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