/*
  * Quicktime Video (RPZA) Video 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

  * QT RPZA Video Decoder by Roberto Togni

  * For more information about the RPZA format, visit:
  *   http://www.pcisys.net/~melanson/codecs/
  *
  * The RPZA decoder outputs RGB555 colorspace data.
  *
  * Note that this decoder reads big endian RGB555 pixel values from the
  * bytestream, arranges them in the host's endian order, and outputs
  * them to the final rendered map in the same host endian order. This is

  * intended behavior as the libavcodec documentation states that RGB555
  * pixels shall be stored in native CPU endianness.

  */
 

 #include <stdint.h>

 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 

 #include "libavutil/internal.h"

 #include "avcodec.h"

 #include "bytestream.h"

 #include "internal.h"

 
 typedef struct RpzaContext {
 
     AVCodecContext *avctx;

     AVFrame *frame;

     GetByteContext gb;

 } RpzaContext;
 
 #define ADVANCE_BLOCK() \
 { \
     pixel_ptr += 4; \
     if (pixel_ptr >= width) \
     { \
         pixel_ptr = 0; \
         row_ptr += stride * 4; \
     } \
     total_blocks--; \
     if (total_blocks < 0) \
     { \

         av_log(s->avctx, AV_LOG_ERROR, "warning: block counter just went negative (this should not happen)\n"); \

         return; \
     } \
 }
 
 static void rpza_decode_stream(RpzaContext *s)
 {
     int width = s->avctx->width;

     int stride = s->frame->linesize[0] / 2;

     int row_inc = stride - 4;
     int chunk_size;

     uint16_t colorA = 0, colorB;
     uint16_t color4[4];
     uint16_t ta, tb;
     uint16_t *pixels = (uint16_t *)s->frame->data[0];

 
     int row_ptr = 0;

     int pixel_ptr = -4;

     int block_ptr;
     int pixel_x, pixel_y;
     int total_blocks;
 
     /* First byte is always 0xe1. Warn if it's different */

     if (bytestream2_peek_byte(&s->gb) != 0xe1)

         av_log(s->avctx, AV_LOG_ERROR, "First chunk byte is 0x%02x instead of 0xe1\n",

                bytestream2_peek_byte(&s->gb));

 
     /* Get chunk size, ingnoring first byte */

     chunk_size = bytestream2_get_be32(&s->gb) & 0x00FFFFFF;

 
     /* If length mismatch use size from MOV file and try to decode anyway */

     if (chunk_size != bytestream2_get_bytes_left(&s->gb) - 4)
         av_log(s->avctx, AV_LOG_WARNING, "MOV chunk size != encoded chunk size\n");

 
     /* Number of 4x4 blocks in frame. */

     total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);

 
     /* Process chunk data */

     while (bytestream2_get_bytes_left(&s->gb)) {

         uint8_t opcode = bytestream2_get_byte(&s->gb); /* Get opcode */

         int n_blocks = (opcode & 0x1f) + 1; /* Extract block counter from opcode */

 
         /* If opcode MSbit is 0, we need more data to decide what to do */
         if ((opcode & 0x80) == 0) {

             colorA = (opcode << 8) | bytestream2_get_byte(&s->gb);

             opcode = 0;

             if ((bytestream2_peek_byte(&s->gb) & 0x80) != 0) {

                 /* Must behave as opcode 110xxxxx, using colorA computed
                  * above. Use fake opcode 0x20 to enter switch block at

                  * the right place */
                 opcode = 0x20;
                 n_blocks = 1;
             }
         }
 

         n_blocks = FFMIN(n_blocks, total_blocks);
 

         switch (opcode & 0xe0) {
 
         /* Skip blocks */
         case 0x80:
             while (n_blocks--) {

               ADVANCE_BLOCK();

             }
             break;
 
         /* Fill blocks with one color */
         case 0xa0:

             colorA = bytestream2_get_be16(&s->gb);

             while (n_blocks--) {

                 ADVANCE_BLOCK()

                 block_ptr = row_ptr + pixel_ptr;
                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                     for (pixel_x = 0; pixel_x < 4; pixel_x++){
                         pixels[block_ptr] = colorA;
                         block_ptr++;
                     }
                     block_ptr += row_inc;
                 }
             }
             break;
 
         /* Fill blocks with 4 colors */
         case 0xc0:

             colorA = bytestream2_get_be16(&s->gb);

         case 0x20:

             colorB = bytestream2_get_be16(&s->gb);

 
             /* sort out the colors */
             color4[0] = colorB;
             color4[1] = 0;
             color4[2] = 0;
             color4[3] = colorA;
 
             /* red components */
             ta = (colorA >> 10) & 0x1F;
             tb = (colorB >> 10) & 0x1F;
             color4[1] |= ((11 * ta + 21 * tb) >> 5) << 10;
             color4[2] |= ((21 * ta + 11 * tb) >> 5) << 10;
 
             /* green components */
             ta = (colorA >> 5) & 0x1F;
             tb = (colorB >> 5) & 0x1F;
             color4[1] |= ((11 * ta + 21 * tb) >> 5) << 5;
             color4[2] |= ((21 * ta + 11 * tb) >> 5) << 5;
 
             /* blue components */
             ta = colorA & 0x1F;
             tb = colorB & 0x1F;
             color4[1] |= ((11 * ta + 21 * tb) >> 5);
             color4[2] |= ((21 * ta + 11 * tb) >> 5);
 

             if (bytestream2_get_bytes_left(&s->gb) < n_blocks * 4)

                 return;

             while (n_blocks--) {

                 ADVANCE_BLOCK();

                 block_ptr = row_ptr + pixel_ptr;
                 for (pixel_y = 0; pixel_y < 4; pixel_y++) {

                     uint8_t index = bytestream2_get_byteu(&s->gb);

                     for (pixel_x = 0; pixel_x < 4; pixel_x++){

                         uint8_t idx = (index >> (2 * (3 - pixel_x))) & 0x03;

                         pixels[block_ptr] = color4[idx];
                         block_ptr++;
                     }
                     block_ptr += row_inc;
                 }
             }
             break;
 
         /* Fill block with 16 colors */
         case 0x00:

             if (bytestream2_get_bytes_left(&s->gb) < 30)

                 return;

             ADVANCE_BLOCK();

             block_ptr = row_ptr + pixel_ptr;
             for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                 for (pixel_x = 0; pixel_x < 4; pixel_x++){
                     /* We already have color of upper left pixel */

                     if ((pixel_y != 0) || (pixel_x != 0))
                         colorA = bytestream2_get_be16u(&s->gb);

                     pixels[block_ptr] = colorA;
                     block_ptr++;
                 }
                 block_ptr += row_inc;
             }
             break;
 
         /* Unknown opcode */
         default:

             av_log(s->avctx, AV_LOG_ERROR, "Unknown opcode %d in rpza chunk."

                  " Skip remaining %d bytes of chunk data.\n", opcode,

                  bytestream2_get_bytes_left(&s->gb));

             return;
         } /* Opcode switch */
     }
 }
 

 static av_cold int rpza_decode_init(AVCodecContext *avctx)

 {

     RpzaContext *s = avctx->priv_data;

 
     s->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_RGB555;

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

 
     return 0;
 }
 
 static int rpza_decode_frame(AVCodecContext *avctx,

                              void *data, int *got_frame,

                              AVPacket *avpkt)

 {

     RpzaContext *s = avctx->priv_data;

     int ret;

     bytestream2_init(&s->gb, avpkt->data, avpkt->size);

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

         return ret;

 
     rpza_decode_stream(s);
 

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

         return ret;
 

     *got_frame      = 1;

 
     /* always report that the buffer was completely consumed */

     return avpkt->size;

 }
 

 static av_cold int rpza_decode_end(AVCodecContext *avctx)

 {

     RpzaContext *s = avctx->priv_data;

     av_frame_free(&s->frame);

 
     return 0;
 }
 

 AVCodec ff_rpza_decoder = {

     .name           = "rpza",

     .long_name      = NULL_IF_CONFIG_SMALL("QuickTime video (RPZA)"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_RPZA,

     .priv_data_size = sizeof(RpzaContext),
     .init           = rpza_decode_init,
     .close          = rpza_decode_end,
     .decode         = rpza_decode_frame,
     .capabilities   = CODEC_CAP_DR1,

 };