text: /*
   * 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)) {
                  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,
  };
  