/*
  * Alias PIX image decoder
  * Copyright (C) 2014 Vittorio Giovara <vittorio.giovara@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 "libavutil/intreadwrite.h"
 
 #include "avcodec.h"
 #include "bytestream.h"
 #include "internal.h"
 
 #define ALIAS_HEADER_SIZE 10
 
 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
                         AVPacket *avpkt)
 {
     AVFrame *f = data;
     GetByteContext gb;
     int width, height, ret, bits_pixel, pixel;
     uint8_t *out_buf;
     uint8_t count;
     int x, y;
 
     bytestream2_init(&gb, avpkt->data, avpkt->size);
 
     if (bytestream2_get_bytes_left(&gb) < ALIAS_HEADER_SIZE) {
         av_log(avctx, AV_LOG_ERROR, "Header too small %d.\n", avpkt->size);
         return AVERROR_INVALIDDATA;
     }
 
     width  = bytestream2_get_be16u(&gb);
     height = bytestream2_get_be16u(&gb);
     bytestream2_skipu(&gb, 4); // obsolete X, Y offset
     bits_pixel = bytestream2_get_be16u(&gb);
 
     if (bits_pixel == 24)
         avctx->pix_fmt = AV_PIX_FMT_BGR24;
     else if (bits_pixel == 8)
         avctx->pix_fmt = AV_PIX_FMT_GRAY8;
     else {
         av_log(avctx, AV_LOG_ERROR, "Invalid pixel format.\n");
         return AVERROR_INVALIDDATA;
     }
 
     ret = ff_set_dimensions(avctx, width, height);
     if (ret < 0)
         return ret;
 
     ret = ff_get_buffer(avctx, f, 0);
     if (ret < 0)
         return ret;
 
     f->pict_type = AV_PICTURE_TYPE_I;
     f->key_frame = 1;
 
     x = 0;
     y = 1;
     out_buf = f->data[0];
     while (bytestream2_get_bytes_left(&gb) > 0) {
         int i;
 
         /* set buffer at the right position at every new line */
         if (x == avctx->width) {
             x = 0;
             out_buf = f->data[0] + f->linesize[0] * y++;
             if (y > avctx->height) {
                 av_log(avctx, AV_LOG_ERROR,
                        "Ended frame decoding with %d bytes left.\n",
                        bytestream2_get_bytes_left(&gb));
                 return AVERROR_INVALIDDATA;
             }
         }
 
         /* read packet and copy data */
         count = bytestream2_get_byteu(&gb);
         if (!count || x + count > avctx->width) {
             av_log(avctx, AV_LOG_ERROR, "Invalid run length %d.\n", count);
             return AVERROR_INVALIDDATA;
         }
 
         if (avctx->pix_fmt == AV_PIX_FMT_BGR24) {
             pixel = bytestream2_get_be24(&gb);
             for (i = 0; i < count; i++) {
                 AV_WB24(out_buf, pixel);
                 out_buf += 3;
             }
         } else { // AV_PIX_FMT_GRAY8
             pixel = bytestream2_get_byte(&gb);
             for (i = 0; i < count; i++)
                 *out_buf++ = pixel;
         }
 
         x += i;
     }
 
     if (x != width || y != height) {
         av_log(avctx, AV_LOG_ERROR, "Picture stopped at %d,%d.\n", x, y);
         return AVERROR_INVALIDDATA;
     }
 
     *got_frame = 1;
     return avpkt->size;
 }
 
 AVCodec ff_alias_pix_decoder = {
     .name         = "alias_pix",
     .long_name    = NULL_IF_CONFIG_SMALL("Alias/Wavefront PIX image"),
     .type         = AVMEDIA_TYPE_VIDEO,
     .id           = AV_CODEC_ID_ALIAS_PIX,
     .decode       = decode_frame,
     .capabilities = CODEC_CAP_DR1,
 };