/*
  * 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"

 #include "bytestream.h"

 #include "config.h"

 #if CONFIG_ZLIB

 #include <zlib.h>
 #endif

 #include "lzw.h"

 #include "tiff.h"

 #include "tiff_data.h"

 #include "faxcompr.h"

 #include "internal.h"

 #include "mathops.h"
 #include "libavutil/attributes.h"

 #include "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/avstring.h"

 typedef struct TiffContext {
     AVCodecContext *avctx;
     AVFrame picture;

     GetByteContext gb;

 
     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;

     int stripsizesoff, stripsize, stripoff, strippos;

     LZWState *lzw;

     uint8_t *deinvert_buf;
     int deinvert_buf_size;
 

     int geotag_count;
     TiffGeoTag *geotags;

 } TiffContext;
 

 static unsigned tget_short(GetByteContext *gb, int le)

 {

     unsigned v = le ? bytestream2_get_le16(gb) : bytestream2_get_be16(gb);

     return v;
 }
 

 static unsigned tget_long(GetByteContext *gb, int le)

 {

     unsigned v = le ? bytestream2_get_le32(gb) : bytestream2_get_be32(gb);

     return v;
 }
 

 static double tget_double(GetByteContext *gb, int le)

 {

     av_alias64 i = { .u64 = le ? bytestream2_get_le64(gb) : bytestream2_get_be64(gb)};

     return i.f64;
 }
 

 static unsigned tget(GetByteContext *gb, int type, int le)

 {
     switch (type) {

     case TIFF_BYTE : return bytestream2_get_byte(gb);

     case TIFF_SHORT: return tget_short(gb, le);
     case TIFF_LONG : return tget_long(gb, le);

     default        : return UINT_MAX;

     }
 }
 

 static void free_geotags(TiffContext *const s)
 {
     int i;
     for (i = 0; i < s->geotag_count; i++) {
         if (s->geotags[i].val)
             av_freep(&s->geotags[i].val);
     }
     av_freep(&s->geotags);
 }
 
 #define RET_GEOKEY(TYPE, array, element)\
     if (key >= TIFF_##TYPE##_KEY_ID_OFFSET &&\
         key - TIFF_##TYPE##_KEY_ID_OFFSET < FF_ARRAY_ELEMS(ff_tiff_##array##_name_type_map))\
         return ff_tiff_##array##_name_type_map[key - TIFF_##TYPE##_KEY_ID_OFFSET].element;
 
 static const char *get_geokey_name(int key)
 {
     RET_GEOKEY(VERT, vert, name);
     RET_GEOKEY(PROJ, proj, name);
     RET_GEOKEY(GEOG, geog, name);
     RET_GEOKEY(CONF, conf, name);
 
     return NULL;
 }
 
 static int get_geokey_type(int key)
 {
     RET_GEOKEY(VERT, vert, type);
     RET_GEOKEY(PROJ, proj, type);
     RET_GEOKEY(GEOG, geog, type);
     RET_GEOKEY(CONF, conf, type);
 
     return AVERROR_INVALIDDATA;
 }
 
 static int cmp_id_key(const void *id, const void *k)
 {
     return *(const int*)id - ((const TiffGeoTagKeyName*)k)->key;
 }
 
 static const char *search_keyval(const TiffGeoTagKeyName *keys, int n, int id)
 {

     TiffGeoTagKeyName *r = bsearch(&id, keys, n, sizeof(keys[0]), cmp_id_key);
     if(r)
         return r->name;
 
     return NULL;

 }
 
 static char *get_geokey_val(int key, int val)
 {
     char *ap;
 
     if (val == TIFF_GEO_KEY_UNDEFINED)
         return av_strdup("undefined");
     if (val == TIFF_GEO_KEY_USER_DEFINED)
         return av_strdup("User-Defined");
 
 #define RET_GEOKEY_VAL(TYPE, array)\
     if (val >= TIFF_##TYPE##_OFFSET &&\
         val - TIFF_##TYPE##_OFFSET < FF_ARRAY_ELEMS(ff_tiff_##array##_codes))\
         return av_strdup(ff_tiff_##array##_codes[val - TIFF_##TYPE##_OFFSET]);
 
     switch (key) {
     case TIFF_GT_MODEL_TYPE_GEOKEY:
         RET_GEOKEY_VAL(GT_MODEL_TYPE, gt_model_type);
         break;
     case TIFF_GT_RASTER_TYPE_GEOKEY:
         RET_GEOKEY_VAL(GT_RASTER_TYPE, gt_raster_type);
         break;
     case TIFF_GEOG_LINEAR_UNITS_GEOKEY:
     case TIFF_PROJ_LINEAR_UNITS_GEOKEY:
     case TIFF_VERTICAL_UNITS_GEOKEY:
         RET_GEOKEY_VAL(LINEAR_UNIT, linear_unit);
         break;
     case TIFF_GEOG_ANGULAR_UNITS_GEOKEY:
     case TIFF_GEOG_AZIMUTH_UNITS_GEOKEY:
         RET_GEOKEY_VAL(ANGULAR_UNIT, angular_unit);
         break;
     case TIFF_GEOGRAPHIC_TYPE_GEOKEY:
         RET_GEOKEY_VAL(GCS_TYPE, gcs_type);
         RET_GEOKEY_VAL(GCSE_TYPE, gcse_type);
         break;
     case TIFF_GEOG_GEODETIC_DATUM_GEOKEY:
         RET_GEOKEY_VAL(GEODETIC_DATUM, geodetic_datum);
         RET_GEOKEY_VAL(GEODETIC_DATUM_E, geodetic_datum_e);
         break;
     case TIFF_GEOG_ELLIPSOID_GEOKEY:
         RET_GEOKEY_VAL(ELLIPSOID, ellipsoid);
         break;
     case TIFF_GEOG_PRIME_MERIDIAN_GEOKEY:
         RET_GEOKEY_VAL(PRIME_MERIDIAN, prime_meridian);
         break;
     case TIFF_PROJECTED_CS_TYPE_GEOKEY:

         ap = av_strdup(search_keyval(ff_tiff_proj_cs_type_codes, FF_ARRAY_ELEMS(ff_tiff_proj_cs_type_codes), val));
         if(ap) return ap;

         break;
     case TIFF_PROJECTION_GEOKEY:

         ap = av_strdup(search_keyval(ff_tiff_projection_codes, FF_ARRAY_ELEMS(ff_tiff_projection_codes), val));
         if(ap) return ap;

         break;
     case TIFF_PROJ_COORD_TRANS_GEOKEY:
         RET_GEOKEY_VAL(COORD_TRANS, coord_trans);
         break;
     case TIFF_VERTICAL_CS_TYPE_GEOKEY:
         RET_GEOKEY_VAL(VERT_CS, vert_cs);
         RET_GEOKEY_VAL(ORTHO_VERT_CS, ortho_vert_cs);
         break;
 
     }
 
     ap = av_malloc(14);
     if (ap)
         snprintf(ap, 14, "Unknown-%d", val);
     return ap;
 }
 
 static char *doubles2str(double *dp, int count, const char *sep)
 {
     int i;
     char *ap, *ap0;

     uint64_t component_len;

     if (!sep) sep = ", ";

     component_len = 15LL + strlen(sep);
     if (count >= (INT_MAX - 1)/component_len)
         return NULL;
     ap = av_malloc(component_len * count + 1);

     if (!ap)
         return NULL;
     ap0   = ap;
     ap[0] = '\0';
     for (i = 0; i < count; i++) {

         unsigned l = snprintf(ap, component_len, "%f%s", dp[i], sep);

         if(l >= component_len) {
             av_free(ap0);

             return NULL;

         }

         ap += l;
     }
     ap0[strlen(ap0) - strlen(sep)] = '\0';
     return ap0;
 }
 

 static char *shorts2str(int16_t *sp, int count, const char *sep)

 {
     int i;
     char *ap, *ap0;

     uint64_t component_len;

     if (!sep) sep = ", ";

     component_len = 7LL + strlen(sep);
     if (count >= (INT_MAX - 1)/component_len)
         return NULL;
     ap = av_malloc(component_len * count + 1);

     if (!ap)
         return NULL;
     ap0   = ap;
     ap[0] = '\0';
     for (i = 0; i < count; i++) {

         unsigned l = snprintf(ap, component_len, "%d%s", sp[i], sep);
         if (l >= component_len) {
             av_free(ap0);
             return NULL;
         }

         ap += l;
     }
     ap0[strlen(ap0) - strlen(sep)] = '\0';
     return ap0;
 }
 

 static int add_doubles_metadata(int count,

                                 const char *name, const char *sep,
                                 TiffContext *s)
 {
     char *ap;
     int i;

     double *dp;
 

     if (count >= INT_MAX / sizeof(int64_t) || count <= 0)

         return AVERROR_INVALIDDATA;

     if (bytestream2_get_bytes_left(&s->gb) < count * sizeof(int64_t))

         return AVERROR_INVALIDDATA;

 
     dp = av_malloc(count * sizeof(double));

     if (!dp)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < count; i++)

         dp[i] = tget_double(&s->gb, s->le);

     ap = doubles2str(dp, count, sep);
     av_freep(&dp);
     if (!ap)
         return AVERROR(ENOMEM);

     av_dict_set(ff_frame_get_metadatap(&s->picture), name, ap, AV_DICT_DONT_STRDUP_VAL);

     return 0;
 }
 

 static int add_shorts_metadata(int count, const char *name,

                                const char *sep, TiffContext *s)
 {
     char *ap;
     int i;

     int16_t *sp;
 

     if (count >= INT_MAX / sizeof(int16_t) || count <= 0)

         return AVERROR_INVALIDDATA;

     if (bytestream2_get_bytes_left(&s->gb) < count * sizeof(int16_t))

         return AVERROR_INVALIDDATA;

 
     sp = av_malloc(count * sizeof(int16_t));

     if (!sp)
         return AVERROR(ENOMEM);
 
     for (i = 0; i < count; i++)

         sp[i] = tget_short(&s->gb, s->le);

     ap = shorts2str(sp, count, sep);
     av_freep(&sp);
     if (!ap)
         return AVERROR(ENOMEM);

     av_dict_set(ff_frame_get_metadatap(&s->picture), name, ap, AV_DICT_DONT_STRDUP_VAL);

     return 0;
 }
 

 static int add_string_metadata(int count, const char *name,
                                TiffContext *s)
 {
     char *value;
 

     if (bytestream2_get_bytes_left(&s->gb) < count || count < 0)

         return AVERROR_INVALIDDATA;
 
     value = av_malloc(count + 1);
     if (!value)
         return AVERROR(ENOMEM);
 
     bytestream2_get_bufferu(&s->gb, value, count);
     value[count] = 0;
 

     av_dict_set(ff_frame_get_metadatap(&s->picture), name, value, AV_DICT_DONT_STRDUP_VAL);

     return 0;
 }
 

 static int add_metadata(int count, int type,

                         const char *name, const char *sep, TiffContext *s)
 {
     switch(type) {

     case TIFF_DOUBLE: return add_doubles_metadata(count, name, sep, s);
     case TIFF_SHORT : return add_shorts_metadata(count, name, sep, s);

     case TIFF_STRING: return add_string_metadata(count, name, s);

     default         : return AVERROR_INVALIDDATA;
     };
 }
 

 #if CONFIG_ZLIB

 static int tiff_uncompress(uint8_t *dst, unsigned long *len, const uint8_t *src,
                            int size)

 {

     z_stream zstream = { 0 };

     int zret;
 

     zstream.next_in = (uint8_t *)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, ret;

     const uint8_t *ssrc = src;

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

     if (size <= 0)
         return AVERROR_INVALIDDATA;
 
 #if CONFIG_ZLIB

     if (s->compr == TIFF_DEFLATE || s->compr == TIFF_ADOBE_DEFLATE) {

         uint8_t *src2 = NULL, *zbuf;

         unsigned long outlen;

         int i, ret;

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

         if (!zbuf)
             return AVERROR(ENOMEM);

         if (s->fill_order) {
             src2 = av_malloc((unsigned)size + FF_INPUT_BUFFER_PADDING_SIZE);
             if (!src2) {
                 av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");
                 av_free(zbuf);
                 return AVERROR(ENOMEM);
             }
             for (i = 0; i < size; i++)
                 src2[i] = ff_reverse[src[i]];
             memset(src2 + size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
             src = src2;
         }

         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(src2);

             av_free(zbuf);

             return AVERROR_UNKNOWN;

         }
         src = zbuf;

         for (line = 0; line < lines; line++) {

             if(s->bpp < 8 && s->avctx->pix_fmt == AV_PIX_FMT_PAL8){

                 horizontal_fill(s->bpp, dst, 1, src, 0, width, 0);
             }else{
                 memcpy(dst, src, width);
             }

             dst += stride;
             src += width;
         }

         av_free(src2);

         av_free(zbuf);
         return 0;
     }
 #endif

     if (s->compr == TIFF_LZW) {

         if (s->fill_order) {
             int i;
             av_fast_padded_malloc(&s->deinvert_buf, &s->deinvert_buf_size, size);
             if (!s->deinvert_buf)
                 return AVERROR(ENOMEM);
             for (i = 0; i < size; i++)
                 s->deinvert_buf[i] = ff_reverse[src[i]];
             src = s->deinvert_buf;
             ssrc = src;
         }

         if (size > 1 && !src[0] && (src[1]&1)) {
             av_log(s->avctx, AV_LOG_ERROR, "Old style LZW is unsupported\n");
         }

         if ((ret = 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 ret;

         }
     }

     if (s->compr == TIFF_CCITT_RLE || s->compr == TIFF_G3
         || s->compr == TIFF_G4) {

         int i, ret = 0;

         uint8_t *src2 = av_malloc((unsigned)size +
                                   FF_INPUT_BUFFER_PADDING_SIZE);

         if (!src2) {

             av_log(s->avctx, AV_LOG_ERROR,
                    "Error allocating temporary buffer\n");

             return AVERROR(ENOMEM);

         }

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

             av_free(src2);

             return AVERROR_INVALIDDATA;

         }

         if (!s->fill_order) {

             memcpy(src2, src, size);

         } else {
             for (i = 0; i < size; i++)

                 src2[i] = ff_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 == AV_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 AVERROR_INVALIDDATA;

         }

         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 == AV_PIX_FMT_PAL8),

                                 dst, 1, src, 0, width, 0);

             } else {
                 int i;
                 for (i = 0; i < width; i++)

                     dst[i] = ff_reverse[src[i]];

             }

             src += width;

             break;
         case TIFF_PACKBITS:

             for (pixels = 0; pixels < width;) {

                 if (ssrc + size - src < 2) {
                     av_log(s->avctx, AV_LOG_ERROR, "Read went out of bounds\n");
                     return AVERROR_INVALIDDATA;
                 }

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

                     code++;

                     if (pixels + code > width) {
                         av_log(s->avctx, AV_LOG_ERROR,
                                "Copy went out of bounds\n");

                         return AVERROR_INVALIDDATA;

                     }

                     if (ssrc + size - src < code) {
                         av_log(s->avctx, AV_LOG_ERROR, "Read went out of bounds\n");
                         return AVERROR_INVALIDDATA;
                     }

                     horizontal_fill(s->bpp * (s->avctx->pix_fmt == AV_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 AVERROR_INVALIDDATA;

                     }
                     c = *src++;

                     horizontal_fill(s->bpp * (s->avctx->pix_fmt == AV_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 AVERROR_INVALIDDATA;

             }

             if (s->bpp < 8 && s->avctx->pix_fmt == AV_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 = AV_PIX_FMT_MONOBLACK;

             break;
         }

     case 21:
     case 41:

     case 81:

         s->avctx->pix_fmt = AV_PIX_FMT_PAL8;

         break;
     case 243:

         s->avctx->pix_fmt = AV_PIX_FMT_RGB24;

         break;
     case 161:

         s->avctx->pix_fmt = s->le ? AV_PIX_FMT_GRAY16LE : AV_PIX_FMT_GRAY16BE;

         break;

     case 162:

         s->avctx->pix_fmt = AV_PIX_FMT_GRAY8A;

         break;

     case 324:

         s->avctx->pix_fmt = AV_PIX_FMT_RGBA;

         break;
     case 483:

         s->avctx->pix_fmt = s->le ? AV_PIX_FMT_RGB48LE : AV_PIX_FMT_RGB48BE;

         break;

     case 644:

         s->avctx->pix_fmt = s->le ? AV_PIX_FMT_RGBA64LE : AV_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 = ff_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 == AV_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] = 0xFFU << 24 | i * 255 / ((1<<s->bpp) - 1) * 0x010101;

         }

     }
     return 0;
 }

 static int tiff_decode_tag(TiffContext *s)

 {

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

     int i, j, k, pos, start;

     int ret;

     uint32_t *pal;

     double *dp;

     tag   = tget_short(&s->gb, s->le);
     type  = tget_short(&s->gb, s->le);
     count = tget_long(&s->gb, s->le);
     off   = tget_long(&s->gb, s->le);
     start = bytestream2_tell(&s->gb);

     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:

             bytestream2_seek(&s->gb, -4, SEEK_CUR);
             value = tget(&s->gb, type, s->le);

             break;
         case TIFF_LONG:
             value = off;
             break;

         case TIFF_STRING:

             if (count <= 4) {

                 bytestream2_seek(&s->gb, -4, SEEK_CUR);

                 break;
             }

         default:

             value = UINT_MAX;

             bytestream2_seek(&s->gb, off, SEEK_SET);

         }

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

             bytestream2_seek(&s->gb, -4, SEEK_CUR);

         } else {

             bytestream2_seek(&s->gb, off, SEEK_SET);

         }
     }
 

     switch (tag) {

     case TIFF_WIDTH:
         s->width = value;
         break;
     case TIFF_HEIGHT:
         s->height = value;
         break;
     case TIFF_BPP:

         if (count > 4U) {

             av_log(s->avctx, AV_LOG_ERROR,
                    "This format is not supported (bpp=%d, %d components)\n",

                    value, count);

             return AVERROR_INVALIDDATA;

         }

         s->bppcount = count;

         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;

                 if (bytestream2_get_bytes_left(&s->gb) < type_sizes[type] * count)

                     return AVERROR_INVALIDDATA;

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

                     s->bpp += tget(&s->gb, type, s->le);

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

         if (s->bpp > 64U) {
             av_log(s->avctx, AV_LOG_ERROR,
                    "This format is not supported (bpp=%d, %d components)\n",
                    s->bpp, count);
             s->bpp = 0;
             return AVERROR_INVALIDDATA;
         }

         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 (value > 4U) {
             av_log(s->avctx, AV_LOG_ERROR,
                    "Samples per pixel %d is too large\n", value);
             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 AVERROR(ENOSYS);

 #endif

         case TIFF_JPEG:
         case TIFF_NEWJPEG:

             av_log(s->avctx, AV_LOG_ERROR,
                    "JPEG compression is not supported\n");

             return AVERROR_PATCHWELCOME;

         default:

             av_log(s->avctx, AV_LOG_ERROR, "Unknown compression method %i\n",
                    s->compr);

             return AVERROR_INVALIDDATA;

         }
         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 AVERROR_INVALIDDATA;

         }
         s->rps = value;
         break;
     case TIFF_STRIP_OFFS:

         if (count == 1) {

             s->strippos = 0;

             s->stripoff = value;

         } else

             s->strippos = off;

         s->strips = count;

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

         s->sot = type;

         if (s->strippos > bytestream2_size(&s->gb)) {

             av_log(s->avctx, AV_LOG_ERROR,
                    "Tag referencing position outside the image\n");

             return AVERROR_INVALIDDATA;

         }
         break;
     case TIFF_STRIP_SIZE:

         if (count == 1) {

             s->stripsizesoff = 0;

             s->stripsize = value;
             s->strips = 1;

         } else {

             s->stripsizesoff = off;

         }
         s->strips = count;

         s->sstype = type;

         if (s->stripsizesoff > bytestream2_size(&s->gb)) {

             av_log(s->avctx, AV_LOG_ERROR,
                    "Tag referencing position outside the image\n");

             return AVERROR_INVALIDDATA;

         }
         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 AVERROR_INVALIDDATA;

         }
         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 || bytestream2_get_bytes_left(&s->gb) < count / 3 * off * 3)

             return AVERROR_INVALIDDATA;

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

         for (k = 2; k >= 0; k--) {
             for (i = 0; i < count / 3; i++) {
                 if (k == 2)

                     pal[i] = 0xFFU << 24;

                 j =  (tget(&s->gb, type, s->le) >> off) << (k * 8);
                 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 AVERROR_PATCHWELCOME;

         }
         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;

 #define ADD_METADATA(count, name, sep)\

     if ((ret = add_metadata(count, type, name, sep, s)) < 0) {\

         av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");\
         return ret;\
     }
     case TIFF_MODEL_PIXEL_SCALE:
         ADD_METADATA(count, "ModelPixelScaleTag", NULL);
         break;
     case TIFF_MODEL_TRANSFORMATION:
         ADD_METADATA(count, "ModelTransformationTag", NULL);
         break;
     case TIFF_MODEL_TIEPOINT:
         ADD_METADATA(count, "ModelTiepointTag", NULL);
         break;
     case TIFF_GEO_KEY_DIRECTORY:
         ADD_METADATA(1, "GeoTIFF_Version", NULL);
         ADD_METADATA(2, "GeoTIFF_Key_Revision", ".");

         s->geotag_count   = tget_short(&s->gb, s->le);

         if (s->geotag_count > count / 4 - 1) {
             s->geotag_count = count / 4 - 1;
             av_log(s->avctx, AV_LOG_WARNING, "GeoTIFF key directory buffer shorter than specified\n");
         }

         if (bytestream2_get_bytes_left(&s->gb) < s->geotag_count * sizeof(int16_t) * 4) {
             s->geotag_count = 0;

             return -1;

         }

         s->geotags = av_mallocz(sizeof(TiffGeoTag) * s->geotag_count);
         if (!s->geotags) {
             av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");

             s->geotag_count = 0;

             return AVERROR(ENOMEM);
         }
         for (i = 0; i < s->geotag_count; i++) {

             s->geotags[i].key    = tget_short(&s->gb, s->le);
             s->geotags[i].type   = tget_short(&s->gb, s->le);
             s->geotags[i].count  = tget_short(&s->gb, s->le);

 
             if (!s->geotags[i].type)

                 s->geotags[i].val  = get_geokey_val(s->geotags[i].key, tget_short(&s->gb, s->le));

             else

                 s->geotags[i].offset = tget_short(&s->gb, s->le);

         }
         break;
     case TIFF_GEO_DOUBLE_PARAMS:

         if (count >= INT_MAX / sizeof(int64_t))
             return AVERROR_INVALIDDATA;
         if (bytestream2_get_bytes_left(&s->gb) < count * sizeof(int64_t))
             return AVERROR_INVALIDDATA;

         dp = av_malloc(count * sizeof(double));
         if (!dp) {
             av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");
             return AVERROR(ENOMEM);
         }
         for (i = 0; i < count; i++)

             dp[i] = tget_double(&s->gb, s->le);

         for (i = 0; i < s->geotag_count; i++) {
             if (s->geotags[i].type == TIFF_GEO_DOUBLE_PARAMS) {
                 if (s->geotags[i].count == 0
                     || s->geotags[i].offset + s->geotags[i].count > count) {
                     av_log(s->avctx, AV_LOG_WARNING, "Invalid GeoTIFF key %d\n", s->geotags[i].key);
                 } else {
                     char *ap = doubles2str(&dp[s->geotags[i].offset], s->geotags[i].count, ", ");
                     if (!ap) {
                         av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");
                         av_freep(&dp);
                         return AVERROR(ENOMEM);
                     }
                     s->geotags[i].val = ap;
                 }
             }
         }
         av_freep(&dp);
         break;
     case TIFF_GEO_ASCII_PARAMS:

         pos = bytestream2_tell(&s->gb);

         for (i = 0; i < s->geotag_count; i++) {
             if (s->geotags[i].type == TIFF_GEO_ASCII_PARAMS) {
                 if (s->geotags[i].count == 0
                     || s->geotags[i].offset +  s->geotags[i].count > count) {
                     av_log(s->avctx, AV_LOG_WARNING, "Invalid GeoTIFF key %d\n", s->geotags[i].key);
                 } else {

                     char *ap;
 
                     bytestream2_seek(&s->gb, pos + s->geotags[i].offset, SEEK_SET);
                     if (bytestream2_get_bytes_left(&s->gb) < s->geotags[i].count)

                         return AVERROR_INVALIDDATA;

                     ap = av_malloc(s->geotags[i].count);

                     if (!ap) {
                         av_log(s->avctx, AV_LOG_ERROR, "Error allocating temporary buffer\n");
                         return AVERROR(ENOMEM);
                     }

                     bytestream2_get_bufferu(&s->gb, ap, s->geotags[i].count);

                     ap[s->geotags[i].count - 1] = '\0'; //replace the "|" delimiter with a 0 byte
                     s->geotags[i].val = ap;
                 }
             }
         }
         break;

     case TIFF_ARTIST:
         ADD_METADATA(count, "artist", NULL);
         break;
     case TIFF_COPYRIGHT:
         ADD_METADATA(count, "copyright", NULL);
         break;
     case TIFF_DATE:
         ADD_METADATA(count, "date", NULL);
         break;
     case TIFF_DOCUMENT_NAME:
         ADD_METADATA(count, "document_name", NULL);
         break;
     case TIFF_HOST_COMPUTER:
         ADD_METADATA(count, "computer", NULL);
         break;
     case TIFF_IMAGE_DESCRIPTION:
         ADD_METADATA(count, "description", NULL);
         break;
     case TIFF_MAKE:
         ADD_METADATA(count, "make", NULL);
         break;
     case TIFF_MODEL:
         ADD_METADATA(count, "model", NULL);
         break;
     case TIFF_PAGE_NAME:
         ADD_METADATA(count, "page_name", NULL);
         break;
     case TIFF_PAGE_NUMBER:
         ADD_METADATA(count, "page_number", " / ");
         break;
     case TIFF_SOFTWARE_NAME:
         ADD_METADATA(count, "software", NULL);
         break;

     default:

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

     }

     bytestream2_seek(&s->gb, start, SEEK_SET);

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

                         void *data, int *got_frame, AVPacket *avpkt)

 {

     TiffContext *const s = avctx->priv_data;

     AVFrame *picture = data;

     AVFrame *const p = &s->picture;

     unsigned off;
     int id, le, ret;

     int i, j, entries;

     int stride;
     unsigned soff, ssize;

     uint8_t *dst;

     GetByteContext stripsizes;
     GetByteContext stripdata;
 
     bytestream2_init(&s->gb, avpkt->data, avpkt->size);

 
     //parse image header

     if (avpkt->size < 8)

         return AVERROR_INVALIDDATA;

     id = bytestream2_get_le16u(&s->gb);

     if (id == 0x4949)
         le = 1;
     else if (id == 0x4D4D)
         le = 0;
     else {

         av_log(avctx, AV_LOG_ERROR, "TIFF header not found\n");

         return AVERROR_INVALIDDATA;

     }
     s->le = le;

     // TIFF_BPP is not a required tag and defaults to 1
     s->bppcount = s->bpp = 1;

     s->invert = 0;

     s->compr = TIFF_RAW;

     s->fill_order = 0;

     free_geotags(s);

     /* metadata has been destroyed from lavc internals, that pointer is not
      * valid anymore */

     av_frame_set_metadata(&s->picture, NULL);

     // 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(&s->gb, le) != 42) {

         av_log(avctx, AV_LOG_ERROR,
                "The answer to life, universe and everything is not correct!\n");

         return AVERROR_INVALIDDATA;

     }

     // Reset these offsets so we can tell if they were set this frame
     s->stripsizesoff = s->strippos = 0;

     /* parse image file directory */

     off = tget_long(&s->gb, le);
     if (off >= UINT_MAX - 14 || avpkt->size < off + 14) {

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

         return AVERROR_INVALIDDATA;

     }

     bytestream2_seek(&s->gb, off, SEEK_SET);
     entries = tget_short(&s->gb, le);

     if (bytestream2_get_bytes_left(&s->gb) < entries * 12)
         return AVERROR_INVALIDDATA;

     for (i = 0; i < entries; i++) {

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

     }

 
     for (i = 0; i<s->geotag_count; i++) {
         const char *keyname = get_geokey_name(s->geotags[i].key);
         if (!keyname) {
             av_log(avctx, AV_LOG_WARNING, "Unknown or unsupported GeoTIFF key %d\n", s->geotags[i].key);
             continue;
         }
         if (get_geokey_type(s->geotags[i].key) != s->geotags[i].type) {
             av_log(avctx, AV_LOG_WARNING, "Type of GeoTIFF key %d is wrong\n", s->geotags[i].key);
             continue;
         }

         ret = av_dict_set(ff_frame_get_metadatap(&s->picture), keyname, s->geotags[i].val, 0);

         if (ret<0) {
             av_log(avctx, AV_LOG_ERROR, "Writing metadata with key '%s' failed\n", keyname);
             return ret;
         }
     }
 

     if (!s->strippos && !s->stripoff) {

         av_log(avctx, AV_LOG_ERROR, "Image data is missing\n");

         return AVERROR_INVALIDDATA;

     }
     /* 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 = avpkt->size - s->stripoff;

     }
     stride = p->linesize[0];
     dst = p->data[0];

 
     if (s->stripsizesoff) {

         if (s->stripsizesoff >= (unsigned)avpkt->size)

             return AVERROR_INVALIDDATA;
         bytestream2_init(&stripsizes, avpkt->data + s->stripsizesoff, avpkt->size - s->stripsizesoff);
     }
     if (s->strippos) {

         if (s->strippos >= (unsigned)avpkt->size)

             return AVERROR_INVALIDDATA;
         bytestream2_init(&stripdata, avpkt->data + s->strippos, avpkt->size - s->strippos);
     }
 

     if (s->rps <= 0) {
         av_log(avctx, AV_LOG_ERROR, "rps %d invalid\n", s->rps);
         return AVERROR_INVALIDDATA;
     }
 

     for (i = 0; i < s->height; i += s->rps) {

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

             ssize = s->stripsize;
 

         if (s->strippos)
             soff = tget(&stripdata, s->sot, s->le);
         else

             soff = s->stripoff;

         if (soff > avpkt->size || ssize > avpkt->size - soff) {

             av_log(avctx, AV_LOG_ERROR, "Invalid strip size/offset\n");

             return AVERROR_INVALIDDATA;

         }

         if (tiff_unpack_strip(s, dst, stride, avpkt->data + 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 == AV_PIX_FMT_RGB48LE ||
             s->avctx->pix_fmt == AV_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 == AV_PIX_FMT_RGB48BE ||
                    s->avctx->pix_fmt == AV_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 == AV_PIX_FMT_PAL8 ? (1<<s->bpp) - 1 : 255) - dst[j];

             dst += s->picture.linesize[0];

         }
     }

     *picture   = s->picture;

     *got_frame = 1;

     return avpkt->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(&s->picture);
     avctx->coded_frame = &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;

     free_geotags(s);
 

     ff_lzw_decode_close(&s->lzw);

     av_freep(&s->deinvert_buf);

     if (s->picture.data[0])

         avctx->release_buffer(avctx, &s->picture);
     return 0;
 }
 

 AVCodec ff_tiff_decoder = {

     .name           = "tiff",
     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_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"),

 };