/*
  * Copyright (c) 2006 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
  */

 
 /**

  * @file

  * TIFF image decoder

  * @author Konstantin Shishkov
  */

 #include "avcodec.h"

 #if CONFIG_ZLIB

 #include <zlib.h>
 #endif

 #include "lzw.h"

 #include "tiff.h"

 #include "faxcompr.h"

 #include "libavutil/common.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 typedef struct TiffContext {
     AVCodecContext *avctx;
     AVFrame picture;
 
     int width, height;

     unsigned int bpp, bppcount;

     uint32_t palette[256];
     int palette_is_set;

     int le;

     enum TiffCompr compr;

     int invert;

     int fax_opts;

     int predictor;

     int fill_order;

     int strips, rps, sstype;

     int sot;

     const uint8_t* stripdata;
     const uint8_t* stripsizes;

     int stripsize, stripoff;

     LZWState *lzw;

 } TiffContext;
 

 static unsigned tget_short(const uint8_t **p, int le) {
     unsigned v = le ? AV_RL16(*p) : AV_RB16(*p);

     *p += 2;
     return v;
 }
 

 static unsigned tget_long(const uint8_t **p, int le) {
     unsigned v = le ? AV_RL32(*p) : AV_RB32(*p);

     *p += 4;
     return v;
 }
 

 static unsigned tget(const uint8_t **p, int type, int le) {

     switch(type){
     case TIFF_BYTE : return *(*p)++;
     case TIFF_SHORT: return tget_short(p, le);
     case TIFF_LONG : return tget_long (p, le);

     default        : return UINT_MAX;

     }
 }
 

 #if CONFIG_ZLIB

 static int tiff_uncompress(uint8_t *dst, unsigned long *len, const uint8_t *src, int size)
 {
     z_stream zstream;
     int zret;
 
     memset(&zstream, 0, sizeof(zstream));
     zstream.next_in = src;
     zstream.avail_in = size;
     zstream.next_out = dst;
     zstream.avail_out = *len;
     zret = inflateInit(&zstream);
     if (zret != Z_OK) {
         av_log(NULL, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
         return zret;
     }
     zret = inflate(&zstream, Z_SYNC_FLUSH);
     inflateEnd(&zstream);
     *len = zstream.total_out;
     return zret == Z_STREAM_END ? Z_OK : zret;
 }

 #endif

 static void av_always_inline horizontal_fill(unsigned int bpp, uint8_t* dst,
                                              int usePtr, const uint8_t *src,
                                              uint8_t c, int width, int offset)
 {

     switch (bpp) {

     case 1:
         while (--width >= 0) {
             dst[(width+offset)*8+7] = (usePtr ? src[width] : c)      & 0x1;
             dst[(width+offset)*8+6] = (usePtr ? src[width] : c) >> 1 & 0x1;
             dst[(width+offset)*8+5] = (usePtr ? src[width] : c) >> 2 & 0x1;
             dst[(width+offset)*8+4] = (usePtr ? src[width] : c) >> 3 & 0x1;
             dst[(width+offset)*8+3] = (usePtr ? src[width] : c) >> 4 & 0x1;
             dst[(width+offset)*8+2] = (usePtr ? src[width] : c) >> 5 & 0x1;
             dst[(width+offset)*8+1] = (usePtr ? src[width] : c) >> 6 & 0x1;
             dst[(width+offset)*8+0] = (usePtr ? src[width] : c) >> 7;
         }
         break;

     case 2:

         while (--width >= 0) {
             dst[(width+offset)*4+3] = (usePtr ? src[width] : c) & 0x3;
             dst[(width+offset)*4+2] = (usePtr ? src[width] : c) >> 2 & 0x3;
             dst[(width+offset)*4+1] = (usePtr ? src[width] : c) >> 4 & 0x3;
             dst[(width+offset)*4+0] = (usePtr ? src[width] : c) >> 6;

         }

         break;
     case 4:

         while (--width >= 0) {
             dst[(width+offset)*2+1] = (usePtr ? src[width] : c) & 0xF;
             dst[(width+offset)*2+0] = (usePtr ? src[width] : c) >> 4;

         }

         break;
     default:

         if (usePtr) {
             memcpy(dst + offset, src, width);
         } else {
             memset(dst + offset, c, width);
         }
     }
 }
 

 static int tiff_unpack_strip(TiffContext *s, uint8_t* dst, int stride, const uint8_t *src, int size, int lines){

     int c, line, pixels, code;

     const uint8_t *ssrc = src;

     int width = ((s->width * s->bpp) + 7) >> 3;

 #if CONFIG_ZLIB

     uint8_t *zbuf; unsigned long outlen;
 
     if(s->compr == TIFF_DEFLATE || s->compr == TIFF_ADOBE_DEFLATE){

         int ret;

         outlen = width * lines;
         zbuf = av_malloc(outlen);

         ret = tiff_uncompress(zbuf, &outlen, src, size);
         if(ret != Z_OK){
             av_log(s->avctx, AV_LOG_ERROR, "Uncompressing failed (%lu of %lu) with error %d\n", outlen, (unsigned long)width * lines, ret);

             av_free(zbuf);
             return -1;
         }
         src = zbuf;
         for(line = 0; line < lines; line++){

             if(s->bpp < 8 && s->avctx->pix_fmt == PIX_FMT_PAL8){
                 horizontal_fill(s->bpp, dst, 1, src, 0, width, 0);
             }else{
                 memcpy(dst, src, width);
             }

             dst += stride;
             src += width;
         }
         av_free(zbuf);
         return 0;
     }
 #endif

     if(s->compr == TIFF_LZW){
         if(ff_lzw_decode_init(s->lzw, 8, src, size, FF_LZW_TIFF) < 0){
             av_log(s->avctx, AV_LOG_ERROR, "Error initializing LZW decoder\n");
             return -1;
         }
     }

     if(s->compr == TIFF_CCITT_RLE || s->compr == TIFF_G3 || s->compr == TIFF_G4){
         int i, ret = 0;
         uint8_t *src2 = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
 
         if(!src2 || (unsigned)size + FF_INPUT_BUFFER_PADDING_SIZE < (unsigned)size){
             av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");
             return -1;
         }

         if(s->fax_opts & 2){
             av_log(s->avctx, AV_LOG_ERROR, "Uncompressed fax mode is not supported (yet)\n");
             av_free(src2);
             return -1;
         }

         if(!s->fill_order){
             memcpy(src2, src, size);
         }else{
             for(i = 0; i < size; i++)

                 src2[i] = av_reverse[src[i]];

         }

         memset(src2+size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
         switch(s->compr){
         case TIFF_CCITT_RLE:
         case TIFF_G3:
         case TIFF_G4:

             ret = ff_ccitt_unpack(s->avctx, src2, size, dst, lines, stride, s->compr, s->fax_opts);

             break;
         }

         if (s->bpp < 8 && s->avctx->pix_fmt == PIX_FMT_PAL8)

             for (line = 0; line < lines; line++) {
                 horizontal_fill(s->bpp, dst, 1, dst, 0, width, 0);
                 dst += stride;
             }

         av_free(src2);
         return ret;
     }

     for(line = 0; line < lines; line++){
         if(src - ssrc > size){
             av_log(s->avctx, AV_LOG_ERROR, "Source data overread\n");
             return -1;
         }
         switch(s->compr){
         case TIFF_RAW:

             if (ssrc + size - src < width)
                 return AVERROR_INVALIDDATA;

             if (!s->fill_order) {

                 horizontal_fill(s->bpp * (s->avctx->pix_fmt == PIX_FMT_PAL8),
                                 dst, 1, src, 0, width, 0);

             } else {
                 int i;
                 for (i = 0; i < width; i++)
                     dst[i] = av_reverse[src[i]];
             }

             src += width;

             break;
         case TIFF_PACKBITS:
             for(pixels = 0; pixels < width;){

                 if (ssrc + size - src < 2)
                     return AVERROR_INVALIDDATA;

                 code = (int8_t)*src++;
                 if(code >= 0){
                     code++;

                     if (pixels + code > width ||
                         ssrc + size - src < code) {

                         av_log(s->avctx, AV_LOG_ERROR, "Copy went out of bounds\n");
                         return -1;
                     }

                     horizontal_fill(s->bpp * (s->avctx->pix_fmt == PIX_FMT_PAL8),
                                     dst, 1, src, 0, code, pixels);

                     src += code;
                     pixels += code;
                 }else if(code != -128){ // -127..-1
                     code = (-code) + 1;
                     if(pixels + code > width){
                         av_log(s->avctx, AV_LOG_ERROR, "Run went out of bounds\n");
                         return -1;
                     }
                     c = *src++;

                     horizontal_fill(s->bpp * (s->avctx->pix_fmt == PIX_FMT_PAL8),
                                     dst, 0, NULL, c, code, pixels);

                     pixels += code;
                 }
             }
             break;

         case TIFF_LZW:
             pixels = ff_lzw_decode(s->lzw, dst, width);
             if(pixels < width){
                 av_log(s->avctx, AV_LOG_ERROR, "Decoded only %i bytes of %i\n", pixels, width);
                 return -1;
             }

             if (s->bpp < 8 && s->avctx->pix_fmt == PIX_FMT_PAL8)

                 horizontal_fill(s->bpp, dst, 1, dst, 0, width, 0);

             break;

         }
         dst += stride;
     }
     return 0;
 }
 

 static int init_image(TiffContext *s)
 {
     int i, ret;
     uint32_t *pal;
 
     switch (s->bpp * 10 + s->bppcount) {
     case 11:

         if (!s->palette_is_set) {
             s->avctx->pix_fmt = PIX_FMT_MONOBLACK;
             break;
         }

     case 21:
     case 41:

     case 81:
         s->avctx->pix_fmt = PIX_FMT_PAL8;
         break;
     case 243:
         s->avctx->pix_fmt = PIX_FMT_RGB24;
         break;
     case 161:
         s->avctx->pix_fmt = PIX_FMT_GRAY16BE;
         break;

     case 162:
         s->avctx->pix_fmt = PIX_FMT_GRAY8A;
         break;

     case 324:
         s->avctx->pix_fmt = PIX_FMT_RGBA;
         break;
     case 483:
         s->avctx->pix_fmt = s->le ? PIX_FMT_RGB48LE : PIX_FMT_RGB48BE;
         break;

     case 644:
         s->avctx->pix_fmt = s->le ? PIX_FMT_RGBA64LE : PIX_FMT_RGBA64BE;
         break;

     default:
         av_log(s->avctx, AV_LOG_ERROR,
                "This format is not supported (bpp=%d, bppcount=%d)\n",
                s->bpp, s->bppcount);
         return AVERROR_INVALIDDATA;
     }
     if (s->width != s->avctx->width || s->height != s->avctx->height) {
         if ((ret = av_image_check_size(s->width, s->height, 0, s->avctx)) < 0)
             return ret;
         avcodec_set_dimensions(s->avctx, s->width, s->height);
     }
     if (s->picture.data[0])
         s->avctx->release_buffer(s->avctx, &s->picture);
     if ((ret = s->avctx->get_buffer(s->avctx, &s->picture)) < 0) {
         av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return ret;
     }

     if (s->avctx->pix_fmt == PIX_FMT_PAL8) {
         if (s->palette_is_set) {
             memcpy(s->picture.data[1], s->palette, sizeof(s->palette));
         } else {
             /* make default grayscale pal */
             pal = (uint32_t *) s->picture.data[1];

             for (i = 0; i < 1<<s->bpp; i++)

                 pal[i] = 0xFF << 24 | i * 255 / ((1<<s->bpp) - 1) * 0x010101;

         }

     }
     return 0;
 }

 static int tiff_decode_tag(TiffContext *s, const uint8_t *start, const uint8_t *buf, const uint8_t *end_buf)

 {

     unsigned tag, type, count, off, value = 0;

     int i, j;

     uint32_t *pal;

     const uint8_t *rp, *gp, *bp;

     if (end_buf - buf < 12)
         return -1;

     tag = tget_short(&buf, s->le);
     type = tget_short(&buf, s->le);
     count = tget_long(&buf, s->le);
     off = tget_long(&buf, s->le);
 

     if (type == 0 || type >= FF_ARRAY_ELEMS(type_sizes)) {
         av_log(s->avctx, AV_LOG_DEBUG, "Unknown tiff type (%u) encountered\n", type);
         return 0;
     }
 

     if(count == 1){
         switch(type){
         case TIFF_BYTE:
         case TIFF_SHORT:
             buf -= 4;
             value = tget(&buf, type, s->le);
             buf = NULL;
             break;
         case TIFF_LONG:
             value = off;
             buf = NULL;
             break;

         case TIFF_STRING:
             if(count <= 4){
                 buf -= 4;
                 break;
             }

         default:

             value = UINT_MAX;

             buf = start + off;
         }

     } else {
         if (count <= 4 && type_sizes[type] * count <= 4) {
             buf -= 4;
         } else {

             buf = start + off;
         }
     }
 
     if(buf && (buf < start || buf > end_buf)){
         av_log(s->avctx, AV_LOG_ERROR, "Tag referencing position outside the image\n");
         return -1;
     }
 
     switch(tag){
     case TIFF_WIDTH:
         s->width = value;
         break;
     case TIFF_HEIGHT:
         s->height = value;
         break;
     case TIFF_BPP:

         s->bppcount = count;

         if(count > 4){
             av_log(s->avctx, AV_LOG_ERROR, "This format is not supported (bpp=%d, %d components)\n", s->bpp, count);
             return -1;
         }

         if(count == 1) s->bpp = value;
         else{
             switch(type){
             case TIFF_BYTE:

                 s->bpp = (off & 0xFF) + ((off >> 8) & 0xFF) + ((off >> 16) & 0xFF) + ((off >> 24) & 0xFF);

                 break;
             case TIFF_SHORT:
             case TIFF_LONG:

                 s->bpp = 0;

                 for(i = 0; i < count && buf < end_buf; i++) s->bpp += tget(&buf, type, s->le);

                 break;
             default:
                 s->bpp = -1;
             }
         }

         break;
     case TIFF_SAMPLES_PER_PIXEL:
         if (count != 1) {
             av_log(s->avctx, AV_LOG_ERROR,
                    "Samples per pixel requires a single value, many provided\n");
             return AVERROR_INVALIDDATA;

         }

         if (s->bppcount == 1)
             s->bpp *= value;
         s->bppcount = value;

         break;
     case TIFF_COMPR:
         s->compr = value;

         s->predictor = 0;

         switch(s->compr){
         case TIFF_RAW:
         case TIFF_PACKBITS:

         case TIFF_LZW:

         case TIFF_CCITT_RLE:
             break;
         case TIFF_G3:
         case TIFF_G4:
             s->fax_opts = 0;

             break;
         case TIFF_DEFLATE:
         case TIFF_ADOBE_DEFLATE:

 #if CONFIG_ZLIB

             break;
 #else
             av_log(s->avctx, AV_LOG_ERROR, "Deflate: ZLib not compiled in\n");
             return -1;
 #endif

         case TIFF_JPEG:
         case TIFF_NEWJPEG:
             av_log(s->avctx, AV_LOG_ERROR, "JPEG compression is not supported\n");
             return -1;

         default:
             av_log(s->avctx, AV_LOG_ERROR, "Unknown compression method %i\n", s->compr);
             return -1;
         }
         break;
     case TIFF_ROWSPERSTRIP:

         if (type == TIFF_LONG && value == UINT_MAX)

             value = s->height;

         if(value < 1){

             av_log(s->avctx, AV_LOG_ERROR, "Incorrect value of rows per strip\n");
             return -1;
         }
         s->rps = value;
         break;
     case TIFF_STRIP_OFFS:
         if(count == 1){
             s->stripdata = NULL;
             s->stripoff = value;
         }else
             s->stripdata = start + off;
         s->strips = count;

         if(s->strips == 1) s->rps = s->height;

         s->sot = type;
         if(s->stripdata > end_buf){
             av_log(s->avctx, AV_LOG_ERROR, "Tag referencing position outside the image\n");
             return -1;
         }
         break;
     case TIFF_STRIP_SIZE:
         if(count == 1){
             s->stripsizes = NULL;
             s->stripsize = value;
             s->strips = 1;
         }else{
             s->stripsizes = start + off;
         }
         s->strips = count;

         s->sstype = type;

         if(s->stripsizes > end_buf){
             av_log(s->avctx, AV_LOG_ERROR, "Tag referencing position outside the image\n");
             return -1;
         }
         break;

     case TIFF_TILE_BYTE_COUNTS:
     case TIFF_TILE_LENGTH:
     case TIFF_TILE_OFFSETS:
     case TIFF_TILE_WIDTH:
         av_log(s->avctx, AV_LOG_ERROR, "Tiled images are not supported\n");
         return AVERROR_PATCHWELCOME;
         break;

     case TIFF_PREDICTOR:

         s->predictor = value;

         break;

     case TIFF_INVERT:
         switch(value){
         case 0:
             s->invert = 1;
             break;
         case 1:
             s->invert = 0;
             break;

         case 2:
         case 3:
             break;
         default:
             av_log(s->avctx, AV_LOG_ERROR, "Color mode %d is not supported\n", value);
             return -1;

         }
         break;

     case TIFF_FILL_ORDER:
         if(value < 1 || value > 2){
             av_log(s->avctx, AV_LOG_ERROR, "Unknown FillOrder value %d, trying default one\n", value);
             value = 1;
         }
         s->fill_order = value - 1;
         break;

     case TIFF_PAL:

         pal = (uint32_t *) s->palette;

         off = type_sizes[type];

         if (count / 3 > 256 || end_buf - buf < count / 3 * off * 3)
             return -1;

         rp = buf;
         gp = buf + count / 3 * off;
         bp = buf + count / 3 * off * 2;

         off = (type_sizes[type] - 1) << 3;

         for(i = 0; i < count / 3; i++){

             j = 0xff << 24;
             j |= (tget(&rp, type, s->le) >> off) << 16;

             j |= (tget(&gp, type, s->le) >> off) << 8;
             j |= tget(&bp, type, s->le) >> off;
             pal[i] = j;
         }

         s->palette_is_set = 1;

         break;
     case TIFF_PLANAR:
         if(value == 2){
             av_log(s->avctx, AV_LOG_ERROR, "Planar format is not supported\n");
             return -1;
         }
         break;

     case TIFF_T4OPTIONS:

         if(s->compr == TIFF_G3)
             s->fax_opts = value;
         break;

     case TIFF_T6OPTIONS:

         if(s->compr == TIFF_G4)
             s->fax_opts = value;

         break;

     default:
         av_log(s->avctx, AV_LOG_DEBUG, "Unknown or unsupported tag %d/0X%0X\n", tag, tag);

     }
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *data_size,

                         AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     TiffContext * const s = avctx->priv_data;
     AVFrame *picture = data;
     AVFrame * const p= (AVFrame*)&s->picture;

     const uint8_t *orig_buf = buf, *end_buf = buf + buf_size;

     unsigned off;
     int id, le, ret;

     int i, j, entries;

     int stride;
     unsigned soff, ssize;

     uint8_t *dst;

 
     //parse image header

     if (end_buf - buf < 8)
         return AVERROR_INVALIDDATA;

     id = AV_RL16(buf); buf += 2;

     if(id == 0x4949) le = 1;
     else if(id == 0x4D4D) le = 0;
     else{
         av_log(avctx, AV_LOG_ERROR, "TIFF header not found\n");
         return -1;
     }
     s->le = le;

     s->invert = 0;

     s->compr = TIFF_RAW;

     s->fill_order = 0;

     // As TIFF 6.0 specification puts it "An arbitrary but carefully chosen number
     // that further identifies the file as a TIFF file"
     if(tget_short(&buf, le) != 42){
         av_log(avctx, AV_LOG_ERROR, "The answer to life, universe and everything is not correct!\n");
         return -1;
     }

     // Reset these pointers so we can tell if they were set this frame
     s->stripsizes = s->stripdata = NULL;

     /* parse image file directory */
     off = tget_long(&buf, le);

     if (off >= UINT_MAX - 14 || end_buf - orig_buf < off + 14) {

         av_log(avctx, AV_LOG_ERROR, "IFD offset is greater than image size\n");

         return AVERROR_INVALIDDATA;

     }
     buf = orig_buf + off;
     entries = tget_short(&buf, le);
     for(i = 0; i < entries; i++){

         if(tiff_decode_tag(s, orig_buf, buf, end_buf) < 0)

             return -1;
         buf += 12;
     }

     if(!s->stripdata && !s->stripoff){
         av_log(avctx, AV_LOG_ERROR, "Image data is missing\n");
         return -1;
     }
     /* now we have the data and may start decoding */

     if ((ret = init_image(s)) < 0)
         return ret;
 

     if(s->strips == 1 && !s->stripsize){
         av_log(avctx, AV_LOG_WARNING, "Image data size missing\n");
         s->stripsize = buf_size - s->stripoff;
     }
     stride = p->linesize[0];
     dst = p->data[0];
     for(i = 0; i < s->height; i += s->rps){

         if(s->stripsizes) {
             if (s->stripsizes >= end_buf)
                 return AVERROR_INVALIDDATA;

             ssize = tget(&s->stripsizes, s->sstype, s->le);

         } else

             ssize = s->stripsize;
 
         if(s->stripdata){

             if (s->stripdata >= end_buf)
                 return AVERROR_INVALIDDATA;

             soff = tget(&s->stripdata, s->sot, s->le);
         }else
             soff = s->stripoff;

 
         if (soff > buf_size || ssize > buf_size - soff) {
             av_log(avctx, AV_LOG_ERROR, "Invalid strip size/offset\n");
             return -1;

         }

         if(tiff_unpack_strip(s, dst, stride, orig_buf + soff, ssize, FFMIN(s->rps, s->height - i)) < 0)
             break;
         dst += s->rps * stride;
     }
     if(s->predictor == 2){
         dst = p->data[0];
         soff = s->bpp >> 3;
         ssize = s->width * soff;

         if (s->avctx->pix_fmt == PIX_FMT_RGB48LE ||
             s->avctx->pix_fmt == PIX_FMT_RGBA64LE) {

             for (i = 0; i < s->height; i++) {
                 for (j = soff; j < ssize; j += 2)
                     AV_WL16(dst + j, AV_RL16(dst + j) + AV_RL16(dst + j - soff));
                 dst += stride;
             }

         } else if (s->avctx->pix_fmt == PIX_FMT_RGB48BE ||
                    s->avctx->pix_fmt == PIX_FMT_RGBA64BE) {

             for (i = 0; i < s->height; i++) {
                 for (j = soff; j < ssize; j += 2)
                     AV_WB16(dst + j, AV_RB16(dst + j) + AV_RB16(dst + j - soff));
                 dst += stride;
             }
         } else {

             for(i = 0; i < s->height; i++) {
                 for(j = soff; j < ssize; j++)
                     dst[j] += dst[j - soff];
                 dst += stride;
             }

         }

     }

     if(s->invert){

         dst = s->picture.data[0];
         for(i = 0; i < s->height; i++){
             for(j = 0; j < s->picture.linesize[0]; j++)
                 dst[j] = (s->avctx->pix_fmt == PIX_FMT_PAL8 ? (1<<s->bpp) - 1 : 255) - dst[j];
             dst += s->picture.linesize[0];

         }
     }

     *picture= *(AVFrame*)&s->picture;
     *data_size = sizeof(AVPicture);
 
     return buf_size;
 }
 

 static av_cold int tiff_init(AVCodecContext *avctx){

     TiffContext *s = avctx->priv_data;
 
     s->width = 0;
     s->height = 0;
     s->avctx = avctx;
     avcodec_get_frame_defaults((AVFrame*)&s->picture);
     avctx->coded_frame= (AVFrame*)&s->picture;

     ff_lzw_decode_open(&s->lzw);

     ff_ccitt_unpack_init();

 
     return 0;
 }
 

 static av_cold int tiff_end(AVCodecContext *avctx)

 {
     TiffContext * const s = avctx->priv_data;
 

     ff_lzw_decode_close(&s->lzw);

     if(s->picture.data[0])
         avctx->release_buffer(avctx, &s->picture);
     return 0;
 }
 

 AVCodec ff_tiff_decoder = {

     .name           = "tiff",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_TIFF,
     .priv_data_size = sizeof(TiffContext),
     .init           = tiff_init,
     .close          = tiff_end,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("TIFF image"),

 };