53 lines
1.5 KiB
C
53 lines
1.5 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 implementations of the randomization functions
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* WebRtcSpl_IncreaseSeed()
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* WebRtcSpl_RandU()
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* WebRtcSpl_RandN()
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* WebRtcSpl_RandUArray()
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*
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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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WebRtc_UWord32 WebRtcSpl_IncreaseSeed(WebRtc_UWord32 *seed)
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{
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seed[0] = (seed[0] * ((WebRtc_Word32)69069) + 1) & (WEBRTC_SPL_MAX_SEED_USED - 1);
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return seed[0];
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}
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WebRtc_Word16 WebRtcSpl_RandU(WebRtc_UWord32 *seed)
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{
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return (WebRtc_Word16)(WebRtcSpl_IncreaseSeed(seed) >> 16);
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}
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WebRtc_Word16 WebRtcSpl_RandN(WebRtc_UWord32 *seed)
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{
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return WebRtcSpl_kRandNTable[WebRtcSpl_IncreaseSeed(seed) >> 23];
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}
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// Creates an array of uniformly distributed variables
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WebRtc_Word16 WebRtcSpl_RandUArray(WebRtc_Word16* vector,
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WebRtc_Word16 vector_length,
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WebRtc_UWord32* seed)
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{
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int i;
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for (i = 0; i < vector_length; i++)
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{
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vector[i] = WebRtcSpl_RandU(seed);
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}
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return vector_length;
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}
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