/*
  * Tiertex Limited SEQ Video Decoder
  * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.net)
  *
  * 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

  * Tiertex Limited SEQ video decoder
  */
 

 #define BITSTREAM_READER_LE

 #include "avcodec.h"

 #include "get_bits.h"

 #include "internal.h"

 
 
 typedef struct SeqVideoContext {
     AVCodecContext *avctx;

     AVFrame *frame;

 } SeqVideoContext;
 
 

 static const unsigned char *seq_unpack_rle_block(const unsigned char *src,
                                                  const unsigned char *src_end,
                                                  unsigned char *dst, int dst_size)

 {
     int i, len, sz;
     GetBitContext gb;
     int code_table[64];
 

     /* get the rle codes */
     init_get_bits(&gb, src, (src_end - src) * 8);

     for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {

         if (get_bits_left(&gb) < 4)
             return NULL;

         code_table[i] = get_sbits(&gb, 4);
         sz += FFABS(code_table[i]);
     }
     src += (get_bits_count(&gb) + 7) / 8;
 
     /* do the rle unpacking */
     for (i = 0; i < 64 && dst_size > 0; i++) {
         len = code_table[i];
         if (len < 0) {
             len = -len;

             if (src_end - src < 1)
                 return NULL;

             memset(dst, *src++, FFMIN(len, dst_size));
         } else {

             if (src_end - src < len)
                 return NULL;

             memcpy(dst, src, FFMIN(len, dst_size));
             src += len;
         }
         dst += len;
         dst_size -= len;
     }
     return src;
 }
 

 static const unsigned char *seq_decode_op1(SeqVideoContext *seq,
                                            const unsigned char *src,
                                            const unsigned char *src_end,
                                            unsigned char *dst)

 {

     const unsigned char *color_table;

     int b, i, len, bits;
     GetBitContext gb;

     unsigned char block[8 * 8];

     if (src_end - src < 1)
         return NULL;

     len = *src++;
     if (len & 0x80) {
         switch (len & 3) {
         case 1:

             src = seq_unpack_rle_block(src, src_end, block, sizeof(block));

             for (b = 0; b < 8; b++) {

                 memcpy(dst, &block[b * 8], 8);

                 dst += seq->frame->linesize[0];

             }
             break;
         case 2:

             src = seq_unpack_rle_block(src, src_end, block, sizeof(block));

             for (i = 0; i < 8; i++) {
                 for (b = 0; b < 8; b++)

                     dst[b * seq->frame->linesize[0]] = block[i * 8 + b];

                 ++dst;
             }
             break;
         }
     } else {

         if (len <= 0)
             return NULL;
         bits = ff_log2_tab[len - 1] + 1;
         if (src_end - src < len + 8 * bits)
             return NULL;

         color_table = src;
         src += len;
         init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
         for (b = 0; b < 8; b++) {
             for (i = 0; i < 8; i++)
                 dst[i] = color_table[get_bits(&gb, bits)];

             dst += seq->frame->linesize[0];

         }
     }
 
     return src;
 }
 

 static const unsigned char *seq_decode_op2(SeqVideoContext *seq,
                                            const unsigned char *src,
                                            const unsigned char *src_end,
                                            unsigned char *dst)

 {
     int i;
 

     if (src_end - src < 8 * 8)
         return NULL;
 

     for (i = 0; i < 8; i++) {
         memcpy(dst, src, 8);
         src += 8;

         dst += seq->frame->linesize[0];

     }
 
     return src;
 }
 

 static const unsigned char *seq_decode_op3(SeqVideoContext *seq,
                                            const unsigned char *src,
                                            const unsigned char *src_end,
                                            unsigned char *dst)

 {
     int pos, offset;
 
     do {

         if (src_end - src < 2)
             return NULL;

         pos = *src++;

         offset = ((pos >> 3) & 7) * seq->frame->linesize[0] + (pos & 7);

         dst[offset] = *src++;
     } while (!(pos & 0x80));
 
     return src;
 }
 

 static int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)

 {

     const unsigned char *data_end = data + data_size;

     GetBitContext gb;
     int flags, i, j, x, y, op;
     unsigned char c[3];
     unsigned char *dst;

     uint32_t *palette;

 
     flags = *data++;
 
     if (flags & 1) {

         palette = (uint32_t *)seq->frame->data[1];

         if (data_end - data < 256 * 3)
             return AVERROR_INVALIDDATA;

         for (i = 0; i < 256; i++) {
             for (j = 0; j < 3; j++, data++)
                 c[j] = (*data << 2) | (*data >> 4);

             palette[i] = 0xFFU << 24 | AV_RB24(c);

         }

         seq->frame->palette_has_changed = 1;

     }
 
     if (flags & 2) {

         if (data_end - data < 128)
             return AVERROR_INVALIDDATA;

         init_get_bits(&gb, data, 128 * 8); data += 128;
         for (y = 0; y < 128; y += 8)
             for (x = 0; x < 256; x += 8) {

                 dst = &seq->frame->data[0][y * seq->frame->linesize[0] + x];

                 op = get_bits(&gb, 2);
                 switch (op) {
                 case 1:

                     data = seq_decode_op1(seq, data, data_end, dst);

                     break;
                 case 2:

                     data = seq_decode_op2(seq, data, data_end, dst);

                     break;
                 case 3:

                     data = seq_decode_op3(seq, data, data_end, dst);

                     break;
                 }

                 if (!data)
                     return AVERROR_INVALIDDATA;

             }
     }

     return 0;

 }
 

 static av_cold int seqvideo_decode_init(AVCodecContext *avctx)

 {

     SeqVideoContext *seq = avctx->priv_data;

     int ret;

 
     seq->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     ret = ff_set_dimensions(avctx, 256, 128);
     if (ret < 0)
         return ret;
 

     seq->frame = av_frame_alloc();
     if (!seq->frame)
         return AVERROR(ENOMEM);

 
     return 0;
 }
 

 static int seqvideo_decode_frame(AVCodecContext *avctx,

                                  void *data, int *got_frame,

                                  AVPacket *avpkt)

 {

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

     int ret;

     SeqVideoContext *seq = avctx->priv_data;

     if ((ret = ff_reget_buffer(avctx, seq->frame)) < 0)

         return ret;

     if (seqvideo_decode(seq, buf, buf_size))
         return AVERROR_INVALIDDATA;

     if ((ret = av_frame_ref(data, seq->frame)) < 0)

         return ret;

     *got_frame       = 1;

 
     return buf_size;
 }
 

 static av_cold int seqvideo_decode_end(AVCodecContext *avctx)

 {

     SeqVideoContext *seq = avctx->priv_data;

     av_frame_free(&seq->frame);

 
     return 0;
 }
 

 AVCodec ff_tiertexseqvideo_decoder = {

     .name           = "tiertexseqvideo",

     .long_name      = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_TIERTEXSEQVIDEO,

     .priv_data_size = sizeof(SeqVideoContext),
     .init           = seqvideo_decode_init,
     .close          = seqvideo_decode_end,
     .decode         = seqvideo_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };