/*

 * Westwood Studios VQA Video Decoder

 * Copyright (c) 2003 Mike Melanson <melanson@pcisys.net>

 * Copyright (c) 2021 Pekka Väänänen <pekka.vaananen@iki.fi>

 *

 * 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.

 *

 * VQA3 introduces a 15-bit high color codebook, delta coding, replaces

 * the above "split byte" scheme with RLE compression, and extends the

 * "format80" compression with relative references. In VQA3 the whole

 * codebook is always updated as a whole without splitting it into pieces.

 */

#include <stdio.h>

#include <string.h>

#include "libavutil/intreadwrite.h"

#include "libavutil/mem.h"

#include "avcodec.h"

#include "bytestream.h"

#include "codec_internal.h"

#include "decode.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 * sizeof(uint16_t))

#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')

#define VPTR_TAG MKBETAG('V', 'P', 'T', 'R')

#define VPRZ_TAG MKBETAG('V', 'P', 'R', 'Z')

typedef struct VqaContext {

    AVFrame *frame;

    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;

    int colors;

    s->avctx = avctx;

    /* 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];

    if (s->vqa_version < 1 || s->vqa_version > 3) {

        avpriv_request_sample(avctx, "VQA Version %i", s->vqa_version);

        return AVERROR_INVALIDDATA;

    }

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

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

    if ((ret = ff_set_dimensions(avctx, s->width, s->height)) < 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];

    colors = (s->avctx->extradata[14] << 8) | s->avctx->extradata[15];

    if (colors > 0) {

        avctx->pix_fmt = AV_PIX_FMT_PAL8;

    } else {

        avctx->pix_fmt = AV_PIX_FMT_RGB555LE;

    }

    /* 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;

    }

    s->frame = av_frame_alloc();

    if (!s->frame)

        return AVERROR(ENOMEM);

    /* allocate codebooks */

    s->codebook_size = MAX_CODEBOOK_SIZE;

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

    if (!s->codebook)

        return AVERROR(ENOMEM);

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

    if (!s->next_codebook_buffer)

        return AVERROR(ENOMEM);

    /* 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)

        return AVERROR(ENOMEM);

    /* 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;

}

#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;

    int relative = 0;

    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;

    }

    /* the "new" scheme makes references relative to destination pointer */

    if (bytestream2_peek_byte(&s->gb) == 0x00) {

        relative = 1;

        bytestream2_get_byte(&s->gb);

        ff_tlog(s->avctx, "found new format stream ");

    }

    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);

            if (relative)

                src_pos = dest_index - src_pos;

            ff_tlog(s->avctx, "(1) copy %X bytes from 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);

            if (relative)

                src_pos = dest_index - src_pos;

            ff_tlog(s->avctx, "(3) copy %X bytes from 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_frame_pal8(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: %s (%08X)\n",

                   av_fourcc2str(av_bswap32(chunk_type)), 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:

                av_log(s->avctx, AV_LOG_ERROR, "VQA3 shouldn't have a color palette");

                return AVERROR_INVALIDDATA;

            }

            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 */

            res = decode_format80(s, 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;

            if (res < 0)

                return res;

        }

    }

    return 0;

}

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

{

    unsigned int chunk_type;

    unsigned int chunk_size;

    unsigned int index = 0;

    int res;

    int cbf0_chunk = -1;

    int cbfz_chunk = -1;

    int vptr_chunk = -1;

    int vprz_chunk = -1;

    GetByteContext gb_stream;

    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 VPTR_TAG:

            vptr_chunk = index;

            break;

        case VPRZ_TAG:

            vprz_chunk = index;

            break;

        default:

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

                   av_fourcc2str(av_bswap32(chunk_type)), chunk_type);

            break;

        }

        bytestream2_skip(&s->gb, chunk_size + (chunk_size & 0x01));

    }

    /* 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 (vptr_chunk != -1) {

        /* copy uncompressed tile data */

        bytestream2_seek(&s->gb, vptr_chunk, SEEK_SET);

        chunk_size = bytestream2_get_be32(&s->gb);

        if (chunk_size > s->decode_buffer_size) {

            av_log(s->avctx, AV_LOG_ERROR, "VPTR chunk didn't fit in decode buffer");

            return AVERROR_INVALIDDATA;

        }

        bytestream2_get_buffer(&s->gb, s->decode_buffer, chunk_size);

    } else if (vprz_chunk != -1) {

        /* decompress the tile data */

        bytestream2_seek(&s->gb, vprz_chunk, SEEK_SET);

        chunk_size = bytestream2_get_be32(&s->gb);

        if ((res = decode_format80(s, chunk_size, s->decode_buffer, s->decode_buffer_size, 0)) < 0)

            return res;

    } else {

        av_log(s->avctx, AV_LOG_ERROR, "frame has no block data\n");

        return AVERROR_INVALIDDATA;

    }

    /* now uncompress the per-row RLE of the decode buffer and draw the blocks in framebuffer */

    bytestream2_init(&gb_stream, s->decode_buffer, s->decode_buffer_size);

    for (int y_pos = 0; y_pos < s->height; y_pos += s->vector_height) {

        int x_pos = 0;

        while (x_pos < s->width) {

            int vector_index = 0;

            int count = 0;

            uint16_t code;

            int type;

            if (bytestream2_get_bytes_left(&gb_stream) < 2)

                return AVERROR_INVALIDDATA;

            code = bytestream2_get_le16(&gb_stream);

            type = code >> 13;

            code &= 0x1fff;

            if (type == 0) {

                x_pos += 4 * code;

                continue;

            } else if (type < 3) {

                vector_index = code & 0xff;

                count = ((code & 0x1f00) >> 7) + 1 + type;

            } else if (type < 5) {

                vector_index = code;

                count = 1;

            } else if (type < 7) {

                vector_index = code;

                count = bytestream2_get_byte(&gb_stream);

            } else {

                av_log(s->avctx, AV_LOG_ERROR, " unknown type in VPTR chunk (%d)\n",type);

                return AVERROR_INVALIDDATA;

            }

            if (count < 0 || count > (s->width - x_pos) / s->vector_width) {

                av_log(s->avctx, AV_LOG_ERROR, "invalid count: %d\n", count);

                return AVERROR_INVALIDDATA;

            }

            while (count-- && x_pos < s->width) {

                const int bytes_per_vector = 4 * s->vector_height * sizeof(uint16_t);

                unsigned char *src = s->codebook + vector_index * bytes_per_vector;

                unsigned char *dst = s->frame->data[0] + y_pos * s->frame->linesize[0]

                    + sizeof(uint16_t) * x_pos;

                if (vector_index >= MAX_VECTORS)

                    return AVERROR_INVALIDDATA;

                for (int y = 0; y < s->vector_height; y++) {

                    int size = 4 * sizeof(uint16_t);

                    memcpy(dst, src, size);

                    dst += s->frame->linesize[0];

                    src += size;

                }

                /* we might want to read the next block index from stream */

                if ((type == 2) && count > 0) {

                    vector_index = bytestream2_get_byte(&gb_stream);

                }

                x_pos += 4;

            }

            if (count > 0) {

                av_log(s->avctx, AV_LOG_ERROR, "had %d leftover vectors\n", count);

                return AVERROR_BUG;

            }

        }

    }

    return 0;

}

static int vqa_decode_frame(AVCodecContext *avctx, AVFrame *rframe,

                            int *got_frame, AVPacket *avpkt)

{

    VqaContext *s = avctx->priv_data;

    int res;

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

        return res;

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

    if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {

        if ((res = vqa_decode_frame_pal8(s, s->frame)) < 0)

            return res;

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

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

#if FF_API_PALETTE_HAS_CHANGED

FF_DISABLE_DEPRECATION_WARNINGS

        s->frame->palette_has_changed = 1;

FF_ENABLE_DEPRECATION_WARNINGS

#endif

    } else if (avctx->pix_fmt == AV_PIX_FMT_RGB555LE) {

        if ((res = vqa_decode_frame_hicolor(s, s->frame)) < 0)

            return res;

    } else {

        av_log(s->avctx, AV_LOG_ERROR, "unsupported pixel format\n");

        return AVERROR_BUG;

    }

    if ((res = av_frame_ref(rframe, s->frame)) < 0)

        return res;

    *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_frame_free(&s->frame);

    av_freep(&s->codebook);

    av_freep(&s->next_codebook_buffer);

    av_freep(&s->decode_buffer);

    return 0;

}

static const FFCodecDefault vqa_defaults[] = {

    { "max_pixels", "640*480" },

    { NULL },

};

const FFCodec ff_vqa_decoder = {

    .p.name         = "vqavideo",

    CODEC_LONG_NAME("Westwood Studios VQA (Vector Quantized Animation) video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_WS_VQA,

    .priv_data_size = sizeof(VqaContext),

    .init           = vqa_decode_init,

    .close          = vqa_decode_end,

    FF_CODEC_DECODE_CB(vqa_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .defaults       = vqa_defaults,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};