text: /*-----------------------------------------------------------------------------
  * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
  *
  * $Date: 16/10/14 6:01p $Revision:  V.1.4.5
  *
  * Project:      CMSIS DSP Library
  * Title:        arm_fir_interpolate_init_f32.c
  *
  * Description:  Floating-point FIR interpolator initialization function
  *
  * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *   - Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  *   - Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in
  *     the documentation and/or other materials provided with the
  *     distribution.
  *   - Neither the name of ARM LIMITED nor the names of its contributors
  *     may be used to endorse or promote products derived from this
  *     software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  * ---------------------------------------------------------------------------*/
  
  #include "arm_math.h"
  
  /**
   * @ingroup groupFilters
   */
  
  /**
   * @addtogroup FIR_Interpolate
   * @{
   */
  
  /**
   * @brief  Initialization function for the floating-point FIR interpolator.
   * @param[in,out] *S        points to an instance of the floating-point FIR interpolator structure.
   * @param[in]     L         upsample factor.
   * @param[in]     numTaps   number of filter coefficients in the filter.
   * @param[in]     *pCoeffs  points to the filter coefficient buffer.
   * @param[in]     *pState   points to the state buffer.
   * @param[in]     blockSize number of input samples to process per call.
   * @return        The function returns ARM_MATH_SUCCESS if initialization was successful or ARM_MATH_LENGTH_ERROR if
   * the filter length <code>numTaps</code> is not a multiple of the interpolation factor <code>L</code>.
   *
   * <b>Description:</b>
   * \par
   * <code>pCoeffs</code> points to the array of filter coefficients stored in time reversed order:
   * <pre>
   *    {b[numTaps-1], b[numTaps-2], b[numTaps-2], ..., b[1], b[0]}
   * </pre>
   * The length of the filter <code>numTaps</code> must be a multiple of the interpolation factor <code>L</code>.
   * \par
   * <code>pState</code> points to the array of state variables.
   * <code>pState</code> is of length <code>(numTaps/L)+blockSize-1</code> words
   * where <code>blockSize</code> is the number of input samples processed by each call to <code>arm_fir_interpolate_f32()</code>.
   */
  
  arm_status arm_fir_interpolate_init_f32(
      arm_fir_interpolate_instance_f32 * S,
      uint8_t L,
      uint16_t numTaps,
      float32_t * pCoeffs,
      float32_t * pState,
      uint32_t blockSize)
  {
      arm_status status;
  
      /* The filter length must be a multiple of the interpolation factor */
      if((numTaps % L) != 0u)
      {
          /* Set status as ARM_MATH_LENGTH_ERROR */
          status = ARM_MATH_LENGTH_ERROR;
      }
      else
      {
  
          /* Assign coefficient pointer */
          S->pCoeffs = pCoeffs;
  
          /* Assign Interpolation factor */
          S->L = L;
  
          /* Assign polyPhaseLength */
          S->phaseLength = numTaps / L;
  
          /* Clear state buffer and size of state array is always phaseLength + blockSize - 1 */
          memset(pState, 0,
                 (blockSize +
                  ((uint32_t) S->phaseLength - 1u)) * sizeof(float32_t));
  
          /* Assign state pointer */
          S->pState = pState;
  
          status = ARM_MATH_SUCCESS;
      }
  
      return (status);
  
  }
  
  /**
   * @} end of FIR_Interpolate group
   */
  