/*
  * 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
  * @author Mike Melanson (melanson@pcisys.net)
  * @see 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"

 #include "bytestream.h"

 #include "internal.h"

 
 #define PALETTE_COUNT 256
 #define VQA_HEADER_SIZE 0x2A
 

 /* 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;

     GetByteContext gb;

     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;

     int i, j, codebook_index, ret;

 
     s->avctx = avctx;

     avctx->pix_fmt = AV_PIX_FMT_PAL8;

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

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

         return AVERROR(EINVAL);

     }
 
     /* load up the VQA parameters from the header */

     s->vqa_version = s->avctx->extradata[0];

     switch (s->vqa_version) {
     case 1:
     case 2:
         break;
     case 3:
         avpriv_report_missing_feature(avctx, "VQA Version %d", s->vqa_version);
         return AVERROR_PATCHWELCOME;
     default:
         avpriv_request_sample(avctx, "VQA Version %i", s->vqa_version);

         return AVERROR_PATCHWELCOME;

     }

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

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

         s->width= s->height= 0;

         return ret;

     }

     s->vector_width = s->avctx->extradata[10];
     s->vector_height = s->avctx->extradata[11];
     s->partial_count = s->partial_countdown = s->avctx->extradata[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 AVERROR_INVALIDDATA;

     }
 

     if (s->width % s->vector_width || s->height % s->vector_height) {

         av_log(avctx, AV_LOG_ERROR, "Image size not multiple of block size\n");
         return AVERROR_INVALIDDATA;
     }
 

     /* allocate codebooks */

     s->codebook_size = MAX_CODEBOOK_SIZE;
     s->codebook = av_malloc(s->codebook_size);

     if (!s->codebook)
         goto fail;

     s->next_codebook_buffer = av_malloc(s->codebook_size);

     if (!s->next_codebook_buffer)
         goto fail;
 
     /* allocate decode buffer */
     s->decode_buffer_size = (s->width / s->vector_width) *
         (s->height / s->vector_height) * 2;

     s->decode_buffer = av_mallocz(s->decode_buffer_size);

     if (!s->decode_buffer)
         goto fail;

 
     /* 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;
 
     return 0;

 fail:
     av_freep(&s->codebook);
     av_freep(&s->next_codebook_buffer);
     av_freep(&s->decode_buffer);
     return AVERROR(ENOMEM);

 }
 
 #define CHECK_COUNT() \
     if (dest_index + count > dest_size) { \

         av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: next op would overflow dest_index\n"); \
         av_log(s->avctx, AV_LOG_ERROR, "current dest_index = %d, count = %d, dest_size = %d\n", \

             dest_index, count, dest_size); \

         return AVERROR_INVALIDDATA; \

     }
 

 #define CHECK_COPY(idx) \
     if (idx < 0 || idx + count > dest_size) { \

         av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: next op would overflow dest_index\n"); \
         av_log(s->avctx, AV_LOG_ERROR, "current src_pos = %d, count = %d, dest_size = %d\n", \

             src_pos, count, dest_size); \
         return AVERROR_INVALIDDATA; \

     }
 

 static int decode_format80(VqaContext *s, int src_size,

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

 
     int dest_index = 0;

     int count, opcode, start;

     int src_pos;
     unsigned char color;
     int i;
 

     if (src_size < 0 || src_size > bytestream2_get_bytes_left(&s->gb)) {
         av_log(s->avctx, AV_LOG_ERROR, "Chunk size %d is out of range\n",
                src_size);
         return AVERROR_INVALIDDATA;
     }
 

     start = bytestream2_tell(&s->gb);
     while (bytestream2_tell(&s->gb) - start < src_size) {
         opcode = bytestream2_get_byte(&s->gb);

         ff_tlog(s->avctx, "opcode %02X: ", opcode);

 
         /* 0x80 means that frame is finished */

         if (opcode == 0x80)

             break;

 
         if (dest_index >= dest_size) {

             av_log(s->avctx, AV_LOG_ERROR, "decode_format80 problem: dest_index (%d) exceeded dest_size (%d)\n",

                 dest_index, dest_size);

             return AVERROR_INVALIDDATA;

         }
 

         if (opcode == 0xFF) {

             count   = bytestream2_get_le16(&s->gb);
             src_pos = bytestream2_get_le16(&s->gb);

             ff_tlog(s->avctx, "(1) copy %X bytes from absolute pos %X\n", count, src_pos);

             CHECK_COUNT();

             CHECK_COPY(src_pos);

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

         } else if (opcode == 0xFE) {

             count = bytestream2_get_le16(&s->gb);
             color = bytestream2_get_byte(&s->gb);

             ff_tlog(s->avctx, "(2) set %X bytes to %02X\n", count, color);

             CHECK_COUNT();
             memset(&dest[dest_index], color, count);
             dest_index += count;
 

         } else if ((opcode & 0xC0) == 0xC0) {

             count = (opcode & 0x3F) + 3;

             src_pos = bytestream2_get_le16(&s->gb);

             ff_tlog(s->avctx, "(3) copy %X bytes from absolute pos %X\n", count, src_pos);

             CHECK_COUNT();

             CHECK_COPY(src_pos);

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

         } else if (opcode > 0x80) {

             count = opcode & 0x3F;

             ff_tlog(s->avctx, "(4) copy %X bytes from source to dest\n", count);

             CHECK_COUNT();

             bytestream2_get_buffer(&s->gb, &dest[dest_index], count);

             dest_index += count;
 
         } else {
 

             count = ((opcode & 0x70) >> 4) + 3;

             src_pos = bytestream2_get_byte(&s->gb) | ((opcode & 0x0F) << 8);

             ff_tlog(s->avctx, "(5) copy %X bytes from relpos %X\n", count, src_pos);

             CHECK_COUNT();

             CHECK_COPY(dest_index - src_pos);

             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(s->avctx, AV_LOG_ERROR, "decode_format80 problem: decode finished with dest_index (%d) < dest_size (%d)\n",

                 dest_index, dest_size);

             memset(dest + dest_index, 0, dest_size - dest_index);
         }

 
     return 0; // let's display what we decoded anyway

 }
 

 static int vqa_decode_chunk(VqaContext *s, AVFrame *frame)

 {
     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 res;

 
     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 (bytestream2_get_bytes_left(&s->gb) >= 8) {

         chunk_type = bytestream2_get_be32u(&s->gb);
         index      = bytestream2_tell(&s->gb);
         chunk_size = bytestream2_get_be32u(&s->gb);

 
         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, "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;

         bytestream2_skip(&s->gb, 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, "problem: found both CPL0 and CPLZ chunks\n");

         return AVERROR_INVALIDDATA;

     }
 
     /* 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) {
 

         bytestream2_seek(&s->gb, cpl0_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);

         /* sanity check the palette size */

         if (chunk_size / 3 > 256 || chunk_size > bytestream2_get_bytes_left(&s->gb)) {

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

                 chunk_size / 3);

             return AVERROR_INVALIDDATA;

         }
         for (i = 0; i < chunk_size / 3; i++) {
             /* scale by 4 to transform 6-bit palette -> 8-bit */

             r = bytestream2_get_byteu(&s->gb) * 4;
             g = bytestream2_get_byteu(&s->gb) * 4;
             b = bytestream2_get_byteu(&s->gb) * 4;

             s->palette[i] = 0xFFU << 24 | r << 16 | g << 8 | b;

             s->palette[i] |= s->palette[i] >> 6 & 0x30303;

         }
     }
 
     /* 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, "problem: found both CBF0 and CBFZ chunks\n");

         return AVERROR_INVALIDDATA;

     }
 

     /* decompress the full codebook chunk */

     if (cbfz_chunk != -1) {
 

         bytestream2_seek(&s->gb, cbfz_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);

         if ((res = decode_format80(s, chunk_size, s->codebook,

                                    s->codebook_size, 0)) < 0)
             return res;

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

         bytestream2_seek(&s->gb, cbf0_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);

         /* sanity check the full codebook size */

         if (chunk_size > MAX_CODEBOOK_SIZE) {

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

                 chunk_size);

             return AVERROR_INVALIDDATA;

         }
 

         bytestream2_get_buffer(&s->gb, s->codebook, 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, "problem: no VPTZ chunk found\n");

         return AVERROR_INVALIDDATA;

     }
 

     bytestream2_seek(&s->gb, vptz_chunk, SEEK_SET);
     chunk_size = bytestream2_get_be32(&s->gb);

     if ((res = decode_format80(s, chunk_size,

                                s->decode_buffer, s->decode_buffer_size, 1)) < 0)
         return res;

 
     /* render the final PAL8 frame */

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

     for (y = 0; y < s->height; y += s->vector_height) {
         for (x = 0; x < s->width; x += 4, lobytes++, hibytes++) {

             pixel_ptr = y * frame->linesize[0] + 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--) {

                         frame->data[0][pixel_ptr + 0] = 255 - lobyte;
                         frame->data[0][pixel_ptr + 1] = 255 - lobyte;
                         frame->data[0][pixel_ptr + 2] = 255 - lobyte;
                         frame->data[0][pixel_ptr + 3] = 255 - lobyte;
                         pixel_ptr += 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--) {

                 frame->data[0][pixel_ptr + 0] = s->codebook[vector_index++];
                 frame->data[0][pixel_ptr + 1] = s->codebook[vector_index++];
                 frame->data[0][pixel_ptr + 2] = s->codebook[vector_index++];
                 frame->data[0][pixel_ptr + 3] = s->codebook[vector_index++];
                 pixel_ptr += 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, "problem: found both CBP0 and CBPZ chunks\n");

         return AVERROR_INVALIDDATA;

     }
 
     if (cbp0_chunk != -1) {
 

         bytestream2_seek(&s->gb, cbp0_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);

         if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {

             av_log(s->avctx, AV_LOG_ERROR, "cbp0 chunk too large (%u bytes)\n",
                    chunk_size);

             return AVERROR_INVALIDDATA;
         }
 

         /* accumulate partial codebook */

         bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
                                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) {
 

         bytestream2_seek(&s->gb, cbpz_chunk, SEEK_SET);
         chunk_size = bytestream2_get_be32(&s->gb);

         if (chunk_size > MAX_CODEBOOK_SIZE - s->next_codebook_buffer_index) {

             av_log(s->avctx, AV_LOG_ERROR, "cbpz chunk too large (%u bytes)\n",
                    chunk_size);

             return AVERROR_INVALIDDATA;
         }
 

         /* accumulate partial codebook */

         bytestream2_get_buffer(&s->gb, &s->next_codebook_buffer[s->next_codebook_buffer_index],
                                chunk_size);

         s->next_codebook_buffer_index += chunk_size;
 
         s->partial_countdown--;

         if (s->partial_countdown <= 0) {

             bytestream2_init(&s->gb, s->next_codebook_buffer, s->next_codebook_buffer_index);

             /* decompress codebook */

             if ((res = decode_format80(s, s->next_codebook_buffer_index,

                                        s->codebook, s->codebook_size, 0)) < 0)
                 return res;

 
             /* reset accounting */
             s->next_codebook_buffer_index = 0;
             s->partial_countdown = s->partial_count;
         }

     }

 
     return 0;

 }
 
 static int vqa_decode_frame(AVCodecContext *avctx,

                             void *data, int *got_frame,

                             AVPacket *avpkt)

 {

     VqaContext *s = avctx->priv_data;

     AVFrame *frame = data;

     int res;

     if ((res = ff_get_buffer(avctx, frame, 0)) < 0)

         return res;

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

     if ((res = vqa_decode_chunk(s, frame)) < 0)

         return res;

 
     /* make the palette available on the way out */

     memcpy(frame->data[1], s->palette, PALETTE_COUNT * 4);
     frame->palette_has_changed = 1;

     *got_frame      = 1;

 
     /* report that the buffer was completely consumed */

     return avpkt->size;

 }
 

 static av_cold int vqa_decode_end(AVCodecContext *avctx)

 {

     VqaContext *s = avctx->priv_data;

     av_freep(&s->codebook);
     av_freep(&s->next_codebook_buffer);
     av_freep(&s->decode_buffer);

 
     return 0;
 }
 

 AVCodec ff_vqa_decoder = {

     .name           = "vqavideo",

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

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_WS_VQA,

     .priv_data_size = sizeof(VqaContext),
     .init           = vqa_decode_init,
     .close          = vqa_decode_end,
     .decode         = vqa_decode_frame,

     .capabilities   = AV_CODEC_CAP_DR1,

 };