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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
WebRtcIlbcfix_CbMemEnergyCalc.c
******************************************************************/
#include "modules/audio_coding/codecs/ilbc/cb_mem_energy_calc.h"
#include "modules/audio_coding/codecs/ilbc/defines.h"
/* Compute the energy of the rest of the cb memory
* by step wise adding and subtracting the next
* sample and the last sample respectively */
void WebRtcIlbcfix_CbMemEnergyCalc(
int32_t energy, /* (i) input start energy */
size_t range, /* (i) number of iterations */
int16_t *ppi, /* (i) input pointer 1 */
int16_t *ppo, /* (i) input pointer 2 */
int16_t *energyW16, /* (o) Energy in the CB vectors */
int16_t *energyShifts, /* (o) Shift value of the energy */
int scale, /* (i) The scaling of all energy values */
size_t base_size /* (i) Index to where energy values should be stored */
)
{
size_t j;
int16_t shft;
int32_t tmp;
int16_t *eSh_ptr;
int16_t *eW16_ptr;
eSh_ptr = &energyShifts[1+base_size];
eW16_ptr = &energyW16[1+base_size];
for (j = 0; j + 1 < range; j++) {
/* Calculate next energy by a +/-
operation on the edge samples */
tmp = (*ppi) * (*ppi) - (*ppo) * (*ppo);
energy += tmp >> scale;
energy = WEBRTC_SPL_MAX(energy, 0);
ppi--;
ppo--;
/* Normalize the energy into a int16_t and store
the number of shifts */
shft = (int16_t)WebRtcSpl_NormW32(energy);
*eSh_ptr++ = shft;
tmp = energy << shft;
*eW16_ptr++ = (int16_t)(tmp >> 16);
}
}