/*
  * CamStudio decoder
  * Copyright (c) 2006 Reimar Doeffinger
  *

  * 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 <stdio.h>
 #include <stdlib.h>
 
 #include "avcodec.h"

 #include "internal.h"

 #include "libavutil/common.h"

 #if CONFIG_ZLIB

 #include <zlib.h>
 #endif

 #include "libavutil/lzo.h"

 typedef struct CamStudioContext {

     AVFrame *pic;

     int linelen, height, bpp;
     unsigned int decomp_size;
     unsigned char* decomp_buf;
 } CamStudioContext;
 

 static void copy_frame_default(AVFrame *f, const uint8_t *src,

                                int linelen, int height) {

     int i, src_stride = FFALIGN(linelen, 4);

     uint8_t *dst = f->data[0];
     dst += (height - 1) * f->linesize[0];
     for (i = height; i; i--) {
         memcpy(dst, src, linelen);

         src += src_stride;

         dst -= f->linesize[0];
     }
 }
 

 static void add_frame_default(AVFrame *f, const uint8_t *src,

                               int linelen, int height) {

     int i, j, src_stride = FFALIGN(linelen, 4);

     uint8_t *dst = f->data[0];
     dst += (height - 1) * f->linesize[0];
     for (i = height; i; i--) {
         for (j = linelen; j; j--)
             *dst++ += *src++;

         src += src_stride - linelen;

         dst -= f->linesize[0] + linelen;
     }
 }
 

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

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

     CamStudioContext *c = avctx->priv_data;

     int ret;

 
     if (buf_size < 2) {
         av_log(avctx, AV_LOG_ERROR, "coded frame too small\n");

         return AVERROR_INVALIDDATA;

     }
 

     if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)

         return ret;

 
     // decompress data
     switch ((buf[0] >> 1) & 7) {
         case 0: { // lzo compression

             int outlen = c->decomp_size, inlen = buf_size - 2;

             if (av_lzo1x_decode(c->decomp_buf, &outlen, &buf[2], &inlen) || outlen) {

                 av_log(avctx, AV_LOG_ERROR, "error during lzo decompression\n");

                 return AVERROR_INVALIDDATA;
             }

             break;
         }
         case 1: { // zlib compression

 #if CONFIG_ZLIB

             unsigned long dlen = c->decomp_size;

             if (uncompress(c->decomp_buf, &dlen, &buf[2], buf_size - 2) != Z_OK) {

                 av_log(avctx, AV_LOG_ERROR, "error during zlib decompression\n");

                 return AVERROR_INVALIDDATA;
             }

             break;
 #else
             av_log(avctx, AV_LOG_ERROR, "compiled without zlib support\n");

             return AVERROR(ENOSYS);

 #endif
         }
         default:
             av_log(avctx, AV_LOG_ERROR, "unknown compression\n");

             return AVERROR_INVALIDDATA;

     }
 
     // flip upside down, add difference frame
     if (buf[0] & 1) { // keyframe

         c->pic->pict_type = AV_PICTURE_TYPE_I;
         c->pic->key_frame = 1;
               copy_frame_default(c->pic, c->decomp_buf,

                                  c->linelen, c->height);

     } else {

         c->pic->pict_type = AV_PICTURE_TYPE_P;
         c->pic->key_frame = 0;
               add_frame_default(c->pic, c->decomp_buf,

                                 c->linelen, c->height);

     }
 

     *got_frame = 1;

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

     return buf_size;
 }
 

 static av_cold int decode_init(AVCodecContext *avctx) {

     CamStudioContext *c = avctx->priv_data;

     int stride;

     switch (avctx->bits_per_coded_sample) {

         case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555LE; break;

         case 24: avctx->pix_fmt = AV_PIX_FMT_BGR24; break;

         case 32: avctx->pix_fmt = AV_PIX_FMT_BGR0; break;

         default:
             av_log(avctx, AV_LOG_ERROR,

                    "CamStudio codec error: invalid depth %i bpp\n",

                    avctx->bits_per_coded_sample);

             return AVERROR_INVALIDDATA;

     }

     c->bpp = avctx->bits_per_coded_sample;
     c->linelen = avctx->width * avctx->bits_per_coded_sample / 8;

     c->height = avctx->height;

     stride = FFALIGN(c->linelen, 4);

     c->decomp_size = c->height * stride;

     c->decomp_buf = av_malloc(c->decomp_size + AV_LZO_OUTPUT_PADDING);

     if (!c->decomp_buf) {
         av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");

         return AVERROR(ENOMEM);

     }

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

     return 0;
 }
 

 static av_cold int decode_end(AVCodecContext *avctx) {

     CamStudioContext *c = avctx->priv_data;

     av_freep(&c->decomp_buf);

     av_frame_free(&c->pic);

     return 0;
 }
 

 AVCodec ff_cscd_decoder = {

     .name           = "camstudio",

     .long_name      = NULL_IF_CONFIG_SMALL("CamStudio"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_CSCD,

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

     .capabilities   = AV_CODEC_CAP_DR1,

 };