Clamp float samples to [-1, 1] before scaling to short - #5
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addFloatSamplesToInputBuffer multiplied each input float by 32767.0f and assigned the result directly into a short, with no range check. sonic.h documents that values must be in [-1, 1], but nothing enforced it, and converting an out-of-range float to short is undefined behavior in C, not just lossy truncation. Every other input path in this file (volume, speed, pitch, rate, sample rate, channel count, and scaleSamples' int16 output) clamps defensively instead of trusting the caller; this path was the exception. Clamp with the existing CLAMP macro before the multiply. Adds sonicTestFloatSampleClamping to tests/input_clamping_test.c, writing out-of-range floats and checking the output stays within [-32767, 32767] via the bit-exact passthrough path that default stream settings take. Ported from waywardgeek/sonic#63, which fixes the same bug (also present here, byte-identical addFloatSamplesToInputBuffer) upstream.
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Summary
addFloatSamplesToInputBuffermultiplied each input float by32767.0fand assigned the result directly into ashort, with no range check.sonic.hdocuments that values must be in[-1, 1], but nothing enforced it, and converting an out-of-range float toshortis undefined behavior in C, not just lossy truncation. Every other input path in this file (volume, speed, pitch, rate, sample rate, channel count, andscaleSamples' int16 output) clamps defensively instead of trusting the caller; this path was the exception.Clamps with the existing
CLAMPmacro before the multiply.Same bug, same fix as waywardgeek/sonic#63 — this repo's
addFloatSamplesToInputBufferis byte-identical to what that file had upstream, so the fix ports directly.Test plan
cd tests && make runtests && ./runtests— passes, addssonicTestFloatSampleClampingtotests/input_clamping_test.c-fsanitize=address,undefined— no finding from this path; only the separate, already-knownfindSincCoefficientleft-shift issue remains