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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  * Some code in this file was originally from file omxSP_FFTGetBufSize_R_S32.c
     11  * which was licensed as follows.
     12  * It has been relicensed with permission from the copyright holders.
     13  */
     14 
     15 /*
     16  * OpenMAX DL: v1.0.2
     17  * Last Modified Revision:
     18  * Last Modified Date:
     19  */
     20 
     21 #include "dl/api/arm/armOMX.h"
     22 #include "dl/api/omxtypes.h"
     23 #include "dl/sp/api/armSP.h"
     24 #include "dl/sp/api/omxSP.h"
     25 
     26 /**
     27  * Function: omxSP_FFTGetBufSize_R_S16
     28  *
     29  * Description:
     30  * Computes the size of the specification structure required for the length
     31  * 2^order real FFT and IFFT functions.
     32  *
     33  * Remarks:
     34  * This function is used in conjunction with the 16-bit functions
     35  * <FFTFwd_RToCCS_S16_Sfs> and <FFTInv_CCSToR_S16_Sfs>.
     36  *
     37  * Parameters:
     38  * [in]  order       base-2 logarithm of the length; valid in the range
     39  *			   [1,12].
     40  * [out] pSize	   pointer to the number of bytes required for the
     41  *			   specification structure.
     42  *
     43  * Return Value:
     44  * Standard omxError result. See enumeration for possible result codes.
     45  *
     46  */
     47 
     48 OMXResult omxSP_FFTGetBufSize_R_S16(OMX_INT order, OMX_INT *pSize) {
     49   OMX_INT     NBy2,N,twiddleSize;
     50 
     51   /* Order zero not allowed */
     52   if (order == 0) {
     53     return OMX_Sts_BadArgErr;
     54   }
     55 
     56   NBy2 = 1 << (order - 1);
     57   N = NBy2 << 1;
     58   twiddleSize = 5 * N / 8;  /* 3 / 4 (N / 2) + N / 4 */
     59 
     60   /* 2 pointers to store bitreversed array and twiddle factor array */
     61   *pSize = sizeof(ARMsFFTSpec_R_SC16)
     62            /* Twiddle factors  */
     63            + sizeof(OMX_SC16) * twiddleSize
     64            /* Ping Pong buffer for doing the N/2 point complex FFT; */
     65            /* extra size 'N' as a temporary buf for FFTInv_CCSToR_S16_Sfs */
     66            + sizeof(OMX_S16) * (N << 1)
     67            /* Extra bytes to get 32 byte alignment of ptwiddle and pBuf */
     68            + 62 ;
     69 
     70 
     71   return OMX_Sts_NoErr;
     72 }
     73 
     74 /*****************************************************************************
     75  *                              END OF FILE
     76  *****************************************************************************/
     77 
     78