/*
  * 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 "avcodec.h"

 #include "get_bits.h"

 #include "dsputil.h"
 
 #define MAX_HUFF_CODES 16
 

 #include "motionpixels_tablegen.h"

 
 typedef struct HuffCode {
     int code;
     uint8_t size;
     uint8_t delta;
 } HuffCode;
 
 typedef struct MotionPixelsContext {
     AVCodecContext *avctx;
     AVFrame frame;
     DSPContext dsp;
     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_init(AVCodecContext *avctx)
 {
     MotionPixelsContext *mp = avctx->priv_data;

     int w4 = (avctx->width  + 3) & ~3;
     int h4 = (avctx->height + 3) & ~3;

     motionpixels_tableinit();

     mp->avctx = avctx;
     dsputil_init(&mp->dsp, avctx);

     mp->changes_map = av_mallocz(avctx->width * h4);

     mp->offset_bits_len = av_log2(avctx->width * avctx->height) + 1;
     mp->vpt = av_mallocz(avctx->height * sizeof(YuvPixel));

     mp->hpt = av_mallocz(h4 * w4 / 16 * sizeof(YuvPixel));

     avctx->pix_fmt = PIX_FMT_RGB555;

     avcodec_get_frame_defaults(&mp->frame);

     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 void mp_get_code(MotionPixelsContext *mp, GetBitContext *gb, int size, int code)
 {
     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;
         }
         code <<= 1;
         mp_get_code(mp, gb, size, code + 1);
     }
     if (mp->current_codes_count >= MAX_HUFF_CODES) {
         av_log(mp->avctx, AV_LOG_ERROR, "too many codes\n");
         return;
     }
     mp->codes[mp->current_codes_count  ].code = code;
     mp->codes[mp->current_codes_count++].size = size;
 }
 
 static void mp_read_codes_table(MotionPixelsContext *mp, GetBitContext *gb)
 {
     if (mp->codes_count == 1) {
         mp->codes[0].delta = get_bits(gb, 4);
     } else {
         int i;
 
         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;
         mp_get_code(mp, gb, 0, 0);
    }
 }
 
 static 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];
 }
 
 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 int mp_get_vlc(MotionPixelsContext *mp, GetBitContext *gb)
 {
     int i;
 
     i = (mp->codes_count == 1) ? 0 : get_vlc2(gb, mp->vlc.table, mp->max_codes_bits, 1);
     return mp->codes[i].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));
             if ((x & 3) == 0) {
                 if ((y & 3) == 0) {
                     p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb));
                     p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb));
                     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;
 
     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));
             if ((y & 3) == 0) {
                 p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb));
                 p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb));
             }
             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,
                                  void *data, int *data_size,

                                  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;
 
     mp->frame.reference = 1;
     mp->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
     if (avctx->reget_buffer(avctx, &mp->frame)) {
         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
         return -1;
     }
 
     /* le32 bitstream msb first */

     av_fast_malloc(&mp->bswapbuf, &mp->bswapbuf_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
     if (!mp->bswapbuf)

         return AVERROR(ENOMEM);

     mp->dsp.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);

     memset(mp->bswapbuf + buf_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);

     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;
     }
     mp_read_codes_table(mp, &gb);
 
     sz = get_bits(&gb, 18);
     if (avctx->extradata[0] != 5)
         sz += get_bits(&gb, 18);
     if (sz == 0)
         goto end;
 

     if (mp->max_codes_bits <= 0)
         goto end;

     if (init_vlc(&mp->vlc, mp->max_codes_bits, mp->codes_count, &mp->codes[0].size, sizeof(HuffCode), 1, &mp->codes[0].code, sizeof(HuffCode), 4, 0))
         goto end;

     mp_decode_frame_helper(mp, &gb);
     free_vlc(&mp->vlc);
 
 end:
     *data_size = sizeof(AVFrame);
     *(AVFrame *)data = mp->frame;
     return buf_size;
 }
 
 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);
     if (mp->frame.data[0])
         avctx->release_buffer(avctx, &mp->frame);
 
     return 0;
 }
 

 AVCodec ff_motionpixels_decoder = {

     "motionpixels",

     AVMEDIA_TYPE_VIDEO,

     CODEC_ID_MOTIONPIXELS,
     sizeof(MotionPixelsContext),
     mp_decode_init,
     NULL,
     mp_decode_end,
     mp_decode_frame,
     CODEC_CAP_DR1,

     .long_name = NULL_IF_CONFIG_SMALL("Motion Pixels video"),

 };