/*

 * Motion Pixels Video Decoder

 * Copyright (c) 2008 Gregory Montoir (cyx@users.sourceforge.net)

 *

 * 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

 */

#include "libavutil/mem.h"

#include "libavutil/thread.h"

#include "config.h"

#include "avcodec.h"

#include "get_bits.h"

#include "bswapdsp.h"

#include "codec_internal.h"

#include "decode.h"

#define MAX_HUFF_CODES 16

#include "motionpixels_tablegen.h"

typedef struct HuffCode {

    uint8_t size;

    uint8_t delta;

} HuffCode;

typedef struct MotionPixelsContext {

    AVCodecContext *avctx;

    AVFrame *frame;

    BswapDSPContext bdsp;

    uint8_t *changes_map;

    int offset_bits_len;

    int codes_count, current_codes_count;

    int max_codes_bits;

    HuffCode codes[MAX_HUFF_CODES];

    VLC vlc;

    YuvPixel *vpt, *hpt;

    uint8_t gradient_scale[3];

    uint8_t *bswapbuf;

    int bswapbuf_size;

} MotionPixelsContext;

static av_cold int mp_decode_end(AVCodecContext *avctx)

{

    MotionPixelsContext *mp = avctx->priv_data;

    av_freep(&mp->changes_map);

    av_freep(&mp->vpt);

    av_freep(&mp->hpt);

    av_freep(&mp->bswapbuf);

    av_frame_free(&mp->frame);

    return 0;

}

static av_cold int mp_decode_init(AVCodecContext *avctx)

{

    MotionPixelsContext *mp = avctx->priv_data;

    int w4 = (avctx->width  + 3) & ~3;

    int h4 = (avctx->height + 3) & ~3;

    if(avctx->extradata_size < 2){

        av_log(avctx, AV_LOG_ERROR, "extradata too small\n");

        return AVERROR_INVALIDDATA;

    }

    mp->avctx = avctx;

    ff_bswapdsp_init(&mp->bdsp);

    mp->changes_map = av_calloc(avctx->width, h4);

    mp->offset_bits_len = av_log2(avctx->width * avctx->height) + 1;

    mp->vpt = av_calloc(avctx->height, sizeof(*mp->vpt));

    mp->hpt = av_calloc(h4 / 4, w4 / 4 * sizeof(*mp->hpt));

    if (!mp->changes_map || !mp->vpt || !mp->hpt)

        return AVERROR(ENOMEM);

    avctx->pix_fmt = AV_PIX_FMT_RGB555;

    mp->frame = av_frame_alloc();

    if (!mp->frame)

        return AVERROR(ENOMEM);

#if !CONFIG_HARDCODED_TABLES

    static AVOnce init_static_once = AV_ONCE_INIT;

    ff_thread_once(&init_static_once, motionpixels_tableinit);

#endif

    return 0;

}

static void mp_read_changes_map(MotionPixelsContext *mp, GetBitContext *gb, int count, int bits_len, int read_color)

{

    uint16_t *pixels;

    int offset, w, h, color = 0, x, y, i;

    while (count--) {

        offset = get_bits_long(gb, mp->offset_bits_len);

        w      = get_bits(gb, bits_len) + 1;

        h      = get_bits(gb, bits_len) + 1;

        if (read_color)

            color = get_bits(gb, 15);

        x = offset % mp->avctx->width;

        y = offset / mp->avctx->width;

        if (y >= mp->avctx->height)

            continue;

        w = FFMIN(w, mp->avctx->width  - x);

        h = FFMIN(h, mp->avctx->height - y);

        pixels = (uint16_t *)&mp->frame->data[0][y * mp->frame->linesize[0] + x * 2];

        while (h--) {

            mp->changes_map[offset] = w;

            if (read_color)

                for (i = 0; i < w; ++i)

                    pixels[i] = color;

            offset += mp->avctx->width;

            pixels += mp->frame->linesize[0] / 2;

        }

    }

}

static int mp_get_code(MotionPixelsContext *mp, GetBitContext *gb, int size)

{

    while (get_bits1(gb)) {

        ++size;

        if (size > mp->max_codes_bits) {

            av_log(mp->avctx, AV_LOG_ERROR, "invalid code size %d/%d\n", size, mp->max_codes_bits);

            return AVERROR_INVALIDDATA;

        }

        if (mp_get_code(mp, gb, size) < 0)

            return AVERROR_INVALIDDATA;

    }

    if (mp->current_codes_count >= mp->codes_count) {

        av_log(mp->avctx, AV_LOG_ERROR, "too many codes\n");

        return AVERROR_INVALIDDATA;

    }

    mp->codes[mp->current_codes_count++].size = size;

    return 0;

}

static int mp_read_codes_table(MotionPixelsContext *mp, GetBitContext *gb)

{

    if (mp->codes_count == 1) {

        mp->codes[0].delta = get_bits(gb, 4);

    } else {

        int i;

        int ret;

        mp->max_codes_bits = get_bits(gb, 4);

        for (i = 0; i < mp->codes_count; ++i)

            mp->codes[i].delta = get_bits(gb, 4);

        mp->current_codes_count = 0;

        if ((ret = mp_get_code(mp, gb, 0)) < 0)

            return ret;

        if (mp->current_codes_count < mp->codes_count) {

            av_log(mp->avctx, AV_LOG_ERROR, "too few codes\n");

            return AVERROR_INVALIDDATA;

        }

   }

   return 0;

}

static av_always_inline int mp_gradient(MotionPixelsContext *mp, int component, int v)

{

    int delta;

    delta = (v - 7) * mp->gradient_scale[component];

    mp->gradient_scale[component] = (v == 0 || v == 14) ? 2 : 1;

    return delta;

}

static YuvPixel mp_get_yuv_from_rgb(MotionPixelsContext *mp, int x, int y)

{

    int color;

    color = *(uint16_t *)&mp->frame->data[0][y * mp->frame->linesize[0] + x * 2];

    return mp_rgb_yuv_table[color & 0x7FFF];

}

static void mp_set_rgb_from_yuv(MotionPixelsContext *mp, int x, int y, const YuvPixel *p)

{

    int color;

    color = mp_yuv_to_rgb(p->y, p->v, p->u, 1);

    *(uint16_t *)&mp->frame->data[0][y * mp->frame->linesize[0] + x * 2] = color;

}

static av_always_inline int mp_get_vlc(MotionPixelsContext *mp, GetBitContext *gb)

{

    return mp->vlc.table ? get_vlc2(gb, mp->vlc.table, mp->max_codes_bits, 1)

                         : mp->codes[0].delta;

}

static void mp_decode_line(MotionPixelsContext *mp, GetBitContext *gb, int y)

{

    YuvPixel p;

    const int y0 = y * mp->avctx->width;

    int w, i, x = 0;

    p = mp->vpt[y];

    if (mp->changes_map[y0 + x] == 0) {

        memset(mp->gradient_scale, 1, sizeof(mp->gradient_scale));

        ++x;

    }

    while (x < mp->avctx->width) {

        w = mp->changes_map[y0 + x];

        if (w != 0) {

            if ((y & 3) == 0) {

                if (mp->changes_map[y0 + x + mp->avctx->width] < w ||

                    mp->changes_map[y0 + x + mp->avctx->width * 2] < w ||

                    mp->changes_map[y0 + x + mp->avctx->width * 3] < w) {

                    for (i = (x + 3) & ~3; i < x + w; i += 4) {

                        mp->hpt[((y / 4) * mp->avctx->width + i) / 4] = mp_get_yuv_from_rgb(mp, i, y);

                    }

                }

            }

            x += w;

            memset(mp->gradient_scale, 1, sizeof(mp->gradient_scale));

            p = mp_get_yuv_from_rgb(mp, x - 1, y);

        } else {

            p.y += mp_gradient(mp, 0, mp_get_vlc(mp, gb));

            p.y = av_clip_uintp2(p.y, 5);

            if ((x & 3) == 0) {

                if ((y & 3) == 0) {

                    p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb));

                    p.v = av_clip_intp2(p.v, 5);

                    p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb));

                    p.u = av_clip_intp2(p.u, 5);

                    mp->hpt[((y / 4) * mp->avctx->width + x) / 4] = p;

                } else {

                    p.v = mp->hpt[((y / 4) * mp->avctx->width + x) / 4].v;

                    p.u = mp->hpt[((y / 4) * mp->avctx->width + x) / 4].u;

                }

            }

            mp_set_rgb_from_yuv(mp, x, y, &p);

            ++x;

        }

    }

}

static void mp_decode_frame_helper(MotionPixelsContext *mp, GetBitContext *gb)

{

    YuvPixel p;

    int y, y0;

    av_assert1(mp->changes_map[0]);

    for (y = 0; y < mp->avctx->height; ++y) {

        if (mp->changes_map[y * mp->avctx->width] != 0) {

            memset(mp->gradient_scale, 1, sizeof(mp->gradient_scale));

            p = mp_get_yuv_from_rgb(mp, 0, y);

        } else {

            p.y += mp_gradient(mp, 0, mp_get_vlc(mp, gb));

            p.y = av_clip_uintp2(p.y, 5);

            if ((y & 3) == 0) {

                p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb));

                p.v = av_clip_intp2(p.v, 5);

                p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb));

                p.u = av_clip_intp2(p.u, 5);

            }

            mp->vpt[y] = p;

            mp_set_rgb_from_yuv(mp, 0, y, &p);

        }

    }

    for (y0 = 0; y0 < 2; ++y0)

        for (y = y0; y < mp->avctx->height; y += 2)

            mp_decode_line(mp, gb, y);

}

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

                           int *got_frame, AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    MotionPixelsContext *mp = avctx->priv_data;

    GetBitContext gb;

    int i, count1, count2, sz, ret;

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

        return ret;

    /* le32 bitstream msb first */

    av_fast_padded_malloc(&mp->bswapbuf, &mp->bswapbuf_size, buf_size);

    if (!mp->bswapbuf)

        return AVERROR(ENOMEM);

    mp->bdsp.bswap_buf((uint32_t *) mp->bswapbuf, (const uint32_t *) buf,

                       buf_size / 4);

    if (buf_size & 3)

        memcpy(mp->bswapbuf + (buf_size & ~3), buf + (buf_size & ~3), buf_size & 3);

    init_get_bits(&gb, mp->bswapbuf, buf_size * 8);

    memset(mp->changes_map, 0, avctx->width * avctx->height);

    for (i = !(avctx->extradata[1] & 2); i < 2; ++i) {

        count1 = get_bits(&gb, 12);

        count2 = get_bits(&gb, 12);

        mp_read_changes_map(mp, &gb, count1, 8, i);

        mp_read_changes_map(mp, &gb, count2, 4, i);

    }

    mp->codes_count = get_bits(&gb, 4);

    if (mp->codes_count == 0)

        goto end;

    if (mp->changes_map[0] == 0) {

        *(uint16_t *)mp->frame->data[0] = get_bits(&gb, 15);

        mp->changes_map[0] = 1;

    }

    if (mp_read_codes_table(mp, &gb) < 0)

        goto end;

    sz = get_bits(&gb, 18);

    if (avctx->extradata[0] != 5)

        sz += get_bits(&gb, 18);

    if (sz == 0)

        goto end;

    if (mp->codes_count > 1) {

        /* The entries of the mp->codes array are sorted from right to left

         * in the Huffman tree, hence -(int)sizeof(HuffCode). */

        ret = ff_vlc_init_from_lengths(&mp->vlc, mp->max_codes_bits, mp->codes_count,

                                       &mp->codes[mp->codes_count - 1].size,  -(int)sizeof(HuffCode),

                                       &mp->codes[mp->codes_count - 1].delta, -(int)sizeof(HuffCode), 1,

                                       0, 0, avctx);

        if (ret < 0)

            goto end;

    }

    mp_decode_frame_helper(mp, &gb);

    ff_vlc_free(&mp->vlc);

end:

    if ((ret = av_frame_ref(rframe, mp->frame)) < 0)

        return ret;

    *got_frame       = 1;

    return buf_size;

}

const FFCodec ff_motionpixels_decoder = {

    .p.name         = "motionpixels",

    CODEC_LONG_NAME("Motion Pixels video"),

    .p.type         = AVMEDIA_TYPE_VIDEO,

    .p.id           = AV_CODEC_ID_MOTIONPIXELS,

    .priv_data_size = sizeof(MotionPixelsContext),

    .init           = mp_decode_init,

    .close          = mp_decode_end,

    FF_CODEC_DECODE_CB(mp_decode_frame),

    .p.capabilities = AV_CODEC_CAP_DR1,

    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,

};