/*

  * Packed Animation File video decoder

  * Copyright (c) 2012 Paul B Mahol
  *
  * 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 "libavutil/imgutils.h"
 

 #include "avcodec.h"

 #include "bytestream.h"

 #include "copy_block.h"

 #include "internal.h"

 static const uint8_t block_sequences[16][8] = {

     { 0, 0, 0, 0, 0, 0, 0, 0 },
     { 2, 0, 0, 0, 0, 0, 0, 0 },
     { 5, 7, 0, 0, 0, 0, 0, 0 },
     { 5, 0, 0, 0, 0, 0, 0, 0 },
     { 6, 0, 0, 0, 0, 0, 0, 0 },
     { 5, 7, 5, 7, 0, 0, 0, 0 },
     { 5, 7, 5, 0, 0, 0, 0, 0 },
     { 5, 7, 6, 0, 0, 0, 0, 0 },
     { 5, 5, 0, 0, 0, 0, 0, 0 },
     { 3, 0, 0, 0, 0, 0, 0, 0 },
     { 6, 6, 0, 0, 0, 0, 0, 0 },
     { 2, 4, 0, 0, 0, 0, 0, 0 },
     { 2, 4, 5, 7, 0, 0, 0, 0 },
     { 2, 4, 5, 0, 0, 0, 0, 0 },
     { 2, 4, 6, 0, 0, 0, 0, 0 },

     { 2, 4, 5, 7, 5, 7, 0, 0 },

 };
 
 typedef struct PAFVideoDecContext {

     AVFrame  *pic;

     GetByteContext gb;
 

     int width;
     int height;
 
     int current_frame;

     uint8_t *frame[4];

     int frame_size;
     int video_size;

 
     uint8_t *opcodes;
 } PAFVideoDecContext;
 

 static av_cold int paf_video_close(AVCodecContext *avctx)

 {
     PAFVideoDecContext *c = avctx->priv_data;
     int i;
 
     av_frame_free(&c->pic);
 
     for (i = 0; i < 4; i++)
         av_freep(&c->frame[i]);
 
     return 0;
 }
 

 static av_cold int paf_video_init(AVCodecContext *avctx)

 {
     PAFVideoDecContext *c = avctx->priv_data;
     int i;
 

     c->width  = avctx->width;
     c->height = avctx->height;
 

     if (avctx->height & 3 || avctx->width & 3) {

         av_log(avctx, AV_LOG_ERROR,
                "width %d and height %d must be multiplie of 4.\n",
                avctx->width, avctx->height);

         return AVERROR_INVALIDDATA;
     }
 

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

     c->pic = av_frame_alloc();
     if (!c->pic)
         return AVERROR(ENOMEM);
 

     c->frame_size = avctx->width * FFALIGN(avctx->height, 256);
     c->video_size = avctx->width * avctx->height;

     for (i = 0; i < 4; i++) {
         c->frame[i] = av_mallocz(c->frame_size);

         if (!c->frame[i]) {

             paf_video_close(avctx);

             return AVERROR(ENOMEM);

         }

     }
 
     return 0;
 }
 

 static void read4x4block(PAFVideoDecContext *c, uint8_t *dst, int width)

 {
     int i;
 
     for (i = 0; i < 4; i++) {
         bytestream2_get_buffer(&c->gb, dst, 4);

         dst += width;

     }
 }
 

 static void copy_color_mask(uint8_t *dst, int width, uint8_t mask, uint8_t color)

 {
     int i;
 
     for (i = 0; i < 4; i++) {

         if (mask & (1 << 7 - i))

             dst[i] = color;

         if (mask & (1 << 3 - i))
             dst[width + i] = color;

     }
 }
 

 static void copy_src_mask(uint8_t *dst, int width, uint8_t mask, const uint8_t *src)

 {
     int i;
 
     for (i = 0; i < 4; i++) {

         if (mask & (1 << 7 - i))

             dst[i] = src[i];

         if (mask & (1 << 3 - i))
             dst[width + i] = src[width + i];

     }
 }
 

 static void set_src_position(PAFVideoDecContext *c,
                              const uint8_t **p,
                              const uint8_t **pend)
 {
     int val  = bytestream2_get_be16(&c->gb);
     int page = val >> 14;
     int x    = (val & 0x7F);
     int y    = ((val >> 7) & 0x7F);
 
     *p    = c->frame[page] + x * 2 + y * 2 * c->width;
     *pend = c->frame[page] + c->frame_size;
 }
 
 static int decode_0(PAFVideoDecContext *c, uint8_t *pkt, uint8_t code)

 {
     uint32_t opcode_size, offset;

     uint8_t *dst, *dend, mask = 0, color = 0;

     const uint8_t *src, *send, *opcodes;

     int i, j, op = 0;

 
     i = bytestream2_get_byte(&c->gb);
     if (i) {
         if (code & 0x10) {
             int align;
 
             align = bytestream2_tell(&c->gb) & 3;
             if (align)
                 bytestream2_skip(&c->gb, 4 - align);
         }
         do {

             int page, val, x, y;
             val    = bytestream2_get_be16(&c->gb);
             page   = val >> 14;
             x      = (val & 0x7F) * 2;
             y      = ((val >> 7) & 0x7F) * 2;
             dst    = c->frame[page] + x + y * c->width;
             dend   = c->frame[page] + c->frame_size;
             offset = (x & 0x7F) * 2;

             j      = bytestream2_get_le16(&c->gb) + offset;

             if (bytestream2_get_bytes_left(&c->gb) < (j - offset) * 16)
                 return AVERROR_INVALIDDATA;

             do {
                 offset++;

                 if (dst + 3 * c->width + 4 > dend)

                     return AVERROR_INVALIDDATA;

                 read4x4block(c, dst, c->width);

                 if ((offset & 0x3F) == 0)

                     dst += c->width * 3;

                 dst += 4;
             } while (offset < j);
         } while (--i);
     }
 

     dst  = c->frame[c->current_frame];
     dend = c->frame[c->current_frame] + c->frame_size;

     do {

         set_src_position(c, &src, &send);
         if ((src + 3 * c->width + 4 > send) ||

             (dst + 3 * c->width + 4 > dend) ||
             bytestream2_get_bytes_left(&c->gb) < 4)

             return AVERROR_INVALIDDATA;

         copy_block4(dst, src, c->width, c->width, 4);

         i++;
         if ((i & 0x3F) == 0)

             dst += c->width * 3;

         dst += 4;
     } while (i < c->video_size / 16);
 
     opcode_size = bytestream2_get_le16(&c->gb);
     bytestream2_skip(&c->gb, 2);
 
     if (bytestream2_get_bytes_left(&c->gb) < opcode_size)
         return AVERROR_INVALIDDATA;
 
     opcodes = pkt + bytestream2_tell(&c->gb);
     bytestream2_skipu(&c->gb, opcode_size);
 
     dst = c->frame[c->current_frame];
 

     for (i = 0; i < c->height; i += 4, dst += c->width * 3)
         for (j = 0; j < c->width; j += 4, dst += 4) {

             int opcode, k = 0;

             if (op > opcode_size)

                 return AVERROR_INVALIDDATA;
             if (j & 4) {

                 opcode = opcodes[op] & 15;
                 op++;

             } else {

                 opcode = opcodes[op] >> 4;

             }
 
             while (block_sequences[opcode][k]) {

                 offset = c->width * 2;

                 code   = block_sequences[opcode][k++];
 
                 switch (code) {
                 case 2:
                     offset = 0;
                 case 3:

                     color = bytestream2_get_byte(&c->gb);

                 case 4:

                     mask = bytestream2_get_byte(&c->gb);
                     copy_color_mask(dst + offset, c->width, mask, color);

                     break;
                 case 5:
                     offset = 0;
                 case 6:

                     set_src_position(c, &src, &send);

                 case 7:

                     if (src + offset + c->width + 4 > send)

                         return AVERROR_INVALIDDATA;
                     mask = bytestream2_get_byte(&c->gb);

                     copy_src_mask(dst + offset, c->width, mask, src + offset);

                     break;
                 }
             }
         }
 
     return 0;
 }
 

 static int paf_video_decode(AVCodecContext *avctx, void *data,
                             int *got_frame, AVPacket *pkt)

 {
     PAFVideoDecContext *c = avctx->priv_data;

     uint8_t code, *dst, *end;

     int i, frame, ret;
 

     if (pkt->size < 2)
         return AVERROR_INVALIDDATA;

 
     bytestream2_init(&c->gb, pkt->data, pkt->size);
 
     code = bytestream2_get_byte(&c->gb);

     if ((code & 0xF) > 4 || (code & 0xF) == 3) {

         avpriv_request_sample(avctx, "unknown/invalid code");
         return AVERROR_INVALIDDATA;
     }
 
     if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
         return ret;
 

     if (code & 0x20) {  // frame is keyframe

         for (i = 0; i < 4; i++)
             memset(c->frame[i], 0, c->frame_size);
 

         memset(c->pic->data[1], 0, AVPALETTE_SIZE);

         c->current_frame  = 0;

         c->pic->key_frame = 1;
         c->pic->pict_type = AV_PICTURE_TYPE_I;

     } else {

         c->pic->key_frame = 0;
         c->pic->pict_type = AV_PICTURE_TYPE_P;

     }
 

     if (code & 0x40) {  // palette update

         uint32_t *out = (uint32_t *)c->pic->data[1];

         int index, count;
 
         index = bytestream2_get_byte(&c->gb);
         count = bytestream2_get_byte(&c->gb) + 1;
 

         if (index + count > 256)

             return AVERROR_INVALIDDATA;

         if (bytestream2_get_bytes_left(&c->gb) < 3 * count)

             return AVERROR_INVALIDDATA;
 
         out += index;
         for (i = 0; i < count; i++) {
             unsigned r, g, b;
 
             r = bytestream2_get_byteu(&c->gb);
             r = r << 2 | r >> 4;
             g = bytestream2_get_byteu(&c->gb);
             g = g << 2 | g >> 4;
             b = bytestream2_get_byteu(&c->gb);
             b = b << 2 | b >> 4;

             *out++ = (0xFFU << 24) | (r << 16) | (g << 8) | b;

         }

         c->pic->palette_has_changed = 1;

     }
 
     switch (code & 0x0F) {
     case 0:

         /* Block-based motion compensation using 4x4 blocks with either
          * horizontal or vertical vectors; might incorporate VQ as well. */
         if ((ret = decode_0(c, pkt->data, code)) < 0)

             return ret;
         break;
     case 1:

         /* Uncompressed data. This mode specifies that (width * height) bytes
          * should be copied directly from the encoded buffer into the output. */

         dst = c->frame[c->current_frame];

         // possibly chunk length data

         bytestream2_skip(&c->gb, 2);
         if (bytestream2_get_bytes_left(&c->gb) < c->video_size)
             return AVERROR_INVALIDDATA;
         bytestream2_get_bufferu(&c->gb, dst, c->video_size);
         break;
     case 2:

         /* Copy reference frame: Consume the next byte in the stream as the
          * reference frame (which should be 0, 1, 2, or 3, and should not be
          * the same as the current frame number). */

         frame = bytestream2_get_byte(&c->gb);
         if (frame > 3)
             return AVERROR_INVALIDDATA;
         if (frame != c->current_frame)
             memcpy(c->frame[c->current_frame], c->frame[frame], c->frame_size);
         break;
     case 4:

         /* Run length encoding.*/

         dst = c->frame[c->current_frame];
         end = dst + c->video_size;
 
         bytestream2_skip(&c->gb, 2);
 
         while (dst < end) {
             int8_t code;
             int count;
 
             if (bytestream2_get_bytes_left(&c->gb) < 2)
                 return AVERROR_INVALIDDATA;
 
             code  = bytestream2_get_byteu(&c->gb);
             count = FFABS(code) + 1;
 
             if (dst + count > end)
                 return AVERROR_INVALIDDATA;
             if (code < 0)
                 memset(dst, bytestream2_get_byteu(&c->gb), count);
             else
                 bytestream2_get_buffer(&c->gb, dst, count);
             dst += count;
         }
         break;
     default:

         av_assert0(0);

     }
 

     av_image_copy_plane(c->pic->data[0], c->pic->linesize[0],
                         c->frame[c->current_frame], c->width,
                         c->width, c->height);

 
     c->current_frame = (c->current_frame + 1) & 3;

     if ((ret = av_frame_ref(data, c->pic)) < 0)

         return ret;

     *got_frame = 1;

 
     return pkt->size;
 }
 
 AVCodec ff_paf_video_decoder = {
     .name           = "paf_video",

     .long_name      = NULL_IF_CONFIG_SMALL("Amazing Studio Packed Animation File Video"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_PAF_VIDEO,

     .priv_data_size = sizeof(PAFVideoDecContext),

     .init           = paf_video_init,
     .close          = paf_video_close,
     .decode         = paf_video_decode,

     .capabilities   = AV_CODEC_CAP_DR1,

 };