/*
  * Interplay C93 video decoder
  * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com>
  *
  * 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 "avcodec.h"
 #include "bytestream.h"
 
 typedef struct {
     AVFrame pictures[2];
     int currentpic;
 } C93DecoderContext;
 
 typedef enum {
     C93_8X8_FROM_PREV  = 0x02,
     C93_4X4_FROM_PREV  = 0x06,
     C93_4X4_FROM_CURR  = 0x07,
     C93_8X8_2COLOR     = 0x08,
     C93_4X4_2COLOR     = 0x0A,
     C93_4X4_4COLOR_GRP = 0x0B,
     C93_4X4_4COLOR     = 0x0D,
     C93_NOOP           = 0x0E,
     C93_8X8_INTRA      = 0x0F,
 } C93BlockType;
 
 #define WIDTH   320
 #define HEIGHT  192
 
 #define C93_HAS_PALETTE 0x01
 #define C93_FIRST_FRAME 0x02
 

 static av_cold int decode_init(AVCodecContext *avctx)

 {

     C93DecoderContext * const c93 = avctx->priv_data;
 
     avcodec_get_frame_defaults(&c93->pictures[0]);
     avcodec_get_frame_defaults(&c93->pictures[1]);

     avctx->pix_fmt = PIX_FMT_PAL8;
     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx)

 {
     C93DecoderContext * const c93 = avctx->priv_data;
 
     if (c93->pictures[0].data[0])
         avctx->release_buffer(avctx, &c93->pictures[0]);
     if (c93->pictures[1].data[0])
         avctx->release_buffer(avctx, &c93->pictures[1]);
     return 0;
 }
 

 static inline int copy_block(AVCodecContext *avctx, uint8_t *to,

         uint8_t *from, int offset, int height, int stride)
 {
     int i;
     int width = height;
     int from_x = offset % WIDTH;
     int from_y = offset / WIDTH;
     int overflow = from_x + width - WIDTH;
 
     if (!from) {
         /* silently ignoring predictive blocks in first frame */
         return 0;
     }
 
     if (from_y + height > HEIGHT) {
         av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n",
                offset);
         return -1;
     }
 
     if (overflow > 0) {
         width -= overflow;
         for (i = 0; i < height; i++) {
             memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow);
         }
     }
 
     for (i = 0; i < height; i++) {
         memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width);
     }
 
     return 0;
 }
 

 static inline void draw_n_color(uint8_t *out, int stride, int width,

          int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col)
 {
     int x, y;
     for (y = 0; y < height; y++) {
         if (grps)
             cols[0] = grps[3 * (y >> 1)];
         for (x = 0; x < width; x++) {
             if (grps)
                 cols[1]= grps[(x >> 1) + 1];
             out[x + y*stride] = cols[col & ((1 << bpp) - 1)];
             col >>= bpp;
         }
     }
 }
 

 static int decode_frame(AVCodecContext *avctx, void *data,

                             int *data_size, AVPacket *avpkt)

 {

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

     C93DecoderContext * const c93 = avctx->priv_data;
     AVFrame * const newpic = &c93->pictures[c93->currentpic];
     AVFrame * const oldpic = &c93->pictures[c93->currentpic^1];
     AVFrame *picture = data;
     uint8_t *out;

     int stride, i, x, y, bt = 0;

 
     c93->currentpic ^= 1;
 

     newpic->reference = 3;

     newpic->buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |
                          FF_BUFFER_HINTS_REUSABLE | FF_BUFFER_HINTS_READABLE;
     if (avctx->reget_buffer(avctx, newpic)) {
         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
         return -1;
     }
 
     stride = newpic->linesize[0];
 
     if (buf[0] & C93_FIRST_FRAME) {

         newpic->pict_type = AV_PICTURE_TYPE_I;

         newpic->key_frame = 1;
     } else {

         newpic->pict_type = AV_PICTURE_TYPE_P;

         newpic->key_frame = 0;
     }
 
     if (*buf++ & C93_HAS_PALETTE) {
         uint32_t *palette = (uint32_t *) newpic->data[1];

         const uint8_t *palbuf = buf + buf_size - 768 - 1;

         for (i = 0; i < 256; i++) {

             palette[i] = 0xFF << 24 | bytestream_get_be24(&palbuf);

         }
     } else {
         if (oldpic->data[1])
             memcpy(newpic->data[1], oldpic->data[1], 256 * 4);
     }
 
     for (y = 0; y < HEIGHT; y += 8) {
         out = newpic->data[0] + y * stride;
         for (x = 0; x < WIDTH; x += 8) {
             uint8_t *copy_from = oldpic->data[0];
             unsigned int offset, j;
             uint8_t cols[4], grps[4];

             C93BlockType block_type;

 
             if (!bt)
                 bt = *buf++;
 

             block_type= bt & 0x0F;
             switch (block_type) {

             case C93_8X8_FROM_PREV:
                 offset = bytestream_get_le16(&buf);

                 if (copy_block(avctx, out, copy_from, offset, 8, stride))

                     return -1;
                 break;
 
             case C93_4X4_FROM_CURR:
                 copy_from = newpic->data[0];
             case C93_4X4_FROM_PREV:
                 for (j = 0; j < 8; j += 4) {
                     for (i = 0; i < 8; i += 4) {
                         offset = bytestream_get_le16(&buf);

                         if (copy_block(avctx, &out[j*stride+i],

                                            copy_from, offset, 4, stride))
                             return -1;
                     }
                 }
                 break;
 
             case C93_8X8_2COLOR:
                 bytestream_get_buffer(&buf, cols, 2);
                 for (i = 0; i < 8; i++) {

                     draw_n_color(out + i*stride, stride, 8, 1, 1, cols,

                                      NULL, *buf++);
                 }
 
                 break;
 
             case C93_4X4_2COLOR:
             case C93_4X4_4COLOR:
             case C93_4X4_4COLOR_GRP:
                 for (j = 0; j < 8; j += 4) {
                     for (i = 0; i < 8; i += 4) {

                         if (block_type == C93_4X4_2COLOR) {

                             bytestream_get_buffer(&buf, cols, 2);

                             draw_n_color(out + i + j*stride, stride, 4, 4,

                                     1, cols, NULL, bytestream_get_le16(&buf));

                         } else if (block_type == C93_4X4_4COLOR) {

                             bytestream_get_buffer(&buf, cols, 4);

                             draw_n_color(out + i + j*stride, stride, 4, 4,

                                     2, cols, NULL, bytestream_get_le32(&buf));
                         } else {
                             bytestream_get_buffer(&buf, grps, 4);

                             draw_n_color(out + i + j*stride, stride, 4, 4,

                                     1, cols, grps, bytestream_get_le16(&buf));
                         }
                     }
                 }
                 break;
 
             case C93_NOOP:
                 break;
 
             case C93_8X8_INTRA:
                 for (j = 0; j < 8; j++)
                     bytestream_get_buffer(&buf, out + j*stride, 8);
                 break;
 
             default:
                 av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n",

                        block_type, x, y);

                 return -1;
             }
             bt >>= 4;
             out += 8;
         }
     }
 
     *picture = *newpic;
     *data_size = sizeof(AVFrame);
 
     return buf_size;
 }
 

 AVCodec ff_c93_decoder = {

     .name           = "c93",
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = CODEC_ID_C93,
     .priv_data_size = sizeof(C93DecoderContext),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,
     .capabilities   = CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"),

 };