1 /* 2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 12 /* 13 * This file contains implementations of the randomization functions 14 * WebRtcSpl_IncreaseSeed() 15 * WebRtcSpl_RandU() 16 * WebRtcSpl_RandN() 17 * WebRtcSpl_RandUArray() 18 * 19 * The description header can be found in signal_processing_library.h 20 * 21 */ 22 23 #include "signal_processing_library.h" 24 25 WebRtc_UWord32 WebRtcSpl_IncreaseSeed(WebRtc_UWord32 *seed) 26 { 27 seed[0] = (seed[0] * ((WebRtc_Word32)69069) + 1) & (WEBRTC_SPL_MAX_SEED_USED - 1); 28 return seed[0]; 29 } 30 31 WebRtc_Word16 WebRtcSpl_RandU(WebRtc_UWord32 *seed) 32 { 33 return (WebRtc_Word16)(WebRtcSpl_IncreaseSeed(seed) >> 16); 34 } 35 36 WebRtc_Word16 WebRtcSpl_RandN(WebRtc_UWord32 *seed) 37 { 38 return WebRtcSpl_kRandNTable[WebRtcSpl_IncreaseSeed(seed) >> 23]; 39 } 40 41 // Creates an array of uniformly distributed variables 42 WebRtc_Word16 WebRtcSpl_RandUArray(WebRtc_Word16* vector, 43 WebRtc_Word16 vector_length, 44 WebRtc_UWord32* seed) 45 { 46 int i; 47 for (i = 0; i < vector_length; i++) 48 { 49 vector[i] = WebRtcSpl_RandU(seed); 50 } 51 return vector_length; 52 } 53
