text: /*
   * BMP image format decoder
   * Copyright (c) 2005 Mans Rullgard
   *
   * 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"
  #include "bmp.h"
  #include "msrledec.h"
  
  static av_cold int bmp_decode_init(AVCodecContext *avctx){
      BMPContext *s = avctx->priv_data;
  
      avcodec_get_frame_defaults((AVFrame*)&s->picture);
      avctx->coded_frame = (AVFrame*)&s->picture;
  
      return 0;
  }
  
  static int bmp_decode_frame(AVCodecContext *avctx,
                              void *data, int *data_size,
                              AVPacket *avpkt)
  {
      const uint8_t *buf = avpkt->data;
      int buf_size = avpkt->size;
      BMPContext *s = avctx->priv_data;
      AVFrame *picture = data;
      AVFrame *p = &s->picture;
      unsigned int fsize, hsize;
      int width, height;
      unsigned int depth;
      BiCompression comp;
      unsigned int ihsize;
      int i, j, n, linesize;
      uint32_t rgb[3];
      uint32_t alpha = 0;
      uint8_t *ptr;
      int dsize;
      const uint8_t *buf0 = buf;
  
      if(buf_size < 14){
          av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
          return -1;
      }
  
      if(bytestream_get_byte(&buf) != 'B' ||
         bytestream_get_byte(&buf) != 'M') {
          av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
          return -1;
      }
  
      fsize = bytestream_get_le32(&buf);
      if(buf_size < fsize){
          av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d), trying to decode anyway\n",
                 buf_size, fsize);
          fsize = buf_size;
      }
  
      buf += 2; /* reserved1 */
      buf += 2; /* reserved2 */
  
      hsize = bytestream_get_le32(&buf); /* header size */
      ihsize = bytestream_get_le32(&buf);       /* more header size */
      if(ihsize + 14 > hsize){
          av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
          return -1;
      }
  
      /* sometimes file size is set to some headers size, set a real size in that case */
      if(fsize == 14 || fsize == ihsize + 14)
          fsize = buf_size - 2;
  
      if(fsize <= hsize){
          av_log(avctx, AV_LOG_ERROR, "declared file size is less than header size (%d < %d)\n",
                 fsize, hsize);
          return -1;
      }
  
      switch(ihsize){
      case  40: // windib
      case  56: // windib v3
      case  64: // OS/2 v2
      case 108: // windib v4
      case 124: // windib v5
          width = bytestream_get_le32(&buf);
          height = bytestream_get_le32(&buf);
          break;
      case  12: // OS/2 v1
          width  = bytestream_get_le16(&buf);
          height = bytestream_get_le16(&buf);
          break;
      default:
          av_log(avctx, AV_LOG_ERROR, "unsupported BMP file, patch welcome\n");
          return -1;
      }
  
      if(bytestream_get_le16(&buf) != 1){ /* planes */
          av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
          return -1;
      }
  
      depth = bytestream_get_le16(&buf);
  
      if(ihsize == 40 || ihsize == 64 || ihsize == 56)
          comp = bytestream_get_le32(&buf);
      else
          comp = BMP_RGB;
  
      if(comp != BMP_RGB && comp != BMP_BITFIELDS && comp != BMP_RLE4 && comp != BMP_RLE8){
          av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
          return -1;
      }
  
      if(comp == BMP_BITFIELDS){
          buf += 20;
          rgb[0] = bytestream_get_le32(&buf);
          rgb[1] = bytestream_get_le32(&buf);
          rgb[2] = bytestream_get_le32(&buf);
          if (ihsize >= 108)
              alpha = bytestream_get_le32(&buf);
      }
  
      avctx->width = width;
      avctx->height = height > 0? height: -height;
  
      avctx->pix_fmt = PIX_FMT_NONE;
  
      switch(depth){
      case 32:
          if(comp == BMP_BITFIELDS){
              if (rgb[0] == 0xFF000000 && rgb[1] == 0x00FF0000 && rgb[2] == 0x0000FF00)
                  avctx->pix_fmt = alpha ? PIX_FMT_ABGR : PIX_FMT_0BGR;
              else if (rgb[0] == 0x00FF0000 && rgb[1] == 0x0000FF00 && rgb[2] == 0x000000FF)
                  avctx->pix_fmt = alpha ? PIX_FMT_BGRA : PIX_FMT_BGR0;
              else if (rgb[0] == 0x0000FF00 && rgb[1] == 0x00FF0000 && rgb[2] == 0xFF000000)
                  avctx->pix_fmt = alpha ? PIX_FMT_ARGB : PIX_FMT_0RGB;
              else if (rgb[0] == 0x000000FF && rgb[1] == 0x0000FF00 && rgb[2] == 0x00FF0000)
                  avctx->pix_fmt = alpha ? PIX_FMT_RGBA : PIX_FMT_RGB0;
              else {
                  av_log(avctx, AV_LOG_ERROR, "Unknown bitfields %0X %0X %0X\n", rgb[0], rgb[1], rgb[2]);
                  return AVERROR(EINVAL);
              }
          } else {
              avctx->pix_fmt = PIX_FMT_BGRA;
          }
          break;
      case 24:
          avctx->pix_fmt = PIX_FMT_BGR24;
          break;
      case 16:
          if(comp == BMP_RGB)
              avctx->pix_fmt = PIX_FMT_RGB555;
          else if (comp == BMP_BITFIELDS) {
              if (rgb[0] == 0xF800 && rgb[1] == 0x07E0 && rgb[2] == 0x001F)
                 avctx->pix_fmt = PIX_FMT_RGB565;
              else if (rgb[0] == 0x7C00 && rgb[1] == 0x03E0 && rgb[2] == 0x001F)
                 avctx->pix_fmt = PIX_FMT_RGB555;
              else if (rgb[0] == 0x0F00 && rgb[1] == 0x00F0 && rgb[2] == 0x000F)
                 avctx->pix_fmt = PIX_FMT_RGB444;
              else {
                 av_log(avctx, AV_LOG_ERROR, "Unknown bitfields %0X %0X %0X\n", rgb[0], rgb[1], rgb[2]);
                 return AVERROR(EINVAL);
              }
          }
          break;
      case 8:
          if(hsize - ihsize - 14 > 0)
              avctx->pix_fmt = PIX_FMT_PAL8;
          else
              avctx->pix_fmt = PIX_FMT_GRAY8;
          break;
      case 1:
      case 4:
          if(hsize - ihsize - 14 > 0){
              avctx->pix_fmt = PIX_FMT_PAL8;
          }else{
              av_log(avctx, AV_LOG_ERROR, "Unknown palette for %d-colour BMP\n", 1<<depth);
              return -1;
          }
          break;
      default:
          av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
          return -1;
      }
  
      if(avctx->pix_fmt == PIX_FMT_NONE){
          av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
          return -1;
      }
  
      if(p->data[0])
          avctx->release_buffer(avctx, p);
  
      p->reference = 0;
      if(avctx->get_buffer(avctx, p) < 0){
          av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
          return -1;
      }
      p->pict_type = AV_PICTURE_TYPE_I;
      p->key_frame = 1;
  
      buf = buf0 + hsize;
      dsize = buf_size - hsize;
  
      /* Line size in file multiple of 4 */
      n = ((avctx->width * depth + 31) / 8) & ~3;
  
      if(n * avctx->height > dsize && comp != BMP_RLE4 && comp != BMP_RLE8){
          av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
                 dsize, n * avctx->height);
          return -1;
      }
  
      // RLE may skip decoding some picture areas, so blank picture before decoding
      if(comp == BMP_RLE4 || comp == BMP_RLE8)
          memset(p->data[0], 0, avctx->height * p->linesize[0]);
  
      if(depth == 4 || depth == 8)
          memset(p->data[1], 0, 1024);
  
      if(height > 0){
          ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
          linesize = -p->linesize[0];
      } else {
          ptr = p->data[0];
          linesize = p->linesize[0];
      }
  
      if(avctx->pix_fmt == PIX_FMT_PAL8){
          int colors = 1 << depth;
          if(ihsize >= 36){
              int t;
              buf = buf0 + 46;
              t = bytestream_get_le32(&buf);
              if(t < 0 || t > (1 << depth)){
                  av_log(avctx, AV_LOG_ERROR, "Incorrect number of colors - %X for bitdepth %d\n", t, depth);
              }else if(t){
                  colors = t;
              }
          }
          buf = buf0 + 14 + ihsize; //palette location
          if((hsize-ihsize-14) < (colors << 2)){ // OS/2 bitmap, 3 bytes per palette entry
              for(i = 0; i < colors; i++)
                  ((uint32_t*)p->data[1])[i] = (0xff<<24) | bytestream_get_le24(&buf);
          }else{
              for(i = 0; i < colors; i++)
                  ((uint32_t*)p->data[1])[i] = 0xFFU << 24 | bytestream_get_le32(&buf);
          }
          buf = buf0 + hsize;
      }
      if(comp == BMP_RLE4 || comp == BMP_RLE8){
          if(height < 0){
              p->data[0] += p->linesize[0] * (avctx->height - 1);
              p->linesize[0] = -p->linesize[0];
          }
          ff_msrle_decode(avctx, (AVPicture*)p, depth, buf, dsize);
          if(height < 0){
              p->data[0] += p->linesize[0] * (avctx->height - 1);
              p->linesize[0] = -p->linesize[0];
          }
      }else{
          switch(depth){
          case 1:
              for (i = 0; i < avctx->height; i++) {
                  int j;
                  for (j = 0; j < n; j++) {
                      ptr[j*8+0] =  buf[j] >> 7;
                      ptr[j*8+1] = (buf[j] >> 6) & 1;
                      ptr[j*8+2] = (buf[j] >> 5) & 1;
                      ptr[j*8+3] = (buf[j] >> 4) & 1;
                      ptr[j*8+4] = (buf[j] >> 3) & 1;
                      ptr[j*8+5] = (buf[j] >> 2) & 1;
                      ptr[j*8+6] = (buf[j] >> 1) & 1;
                      ptr[j*8+7] =  buf[j]       & 1;
                  }
                  buf += n;
                  ptr += linesize;
              }
              break;
          case 8:
          case 24:
          case 32:
              for(i = 0; i < avctx->height; i++){
                  memcpy(ptr, buf, n);
                  buf += n;
                  ptr += linesize;
              }
              break;
          case 4:
              for(i = 0; i < avctx->height; i++){
                  int j;
                  for(j = 0; j < n; j++){
                      ptr[j*2+0] = (buf[j] >> 4) & 0xF;
                      ptr[j*2+1] = buf[j] & 0xF;
                  }
                  buf += n;
                  ptr += linesize;
              }
              break;
          case 16:
              for(i = 0; i < avctx->height; i++){
                  const uint16_t *src = (const uint16_t *) buf;
                  uint16_t *dst = (uint16_t *) ptr;
  
                  for(j = 0; j < avctx->width; j++)
                      *dst++ = av_le2ne16(*src++);
  
                  buf += n;
                  ptr += linesize;
              }
              break;
          default:
              av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
              return -1;
          }
      }
  
      *picture = s->picture;
      *data_size = sizeof(AVPicture);
  
      return buf_size;
  }
  
  static av_cold int bmp_decode_end(AVCodecContext *avctx)
  {
      BMPContext* c = avctx->priv_data;
  
      if (c->picture.data[0])
          avctx->release_buffer(avctx, &c->picture);
  
      return 0;
  }
  
  AVCodec ff_bmp_decoder = {
      .name           = "bmp",
      .type           = AVMEDIA_TYPE_VIDEO,
      .id             = CODEC_ID_BMP,
      .priv_data_size = sizeof(BMPContext),
      .init           = bmp_decode_init,
      .close          = bmp_decode_end,
      .decode         = bmp_decode_frame,
      .capabilities   = CODEC_CAP_DR1,
      .long_name = NULL_IF_CONFIG_SMALL("BMP image"),
  };
  