/*

  * 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];
     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);

     }
 
     avctx->width = width;
     avctx->height = height > 0? height: -height;
 
     avctx->pix_fmt = PIX_FMT_NONE;
 
     switch(depth){
     case 32:
         if(comp == BMP_BITFIELDS){
             rgb[0] = (rgb[0] >> 15) & 3;
             rgb[1] = (rgb[1] >> 15) & 3;
             rgb[2] = (rgb[2] >> 15) & 3;
 
             if(rgb[0] + rgb[1] + rgb[2] != 3 ||
                rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){
                 break;
             }
         } else {
             rgb[0] = 2;
             rgb[1] = 1;
             rgb[2] = 0;
         }
 

         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;

         if(comp == BMP_BITFIELDS)
             avctx->pix_fmt = rgb[1] == 0x07E0 ? PIX_FMT_RGB565 : PIX_FMT_RGB555;
         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] = 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:

             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;
         case 32:
             for(i = 0; i < avctx->height; i++){
                 const uint8_t *src = buf;
                 uint8_t *dst = ptr;
 
                 for(j = 0; j < avctx->width; j++){
                     dst[0] = src[rgb[2]];
                     dst[1] = src[rgb[1]];
                     dst[2] = src[rgb[0]];

 /* The Microsoft documentation states:
  * "The high byte in each DWORD is not used."
  * Both GIMP and ImageMagick store the alpha transparency value
  * in the high byte for 32bit bmp files.
  */
                     dst[3] = src[3];
                     dst += 4;

                     src += 4;
                 }
 
                 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"),

 };