/*
  * LSP routines for ACELP-based codecs
  *

  * Copyright (c) 2007 Reynaldo H. Verdejo Pinochet (QCELP decoder)

  * Copyright (c) 2008 Vladimir Voroshilov
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #include <inttypes.h>
 
 #include "avcodec.h"
 #define FRAC_BITS 14
 #include "mathops.h"
 #include "lsp.h"

 #include "celp_math.h"

 void ff_acelp_reorder_lsf(int16_t* lsfq, int lsfq_min_distance, int lsfq_min, int lsfq_max, int lp_order)

 {
     int i, j;
 
     /* sort lsfq in ascending order. float bubble agorithm,
        O(n) if data already sorted, O(n^2) - otherwise */

     for(i=0; i<lp_order-1; i++)

         for(j=i; j>=0 && lsfq[j] > lsfq[j+1]; j--)
             FFSWAP(int16_t, lsfq[j], lsfq[j+1]);
 

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

     {
         lsfq[i] = FFMAX(lsfq[i], lsfq_min);
         lsfq_min = lsfq[i] + lsfq_min_distance;
     }

     lsfq[lp_order-1] = FFMIN(lsfq[lp_order-1], lsfq_max);//Is warning required ?

 }
 

 void ff_set_min_dist_lsf(float *lsf, double min_spacing, int size)

 {
     int i;
     float prev = 0.0;
     for (i = 0; i < size; i++)
         prev = lsf[i] = FFMAX(lsf[i], prev + min_spacing);
 }
 

 void ff_acelp_lsf2lsp(int16_t *lsp, const int16_t *lsf, int lp_order)

 {
     int i;
 
     /* Convert LSF to LSP, lsp=cos(lsf) */

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

         // 20861 = 2.0 / PI in (0.15)
         lsp[i] = ff_cos(lsf[i] * 20861 >> 15); // divide by PI and (0,13) -> (0,14)
 }
 

 void ff_acelp_lsf2lspd(double *lsp, const float *lsf, int lp_order)
 {
     int i;
 
     for(i = 0; i < lp_order; i++)
         lsp[i] = cos(2.0 * M_PI * lsf[i]);
 }
 

 /**
  * \brief decodes polynomial coefficients from LSP
  * \param f [out] decoded polynomial coefficients (-0x20000000 <= (3.22) <= 0x1fffffff)
  * \param lsp LSP coefficients (-0x8000 <= (0.15) <= 0x7fff)
  */

 static void lsp2poly(int* f, const int16_t* lsp, int lp_half_order)

 {
     int i, j;
 
     f[0] = 0x400000;          // 1.0 in (3.22)
     f[1] = -lsp[0] << 8;      // *2 and (0.15) -> (3.22)
 

     for(i=2; i<=lp_half_order; i++)

     {
         f[i] = f[i-2];
         for(j=i; j>1; j--)

             f[j] -= MULL(f[j-1], lsp[2*i-2], FRAC_BITS) - f[j-2];

 
         f[1] -= lsp[2*i-2] << 8;
     }
 }
 

 void ff_acelp_lsp2lpc(int16_t* lp, const int16_t* lsp, int lp_half_order)

 {
     int i;

     int f1[MAX_LP_HALF_ORDER+1]; // (3.22)
     int f2[MAX_LP_HALF_ORDER+1]; // (3.22)

     lsp2poly(f1, lsp  , lp_half_order);
     lsp2poly(f2, lsp+1, lp_half_order);

 
     /* 3.2.6 of G.729, Equations 25 and  26*/
     lp[0] = 4096;

     for(i=1; i<lp_half_order+1; i++)

     {
         int ff1 = f1[i] + f1[i-1]; // (3.22)
         int ff2 = f2[i] - f2[i-1]; // (3.22)
 
         ff1 += 1 << 10; // for rounding
         lp[i]    = (ff1 + ff2) >> 11; // divide by 2 and (3.22) -> (3.12)

         lp[(lp_half_order << 1) + 1 - i] = (ff1 - ff2) >> 11; // divide by 2 and (3.22) -> (3.12)

     }
 }
 

 void ff_amrwb_lsp2lpc(const double *lsp, float *lp, int lp_order)
 {
     int lp_half_order = lp_order >> 1;
     double buf[lp_half_order + 1];
     double pa[lp_half_order + 1];
     double *qa = buf + 1;
     int i,j;
 
     qa[-1] = 0.0;
 
     ff_lsp2polyf(lsp    , pa, lp_half_order    );
     ff_lsp2polyf(lsp + 1, qa, lp_half_order - 1);
 
     for (i = 1, j = lp_order - 1; i < lp_half_order; i++, j--) {
         double paf =  pa[i]            * (1 + lsp[lp_order - 1]);
         double qaf = (qa[i] - qa[i-2]) * (1 - lsp[lp_order - 1]);
         lp[i-1]  = (paf + qaf) * 0.5;
         lp[j-1]  = (paf - qaf) * 0.5;
     }
 
     lp[lp_half_order - 1] = (1.0 + lsp[lp_order - 1]) *
         pa[lp_half_order] * 0.5;
 
     lp[lp_order - 1] = lsp[lp_order - 1];
 }
 

 void ff_acelp_lp_decode(int16_t* lp_1st, int16_t* lp_2nd, const int16_t* lsp_2nd, const int16_t* lsp_prev, int lp_order)

 {

     int16_t lsp_1st[MAX_LP_ORDER]; // (0.15)

     int i;
 
     /* LSP values for first subframe (3.2.5 of G.729, Equation 24)*/

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

 #ifdef G729_BITEXACT
         lsp_1st[i] = (lsp_2nd[i] >> 1) + (lsp_prev[i] >> 1);
 #else
         lsp_1st[i] = (lsp_2nd[i] + lsp_prev[i]) >> 1;
 #endif
 

     ff_acelp_lsp2lpc(lp_1st, lsp_1st, lp_order >> 1);

 
     /* LSP values for second subframe (3.2.5 of G.729)*/

     ff_acelp_lsp2lpc(lp_2nd, lsp_2nd, lp_order >> 1);

 }

 void ff_lsp2polyf(const double *lsp, double *f, int lp_half_order)

 {
     int i, j;
 
     f[0] = 1.0;
     f[1] = -2 * lsp[0];
     lsp -= 2;
     for(i=2; i<=lp_half_order; i++)
     {
         double val = -2 * lsp[2*i];
         f[i] = val * f[i-1] + 2*f[i-2];
         for(j=i-1; j>1; j--)
             f[j] += f[j-1] * val + f[j-2];
         f[1] += val;
     }
 }
 

 void ff_acelp_lspd2lpc(const double *lsp, float *lpc, int lp_half_order)

 {

     double pa[MAX_LP_HALF_ORDER+1], qa[MAX_LP_HALF_ORDER+1];

     float *lpc2 = lpc + (lp_half_order << 1) - 1;

     assert(lp_half_order <= MAX_LP_HALF_ORDER);
 

     ff_lsp2polyf(lsp,     pa, lp_half_order);
     ff_lsp2polyf(lsp + 1, qa, lp_half_order);

     while (lp_half_order--) {
         double paf = pa[lp_half_order+1] + pa[lp_half_order];
         double qaf = qa[lp_half_order+1] - qa[lp_half_order];

         lpc [ lp_half_order] = 0.5*(paf+qaf);
         lpc2[-lp_half_order] = 0.5*(paf-qaf);

     }
 }

 
 void ff_sort_nearly_sorted_floats(float *vals, int len)
 {
     int i,j;
 
     for (i = 0; i < len - 1; i++)
         for (j = i; j >= 0 && vals[j] > vals[j+1]; j--)
             FFSWAP(float, vals[j], vals[j+1]);
 }