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Prevent unnecessary memory copying in nvwave #19791

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Prevent unnecessary memory copying in nvwave #19791

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93c17de
Prevent unnecessary memory copying in nvwave
gexgd0419 Mar 16, 2026
01154ea
Separate casting to another line
gexgd0419 Mar 16, 2026
0004840
Merge branch 'nvaccess:beta' into beta
gexgd0419 Mar 16, 2026
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10 changes: 6 additions & 4 deletions source/nvwave.py
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,8 @@
c_void_p,
CFUNCTYPE,
c_float,
string_at,
c_char_p,
cast,
)
from comtypes import HRESULT
from comtypes.hresult import E_INVALIDARG
Expand Down Expand Up @@ -339,12 +340,13 @@ def feed(
# turn off trimming temporarily.
if self._purpose is AudioPurpose.SPEECH and self._isLeadingSilenceInserted:
self.startTrimmingLeadingSilence(False)
if not isinstance(data, bytes):
data = string_at(data, size)
# wasPlay_feed requires c_char_p, so cast data to c_char_p before calling.
# Casting bytes to c_char_p is also fine, as long as the original data is not released.
dataptr = cast(data, c_char_p)
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@SaschaCowley SaschaCowley Mar 17, 2026

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Is there a reason not to perform this cast directly in the call to wasapi.wasPlay_feed?

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@gexgd0419 gexgd0419 Mar 17, 2026

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See comment from @LeonarddeR :

I think it's better to keep the cast out of the wasPlay_feed call, otherwise it is hard to track issues caused by cast failures.

try:
wasapi.wasPlay_feed(
self._player,
data,
dataptr,
size if size is not None else len(data),
byref(feedId) if onDone else None,
)
Expand Down
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