/*
  * Westwood Studios VQA 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

  * VQA Video Decoder by Mike Melanson (melanson@pcisys.net)

  * For more information about the VQA format, visit:
  *   http://wiki.multimedia.cx/index.php?title=VQA

  *

  * The VQA video decoder outputs PAL8 or RGB555 colorspace data, depending
  * on the type of data in the file.

  *
  * This decoder needs the 42-byte VQHD header from the beginning
  * of the VQA file passed through the extradata field. The VQHD header
  * is laid out as:
  *
  *   bytes 0-3   chunk fourcc: 'VQHD'
  *   bytes 4-7   chunk size in big-endian format, should be 0x0000002A

  *   bytes 8-49  VQHD chunk data

  *

  * Bytes 8-49 are what this decoder expects to see.

  *
  * Briefly, VQA is a vector quantized animation format that operates in a

  * VGA palettized colorspace. It operates on pixel vectors (blocks)

  * of either 4x2 or 4x4 in size. Compressed VQA chunks can contain vector
  * codebooks, palette information, and code maps for rendering vectors onto
  * frames. Any of these components can also be compressed with a run-length
  * encoding (RLE) algorithm commonly referred to as "format80".
  *
  * VQA takes a novel approach to rate control. Each group of n frames
  * (usually, n = 8) relies on a different vector codebook. Rather than
  * transporting an entire codebook every 8th frame, the new codebook is
  * broken up into 8 pieces and sent along with the compressed video chunks
  * for each of the 8 frames preceding the 8 frames which require the
  * codebook. A full codebook is also sent on the very first frame of a
  * file. This is an interesting technique, although it makes random file
  * seeking difficult despite the fact that the frames are all intracoded.
  *

  * V1,2 VQA uses 12-bit codebook indexes. If the 12-bit indexes were

  * packed into bytes and then RLE compressed, bytewise, the results would
  * be poor. That is why the coding method divides each index into 2 parts,

  * the top 4 bits and the bottom 8 bits, then RL encodes the 4-bit pieces

  * together and the 8-bit pieces together. If most of the vectors are
  * clustered into one group of 256 vectors, most of the 4-bit index pieces
  * should be the same.
  */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 

 #include "libavutil/intreadwrite.h"

 #include "libavutil/imgutils.h"

 #include "avcodec.h"
 
 #define PALETTE_COUNT 256
 #define VQA_HEADER_SIZE 0x2A
 #define CHUNK_PREAMBLE_SIZE 8
 

 /* allocate the maximum vector space, regardless of the file version:
  * (0xFF00 codebook vectors + 0x100 solid pixel vectors) * (4x4 pixels/block) */
 #define MAX_CODEBOOK_VECTORS 0xFF00
 #define SOLID_PIXEL_VECTORS 0x100
 #define MAX_VECTORS (MAX_CODEBOOK_VECTORS + SOLID_PIXEL_VECTORS)
 #define MAX_CODEBOOK_SIZE (MAX_VECTORS * 4 * 4)

 #define CBF0_TAG MKBETAG('C', 'B', 'F', '0')
 #define CBFZ_TAG MKBETAG('C', 'B', 'F', 'Z')
 #define CBP0_TAG MKBETAG('C', 'B', 'P', '0')
 #define CBPZ_TAG MKBETAG('C', 'B', 'P', 'Z')
 #define CPL0_TAG MKBETAG('C', 'P', 'L', '0')
 #define CPLZ_TAG MKBETAG('C', 'P', 'L', 'Z')
 #define VPTZ_TAG MKBETAG('V', 'P', 'T', 'Z')

 
 typedef struct VqaContext {
 
     AVCodecContext *avctx;
     AVFrame frame;
 

     const unsigned char *buf;

     int size;
 

     uint32_t palette[PALETTE_COUNT];

 
     int width;   /* width of a frame */
     int height;   /* height of a frame */
     int vector_width;  /* width of individual vector */
     int vector_height;  /* height of individual vector */
     int vqa_version;  /* this should be either 1, 2 or 3 */
 
     unsigned char *codebook;         /* the current codebook */

     int codebook_size;

     unsigned char *next_codebook_buffer;  /* accumulator for next codebook */
     int next_codebook_buffer_index;
 
     unsigned char *decode_buffer;
     int decode_buffer_size;
 
     /* number of frames to go before replacing codebook */
     int partial_countdown;
     int partial_count;
 
 } VqaContext;
 

 static av_cold int vqa_decode_init(AVCodecContext *avctx)

 {

     VqaContext *s = avctx->priv_data;

     unsigned char *vqa_header;

     int i, j, codebook_index;

 
     s->avctx = avctx;
     avctx->pix_fmt = PIX_FMT_PAL8;
 
     /* make sure the extradata made it */
     if (s->avctx->extradata_size != VQA_HEADER_SIZE) {

         av_log(s->avctx, AV_LOG_ERROR, "  VQA video: expected extradata size of %d\n", VQA_HEADER_SIZE);

         return -1;
     }
 
     /* load up the VQA parameters from the header */
     vqa_header = (unsigned char *)s->avctx->extradata;
     s->vqa_version = vqa_header[0];

     if (s->vqa_version < 1 || s->vqa_version > 3) {
         av_log(s->avctx, AV_LOG_ERROR, "  VQA video: unsupported version %d\n", s->vqa_version);
         return -1;
     }

     s->width = AV_RL16(&vqa_header[6]);
     s->height = AV_RL16(&vqa_header[8]);

     if(av_image_check_size(s->width, s->height, 0, avctx)){

         s->width= s->height= 0;
         return -1;
     }

     s->vector_width = vqa_header[10];
     s->vector_height = vqa_header[11];
     s->partial_count = s->partial_countdown = vqa_header[13];
 
     /* the vector dimensions have to meet very stringent requirements */
     if ((s->vector_width != 4) ||
         ((s->vector_height != 2) && (s->vector_height != 4))) {
         /* return without further initialization */
         return -1;
     }
 
     /* allocate codebooks */

     s->codebook_size = MAX_CODEBOOK_SIZE;
     s->codebook = av_malloc(s->codebook_size);
     s->next_codebook_buffer = av_malloc(s->codebook_size);
 
     /* initialize the solid-color vectors */
     if (s->vector_height == 4) {
         codebook_index = 0xFF00 * 16;
         for (i = 0; i < 256; i++)
             for (j = 0; j < 16; j++)
                 s->codebook[codebook_index++] = i;

     } else {

         codebook_index = 0xF00 * 8;
         for (i = 0; i < 256; i++)
             for (j = 0; j < 8; j++)
                 s->codebook[codebook_index++] = i;

     }
     s->next_codebook_buffer_index = 0;
 
     /* allocate decode buffer */
     s->decode_buffer_size = (s->width / s->vector_width) *
         (s->height / s->vector_height) * 2;
     s->decode_buffer = av_malloc(s->decode_buffer_size);
 

     avcodec_get_frame_defaults(&s->frame);

     s->frame.data[0] = NULL;
 
     return 0;
 }
 
 #define CHECK_COUNT() \
     if (dest_index + count > dest_size) { \

         av_log(NULL, AV_LOG_ERROR, "  VQA video: decode_format80 problem: next op would overflow dest_index\n"); \
         av_log(NULL, AV_LOG_ERROR, "  VQA video: current dest_index = %d, count = %d, dest_size = %d\n", \

             dest_index, count, dest_size); \
         return; \
     }
 

 static void decode_format80(const unsigned char *src, int src_size,

     unsigned char *dest, int dest_size, int check_size) {

 
     int src_index = 0;
     int dest_index = 0;
     int count;
     int src_pos;
     unsigned char color;
     int i;
 
     while (src_index < src_size) {
 

         av_dlog(NULL, "      opcode %02X: ", src[src_index]);

 
         /* 0x80 means that frame is finished */
         if (src[src_index] == 0x80)
             return;
 
         if (dest_index >= dest_size) {

             av_log(NULL, AV_LOG_ERROR, "  VQA video: decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",

                 dest_index, dest_size);
             return;
         }
 
         if (src[src_index] == 0xFF) {
 
             src_index++;

             count = AV_RL16(&src[src_index]);

             src_index += 2;

             src_pos = AV_RL16(&src[src_index]);

             src_index += 2;

             av_dlog(NULL, "(1) copy %X bytes from absolute pos %X\n", count, src_pos);

             CHECK_COUNT();

             if (src_pos + count > dest_size)
                 return;

             for (i = 0; i < count; i++)
                 dest[dest_index + i] = dest[src_pos + i];
             dest_index += count;
 
         } else if (src[src_index] == 0xFE) {
 
             src_index++;

             count = AV_RL16(&src[src_index]);

             src_index += 2;
             color = src[src_index++];

             av_dlog(NULL, "(2) set %X bytes to %02X\n", count, color);

             CHECK_COUNT();
             memset(&dest[dest_index], color, count);
             dest_index += count;
 
         } else if ((src[src_index] & 0xC0) == 0xC0) {
 
             count = (src[src_index++] & 0x3F) + 3;

             src_pos = AV_RL16(&src[src_index]);

             src_index += 2;

             av_dlog(NULL, "(3) copy %X bytes from absolute pos %X\n", count, src_pos);

             CHECK_COUNT();

             if (src_pos + count > dest_size)
                 return;

             for (i = 0; i < count; i++)
                 dest[dest_index + i] = dest[src_pos + i];
             dest_index += count;
 
         } else if (src[src_index] > 0x80) {
 
             count = src[src_index++] & 0x3F;

             av_dlog(NULL, "(4) copy %X bytes from source to dest\n", count);

             CHECK_COUNT();
             memcpy(&dest[dest_index], &src[src_index], count);
             src_index += count;
             dest_index += count;
 
         } else {
 
             count = ((src[src_index] & 0x70) >> 4) + 3;

             src_pos = AV_RB16(&src[src_index]) & 0x0FFF;

             src_index += 2;

             av_dlog(NULL, "(5) copy %X bytes from relpos %X\n", count, src_pos);

             CHECK_COUNT();

             if (dest_index < src_pos)
                 return;

             for (i = 0; i < count; i++)
                 dest[dest_index + i] = dest[dest_index - src_pos + i];
             dest_index += count;
         }
     }
 

     /* validate that the entire destination buffer was filled; this is
      * important for decoding frame maps since each vector needs to have a
      * codebook entry; it is not important for compressed codebooks because
      * not every entry needs to be filled */
     if (check_size)
         if (dest_index < dest_size)

             av_log(NULL, AV_LOG_ERROR, "  VQA video: decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",

                 dest_index, dest_size);

 }
 
 static void vqa_decode_chunk(VqaContext *s)
 {
     unsigned int chunk_type;
     unsigned int chunk_size;
     int byte_skip;
     unsigned int index = 0;
     int i;
     unsigned char r, g, b;

     int index_shift;

 
     int cbf0_chunk = -1;
     int cbfz_chunk = -1;
     int cbp0_chunk = -1;
     int cbpz_chunk = -1;
     int cpl0_chunk = -1;
     int cplz_chunk = -1;
     int vptz_chunk = -1;
 
     int x, y;
     int lines = 0;
     int pixel_ptr;
     int vector_index = 0;
     int lobyte = 0;
     int hibyte = 0;
     int lobytes = 0;
     int hibytes = s->decode_buffer_size / 2;
 
     /* first, traverse through the frame and find the subchunks */
     while (index < s->size) {
 

         chunk_type = AV_RB32(&s->buf[index]);
         chunk_size = AV_RB32(&s->buf[index + 4]);

 
         switch (chunk_type) {
 
         case CBF0_TAG:
             cbf0_chunk = index;
             break;
 
         case CBFZ_TAG:
             cbfz_chunk = index;
             break;
 
         case CBP0_TAG:
             cbp0_chunk = index;
             break;
 
         case CBPZ_TAG:
             cbpz_chunk = index;
             break;
 
         case CPL0_TAG:
             cpl0_chunk = index;
             break;
 
         case CPLZ_TAG:
             cplz_chunk = index;
             break;
 
         case VPTZ_TAG:
             vptz_chunk = index;
             break;
 
         default:

             av_log(s->avctx, AV_LOG_ERROR, "  VQA video: Found unknown chunk type: %c%c%c%c (%08X)\n",

             (chunk_type >> 24) & 0xFF,
             (chunk_type >> 16) & 0xFF,
             (chunk_type >>  8) & 0xFF,
             (chunk_type >>  0) & 0xFF,
             chunk_type);
             break;
         }
 
         byte_skip = chunk_size & 0x01;
         index += (CHUNK_PREAMBLE_SIZE + chunk_size + byte_skip);
     }
 
     /* next, deal with the palette */
     if ((cpl0_chunk != -1) && (cplz_chunk != -1)) {
 
         /* a chunk should not have both chunk types */

         av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: found both CPL0 and CPLZ chunks\n");

         return;
     }
 
     /* decompress the palette chunk */
     if (cplz_chunk != -1) {
 
 /* yet to be handled */
 
     }
 
     /* convert the RGB palette into the machine's endian format */
     if (cpl0_chunk != -1) {
 

         chunk_size = AV_RB32(&s->buf[cpl0_chunk + 4]);

         /* sanity check the palette size */
         if (chunk_size / 3 > 256) {

             av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: found a palette chunk with %d colors\n",

                 chunk_size / 3);
             return;
         }
         cpl0_chunk += CHUNK_PREAMBLE_SIZE;
         for (i = 0; i < chunk_size / 3; i++) {
             /* scale by 4 to transform 6-bit palette -> 8-bit */
             r = s->buf[cpl0_chunk++] * 4;
             g = s->buf[cpl0_chunk++] * 4;
             b = s->buf[cpl0_chunk++] * 4;

             s->palette[i] = (r << 16) | (g << 8) | (b);

         }
     }
 
     /* next, look for a full codebook */
     if ((cbf0_chunk != -1) && (cbfz_chunk != -1)) {
 
         /* a chunk should not have both chunk types */

         av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: found both CBF0 and CBFZ chunks\n");

         return;
     }
 

     /* decompress the full codebook chunk */

     if (cbfz_chunk != -1) {
 

         chunk_size = AV_RB32(&s->buf[cbfz_chunk + 4]);

         cbfz_chunk += CHUNK_PREAMBLE_SIZE;
         decode_format80(&s->buf[cbfz_chunk], chunk_size,
             s->codebook, s->codebook_size, 0);

     }
 
     /* copy a full codebook */
     if (cbf0_chunk != -1) {
 

         chunk_size = AV_RB32(&s->buf[cbf0_chunk + 4]);

         /* sanity check the full codebook size */

         if (chunk_size > MAX_CODEBOOK_SIZE) {

             av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: CBF0 chunk too large (0x%X bytes)\n",

                 chunk_size);
             return;

         }
         cbf0_chunk += CHUNK_PREAMBLE_SIZE;
 
         memcpy(s->codebook, &s->buf[cbf0_chunk], chunk_size);
     }
 
     /* decode the frame */
     if (vptz_chunk == -1) {
 
         /* something is wrong if there is no VPTZ chunk */

         av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: no VPTZ chunk found\n");

         return;
     }
 

     chunk_size = AV_RB32(&s->buf[vptz_chunk + 4]);

     vptz_chunk += CHUNK_PREAMBLE_SIZE;
     decode_format80(&s->buf[vptz_chunk], chunk_size,

         s->decode_buffer, s->decode_buffer_size, 1);

 
     /* render the final PAL8 frame */

     if (s->vector_height == 4)
         index_shift = 4;
     else
         index_shift = 3;

     for (y = 0; y < s->frame.linesize[0] * s->height;

         y += s->frame.linesize[0] * s->vector_height) {
 
         for (x = y; x < y + s->width; x += 4, lobytes++, hibytes++) {
             pixel_ptr = x;
 
             /* get the vector index, the method for which varies according to
              * VQA file version */
             switch (s->vqa_version) {
 
             case 1:

                 lobyte = s->decode_buffer[lobytes * 2];
                 hibyte = s->decode_buffer[(lobytes * 2) + 1];
                 vector_index = ((hibyte << 8) | lobyte) >> 3;
                 vector_index <<= index_shift;
                 lines = s->vector_height;
                 /* uniform color fill - a quick hack */
                 if (hibyte == 0xFF) {
                     while (lines--) {
                         s->frame.data[0][pixel_ptr + 0] = 255 - lobyte;
                         s->frame.data[0][pixel_ptr + 1] = 255 - lobyte;
                         s->frame.data[0][pixel_ptr + 2] = 255 - lobyte;
                         s->frame.data[0][pixel_ptr + 3] = 255 - lobyte;
                         pixel_ptr += s->frame.linesize[0];
                     }
                     lines=0;
                 }

                 break;
 
             case 2:
                 lobyte = s->decode_buffer[lobytes];
                 hibyte = s->decode_buffer[hibytes];
                 vector_index = (hibyte << 8) | lobyte;

                 vector_index <<= index_shift;

                 lines = s->vector_height;

                 break;
 
             case 3:
 /* not implemented yet */
                 lines = 0;
                 break;
             }
 
             while (lines--) {
                 s->frame.data[0][pixel_ptr + 0] = s->codebook[vector_index++];
                 s->frame.data[0][pixel_ptr + 1] = s->codebook[vector_index++];
                 s->frame.data[0][pixel_ptr + 2] = s->codebook[vector_index++];
                 s->frame.data[0][pixel_ptr + 3] = s->codebook[vector_index++];
                 pixel_ptr += s->frame.linesize[0];
             }
         }
     }
 
     /* handle partial codebook */
     if ((cbp0_chunk != -1) && (cbpz_chunk != -1)) {
         /* a chunk should not have both chunk types */

         av_log(s->avctx, AV_LOG_ERROR, "  VQA video: problem: found both CBP0 and CBPZ chunks\n");

         return;
     }
 
     if (cbp0_chunk != -1) {
 

         chunk_size = AV_RB32(&s->buf[cbp0_chunk + 4]);

         cbp0_chunk += CHUNK_PREAMBLE_SIZE;
 
         /* accumulate partial codebook */
         memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
             &s->buf[cbp0_chunk], chunk_size);
         s->next_codebook_buffer_index += chunk_size;
 
         s->partial_countdown--;
         if (s->partial_countdown == 0) {
 
             /* time to replace codebook */

             memcpy(s->codebook, s->next_codebook_buffer,

                 s->next_codebook_buffer_index);
 
             /* reset accounting */
             s->next_codebook_buffer_index = 0;
             s->partial_countdown = s->partial_count;
         }
     }
 
     if (cbpz_chunk != -1) {
 

         chunk_size = AV_RB32(&s->buf[cbpz_chunk + 4]);

         cbpz_chunk += CHUNK_PREAMBLE_SIZE;

         /* accumulate partial codebook */
         memcpy(&s->next_codebook_buffer[s->next_codebook_buffer_index],
             &s->buf[cbpz_chunk], chunk_size);
         s->next_codebook_buffer_index += chunk_size;
 
         s->partial_countdown--;
         if (s->partial_countdown == 0) {
 
             /* decompress codebook */

             decode_format80(s->next_codebook_buffer,
                 s->next_codebook_buffer_index,

                 s->codebook, s->codebook_size, 0);
 
             /* reset accounting */
             s->next_codebook_buffer_index = 0;
             s->partial_countdown = s->partial_count;
         }

     }
 }
 
 static int vqa_decode_frame(AVCodecContext *avctx,
                             void *data, int *data_size,

                             AVPacket *avpkt)

 {

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

     VqaContext *s = avctx->priv_data;

 
     s->buf = buf;
     s->size = buf_size;
 
     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);
 
     if (avctx->get_buffer(avctx, &s->frame)) {

         av_log(s->avctx, AV_LOG_ERROR, "  VQA Video: get_buffer() failed\n");

         return -1;
     }
 
     vqa_decode_chunk(s);
 
     /* make the palette available on the way out */
     memcpy(s->frame.data[1], s->palette, PALETTE_COUNT * 4);

     s->frame.palette_has_changed = 1;

 
     *data_size = sizeof(AVFrame);
     *(AVFrame*)data = s->frame;
 
     /* report that the buffer was completely consumed */
     return buf_size;
 }
 

 static av_cold int vqa_decode_end(AVCodecContext *avctx)

 {

     VqaContext *s = avctx->priv_data;

 
     av_free(s->codebook);
     av_free(s->next_codebook_buffer);
     av_free(s->decode_buffer);
 
     if (s->frame.data[0])
         avctx->release_buffer(avctx, &s->frame);
 
     return 0;
 }
 

 AVCodec ff_vqa_decoder = {

     "vqavideo",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_WS_VQA,
     sizeof(VqaContext),
     vqa_decode_init,
     NULL,
     vqa_decode_end,
     vqa_decode_frame,
     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Westwood Studios VQA (Vector Quantized Animation) video"),

 };