/*
  * MJPEG encoder
  * Copyright (c) 2016 William Ma, Ted Ying, Jerry Jiang
  *
  * 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
  * Huffman table generation for MJPEG encoder.
  */
 
 #ifndef AVCODEC_MJPEGENC_HUFFMAN_H
 #define AVCODEC_MJPEGENC_HUFFMAN_H
 

 #include <stdint.h>
 

 typedef struct MJpegEncHuffmanContext {
     int val_count[256];
 } MJpegEncHuffmanContext;
 
 // Uses the package merge algorithm to compute the Huffman table.
 void ff_mjpeg_encode_huffman_init(MJpegEncHuffmanContext *s);
 static inline void ff_mjpeg_encode_huffman_increment(MJpegEncHuffmanContext *s,
                                                      uint8_t val)
 {
     s->val_count[val]++;
 }

 void ff_mjpeg_encode_huffman_close(MJpegEncHuffmanContext *s,
                                    uint8_t bits[17], uint8_t val[],
                                    int max_nval);

 
 
 /**
  * Used to assign a occurrence count or "probability" to an input value
  */
 typedef struct PTable {
     int value;  ///< input value
     int prob;   ///< number of occurences of this value in input
 } PTable;
 
 /**
  * Used to store intermediate lists in the package merge algorithm
  */
 typedef struct PackageMergerList {
     int nitems;             ///< number of items in the list and probability      ex. 4
     int item_idx[515];      ///< index range for each item in items                   0, 2, 5, 9, 13
     int probability[514];   ///< probability of each item                             3, 8, 18, 46
     int items[257 * 16];    ///< chain of all individual values that make up items    A, B, A, B, C, A, B, C, D, C, D, D, E
 } PackageMergerList;
 
 /**
  * Used to store optimal huffman encoding results
  */
 typedef struct HuffTable {
     int code;       ///< code is the input value
     int length;     ///< length of the encoding
 } HuffTable;
 
 void ff_mjpegenc_huffman_compute_bits(PTable *prob_table, HuffTable *distincts,
                                       int size, int max_length);
 #endif /* AVCODEC_MJPEGENC_HUFFMAN_H */