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b943c31fd8
Including C headers inside of `extern "C"` breaks use from C++. Hoist the includes of standard C headers above the block so we don't try to mangle the stdlib. I initially tried to scope this with a targeted change but it's too hard to do correctly that way. This way, we avoid whack-a-mole. Firefox is working around this in their e21461b7b8b39cc31ba53c47d4f6f310c673ff2f commit. Bug: https://bugzilla.mozilla.org/1953080
56 lines
1 KiB
C
56 lines
1 KiB
C
/* Hilbert function */
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/* SPDX-FileCopyrightText: Copyright © 2021 Wim Taymans */
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/* SPDX-License-Identifier: MIT */
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#ifndef HILBERT_H
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#define HILBERT_H
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#include <errno.h>
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#include <stddef.h>
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#include <math.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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static inline void blackman_window(float *taps, int n_taps)
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{
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int n;
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for (n = 0; n < n_taps; n++) {
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float w = 2.0f * (float)M_PI * n / (n_taps-1);
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taps[n] = 0.3635819f - 0.4891775f * cosf(w)
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+ 0.1365995f * cosf(2 * w) - 0.0106411f * cosf(3 * w);
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}
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}
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static inline int hilbert_generate(float *taps, int n_taps)
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{
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int i;
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if ((n_taps & 1) == 0)
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return -EINVAL;
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for (i = 0; i < n_taps; i++) {
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int k = -(n_taps / 2) + i;
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if (k & 1) {
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float pk = (float)M_PI * k;
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taps[i] *= (1.0f - cosf(pk)) / pk;
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} else {
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taps[i] = 0.0f;
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}
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}
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return 0;
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}
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static inline void reverse_taps(float *taps, int n_taps)
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{
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int i;
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for (i = 0; i < n_taps/2; i++)
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SPA_SWAP(taps[i], taps[n_taps-1-i]);
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}
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif /* HILBERT_H */
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