/**

  * @file

  * Common code for Vorbis I encoder and decoder

  * @author Denes Balatoni  ( dbalatoni programozo hu )

  *

  * 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

  */
 

 /**
  * @file
  * Common code for Vorbis I encoder and decoder
  * @author Denes Balatoni  ( dbalatoni programozo hu )
  */
 

 #define BITSTREAM_READER_LE

 #include "avcodec.h"

 #include "get_bits.h"

 
 #include "vorbis.h"

 /* Helper functions */
 

 // x^(1/n)
 unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n)
 {

     unsigned int ret = 0, i, j;

     do {
         ++ret;

         for (i = 0, j = ret; i < n - 1; i++)
             j *= ret;
     } while (j <= x);

     return ret - 1;

 }
 

 // Generate vlc codes from vorbis huffman code lengths

 // the two bits[p] > 32 checks should be redundant, all calling code should
 // already ensure that, but since it allows overwriting the stack it seems
 // reasonable to check redundantly.

 int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, unsigned num)

 {

     uint32_t exit_at_level[33] = { 404 };

     unsigned i, j, p, code;

 #ifdef DEBUG

     GetBitContext gb;

 #endif

     for (p = 0; (bits[p] == 0) && (p < num); ++p)

         ;

     if (p == num)

         return 0;

     codes[p] = 0;

     if (bits[p] > 32)
         return 1;

     for (i = 0; i < bits[p]; ++i)
         exit_at_level[i+1] = 1 << i;

 #ifdef DEBUG

     av_log(NULL, AV_LOG_INFO, " %u. of %u code len %d code %d - ", p, num, bits[p], codes[p]);
     init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);

     for (i = 0; i < bits[p]; ++i)

         av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
     av_log(NULL, AV_LOG_INFO, "\n");
 #endif

     ++p;

     for (; p < num; ++p) {

         if (bits[p] > 32)

              return 1;
         if (bits[p] == 0)
              continue;

         // find corresponding exit(node which the tree can grow further from)

         for (i = bits[p]; i > 0; --i)

             if (exit_at_level[i])
                 break;
         if (!i) // overspecified tree

              return 1;
         code = exit_at_level[i];
         exit_at_level[i] = 0;

         // construct code (append 0s to end) and introduce new exits

         for (j = i + 1 ;j <= bits[p]; ++j)
             exit_at_level[j] = code + (1 << (j - 1));
         codes[p] = code;

 #ifdef DEBUG

         av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);

         init_get_bits(&gb, (uint8_t *)&codes[p], bits[p]);

         for (i = 0; i < bits[p]; ++i)

             av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
         av_log(NULL, AV_LOG_INFO, "\n");

 #endif
 
     }
 

     //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)

     for (p = 1; p < 33; p++)

         if (exit_at_level[p])
             return 1;

     return 0;
 }

 int ff_vorbis_ready_floor1_list(AVCodecContext *avctx,

                                 vorbis_floor1_entry *list, int values)

 {

     int i;

     list[0].sort = 0;
     list[1].sort = 1;
     for (i = 2; i < values; i++) {
         int j;

         list[i].low  = 0;

         list[i].high = 1;
         list[i].sort = i;
         for (j = 2; j < i; j++) {
             int tmp = list[j].x;
             if (tmp < list[i].x) {

                 if (tmp > list[list[i].low].x)

                     list[i].low  =  j;

             } else {

                 if (tmp < list[list[i].high].x)
                     list[i].high = j;

             }
         }
     }
     for (i = 0; i < values - 1; i++) {
         int j;
         for (j = i + 1; j < values; j++) {

             if (list[i].x == list[j].x) {

                 av_log(avctx, AV_LOG_ERROR,

                        "Duplicate value found in floor 1 X coordinates\n");
                 return AVERROR_INVALIDDATA;
             }

             if (list[list[i].sort].x > list[list[j].sort].x) {
                 int tmp = list[i].sort;
                 list[i].sort = list[j].sort;
                 list[j].sort = tmp;
             }
         }
     }

     return 0;

 }
 

 static inline void render_line_unrolled(intptr_t x, int y, int x1,

                                         intptr_t sy, int ady, int adx,

                                         float *buf)

 {

     int err = -adx;

     x -= x1 - 1;
     buf += x1 - 1;

     while (++x < 0) {
         err += ady;
         if (err >= 0) {
             err += ady - adx;

             y   += sy;

             buf[x++] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

         }

         buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

     }
     if (x <= 0) {
         if (err + ady >= 0)
             y += sy;

         buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

     }
 }
 

 static void render_line(int x0, int y0, int x1, int y1, float *buf)

 {

     int dy  = y1 - y0;

     int adx = x1 - x0;

     int ady = FFABS(dy);

     int sy  = dy < 0 ? -1 : 1;

     buf[x0] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y0)];

     if (ady*2 <= adx) { // optimized common case

         render_line_unrolled(x0, y0, x1, sy, ady, adx, buf);
     } else {

         int base  = dy / adx;
         int x     = x0;

         int y     = y0;

         int err   = -adx;

         ady -= FFABS(base) * adx;
         while (++x < x1) {
             y += base;
             err += ady;
             if (err >= 0) {
                 err -= adx;

                 y   += sy;

             }

             buf[x] = ff_vorbis_floor1_inverse_db_table[av_clip_uint8(y)];

         }

     }

 }
 

 void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values,

                                   uint16_t *y_list, int *flag,

                                   int multiplier, float *out, int samples)

 {

     int lx, ly, i;

     lx = 0;
     ly = y_list[0] * multiplier;
     for (i = 1; i < values; i++) {
         int pos = list[i].sort;
         if (flag[pos]) {

             int x1 = list[pos].x;
             int y1 = y_list[pos] * multiplier;
             if (lx < samples)
                 render_line(lx, ly, FFMIN(x1,samples), y1, out);
             lx = x1;
             ly = y1;

         }

         if (lx >= samples)
             break;

     }

     if (lx < samples)
         render_line(lx, ly, samples, ly, out);

 }