[openal] Fix AL_SAMPLE_OFFSET and AL_BYTE_OFFSET with buffer 0 - #27420
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[openal] Fix AL_SAMPLE_OFFSET and AL_BYTE_OFFSET with buffer 0#27420sbc100 wants to merge 1 commit into
sbc100 wants to merge 1 commit into
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When `AL_SAMPLE_OFFSET` or `AL_BYTE_OFFSET` is set on a source, the
library looks up the format of the queued audio data to convert the
offset into seconds for `sourceSeek`.
Previously, this iteration used `for (var bufId in src.bufQueue)` and
checked `if (bufId)`. Because `for..in` iterates over array index
strings (`"0"`, `"1"`, etc.), `bufId` received `"0"` on the first
iteration. In JavaScript, non-empty strings are truthy, so `if (bufId)`
evaluated `if ("0")`, which is always true.
As a result, the loop never skipped index 0. If `src.bufQueue[0]`
happened to be the default placeholder dummy zero buffer (which has
`frequency: 0`), it would read `frequency = 0` and cause a division by
zero (`value /= 0`), failing range validation with `AL_INVALID_VALUE`.
This change replaces both loops in `src/lib/libopenal.js` with
`for (var buf of src.bufQueue)` and checks `if (buf.id !== 0)`. A new
test case is added to `test/openal/test_openal_error.c` to verify this
behavior.
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When
AL_SAMPLE_OFFSETorAL_BYTE_OFFSETis set on a source, the library looks up the format of the queued audio data to convert the offset into seconds forsourceSeek.Previously, this iteration used
for (var bufId in src.bufQueue)and checkedif (bufId). Becausefor..initerates over array index strings ("0","1", etc.),bufIdreceived"0"on the first iteration. In JavaScript, non-empty strings are truthy, soif (bufId)evaluatedif ("0"), which is always true.As a result, the loop never skipped index 0. If
src.bufQueue[0]happened to be the default placeholder dummy zero buffer (which hasfrequency: 0), it would readfrequency = 0and cause a division by zero (value /= 0), failing range validation withAL_INVALID_VALUE.This change replaces both loops in
src/lib/libopenal.jswithfor (var buf of src.bufQueue)and checksif (buf.id !== 0). A new test case is added totest/openal/test_openal_error.cto verify this behavior.The original bug was introduced in fcf8d12.
It seems that there was an attempt to fix this in #10466 but I think this code always yield true both before and after this change because "0" string is truthy.