,14 @@ Sint32 SDL_rand_n(Sint32 n)
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// fixed point number. Multiply by the 31.0 bit n to get a 31.32 bit
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// result. Shift right by 32 to get the 31 bit integer that we want.
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if (n < 0) {
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// The algorithm looks like it works for numbers < 0 but it has an
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// infintesimal chance of returning a value out of range.
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// Returning -SDL_rand_n(abs(n)) blows up at INT_MIN instead.
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// It's easier to just say no.
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return 0;
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}
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// On 32-bit arch, the compiler will optimize to a single 32-bit multiply
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Uint64 val = (Uint64)SDL_rand_bits() * n;
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return (Sint32)(val >> 32);
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