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      1 /*
      2  *  Copyright (c) 2013 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  *  This file was originally licensed as follows. It has been
     11  *  relicensed with permission from the copyright holders.
     12  */
     13 
     14 /**
     15  *
     16  * File Name:  omxSP_FFTGetBufSize_R_S32.c
     17  * OpenMAX DL: v1.0.2
     18  * Last Modified Revision:   7777
     19  * Last Modified Date:       Thu, 27 Sep 2007
     20  *
     21  * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
     22  *
     23  *
     24  * Description:
     25  * Computes the size of the specification structure required.
     26  */
     27 
     28 #include "dl/api/arm/armOMX.h"
     29 #include "dl/api/omxtypes.h"
     30 #include "dl/sp/api/armSP.h"
     31 #include "dl/sp/api/omxSP.h"
     32 
     33 /**
     34  * Function: omxSP_FFTGetBufSize_R_S32
     35  *
     36  * Description:
     37  * Computes the size of the specification structure required for the length
     38  * 2^order real FFT and IFFT functions.
     39  *
     40  * Remarks:
     41  * This function is used in conjunction with the 32-bit functions
     42  * <FFTFwd_RToCCS_S32_Sfs> and <FFTInv_CCSToR_S32_Sfs>.
     43  *
     44  * Parameters:
     45  * [in]  order       base-2 logarithm of the length; valid in the range
     46  *			   [0,12].
     47  * [out] pSize	   pointer to the number of bytes required for the
     48  *			   specification structure.
     49  *
     50  * Return Value:
     51  * Standard omxError result. See enumeration for possible result codes.
     52  *
     53  */
     54 
     55 OMXResult omxSP_FFTGetBufSize_R_S32(
     56      OMX_INT order,
     57      OMX_INT *pSize
     58  )
     59 {
     60     OMX_INT     NBy2,N,twiddleSize;
     61 
     62 
     63     /* Check for order zero */
     64     if (order == 0)
     65     {
     66         *pSize = sizeof(ARMsFFTSpec_R_SC32)
     67                 + sizeof(OMX_S32) * (2); /* Extra size 'N' is used in FFTInv_CCSToR_S32S16_Sfs as a temporary buf */
     68 
     69         return OMX_Sts_NoErr;
     70     }
     71 
     72     NBy2 = 1 << (order - 1);
     73     N = NBy2<<1;
     74     twiddleSize = 5*N/8;            /* 3/4(N/2) + N/4 */
     75 
     76     /* 2 pointers to store bitreversed array and twiddle factor array */
     77     *pSize = sizeof(ARMsFFTSpec_R_SC32)
     78         /* Twiddle factors  */
     79            + sizeof(OMX_SC32) * twiddleSize
     80         /* Ping Pong buffer for doing the N/2 point complex FFT  */
     81            + sizeof(OMX_S32) * (N<<1)  /* Extra size 'N' is used in FFTInv_CCSToR_S32_Sfs as a temporary buf */
     82            + 62 ;  /* Extra bytes to get 32 byte alignment of ptwiddle and pBuf */
     83 
     84 
     85     return OMX_Sts_NoErr;
     86 }
     87 
     88 /*****************************************************************************
     89  *                              END OF FILE
     90  *****************************************************************************/
     91 
     92