/*
  * Deluxe Paint Animation decoder
  * Copyright (c) 2009 Peter Ross
  *
  * 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

  * Deluxe Paint Animation decoder
  */
 
 #include "avcodec.h"
 #include "bytestream.h"

 #include "internal.h"

 
 typedef struct AnmContext {

     AVFrame *frame;

     int palette[AVPALETTE_COUNT];

     GetByteContext gb;

     int x;  ///< x coordinate position
 } AnmContext;
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {
     AnmContext *s = avctx->priv_data;
     int i;
 

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

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

     bytestream2_init(&s->gb, avctx->extradata, avctx->extradata_size);

     if (bytestream2_get_bytes_left(&s->gb) < 16 * 8 + 4 * 256) {
         av_frame_free(&s->frame);

         return AVERROR_INVALIDDATA;

     }

     bytestream2_skipu(&s->gb, 16 * 8);

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

         s->palette[i] = bytestream2_get_le32u(&s->gb);

 
     return 0;
 }
 
 /**
  * Perform decode operation

  * @param dst     pointer to destination image buffer
  * @param dst_end pointer to end of destination image buffer
  * @param gb GetByteContext (optional, see below)

  * @param pixel Fill color (optional, see below)
  * @param count Pixel count
  * @param x Pointer to x-axis counter
  * @param width Image width
  * @param linesize Destination image buffer linesize
  * @return non-zero if destination buffer is exhausted
  *

  * a copy operation is achieved when 'gb' is set

  * a fill operation is achieved when 'gb' is null and pixel is >= 0
  * a skip operation is achieved when 'gb' is null and pixel is < 0

  */
 static inline int op(uint8_t **dst, const uint8_t *dst_end,

                      GetByteContext *gb,

                      int pixel, int count,
                      int *x, int width, int linesize)
 {
     int remaining = width - *x;
     while(count > 0) {
         int striplen = FFMIN(count, remaining);

         if (gb) {
             if (bytestream2_get_bytes_left(gb) < striplen)

                 goto exhausted;

             bytestream2_get_bufferu(gb, *dst, striplen);

         } else if (pixel >= 0)
             memset(*dst, pixel, striplen);
         *dst      += striplen;
         remaining -= striplen;
         count     -= striplen;
         if (remaining <= 0) {
             *dst      += linesize - width;
             remaining  = width;
         }
         if (linesize > 0) {
             if (*dst >= dst_end) goto exhausted;
         } else {
             if (*dst <= dst_end) goto exhausted;
         }
     }
     *x = width - remaining;
     return 0;
 
 exhausted:
     *x = width - remaining;
     return 1;
 }
 
 static int decode_frame(AVCodecContext *avctx,

                         void *data, int *got_frame,

                         AVPacket *avpkt)
 {
     AnmContext *s = avctx->priv_data;
     const int buf_size = avpkt->size;
     uint8_t *dst, *dst_end;

     int count, ret;

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

         return ret;

     dst     = s->frame->data[0];
     dst_end = s->frame->data[0] + s->frame->linesize[0]*avctx->height;

     bytestream2_init(&s->gb, avpkt->data, buf_size);
 
     if (bytestream2_get_byte(&s->gb) != 0x42) {

         avpriv_request_sample(avctx, "Unknown record type");

         return AVERROR_INVALIDDATA;

     }

     if (bytestream2_get_byte(&s->gb)) {

         avpriv_request_sample(avctx, "Padding bytes");

         return AVERROR_PATCHWELCOME;

     }

     bytestream2_skip(&s->gb, 2);

 
     s->x = 0;
     do {
         /* if statements are ordered by probability */

 #define OP(gb, pixel, count) \

     op(&dst, dst_end, (gb), (pixel), (count), &s->x, avctx->width, s->frame->linesize[0])

         int type = bytestream2_get_byte(&s->gb);

         count = type & 0x7F;
         type >>= 7;
         if (count) {

             if (OP(type ? NULL : &s->gb, -1, count)) break;

         } else if (!type) {
             int pixel;

             count = bytestream2_get_byte(&s->gb);  /* count==0 gives nop */
             pixel = bytestream2_get_byte(&s->gb);

             if (OP(NULL, pixel, count)) break;
         } else {
             int pixel;

             type = bytestream2_get_le16(&s->gb);

             count = type & 0x3FFF;
             type >>= 14;
             if (!count) {
                 if (type == 0)
                     break; // stop
                 if (type == 2) {

                     avpriv_request_sample(avctx, "Unknown opcode");

                     return AVERROR_PATCHWELCOME;

                 }
                 continue;
             }

             pixel = type == 3 ? bytestream2_get_byte(&s->gb) : -1;

             if (type == 1) count += 0x4000;

             if (OP(type == 2 ? &s->gb : NULL, pixel, count)) break;

         }

     } while (bytestream2_get_bytes_left(&s->gb) > 0);

     memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);

     *got_frame = 1;

     if ((ret = av_frame_ref(data, s->frame)) < 0)
         return ret;
 

     return buf_size;
 }
 
 static av_cold int decode_end(AVCodecContext *avctx)
 {
     AnmContext *s = avctx->priv_data;

 
     av_frame_free(&s->frame);

     return 0;
 }
 

 AVCodec ff_anm_decoder = {

     .name           = "anm",

     .long_name      = NULL_IF_CONFIG_SMALL("Deluxe Paint Animation"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_ANM,

     .priv_data_size = sizeof(AnmContext),
     .init           = decode_init,
     .close          = decode_end,
     .decode         = decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,

 };