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Fix a GCC warning due to unsigned substraction

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Given

    unsigned int reqRate, setRate, deviation;

then 

    setRate - reqRate

is also an unsigned int - the code works "by chance" as `abs` casts that to an int which overflows and is technically undefined behaviour, for instance for setRate = 44100 and reqRate = 48000.

Thus cast them to int when computing the absolute value to ensure no UB.
This commit is contained in:
Jean-Michaël Celerier 2020-12-21 19:22:16 +01:00 • committed by Phil Burk
commit a7bda88e6b
1 changed files with 1 additions and 1 deletions
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2
src/hostapi/alsa/pa_linux_alsa.c
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@ -3204,7 +3204,7 @@ static int SetApproximateSampleRate( snd_pcm_t *pcm, snd_pcm_hw_params_t *hwPara
ENSURE_( alsa_snd_pcm_hw_params_set_rate_near( pcm, hwParams, &setRate, NULL ), paUnanticipatedHostError ); ENSURE_( alsa_snd_pcm_hw_params_set_rate_near( pcm, hwParams, &setRate, NULL ), paUnanticipatedHostError );
/* The value actually set will be put in 'setRate' (may be way off); check the deviation as a proportion /* The value actually set will be put in 'setRate' (may be way off); check the deviation as a proportion
* of the requested-rate with reference to the max-deviate-ratio (larger values allow less deviation) */ * of the requested-rate with reference to the max-deviate-ratio (larger values allow less deviation) */
deviation = abs( setRate - reqRate ); deviation = abs( (int)setRate - (int)reqRate );
if( deviation > 0 && deviation * RATE_MAX_DEVIATE_RATIO > reqRate ) if( deviation > 0 && deviation * RATE_MAX_DEVIATE_RATIO > reqRate )
result = paInvalidSampleRate; result = paInvalidSampleRate;