/*
  * Microsoft Video-1 Decoder

  * Copyright (C) 2003 The FFmpeg project

  *

  * 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

  */
 
 /**

  * @file

  * Microsoft Video-1 Decoder by Mike Melanson (melanson@pcisys.net)
  * For more information about the MS Video-1 format, visit:
  *   http://www.pcisys.net/~melanson/codecs/
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 

 #include "libavutil/internal.h"

 #include "libavutil/intreadwrite.h"

 #include "avcodec.h"

 #include "internal.h"

 
 #define PALETTE_COUNT 256
 #define CHECK_STREAM_PTR(n) \
   if ((stream_ptr + n) > s->size ) { \

     av_log(s->avctx, AV_LOG_ERROR, " MS Video-1 warning: stream_ptr out of bounds (%d >= %d)\n", \

       stream_ptr + n, s->size); \
     return; \
   }
 
 typedef struct Msvideo1Context {
 
     AVCodecContext *avctx;

     AVFrame *frame;

     const unsigned char *buf;

     int size;
 
     int mode_8bit;  /* if it's not 8-bit, it's 16-bit */
 

     uint32_t pal[256];

 } Msvideo1Context;
 

 static av_cold int msvideo1_decode_init(AVCodecContext *avctx)

 {

     Msvideo1Context *s = avctx->priv_data;

 
     s->avctx = avctx;
 

     /* figure out the colorspace based on the presence of a palette */

     if (s->avctx->bits_per_coded_sample == 8) {

         s->mode_8bit = 1;

         avctx->pix_fmt = AV_PIX_FMT_PAL8;

         if (avctx->extradata_size >= AVPALETTE_SIZE)
             memcpy(s->pal, avctx->extradata, AVPALETTE_SIZE);

     } else {
         s->mode_8bit = 0;

         avctx->pix_fmt = AV_PIX_FMT_RGB555;

     }
 

     s->frame = av_frame_alloc();
     if (!s->frame)
         return AVERROR(ENOMEM);

 
     return 0;
 }
 
 static void msvideo1_decode_8bit(Msvideo1Context *s)
 {
     int block_ptr, pixel_ptr;
     int total_blocks;
     int pixel_x, pixel_y;  /* pixel width and height iterators */
     int block_x, block_y;  /* block width and height iterators */
     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
     int block_inc;
     int row_dec;
 
     /* decoding parameters */
     int stream_ptr;
     unsigned char byte_a, byte_b;
     unsigned short flags;
     int skip_blocks;
     unsigned char colors[8];

     unsigned char *pixels = s->frame->data[0];
     int stride = s->frame->linesize[0];

 
     stream_ptr = 0;
     skip_blocks = 0;
     blocks_wide = s->avctx->width / 4;
     blocks_high = s->avctx->height / 4;
     total_blocks = blocks_wide * blocks_high;
     block_inc = 4;
     row_dec = stride + 4;
 
     for (block_y = blocks_high; block_y > 0; block_y--) {
         block_ptr = ((block_y * 4) - 1) * stride;
         for (block_x = blocks_wide; block_x > 0; block_x--) {
             /* check if this block should be skipped */
             if (skip_blocks) {
                 block_ptr += block_inc;
                 skip_blocks--;
                 total_blocks--;
                 continue;
             }
 
             pixel_ptr = block_ptr;
 
             /* get the next two bytes in the encoded data stream */
             CHECK_STREAM_PTR(2);
             byte_a = s->buf[stream_ptr++];
             byte_b = s->buf[stream_ptr++];
 
             /* check if the decode is finished */
             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0))
                 return;
             else if ((byte_b & 0xFC) == 0x84) {
                 /* skip code, but don't count the current block */
                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
             } else if (byte_b < 0x80) {
                 /* 2-color encoding */
                 flags = (byte_b << 8) | byte_a;
 
                 CHECK_STREAM_PTR(2);
                 colors[0] = s->buf[stream_ptr++];
                 colors[1] = s->buf[stream_ptr++];
 
                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
                         pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
                     pixel_ptr -= row_dec;
                 }
             } else if (byte_b >= 0x90) {
                 /* 8-color encoding */
                 flags = (byte_b << 8) | byte_a;
 
                 CHECK_STREAM_PTR(8);
                 memcpy(colors, &s->buf[stream_ptr], 8);
                 stream_ptr += 8;
 
                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                     for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)

                         pixels[pixel_ptr++] =
                             colors[((pixel_y & 0x2) << 1) +

                                 (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
                     pixel_ptr -= row_dec;
                 }
             } else {
                 /* 1-color encoding */
                 colors[0] = byte_a;
 
                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
                         pixels[pixel_ptr++] = colors[0];
                     pixel_ptr -= row_dec;
                 }
             }
 
             block_ptr += block_inc;
             total_blocks--;
         }
     }
 
     /* make the palette available on the way out */

     if (s->avctx->pix_fmt == AV_PIX_FMT_PAL8)

         memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);

 }
 
 static void msvideo1_decode_16bit(Msvideo1Context *s)
 {
     int block_ptr, pixel_ptr;
     int total_blocks;
     int pixel_x, pixel_y;  /* pixel width and height iterators */
     int block_x, block_y;  /* block width and height iterators */
     int blocks_wide, blocks_high;  /* width and height in 4x4 blocks */
     int block_inc;
     int row_dec;
 
     /* decoding parameters */
     int stream_ptr;
     unsigned char byte_a, byte_b;
     unsigned short flags;
     int skip_blocks;
     unsigned short colors[8];

     unsigned short *pixels = (unsigned short *)s->frame->data[0];
     int stride = s->frame->linesize[0] / 2;

 
     stream_ptr = 0;
     skip_blocks = 0;
     blocks_wide = s->avctx->width / 4;
     blocks_high = s->avctx->height / 4;
     total_blocks = blocks_wide * blocks_high;
     block_inc = 4;
     row_dec = stride + 4;
 
     for (block_y = blocks_high; block_y > 0; block_y--) {
         block_ptr = ((block_y * 4) - 1) * stride;
         for (block_x = blocks_wide; block_x > 0; block_x--) {
             /* check if this block should be skipped */
             if (skip_blocks) {
                 block_ptr += block_inc;
                 skip_blocks--;
                 total_blocks--;
                 continue;
             }
 
             pixel_ptr = block_ptr;
 
             /* get the next two bytes in the encoded data stream */
             CHECK_STREAM_PTR(2);
             byte_a = s->buf[stream_ptr++];
             byte_b = s->buf[stream_ptr++];
 
             /* check if the decode is finished */
             if ((byte_a == 0) && (byte_b == 0) && (total_blocks == 0)) {
                 return;
             } else if ((byte_b & 0xFC) == 0x84) {
                 /* skip code, but don't count the current block */
                 skip_blocks = ((byte_b - 0x84) << 8) + byte_a - 1;
             } else if (byte_b < 0x80) {
                 /* 2- or 8-color encoding modes */
                 flags = (byte_b << 8) | byte_a;
 
                 CHECK_STREAM_PTR(4);

                 colors[0] = AV_RL16(&s->buf[stream_ptr]);

                 stream_ptr += 2;

                 colors[1] = AV_RL16(&s->buf[stream_ptr]);

                 stream_ptr += 2;
 
                 if (colors[0] & 0x8000) {
                     /* 8-color encoding */
                     CHECK_STREAM_PTR(12);

                     colors[2] = AV_RL16(&s->buf[stream_ptr]);

                     stream_ptr += 2;

                     colors[3] = AV_RL16(&s->buf[stream_ptr]);

                     stream_ptr += 2;

                     colors[4] = AV_RL16(&s->buf[stream_ptr]);

                     stream_ptr += 2;

                     colors[5] = AV_RL16(&s->buf[stream_ptr]);

                     stream_ptr += 2;

                     colors[6] = AV_RL16(&s->buf[stream_ptr]);

                     stream_ptr += 2;

                     colors[7] = AV_RL16(&s->buf[stream_ptr]);

                     stream_ptr += 2;
 
                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)

                             pixels[pixel_ptr++] =
                                 colors[((pixel_y & 0x2) << 1) +

                                     (pixel_x & 0x2) + ((flags & 0x1) ^ 1)];
                         pixel_ptr -= row_dec;
                     }
                 } else {
                     /* 2-color encoding */
                     for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                         for (pixel_x = 0; pixel_x < 4; pixel_x++, flags >>= 1)
                             pixels[pixel_ptr++] = colors[(flags & 0x1) ^ 1];
                         pixel_ptr -= row_dec;
                     }
                 }
             } else {
                 /* otherwise, it's a 1-color block */
                 colors[0] = (byte_b << 8) | byte_a;
 
                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                     for (pixel_x = 0; pixel_x < 4; pixel_x++)
                         pixels[pixel_ptr++] = colors[0];
                     pixel_ptr -= row_dec;
                 }
             }
 
             block_ptr += block_inc;
             total_blocks--;
         }
     }
 }
 
 static int msvideo1_decode_frame(AVCodecContext *avctx,

                                 void *data, int *got_frame,

                                 AVPacket *avpkt)

 {

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

     Msvideo1Context *s = avctx->priv_data;

     int ret;

 
     s->buf = buf;
     s->size = buf_size;
 

     if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)

         return ret;

     if (s->mode_8bit) {
         const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
 
         if (pal) {
             memcpy(s->pal, pal, AVPALETTE_SIZE);

             s->frame->palette_has_changed = 1;

         }
     }
 

     if (s->mode_8bit)
         msvideo1_decode_8bit(s);
     else
         msvideo1_decode_16bit(s);
 

     if ((ret = av_frame_ref(data, s->frame)) < 0)

         return ret;
 

     *got_frame      = 1;

 
     /* report that the buffer was completely consumed */
     return buf_size;
 }
 

 static av_cold int msvideo1_decode_end(AVCodecContext *avctx)

 {

     Msvideo1Context *s = avctx->priv_data;

     av_frame_free(&s->frame);

 
     return 0;
 }
 

 AVCodec ff_msvideo1_decoder = {

     .name           = "msvideo1",

     .long_name      = NULL_IF_CONFIG_SMALL("Microsoft Video 1"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_MSVIDEO1,

     .priv_data_size = sizeof(Msvideo1Context),
     .init           = msvideo1_decode_init,
     .close          = msvideo1_decode_end,
     .decode         = msvideo1_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };