/*
  * CCITT Fax Group 3 and 4 decompression
  * Copyright (c) 2008 Konstantin Shishkov
  *
  * 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
  */
 
 /**
  * CCITT Fax Group 3 and 4 decompression

  * @file

  * @author Konstantin Shishkov
  */
 #include "avcodec.h"

 #include "get_bits.h"

 #include "put_bits.h"

 #include "faxcompr.h"
 
 #define CCITT_SYMS 104
 
 static const uint16_t ccitt_syms[CCITT_SYMS] = {
     0,    1,    2,    3,    4,    5,    6,    7,    8,    9,   10,   11,   12,
    13,   14,   15,   16,   17,   18,   19,   20,   21,   22,   23,   24,   25,
    26,   27,   28,   29,   30,   31,   32,   33,   34,   35,   36,   37,   38,
    39,   40,   41,   42,   43,   44,   45,   46,   47,   48,   49,   50,   51,
    52,   53,   54,   55,   56,   57,   58,   59,   60,   61,   62,   63,   64,
   128,  192,  256,  320,  384,  448,  512,  576,  640,  704,  768,  832,  896,
   960, 1024, 1088, 1152, 1216, 1280, 1344, 1408, 1472, 1536, 1600, 1664, 1728,
  1792, 1856, 1920, 1984, 2048, 2112, 2176, 2240, 2304, 2368, 2432, 2496, 2560
 };
 
 static const uint8_t ccitt_codes_bits[2][CCITT_SYMS] =
 {
   {
     0x35, 0x07, 0x07, 0x08, 0x0B, 0x0C, 0x0E, 0x0F, 0x13, 0x14, 0x07, 0x08, 0x08,
     0x03, 0x34, 0x35, 0x2A, 0x2B, 0x27, 0x0C, 0x08, 0x17, 0x03, 0x04, 0x28, 0x2B,
     0x13, 0x24, 0x18, 0x02, 0x03, 0x1A, 0x1B, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
     0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x04, 0x05, 0x0A, 0x0B, 0x52, 0x53, 0x54,
     0x55, 0x24, 0x25, 0x58, 0x59, 0x5A, 0x5B, 0x4A, 0x4B, 0x32, 0x33, 0x34, 0x1B,
     0x12, 0x17, 0x37, 0x36, 0x37, 0x64, 0x65, 0x68, 0x67, 0xCC, 0xCD, 0xD2, 0xD3,
     0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0x98, 0x99, 0x9A, 0x18, 0x9B,
     0x08, 0x0C, 0x0D, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x1C, 0x1D, 0x1E, 0x1F
   },
   {
     0x37, 0x02, 0x03, 0x02, 0x03, 0x03, 0x02, 0x03, 0x05, 0x04, 0x04, 0x05, 0x07,
     0x04, 0x07, 0x18, 0x17, 0x18, 0x08, 0x67, 0x68, 0x6C, 0x37, 0x28, 0x17, 0x18,
     0xCA, 0xCB, 0xCC, 0xCD, 0x68, 0x69, 0x6A, 0x6B, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6,
     0xD7, 0x6C, 0x6D, 0xDA, 0xDB, 0x54, 0x55, 0x56, 0x57, 0x64, 0x65, 0x52, 0x53,
     0x24, 0x37, 0x38, 0x27, 0x28, 0x58, 0x59, 0x2B, 0x2C, 0x5A, 0x66, 0x67, 0x0F,
     0xC8, 0xC9, 0x5B, 0x33, 0x34, 0x35, 0x6C, 0x6D, 0x4A, 0x4B, 0x4C, 0x4D, 0x72,
     0x73, 0x74, 0x75, 0x76, 0x77, 0x52, 0x53, 0x54, 0x55, 0x5A, 0x5B, 0x64, 0x65,
     0x08, 0x0C, 0x0D, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x1C, 0x1D, 0x1E, 0x1F
   }
 };
 
 static const uint8_t ccitt_codes_lens[2][CCITT_SYMS] =
 {
   {
      8,  6,  4,  4,  4,  4,  4,  4,  5,  5,  5,  5,  6,  6,  6,  6,  6,  6,  7,  7,
      7,  7,  7,  7,  7,  7,  7,  7,  7,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,
      8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,  8,
      8,  8,  8,  8,  5,  5,  6,  7,  8,  8,  8,  8,  8,  8,  9,  9,  9,  9,  9,  9,
      9,  9,  9,  9,  9,  9,  9,  9,  9,  6,  9, 11, 11, 11, 12, 12, 12, 12, 12, 12,
     12, 12, 12, 12
   },
   {
     10,  3,  2,  2,  3,  4,  4,  5,  6,  6,  7,  7,  7,  8,  8,  9, 10, 10, 10, 11,
     11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
     12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
     12, 12, 12, 12, 10, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13,
     13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 11, 11, 11, 12, 12, 12, 12, 12, 12,
     12, 12, 12, 12
   }
 };
 
 static const uint8_t ccitt_group3_2d_bits[11] = {
     1, 1, 2, 2, 2, 1, 3, 3, 3, 1, 1
 };
 
 static const uint8_t ccitt_group3_2d_lens[11] = {
     4, 3, 7, 6, 3, 1, 3, 6, 7, 7, 9
 };
 
 static VLC ccitt_vlc[2], ccitt_group3_2d_vlc;
 

 av_cold void ff_ccitt_unpack_init(void)

 {
     static VLC_TYPE code_table1[528][2];
     static VLC_TYPE code_table2[648][2];
     int i;
     static int initialized = 0;
 
     if(initialized)
         return;
     ccitt_vlc[0].table = code_table1;
     ccitt_vlc[0].table_allocated = 528;
     ccitt_vlc[1].table = code_table2;
     ccitt_vlc[1].table_allocated = 648;
     for(i = 0; i < 2; i++){
         init_vlc_sparse(&ccitt_vlc[i], 9, CCITT_SYMS,
                         ccitt_codes_lens[i], 1, 1,
                         ccitt_codes_bits[i], 1, 1,
                         ccitt_syms, 2, 2,
                         INIT_VLC_USE_NEW_STATIC);
     }
     INIT_VLC_STATIC(&ccitt_group3_2d_vlc, 9, 11,
                     ccitt_group3_2d_lens, 1, 1,
                     ccitt_group3_2d_bits, 1, 1, 512);
     initialized = 1;
 }
 
 
 static int decode_group3_1d_line(AVCodecContext *avctx, GetBitContext *gb,

                                  unsigned int pix_left, int *runs, const int *runend)

 {

     int mode = 0;
     unsigned int run=0;

     unsigned int t;
     for(;;){
         t = get_vlc2(gb, ccitt_vlc[mode].table, 9, 2);
         run += t;
         if(t < 64){
             *runs++ = run;

             if(runs >= runend){
                 av_log(avctx, AV_LOG_ERROR, "Run overrun\n");
                 return -1;
             }

             if(pix_left <= run){
                 if(pix_left == run)

                     break;
                 av_log(avctx, AV_LOG_ERROR, "Run went out of bounds\n");
                 return -1;
             }

             pix_left -= run;

             run = 0;
             mode = !mode;
         }else if((int)t == -1){
             av_log(avctx, AV_LOG_ERROR, "Incorrect code\n");
             return -1;
         }
     }
     *runs++ = 0;
     return 0;
 }
 
 static int decode_group3_2d_line(AVCodecContext *avctx, GetBitContext *gb,

                                  unsigned int width, int *runs, const int *runend, const int *ref)

 {

     int mode = 0, saved_run = 0, t;

     int run_off = *ref++;

     unsigned int offs=0, run= 0;

     runend--; // for the last written 0
 

     while(offs < width){

         int cmode = get_vlc2(gb, ccitt_group3_2d_vlc.table, 9, 1);
         if(cmode == -1){
             av_log(avctx, AV_LOG_ERROR, "Incorrect mode VLC\n");
             return -1;
         }
         if(!cmode){//pass mode
             run_off += *ref++;
             run = run_off - offs;

             offs= run_off;

             run_off += *ref++;

             if(offs > width){

                 av_log(avctx, AV_LOG_ERROR, "Run went out of bounds\n");
                 return -1;
             }
             saved_run += run;
         }else if(cmode == 1){//horizontal mode
             int k;
             for(k = 0; k < 2; k++){
                 run = 0;
                 for(;;){
                     t = get_vlc2(gb, ccitt_vlc[mode].table, 9, 2);
                     if(t == -1){
                         av_log(avctx, AV_LOG_ERROR, "Incorrect code\n");
                         return -1;
                     }
                     run += t;
                     if(t < 64)
                         break;
                 }
                 *runs++ = run + saved_run;

                 if(runs >= runend){
                     av_log(avctx, AV_LOG_ERROR, "Run overrun\n");
                     return -1;
                 }

                 saved_run = 0;

                 offs += run;

                 if(offs > width || run > width){

                     av_log(avctx, AV_LOG_ERROR, "Run went out of bounds\n");
                     return -1;
                 }
                 mode = !mode;
             }
         }else if(cmode == 9 || cmode == 10){
             av_log(avctx, AV_LOG_ERROR, "Special modes are not supported (yet)\n");
             return -1;
         }else{//vertical mode
             run = run_off - offs + (cmode - 5);

             run_off -= *--ref;

             offs += run;

             if(offs > width || run > width){

                 av_log(avctx, AV_LOG_ERROR, "Run went out of bounds\n");
                 return -1;
             }
             *runs++ = run + saved_run;

             if(runs >= runend){
                 av_log(avctx, AV_LOG_ERROR, "Run overrun\n");
                 return -1;
             }

             saved_run = 0;
             mode = !mode;
         }

         //sync line pointers
         while(run_off <= offs){
             run_off += *ref++;
             run_off += *ref++;
         }

     }
     *runs++ = saved_run;
     *runs++ = 0;
     return 0;
 }
 
 static void put_line(uint8_t *dst, int size, int width, const int *runs)
 {
     PutBitContext pb;

     int run, mode = ~0, pix_left = width, run_idx = 0;

 
     init_put_bits(&pb, dst, size*8);
     while(pix_left > 0){
         run = runs[run_idx++];

         mode = ~mode;

         pix_left -= run;
         for(; run > 16; run -= 16)

             put_sbits(&pb, 16, mode);

         if(run)

             put_sbits(&pb, run, mode);

     }

     flush_put_bits(&pb);

 }
 
 static int find_group3_syncmarker(GetBitContext *gb, int srcsize)
 {

     unsigned int state = -1;
     srcsize -= get_bits_count(gb);
     while(srcsize-- > 0){
         state+= state + get_bits1(gb);

         if((state & 0xFFF) == 1)

             return 0;

     }

     return -1;

 }
 

 int ff_ccitt_unpack(AVCodecContext *avctx,

                     const uint8_t *src, int srcsize,
                     uint8_t *dst, int height, int stride,
                     enum TiffCompr compr, int opts)

 {
     int j;
     GetBitContext gb;

     int *runs, *ref, *runend;

     int ret;

     int runsize= avctx->width + 2;

     runs = av_malloc(runsize * sizeof(runs[0]));
     ref  = av_malloc(runsize * sizeof(ref[0]));

     ref[0] = avctx->width;
     ref[1] = 0;
     ref[2] = 0;
     init_get_bits(&gb, src, srcsize*8);
     for(j = 0; j < height; j++){

         runend = runs + runsize;

         if(compr == TIFF_G4){

             ret = decode_group3_2d_line(avctx, &gb, avctx->width, runs, runend, ref);

             if(ret < 0){
                 av_free(runs);
                 av_free(ref);
                 return -1;
             }
         }else{

             int g3d1 = (compr == TIFF_G3) && !(opts & 1);

             if(compr!=TIFF_CCITT_RLE && find_group3_syncmarker(&gb, srcsize*8) < 0)

                 break;

             if(compr==TIFF_CCITT_RLE || g3d1 || get_bits1(&gb))

                 ret = decode_group3_1d_line(avctx, &gb, avctx->width, runs, runend);

             else

                 ret = decode_group3_2d_line(avctx, &gb, avctx->width, runs, runend, ref);

             if(compr==TIFF_CCITT_RLE)
                 align_get_bits(&gb);

         }
         if(ret < 0){
             put_line(dst, stride, avctx->width, ref);
         }else{
             put_line(dst, stride, avctx->width, runs);
             FFSWAP(int*, runs, ref);
         }
         dst += stride;
     }
     av_free(runs);
     av_free(ref);
     return 0;
 }