On 02/09/2015 01:39 PM, Jan Vesely wrote:
> This is more consistent with the rest, and avoids potential undefined
> behavior (signed overflow) in drmRandom()
>
> Signed-off-by: Jan Vesely <jan.vesely@xxxxxxxxxxx>
> ---
> xf86drmRandom.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/xf86drmRandom.c b/xf86drmRandom.c
> index ecab9e2..a084b86 100644
> --- a/xf86drmRandom.c
> +++ b/xf86drmRandom.c
> @@ -98,7 +98,7 @@ typedef struct RandomState {
> unsigned long q; /* m div a */
> unsigned long r; /* m mod a */
> unsigned long check;
> - long seed;
> + unsigned long seed;
> } RandomState;
>
> #if RANDOM_MAIN
> @@ -147,13 +147,13 @@ int drmRandomDestroy(void *state)
> unsigned long drmRandom(void *state)
> {
> RandomState *s = (RandomState *)state;
> - long hi;
> - long lo;
> + unsigned long hi;
> + unsigned long lo;
>
> hi = s->seed / s->q;
> lo = s->seed % s->q;
> s->seed = s->a * lo - s->r * hi;
> - if (s->seed <= 0) s->seed += s->m;
> + if ((s->a * lo) <= (s->r * hi)) s->seed += s->m;
This seems like an unrelated change.
>
> return s->seed;
> }
> @@ -166,7 +166,7 @@ double drmRandomDouble(void *state)
> }
>
> #if RANDOM_MAIN
> -static void check_period(long seed)
> +static void check_period(unsigned long seed)
> {
> unsigned long count = 0;
> unsigned long initial;
> @@ -178,7 +178,7 @@ static void check_period(long seed)
> while (initial != drmRandom(state)) {
> if (!++count) break;
> }
> - printf("With seed of %10ld, period = %10lu (0x%08lx)\n",
> + printf("With seed of %10lu, period = %10lu (0x%08lx)\n",
> seed, count, count);
> drmRandomDestroy(state);
> }
> @@ -195,7 +195,7 @@ int main(void)
> }
> printf("After 10000 iterations: %lu (%lu expected): %s\n",
> rand, state->check,
> - rand - state->check ? "*INCORRECT*" : "CORRECT");
> + rand != state->check ? "*INCORRECT*" : "CORRECT");
So does this.
> drmRandomDestroy(state);
>
> printf("Checking periods...\n");
>
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