/******************************************************************

       iLBC Speech Coder ANSI-C Source Code

       hpInput.c

       Copyright (C) The Internet Society (2004).

       All Rights Reserved.

   ******************************************************************/

   #include "constants.h"

   /*----------------------------------------------------------------*

    *  Input high-pass filter

    *---------------------------------------------------------------*/

   void hpInput(

       float *In,  /* (i) vector to filter */

       int len,    /* (i) length of vector to filter */

       float *Out, /* (o) the resulting filtered vector */

       float *mem  /* (i/o) the filter state */

   ){

       int i;

       float *pi, *po;

       /* all-zero section*/

       pi = &In[0];

       po = &Out[0];

       for (i=0; i<len; i++) {

           *po = hpi_zero_coefsTbl[0] * (*pi);

           *po += hpi_zero_coefsTbl[1] * mem[0];

           *po += hpi_zero_coefsTbl[2] * mem[1];

           mem[1] = mem[0];

           mem[0] = *pi;

           po++;

           pi++;

       }

       /* all-pole section*/

       po = &Out[0];

       for (i=0; i<len; i++) {

           *po -= hpi_pole_coefsTbl[1] * mem[2];

           *po -= hpi_pole_coefsTbl[2] * mem[3];

           mem[3] = mem[2];

           mem[2] = *po;

           po++;

       }

   }