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52 lines
1.2 KiB
C
52 lines
1.2 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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/*
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* This file contains the function WebRtcSpl_ComplexBitReverse().
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* The description header can be found in signal_processing_library.h
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*
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*/
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#include "signal_processing_library.h"
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void WebRtcSpl_ComplexBitReverse(WebRtc_Word16 frfi[], int stages)
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{
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int mr, nn, n, l, m;
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WebRtc_Word16 tr, ti;
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n = 1 << stages;
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mr = 0;
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nn = n - 1;
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// decimation in time - re-order data
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for (m = 1; m <= nn; ++m)
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{
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l = n;
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do
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{
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l >>= 1;
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} while (mr + l > nn);
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mr = (mr & (l - 1)) + l;
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if (mr <= m)
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continue;
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tr = frfi[2 * m];
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frfi[2 * m] = frfi[2 * mr];
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frfi[2 * mr] = tr;
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ti = frfi[2 * m + 1];
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frfi[2 * m + 1] = frfi[2 * mr + 1];
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frfi[2 * mr + 1] = ti;
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}
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}
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