/*
  * Chronomaster DFA Video Decoder
  * Copyright (c) 2011 Konstantin Shishkov
  * based on work by Vladimir "VAG" Gneushev
  *

  * 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
  */
 

 #include <inttypes.h>
 

 #include "avcodec.h"
 #include "bytestream.h"

 #include "internal.h"

 #include "libavutil/avassert.h"

 #include "libavutil/imgutils.h"

 #include "libavutil/mem.h"

 
 typedef struct DfaContext {
     uint32_t pal[256];
     uint8_t *frame_buf;
 } DfaContext;
 
 static av_cold int dfa_decode_init(AVCodecContext *avctx)
 {
     DfaContext *s = avctx->priv_data;
 

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     if (!avctx->width || !avctx->height)
         return AVERROR_INVALIDDATA;
 
     av_assert0(av_image_check_size(avctx->width, avctx->height, 0, avctx) >= 0);

     s->frame_buf = av_mallocz(avctx->width * avctx->height);

     if (!s->frame_buf)
         return AVERROR(ENOMEM);
 
     return 0;
 }
 

 static int decode_copy(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     const int size = width * height;
 

     if (bytestream2_get_buffer(gb, frame, size) != size)

         return AVERROR_INVALIDDATA;

     return 0;
 }
 

 static int decode_tsw1(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     const uint8_t *frame_start = frame;
     const uint8_t *frame_end   = frame + width * height;
     int mask = 0x10000, bitbuf = 0;

     int v, count, segments;
     unsigned offset;

     segments = bytestream2_get_le32(gb);
     offset   = bytestream2_get_le32(gb);

     if (segments == 0 && offset == frame_end - frame)
         return 0; // skip frame

     if (frame_end - frame <= offset)

         return AVERROR_INVALIDDATA;

     frame += offset;

     while (segments--) {

         if (bytestream2_get_bytes_left(gb) < 2)

             return AVERROR_INVALIDDATA;

         if (mask == 0x10000) {

             bitbuf = bytestream2_get_le16u(gb);

             mask = 1;
         }

         if (frame_end - frame < 2)

             return AVERROR_INVALIDDATA;

         if (bitbuf & mask) {

             v = bytestream2_get_le16(gb);

             offset = (v & 0x1FFF) << 1;
             count = ((v >> 13) + 2) << 1;

             if (frame - frame_start < offset || frame_end - frame < count)

                 return AVERROR_INVALIDDATA;

             av_memcpy_backptr(frame, offset, count);
             frame += count;
         } else {

             *frame++ = bytestream2_get_byte(gb);
             *frame++ = bytestream2_get_byte(gb);

         }
         mask <<= 1;
     }
 
     return 0;
 }
 

 static int decode_dsw1(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     const uint8_t *frame_start = frame;
     const uint8_t *frame_end   = frame + width * height;
     int mask = 0x10000, bitbuf = 0;
     int v, offset, count, segments;
 

     segments = bytestream2_get_le16(gb);

     while (segments--) {

         if (bytestream2_get_bytes_left(gb) < 2)

             return AVERROR_INVALIDDATA;

         if (mask == 0x10000) {

             bitbuf = bytestream2_get_le16u(gb);

             mask = 1;
         }

         if (frame_end - frame < 2)

             return AVERROR_INVALIDDATA;

         if (bitbuf & mask) {

             v = bytestream2_get_le16(gb);

             offset = (v & 0x1FFF) << 1;
             count = ((v >> 13) + 2) << 1;

             if (frame - frame_start < offset || frame_end - frame < count)

                 return AVERROR_INVALIDDATA;

             av_memcpy_backptr(frame, offset, count);

             frame += count;
         } else if (bitbuf & (mask << 1)) {

             frame += bytestream2_get_le16(gb);

         } else {

             *frame++ = bytestream2_get_byte(gb);
             *frame++ = bytestream2_get_byte(gb);

         }
         mask <<= 2;
     }
 
     return 0;
 }
 

 static int decode_dds1(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     const uint8_t *frame_start = frame;
     const uint8_t *frame_end   = frame + width * height;
     int mask = 0x10000, bitbuf = 0;
     int i, v, offset, count, segments;
 

     segments = bytestream2_get_le16(gb);

     while (segments--) {

         if (bytestream2_get_bytes_left(gb) < 2)

             return AVERROR_INVALIDDATA;

         if (mask == 0x10000) {

             bitbuf = bytestream2_get_le16u(gb);

             mask = 1;
         }

         if (bitbuf & mask) {

             v = bytestream2_get_le16(gb);

             offset = (v & 0x1FFF) << 2;
             count = ((v >> 13) + 2) << 1;

             if (frame - frame_start < offset || frame_end - frame < count*2 + width)

                 return AVERROR_INVALIDDATA;

             for (i = 0; i < count; i++) {
                 frame[0] = frame[1] =
                 frame[width] = frame[width + 1] = frame[-offset];
 
                 frame += 2;
             }
         } else if (bitbuf & (mask << 1)) {

             v = bytestream2_get_le16(gb)*2;
             if (frame - frame_end < v)
                 return AVERROR_INVALIDDATA;
             frame += v;

         } else {

             if (frame_end - frame < width + 3)

                 return AVERROR_INVALIDDATA;

             frame[0] = frame[1] =

             frame[width] = frame[width + 1] =  bytestream2_get_byte(gb);

             frame += 2;
             frame[0] = frame[1] =

             frame[width] = frame[width + 1] =  bytestream2_get_byte(gb);

             frame += 2;
         }
         mask <<= 2;
     }
 
     return 0;
 }
 

 static int decode_bdlt(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     uint8_t *line_ptr;
     int count, lines, segments;
 

     count = bytestream2_get_le16(gb);

     if (count >= height)

         return AVERROR_INVALIDDATA;

     frame += width * count;

     lines = bytestream2_get_le16(gb);
     if (count + lines > height)

         return AVERROR_INVALIDDATA;

 
     while (lines--) {

         if (bytestream2_get_bytes_left(gb) < 1)

             return AVERROR_INVALIDDATA;

         line_ptr = frame;
         frame += width;

         segments = bytestream2_get_byteu(gb);

         while (segments--) {

             if (frame - line_ptr <= bytestream2_peek_byte(gb))

                 return AVERROR_INVALIDDATA;

             line_ptr += bytestream2_get_byte(gb);
             count = (int8_t)bytestream2_get_byte(gb);

             if (count >= 0) {

                 if (frame - line_ptr < count)

                     return AVERROR_INVALIDDATA;

                 if (bytestream2_get_buffer(gb, line_ptr, count) != count)

                     return AVERROR_INVALIDDATA;

             } else {
                 count = -count;

                 if (frame - line_ptr < count)

                     return AVERROR_INVALIDDATA;

                 memset(line_ptr, bytestream2_get_byte(gb), count);

             }
             line_ptr += count;
         }
     }
 
     return 0;
 }
 

 static int decode_wdlt(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     const uint8_t *frame_end   = frame + width * height;
     uint8_t *line_ptr;
     int count, i, v, lines, segments;

     int y = 0;

     lines = bytestream2_get_le16(gb);
     if (lines > height)

         return AVERROR_INVALIDDATA;

 
     while (lines--) {

         if (bytestream2_get_bytes_left(gb) < 2)

             return AVERROR_INVALIDDATA;

         segments = bytestream2_get_le16u(gb);

         while ((segments & 0xC000) == 0xC000) {

             unsigned skip_lines = -(int16_t)segments;

             unsigned delta = -((int16_t)segments * width);

             if (frame_end - frame <= delta || y + lines + skip_lines > height)

                 return AVERROR_INVALIDDATA;

             frame    += delta;

             y        += skip_lines;

             segments = bytestream2_get_le16(gb);

         }

 
         if (frame_end <= frame)
             return AVERROR_INVALIDDATA;

         if (segments & 0x8000) {
             frame[width - 1] = segments & 0xFF;

             segments = bytestream2_get_le16(gb);

         }
         line_ptr = frame;

         if (frame_end - frame < width)
             return AVERROR_INVALIDDATA;

         frame += width;

         y++;

         while (segments--) {

             if (frame - line_ptr <= bytestream2_peek_byte(gb))

                 return AVERROR_INVALIDDATA;

             line_ptr += bytestream2_get_byte(gb);
             count = (int8_t)bytestream2_get_byte(gb);

             if (count >= 0) {

                 if (frame - line_ptr < count * 2)

                     return AVERROR_INVALIDDATA;

                 if (bytestream2_get_buffer(gb, line_ptr, count * 2) != count * 2)

                     return AVERROR_INVALIDDATA;

                 line_ptr += count * 2;
             } else {
                 count = -count;

                 if (frame - line_ptr < count * 2)

                     return AVERROR_INVALIDDATA;

                 v = bytestream2_get_le16(gb);

                 for (i = 0; i < count; i++)
                     bytestream_put_le16(&line_ptr, v);
             }
         }
     }
 
     return 0;
 }
 

 static int decode_tdlt(GetByteContext *gb, uint8_t *frame, int width, int height)

 {

     const uint8_t *frame_end = frame + width * height;
     uint32_t segments = bytestream2_get_le32(gb);

     int skip, copy;

 
     while (segments--) {

         if (bytestream2_get_bytes_left(gb) < 2)

             return AVERROR_INVALIDDATA;

         copy = bytestream2_get_byteu(gb) * 2;
         skip = bytestream2_get_byteu(gb) * 2;
         if (frame_end - frame < copy + skip ||
             bytestream2_get_bytes_left(gb) < copy)

             return AVERROR_INVALIDDATA;

         frame += skip;
         bytestream2_get_buffer(gb, frame, copy);
         frame += copy;

     }
 
     return 0;

 }
 

 static int decode_blck(GetByteContext *gb, uint8_t *frame, int width, int height)

 {
     memset(frame, 0, width * height);
     return 0;
 }
 
 

 typedef int (*chunk_decoder)(GetByteContext *gb, uint8_t *frame, int width, int height);

 
 static const chunk_decoder decoder[8] = {
     decode_copy, decode_tsw1, decode_bdlt, decode_wdlt,

     decode_tdlt, decode_dsw1, decode_blck, decode_dds1,

 };
 
 static const char* chunk_name[8] = {

     "COPY", "TSW1", "BDLT", "WDLT", "TDLT", "DSW1", "BLCK", "DDS1"

 };
 
 static int dfa_decode_frame(AVCodecContext *avctx,

                             void *data, int *got_frame,

                             AVPacket *avpkt)
 {

     AVFrame *frame = data;

     DfaContext *s = avctx->priv_data;

     GetByteContext gb;

     const uint8_t *buf = avpkt->data;
     uint32_t chunk_type, chunk_size;
     uint8_t *dst;
     int ret;
     int i, pal_elems;

     int version = avctx->extradata_size==2 ? AV_RL16(avctx->extradata) : 0;

     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)

         return ret;
 

     bytestream2_init(&gb, avpkt->data, avpkt->size);
     while (bytestream2_get_bytes_left(&gb) > 0) {
         bytestream2_skip(&gb, 4);
         chunk_size = bytestream2_get_le32(&gb);
         chunk_type = bytestream2_get_le32(&gb);

         if (!chunk_type)
             break;
         if (chunk_type == 1) {
             pal_elems = FFMIN(chunk_size / 3, 256);
             for (i = 0; i < pal_elems; i++) {

                 s->pal[i] = bytestream2_get_be24(&gb) << 2;

                 s->pal[i] |= 0xFFU << 24 | (s->pal[i] >> 6) & 0x30303;

             }

             frame->palette_has_changed = 1;

         } else if (chunk_type <= 9) {

             if (decoder[chunk_type - 2](&gb, s->frame_buf, avctx->width, avctx->height)) {

                 av_log(avctx, AV_LOG_ERROR, "Error decoding %s chunk\n",
                        chunk_name[chunk_type - 2]);

                 return AVERROR_INVALIDDATA;

             }
         } else {

             av_log(avctx, AV_LOG_WARNING,
                    "Ignoring unknown chunk type %"PRIu32"\n",

                    chunk_type);
         }
         buf += chunk_size;
     }
 
     buf = s->frame_buf;

     dst = frame->data[0];

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

         if(version == 0x100) {
             int j;
             for(j = 0; j < avctx->width; j++) {
                 dst[j] = buf[ (i&3)*(avctx->width /4) + (j/4) +
                              ((j&3)*(avctx->height/4) + (i/4))*avctx->width];
             }
         } else {
             memcpy(dst, buf, avctx->width);
             buf += avctx->width;
         }

         dst += frame->linesize[0];

     }

     memcpy(frame->data[1], s->pal, sizeof(s->pal));

     *got_frame = 1;

 
     return avpkt->size;
 }
 
 static av_cold int dfa_decode_end(AVCodecContext *avctx)
 {
     DfaContext *s = avctx->priv_data;
 
     av_freep(&s->frame_buf);
 
     return 0;
 }
 
 AVCodec ff_dfa_decoder = {

     .name           = "dfa",

     .long_name      = NULL_IF_CONFIG_SMALL("Chronomaster DFA"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_DFA,

     .priv_data_size = sizeof(DfaContext),
     .init           = dfa_decode_init,
     .close          = dfa_decode_end,
     .decode         = dfa_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };