code which is not thread-safe in the sense that the
rdft_init method can only be run in a single-threaded.
Currently, inside WebRTC multiple instances of the audio-
processing module are set up which means that the init
method may be run concurrently.
In order to avoid having to protect the init method with
a lock to ensure single-threaded behavior that, this CL
places the FFT functionality inside a class so that there
is no global component of the FFT functionality.
Note that:
1) The nonstandard header for the ooura_fft.cc was copied
from the aec_rdft.cc header, and augmented with a
description of the changes introduced in this CL.
2) The clang warnings for the ooura_fft_sse2.cc,
ooura_fft_neon.cc and ooura_fft_mips.cc were not
addressed as this code was kept as it was before this CL
3) Clang-format was run on all files apart from
ooura_fft_mips.cc (as that would change the format of
the inline assempbly code).
Adding bypass of presubmit to avoid code style and header errors caused by the fact that files with legacy code are being renamed.
NOPRESUBMIT=true
BUG=chromium:638583
Review-Url: https://codereview.webrtc.org/2348213002
Cr-Commit-Position: refs/heads/master@{#14554}
