Fix rate-position desync from repeated sonicSetPitch calls - #10
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adjustRate's wraparound arithmetic (oldRatePosition/newRatePosition) assumes both counters were accumulated under one consistent (oldSampleRate, newSampleRate) ratio -- processStreamInput computes that ratio as stream->rate * stream->pitch. sonicSetRate resets both counters to 0 because changing rate invalidates the ratio the counters were accumulated under; sonicSetPitch changes the exact same ratio but never got the same reset. Left to run, the counters drift further from what the (now-changed) ratio expects with every subsequent pitch change. Eventually the drifted counters overflow interpolate()'s position arithmetic, indexing sincTable far out of bounds -- confirmed via ASan: global-buffer-overflow in findSincCoefficient, called from interpolate, called from adjustRate. Fix: reset oldRatePosition/newRatePosition in sonicSetPitch too, mirroring sonicSetRate exactly. Adds tests/pitch_position_test.c with a deterministic repro (10 fixed pitch values, no randomness) -- verified crashing under ASan before this fix, clean after. Ported from waywardgeek/sonic#73, which fixes the same bug (also present here, byte-identical sonicSetPitch/sonicSetRate/adjustRate) upstream.
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Summary
Same bug, same fix as waywardgeek/sonic#73 — this repo's
sonicSetPitch/sonicSetRate/adjustRateare byte-identical to what those had upstream, so the fix ports directly.adjustRate's wraparound arithmetic (oldRatePosition/newRatePosition) assumes both counters were accumulated under one consistent(oldSampleRate, newSampleRate)ratio —processStreamInputcomputes that ratio asstream->rate * stream->pitch.sonicSetRateresets both counters to 0 because changing rate invalidates the ratio the counters were accumulated under;sonicSetPitchchanges the exact same ratio but never got the same reset.Left to run, the counters drift further from what the (now-changed) ratio expects with every subsequent pitch change. Eventually the drifted counters overflow
interpolate()'s position arithmetic, indexingsincTablefar out of bounds — confirmed via ASan: global-buffer-overflow infindSincCoefficient, called frominterpolate, called fromadjustRate.Fix
Reset
oldRatePosition/newRatePositioninsonicSetPitchtoo, mirroringsonicSetRateexactly.Adds
tests/pitch_position_test.cwith a deterministic repro (10 fixed pitch values, no randomness) — verified crashing under ASan before this fix, clean after.Test plan
cd tests && make runtests && ./runtests— passes, new test included-fsanitize=address,undefined— no finding from this path; only the separate, already-knownfindSincCoefficientfinding remains