/* libFLAC - Free Lossless Audio Codec library

 * Copyright (C) 2000-2009  Josh Coalson

 * Copyright (C) 2011-2025  Xiph.Org Foundation

 *

 * 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 the Xiph.org Foundation 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 FOUNDATION 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.

 */

#ifdef HAVE_CONFIG_H

#  include <config.h>

#endif

#include <math.h>

#include <stdlib.h>

#include "FLAC/assert.h"

#include "FLAC/format.h"

#include "share/compat.h"

#include "private/bitmath.h"

#include "private/lpc.h"

#include "private/macros.h"

#if !defined(NDEBUG) || defined FLAC__OVERFLOW_DETECT || defined FLAC__OVERFLOW_DETECT_VERBOSE

#include <stdio.h>

#endif

/* OPT: #undef'ing this may improve the speed on some architectures */

#define FLAC__LPC_UNROLLED_FILTER_LOOPS

#ifndef FLAC__INTEGER_ONLY_LIBRARY

#if defined(_MSC_VER) && (_MSC_VER < 1800)

#include <float.h>

static inline long int lround(double x) {

  return (long)(x + _copysign(0.5, x));

}

#elif !defined(HAVE_LROUND) && defined(__GNUC__)

static inline long int lround(double x) {

  return (long)(x + __builtin_copysign(0.5, x));

}

/* If this fails, we are in the presence of a mid 90's compiler, move along... */

#endif

void FLAC__lpc_window_data(const FLAC__int32 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len)

{

  uint32_t i;

  for(i = 0; i < data_len; i++)

    out[i] = in[i] * window[i];

}

void FLAC__lpc_window_data_wide(const FLAC__int64 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len)

{

  uint32_t i;

  for(i = 0; i < data_len; i++)

    out[i] = in[i] * window[i];

}

void FLAC__lpc_window_data_partial(const FLAC__int32 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len, uint32_t part_size, uint32_t data_shift)

{

  uint32_t i, j;

  if((part_size + data_shift) < data_len){

    for(i = 0; i < part_size; i++)

      out[i] = in[data_shift+i] * window[i];

    i = flac_min(i,data_len - part_size - data_shift);

    for(j = data_len - part_size; j < data_len; i++, j++)

      out[i] = in[data_shift+i] * window[j];

    if(i < data_len)

      out[i] = 0.0f;

  }

}

void FLAC__lpc_window_data_partial_wide(const FLAC__int64 in[], const FLAC__real window[], FLAC__real out[], uint32_t data_len, uint32_t part_size, uint32_t data_shift)

{

  uint32_t i, j;

  if((part_size + data_shift) < data_len){

    for(i = 0; i < part_size; i++)

      out[i] = in[data_shift+i] * window[i];

    i = flac_min(i,data_len - part_size - data_shift);

    for(j = data_len - part_size; j < data_len; i++, j++)

      out[i] = in[data_shift+i] * window[j];

    if(i < data_len)

      out[i] = 0.0f;

  }

}

void FLAC__lpc_compute_autocorrelation(const FLAC__real data[], uint32_t data_len, uint32_t lag, double autoc[])

{

  /* a readable, but slower, version */

#if 0

  double d;

  uint32_t i;

  FLAC__ASSERT(lag > 0);

  FLAC__ASSERT(lag <= data_len);

  /*

   * Technically we should subtract the mean first like so:

   *   for(i = 0; i < data_len; i++)

   *     data[i] -= mean;

   * but it appears not to make enough of a difference to matter, and

   * most signals are already closely centered around zero

   */

  while(lag--) {

    for(i = lag, d = 0.0; i < data_len; i++)

      d += data[i] * (double)data[i - lag];

    autoc[lag] = d;

  }

#endif

  if (data_len < FLAC__MAX_LPC_ORDER || lag > 16) {

    /*

     * this version tends to run faster because of better data locality

     * ('data_len' is usually much larger than 'lag')

     */

    double d;

    uint32_t sample, coeff;

    const uint32_t limit = data_len - lag;

    FLAC__ASSERT(lag > 0);

    FLAC__ASSERT(lag <= data_len);

    for(coeff = 0; coeff < lag; coeff++)

      autoc[coeff] = 0.0;

    for(sample = 0; sample <= limit; sample++) {

      d = data[sample];

      for(coeff = 0; coeff < lag; coeff++)

        autoc[coeff] += d * data[sample+coeff];

    }

    for(; sample < data_len; sample++) {

      d = data[sample];

      for(coeff = 0; coeff < data_len - sample; coeff++)

        autoc[coeff] += d * data[sample+coeff];

    }

  }

  else if(lag <= 8) {

    #undef MAX_LAG

    #define MAX_LAG 8

    #include "deduplication/lpc_compute_autocorrelation_intrin.c"

  }

  else if(lag <= 12) {

    #undef MAX_LAG

    #define MAX_LAG 12

    #include "deduplication/lpc_compute_autocorrelation_intrin.c"

  }

  else if(lag <= 16) {

    #undef MAX_LAG

    #define MAX_LAG 16

    #include "deduplication/lpc_compute_autocorrelation_intrin.c"

  }

}

void FLAC__lpc_compute_lp_coefficients(const double autoc[], uint32_t *max_order, FLAC__real lp_coeff[][FLAC__MAX_LPC_ORDER], double error[])

{

  uint32_t i, j;

  double r, err, lpc[FLAC__MAX_LPC_ORDER];

  FLAC__ASSERT(0 != max_order);

  FLAC__ASSERT(0 < *max_order);

  FLAC__ASSERT(*max_order <= FLAC__MAX_LPC_ORDER);

  FLAC__ASSERT(autoc[0] != 0.0);

  err = autoc[0];

  for(i = 0; i < *max_order; i++) {

    /* Sum up this iteration's reflection coefficient. */

    r = -autoc[i+1];

    for(j = 0; j < i; j++)

      r -= lpc[j] * autoc[i-j];

    r /= err;

    /* Update LPC coefficients and total error. */

    lpc[i]=r;

    for(j = 0; j < (i>>1); j++) {

      double tmp = lpc[j];

      lpc[j] += r * lpc[i-1-j];

      lpc[i-1-j] += r * tmp;

    }

    if(i & 1)

      lpc[j] += lpc[j] * r;

    err *= (1.0 - r * r);

    /* save this order */

    for(j = 0; j <= i; j++)

      lp_coeff[i][j] = (FLAC__real)(-lpc[j]); /* negate FIR filter coeff to get predictor coeff */

    error[i] = err;

    /* see SF bug https://sourceforge.net/p/flac/bugs/234/ */

    if(err == 0.0) {

      *max_order = i+1;

      return;

    }

  }

}

int FLAC__lpc_quantize_coefficients(const FLAC__real lp_coeff[], uint32_t order, uint32_t precision, FLAC__int32 qlp_coeff[], int *shift)

{

  uint32_t i;

  double cmax;

  FLAC__int32 qmax, qmin;

  FLAC__ASSERT(precision > 0);

  FLAC__ASSERT(precision >= FLAC__MIN_QLP_COEFF_PRECISION);

  /* drop one bit for the sign; from here on out we consider only |lp_coeff[i]| */

  precision--;

  qmax = 1 << precision;

  qmin = -qmax;

  qmax--;

  /* calc cmax = max( |lp_coeff[i]| ) */

  cmax = 0.0;

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

    const double d = fabs(lp_coeff[i]);

    if(d > cmax)

      cmax = d;

  }

  if(cmax <= 0.0) {

    /* => coefficients are all 0, which means our constant-detect didn't work */

    return 2;

  }

  else {

    const int max_shiftlimit = (1 << (FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN-1)) - 1;

    const int min_shiftlimit = -max_shiftlimit - 1;

    int log2cmax;

    (void)frexp(cmax, &log2cmax);

    log2cmax--;

    *shift = (int)precision - log2cmax - 1;

    if(*shift > max_shiftlimit)

      *shift = max_shiftlimit;

    else if(*shift < min_shiftlimit)

      return 1;

  }

  if(*shift >= 0) {

    double error = 0.0;

    FLAC__int32 q;

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

      error += lp_coeff[i] * (1 << *shift);

      q = lround(error);

#ifdef FLAC__OVERFLOW_DETECT

      if(q > qmax+1) /* we expect q==qmax+1 occasionally due to rounding */

        flac_fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q>qmax %d>%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmax,*shift,cmax,precision+1,i,lp_coeff[i]);

      else if(q < qmin)

        flac_fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q<qmin %d<%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmin,*shift,cmax,precision+1,i,lp_coeff[i]);

#endif

      if(q > qmax)

        q = qmax;

      else if(q < qmin)

        q = qmin;

      error -= q;

      qlp_coeff[i] = q;

    }

  }

  /* negative shift is very rare but due to design flaw, negative shift is

   * not allowed in the decoder, so it must be handled specially by scaling

   * down coeffs

   */

  else {

    const int nshift = -(*shift);

    double error = 0.0;

    FLAC__int32 q;

#ifndef NDEBUG

    flac_fprintf(stderr,"FLAC__lpc_quantize_coefficients: negative shift=%d order=%u cmax=%f\n", *shift, order, cmax);

#endif

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

      error += lp_coeff[i] / (1 << nshift);

      q = lround(error);

#ifdef FLAC__OVERFLOW_DETECT

      if(q > qmax+1) /* we expect q==qmax+1 occasionally due to rounding */

        flac_fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q>qmax %d>%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmax,*shift,cmax,precision+1,i,lp_coeff[i]);

      else if(q < qmin)

        flac_fprintf(stderr,"FLAC__lpc_quantize_coefficients: quantizer overflow: q<qmin %d<%d shift=%d cmax=%f precision=%u lpc[%u]=%f\n",q,qmin,*shift,cmax,precision+1,i,lp_coeff[i]);

#endif

      if(q > qmax)

        q = qmax;

      else if(q < qmin)

        q = qmin;

      error -= q;

      qlp_coeff[i] = q;

    }

    *shift = 0;

  }

  return 0;

}

#if defined(_MSC_VER)

// silence MSVC warnings about __restrict modifier

#pragma warning ( disable : 4028 )

#endif

void FLAC__lpc_compute_residual_from_qlp_coefficients(const FLAC__int32 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)

#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)

{

  FLAC__int64 sumo;

  uint32_t i, j;

  FLAC__int32 sum;

  const FLAC__int32 *history;

#ifdef FLAC__OVERFLOW_DETECT_VERBOSE

  flac_fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);

  for(i=0;i<order;i++)

    flac_fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);

  flac_fprintf(stderr,"\n");

#endif

  FLAC__ASSERT(order > 0);

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

    sumo = 0;

    sum = 0;

    history = data;

    for(j = 0; j < order; j++) {

      sum += qlp_coeff[j] * (*(--history));

      sumo += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*history);

      if(sumo > 2147483647ll || sumo < -2147483648ll)

        flac_fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients: OVERFLOW, i=%u, j=%u, c=%d, d=%d, sumo=%" PRId64 "\n",i,j,qlp_coeff[j],*history,sumo);

    }

    *(residual++) = *(data++) - (sum >> lp_quantization);

  }

  /* Here's a slower but clearer version:

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

    sum = 0;

    for(j = 0; j < order; j++)

      sum += qlp_coeff[j] * data[i-j-1];

    residual[i] = data[i] - (sum >> lp_quantization);

  }

  */

}

#else /* fully unrolled version for normal use */

{

  int i;

  FLAC__int32 sum;

  FLAC__ASSERT(order > 0);

  FLAC__ASSERT(order <= 32);

  /*

   * We do unique versions up to 12th order since that's the subset limit.

   * Also they are roughly ordered to match frequency of occurrence to

   * minimize branching.

   */

  if(order <= 12) {

    if(order > 8) {

      if(order > 10) {

        if(order == 12) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[11] * data[i-12];

            sum += qlp_coeff[10] * data[i-11];

            sum += qlp_coeff[9] * data[i-10];

            sum += qlp_coeff[8] * data[i-9];

            sum += qlp_coeff[7] * data[i-8];

            sum += qlp_coeff[6] * data[i-7];

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 11 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[10] * data[i-11];

            sum += qlp_coeff[9] * data[i-10];

            sum += qlp_coeff[8] * data[i-9];

            sum += qlp_coeff[7] * data[i-8];

            sum += qlp_coeff[6] * data[i-7];

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

      else {

        if(order == 10) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[9] * data[i-10];

            sum += qlp_coeff[8] * data[i-9];

            sum += qlp_coeff[7] * data[i-8];

            sum += qlp_coeff[6] * data[i-7];

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 9 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[8] * data[i-9];

            sum += qlp_coeff[7] * data[i-8];

            sum += qlp_coeff[6] * data[i-7];

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

    }

    else if(order > 4) {

      if(order > 6) {

        if(order == 8) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[7] * data[i-8];

            sum += qlp_coeff[6] * data[i-7];

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 7 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[6] * data[i-7];

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

      else {

        if(order == 6) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[5] * data[i-6];

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 5 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[4] * data[i-5];

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

    }

    else {

      if(order > 2) {

        if(order == 4) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[3] * data[i-4];

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 3 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[2] * data[i-3];

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

      else {

        if(order == 2) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[1] * data[i-2];

            sum += qlp_coeff[0] * data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 1 */

          for(i = 0; i < (int)data_len; i++)

            residual[i] = data[i] - ((qlp_coeff[0] * data[i-1]) >> lp_quantization);

        }

      }

    }

  }

  else { /* order > 12 */

    for(i = 0; i < (int)data_len; i++) {

      sum = 0;

      switch(order) {

        case 32: sum += qlp_coeff[31] * data[i-32]; /* Falls through. */

        case 31: sum += qlp_coeff[30] * data[i-31]; /* Falls through. */

        case 30: sum += qlp_coeff[29] * data[i-30]; /* Falls through. */

        case 29: sum += qlp_coeff[28] * data[i-29]; /* Falls through. */

        case 28: sum += qlp_coeff[27] * data[i-28]; /* Falls through. */

        case 27: sum += qlp_coeff[26] * data[i-27]; /* Falls through. */

        case 26: sum += qlp_coeff[25] * data[i-26]; /* Falls through. */

        case 25: sum += qlp_coeff[24] * data[i-25]; /* Falls through. */

        case 24: sum += qlp_coeff[23] * data[i-24]; /* Falls through. */

        case 23: sum += qlp_coeff[22] * data[i-23]; /* Falls through. */

        case 22: sum += qlp_coeff[21] * data[i-22]; /* Falls through. */

        case 21: sum += qlp_coeff[20] * data[i-21]; /* Falls through. */

        case 20: sum += qlp_coeff[19] * data[i-20]; /* Falls through. */

        case 19: sum += qlp_coeff[18] * data[i-19]; /* Falls through. */

        case 18: sum += qlp_coeff[17] * data[i-18]; /* Falls through. */

        case 17: sum += qlp_coeff[16] * data[i-17]; /* Falls through. */

        case 16: sum += qlp_coeff[15] * data[i-16]; /* Falls through. */

        case 15: sum += qlp_coeff[14] * data[i-15]; /* Falls through. */

        case 14: sum += qlp_coeff[13] * data[i-14]; /* Falls through. */

        case 13: sum += qlp_coeff[12] * data[i-13];

                 sum += qlp_coeff[11] * data[i-12];

                 sum += qlp_coeff[10] * data[i-11];

                 sum += qlp_coeff[ 9] * data[i-10];

                 sum += qlp_coeff[ 8] * data[i- 9];

                 sum += qlp_coeff[ 7] * data[i- 8];

                 sum += qlp_coeff[ 6] * data[i- 7];

                 sum += qlp_coeff[ 5] * data[i- 6];

                 sum += qlp_coeff[ 4] * data[i- 5];

                 sum += qlp_coeff[ 3] * data[i- 4];

                 sum += qlp_coeff[ 2] * data[i- 3];

                 sum += qlp_coeff[ 1] * data[i- 2];

                 sum += qlp_coeff[ 0] * data[i- 1];

      }

      residual[i] = data[i] - (sum >> lp_quantization);

    }

  }

}

#endif

void FLAC__lpc_compute_residual_from_qlp_coefficients_wide(const FLAC__int32 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)

#if defined(FLAC__OVERFLOW_DETECT) || !defined(FLAC__LPC_UNROLLED_FILTER_LOOPS)

{

  uint32_t i, j;

  FLAC__int64 sum;

  const FLAC__int32 *history;

#ifdef FLAC__OVERFLOW_DETECT_VERBOSE

  flac_fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: data_len=%d, order=%u, lpq=%d",data_len,order,lp_quantization);

  for(i=0;i<order;i++)

    flac_fprintf(stderr,", q[%u]=%d",i,qlp_coeff[i]);

  flac_fprintf(stderr,"\n");

#endif

  FLAC__ASSERT(order > 0);

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

    sum = 0;

    history = data;

    for(j = 0; j < order; j++)

      sum += (FLAC__int64)qlp_coeff[j] * (FLAC__int64)(*(--history));

    if(FLAC__bitmath_silog2((FLAC__int64)(*data) - (sum >> lp_quantization)) > 32) {

      flac_fprintf(stderr,"FLAC__lpc_compute_residual_from_qlp_coefficients_wide: OVERFLOW, i=%u, data=%d, sum=%" PRId64 ", residual=%" PRId64 "\n", i, *data, (int64_t)(sum >> lp_quantization), ((FLAC__int64)(*data) - (sum >> lp_quantization)));

      break;

    }

    *(residual++) = *(data++) - (FLAC__int32)(sum >> lp_quantization);

  }

}

#else /* fully unrolled version for normal use */

{

  int i;

  FLAC__int64 sum;

  FLAC__ASSERT(order > 0);

  FLAC__ASSERT(order <= 32);

  /*

   * We do unique versions up to 12th order since that's the subset limit.

   * Also they are roughly ordered to match frequency of occurrence to

   * minimize branching.

   */

  if(order <= 12) {

    if(order > 8) {

      if(order > 10) {

        if(order == 12) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[11] * (FLAC__int64)data[i-12];

            sum += qlp_coeff[10] * (FLAC__int64)data[i-11];

            sum += qlp_coeff[9] * (FLAC__int64)data[i-10];

            sum += qlp_coeff[8] * (FLAC__int64)data[i-9];

            sum += qlp_coeff[7] * (FLAC__int64)data[i-8];

            sum += qlp_coeff[6] * (FLAC__int64)data[i-7];

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 11 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[10] * (FLAC__int64)data[i-11];

            sum += qlp_coeff[9] * (FLAC__int64)data[i-10];

            sum += qlp_coeff[8] * (FLAC__int64)data[i-9];

            sum += qlp_coeff[7] * (FLAC__int64)data[i-8];

            sum += qlp_coeff[6] * (FLAC__int64)data[i-7];

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

      else {

        if(order == 10) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[9] * (FLAC__int64)data[i-10];

            sum += qlp_coeff[8] * (FLAC__int64)data[i-9];

            sum += qlp_coeff[7] * (FLAC__int64)data[i-8];

            sum += qlp_coeff[6] * (FLAC__int64)data[i-7];

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 9 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[8] * (FLAC__int64)data[i-9];

            sum += qlp_coeff[7] * (FLAC__int64)data[i-8];

            sum += qlp_coeff[6] * (FLAC__int64)data[i-7];

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

    }

    else if(order > 4) {

      if(order > 6) {

        if(order == 8) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[7] * (FLAC__int64)data[i-8];

            sum += qlp_coeff[6] * (FLAC__int64)data[i-7];

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 7 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[6] * (FLAC__int64)data[i-7];

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

      else {

        if(order == 6) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[5] * (FLAC__int64)data[i-6];

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 5 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[4] * (FLAC__int64)data[i-5];

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

    }

    else {

      if(order > 2) {

        if(order == 4) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[3] * (FLAC__int64)data[i-4];

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 3 */

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[2] * (FLAC__int64)data[i-3];

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

      }

      else {

        if(order == 2) {

          for(i = 0; i < (int)data_len; i++) {

            sum = 0;

            sum += qlp_coeff[1] * (FLAC__int64)data[i-2];

            sum += qlp_coeff[0] * (FLAC__int64)data[i-1];

            residual[i] = data[i] - (sum >> lp_quantization);

          }

        }

        else { /* order == 1 */

          for(i = 0; i < (int)data_len; i++)

            residual[i] = data[i] - ((qlp_coeff[0] * (FLAC__int64)data[i-1]) >> lp_quantization);

        }

      }

    }

  }

  else { /* order > 12 */

    for(i = 0; i < (int)data_len; i++) {

      sum = 0;

      switch(order) {

        case 32: sum += qlp_coeff[31] * (FLAC__int64)data[i-32]; /* Falls through. */

        case 31: sum += qlp_coeff[30] * (FLAC__int64)data[i-31]; /* Falls through. */

        case 30: sum += qlp_coeff[29] * (FLAC__int64)data[i-30]; /* Falls through. */

        case 29: sum += qlp_coeff[28] * (FLAC__int64)data[i-29]; /* Falls through. */

        case 28: sum += qlp_coeff[27] * (FLAC__int64)data[i-28]; /* Falls through. */

        case 27: sum += qlp_coeff[26] * (FLAC__int64)data[i-27]; /* Falls through. */

        case 26: sum += qlp_coeff[25] * (FLAC__int64)data[i-26]; /* Falls through. */

        case 25: sum += qlp_coeff[24] * (FLAC__int64)data[i-25]; /* Falls through. */

        case 24: sum += qlp_coeff[23] * (FLAC__int64)data[i-24]; /* Falls through. */

        case 23: sum += qlp_coeff[22] * (FLAC__int64)data[i-23]; /* Falls through. */

        case 22: sum += qlp_coeff[21] * (FLAC__int64)data[i-22]; /* Falls through. */

        case 21: sum += qlp_coeff[20] * (FLAC__int64)data[i-21]; /* Falls through. */

        case 20: sum += qlp_coeff[19] * (FLAC__int64)data[i-20]; /* Falls through. */

        case 19: sum += qlp_coeff[18] * (FLAC__int64)data[i-19]; /* Falls through. */

        case 18: sum += qlp_coeff[17] * (FLAC__int64)data[i-18]; /* Falls through. */

        case 17: sum += qlp_coeff[16] * (FLAC__int64)data[i-17]; /* Falls through. */

        case 16: sum += qlp_coeff[15] * (FLAC__int64)data[i-16]; /* Falls through. */

        case 15: sum += qlp_coeff[14] * (FLAC__int64)data[i-15]; /* Falls through. */

        case 14: sum += qlp_coeff[13] * (FLAC__int64)data[i-14]; /* Falls through. */

        case 13: sum += qlp_coeff[12] * (FLAC__int64)data[i-13];

                 sum += qlp_coeff[11] * (FLAC__int64)data[i-12];

                 sum += qlp_coeff[10] * (FLAC__int64)data[i-11];

                 sum += qlp_coeff[ 9] * (FLAC__int64)data[i-10];

                 sum += qlp_coeff[ 8] * (FLAC__int64)data[i- 9];

                 sum += qlp_coeff[ 7] * (FLAC__int64)data[i- 8];

                 sum += qlp_coeff[ 6] * (FLAC__int64)data[i- 7];

                 sum += qlp_coeff[ 5] * (FLAC__int64)data[i- 6];

                 sum += qlp_coeff[ 4] * (FLAC__int64)data[i- 5];

                 sum += qlp_coeff[ 3] * (FLAC__int64)data[i- 4];

                 sum += qlp_coeff[ 2] * (FLAC__int64)data[i- 3];

                 sum += qlp_coeff[ 1] * (FLAC__int64)data[i- 2];

                 sum += qlp_coeff[ 0] * (FLAC__int64)data[i- 1];

      }

      residual[i] = data[i] - (sum >> lp_quantization);

    }

  }

}

#endif

FLAC__bool FLAC__lpc_compute_residual_from_qlp_coefficients_limit_residual(const FLAC__int32 * flac_restrict data, uint32_t data_len, const FLAC__int32 * flac_restrict qlp_coeff, uint32_t order, int lp_quantization, FLAC__int32 * flac_restrict residual)

{

  int i;

  FLAC__int64 sum, residual_to_check;

  FLAC__ASSERT(order > 0);

  FLAC__ASSERT(order <= 32);

  for(i = 0; i < (int)data_len; i++) {

    sum = 0;

    switch(order) {

      case 32: sum += qlp_coeff[31] * (FLAC__int64)data[i-32]; /* Falls through. */

      case 31: sum += qlp_coeff[30] * (FLAC__int64)data[i-31]; /* Falls through. */

      case 30: sum += qlp_coeff[29] * (FLAC__int64)data[i-30]; /* Falls through. */

      case 29: sum += qlp_coeff[28] * (FLAC__int64)data[i-29]; /* Falls through. */

      case 28: sum += qlp_coeff[27] * (FLAC__int64)data[i-28]; /* Falls through. */

      case 27: sum += qlp_coeff[26] * (FLAC__int64)data[i-27]; /* Falls through. */

      case 26: sum += qlp_coeff[25] * (FLAC__int64)data[i-26]; /* Falls through. */

      case 25: sum += qlp_coeff[24] * (FLAC__int64)data[i-25]; /* Falls through. */

      case 24: sum += qlp_coeff[23] * (FLAC__int64)data[i-24]; /* Falls through. */

      case 23: sum += qlp_coeff[22] * (FLAC__int64)data[i-23]; /* Falls through. */

      case 22: sum += qlp_coeff[21] * (FLAC__int64)data[i-22]; /* Falls through. */

      case 21: sum += qlp_coeff[20] * (FLAC__int64)data[i-21]; /* Falls through. */

      case 20: sum += qlp_coeff[19] * (FLAC__int64)data[i-20]; /* Falls through. */

      case 19: sum += qlp_coeff[18] * (FLAC__int64)data[i-19]; /* Falls through. */

      case 18: sum += qlp_coeff[17] * (FLAC__int64)data[i-18]; /* Falls through. */

      case 17: sum += qlp_coeff[16] * (FLAC__int64)data[i-17]; /* Falls through. */

      case 16: sum += qlp_coeff[15] * (FLAC__int64)data[i-16]; /* Falls through. */

      case 15: sum += qlp_coeff[14] * (FLAC__int64)data[i-15]; /* Falls through. */

      case 14: sum += qlp_coeff[13] * (FLAC__int64)data[i-14]; /* Falls through. */

      case 13: sum += qlp_coeff[12] * (FLAC__int64)data[i-13]; /* Falls through. */

      case 12: sum += qlp_coeff[11] * (FLAC__int64)data[i-12]; /* Falls through. */

      case 11: sum += qlp_coeff[10] * (FLAC__int64)data[i-11]; /* Falls through. */

      case 10: sum += qlp_coeff[ 9] * (FLAC__int64)data[i-10]; /* Falls through. */

      case  9: sum += qlp_coeff[ 8] * (FLAC__int64)data[i- 9]; /* Falls through. */

      case  8: sum += qlp_coeff[ 7] * (FLAC__int64)data[i- 8]; /* Falls through. */

      case  7: sum += qlp_coeff[ 6] * (FLAC__int64)data[i- 7]; /* Falls through. */

      case  6: sum += qlp_coeff[ 5] * (FLAC__int64)data[i- 6]; /* Falls through. */

      case  5: sum += qlp_coeff[ 4] * (FLAC__int64)data[i- 5]; /* Falls through. */

      case  4: sum += qlp_coeff[ 3] * (FLAC__int64)data[i- 4]; /* Falls through. */

      case  3: sum += qlp_coeff[ 2] * (FLAC__int64)data[i- 3]; /* Falls through. */

      case  2: sum += qlp_coeff[ 1] * (FLAC__int64)data[i- 2]; /* Falls through. */

      case  1: sum += qlp_coeff[ 0] * (FLAC__int64)data[i- 1];