lpcFilter32.cpp

#include "lpcFilter32.h"

int32_t lpcFilter32(int32_t inputSample, int32_t *a, int32_t *memory, int num_coeff, const int fractional_digits)
{
    int32_t output;
    int64_t temp64;

    temp64 = 0;
    for (int i = 0; i < num_coeff; i++)
    {
        temp64 += (int64_t)a[i] * memory[i];
    }
    output = (int32_t)(temp64 >> fractional_digits);
    output = inputSample - output;

    for (int i = num_coeff - 1; i > 0; i--)
    {
        memory[i] = memory[i - 1];
    }
    memory[0] = output;

    return output;
}

//--------------------- License ------------------------------------------------

// Copyright (c) 2016 Finn Bayer, Christoph Eike, Uwe Simmer

// Permission is hereby granted, free of charge, to any person obtaining 
// a copy of this software and associated documentation files 
// (the "Software"), to deal in the Software without restriction, 
// including without limitation the rights to use, copy, modify, merge, 
// publish, distribute, sublicense, and/or sell copies of the Software, 
// and to permit persons to whom the Software is furnished to do so, 
// subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included 
// in all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 
// CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 
// SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

//------------------------------------------------------------------------------