/*
  * MagicYUV decoder
  * Copyright (c) 2016 Paul B Mahol
  *
  * 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 <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "libavutil/qsort.h"
 #include "avcodec.h"
 #include "bytestream.h"
 #include "get_bits.h"
 #include "huffyuvdsp.h"
 #include "internal.h"
 #include "thread.h"
 
 typedef struct Slice {
     uint32_t start;
     uint32_t size;
 } Slice;
 
 typedef enum Prediction {
     LEFT = 1,
     GRADIENT,
     MEDIAN,
 } Prediction;
 
 typedef struct MagicYUVContext {
     AVFrame            *p;
     int                 slice_height;
     int                 nb_slices;
     int                 planes;         // number of encoded planes in bitstream
     int                 decorrelate;    // postprocessing work
     int                 interlaced;     // video is interlaced
     uint8_t             *buf;           // pointer to AVPacket->data
     int                 hshift[4];
     int                 vshift[4];
     Slice               *slices[4];     // slice positions and size in bitstream for each plane
     int                 slices_size[4];
     uint8_t             len[4][256];    // table of code lengths for each plane
     VLC                 vlc[4];         // VLC for each plane
     HuffYUVDSPContext   hdsp;
 } MagicYUVContext;
 
 static av_cold int decode_init(AVCodecContext *avctx)
 {
     MagicYUVContext *s = avctx->priv_data;
     ff_huffyuvdsp_init(&s->hdsp);
     return 0;
 }
 
 typedef struct HuffEntry {
     uint8_t  sym;
     uint8_t  len;
     uint32_t code;
 } HuffEntry;
 
 static int ff_magy_huff_cmp_len(const void *a, const void *b)
 {
     const HuffEntry *aa = a, *bb = b;
     return (aa->len - bb->len) * 256 + aa->sym - bb->sym;
 }
 
 static int build_huff(VLC *vlc, uint8_t *len)
 {
     HuffEntry he[256];
     uint32_t codes[256];
     uint8_t bits[256];
     uint8_t syms[256];
     uint32_t code;
     int i;
 
     for (i = 0; i < 256; i++) {
         he[i].sym = 255 - i;
         he[i].len = len[i];
     }
     AV_QSORT(he, 256, HuffEntry, ff_magy_huff_cmp_len);
 
     code = 1;
     for (i = 255; i >= 0; i--) {
         codes[i] = code >> (32 - he[i].len);
         bits[i]  = he[i].len;
         syms[i]  = he[i].sym;
         code += 0x80000000u >> (he[i].len - 1);
     }
 
     ff_free_vlc(vlc);
     return ff_init_vlc_sparse(vlc, FFMIN(he[255].len, 12), 256,
                               bits,  sizeof(*bits),  sizeof(*bits),
                               codes, sizeof(*codes), sizeof(*codes),
                               syms,  sizeof(*syms),  sizeof(*syms), 0);
 }
 
 static int decode_slice(AVCodecContext *avctx, void *tdata,
                         int j, int threadnr)
 {
     MagicYUVContext *s = avctx->priv_data;
     int interlaced = s->interlaced;
     AVFrame *p = s->p;
     int i, k, x, ret;
     GetBitContext b;
     uint8_t *dst;
 
     for (i = 0; i < s->planes; i++) {
         int height = AV_CEIL_RSHIFT(FFMIN(s->slice_height, avctx->coded_height - j * s->slice_height), s->vshift[i]);
         int width = AV_CEIL_RSHIFT(avctx->coded_width, s->hshift[i]);
         int sheight = AV_CEIL_RSHIFT(s->slice_height, s->vshift[i]);
         int fake_stride = p->linesize[i] * (1 + interlaced);
         int stride = p->linesize[i];

         int flags, pred;

 
         if ((ret = init_get_bits8(&b, s->buf + s->slices[i][j].start, s->slices[i][j].size)) < 0)
             return ret;
 

         flags = get_bits(&b, 8);
         pred  = get_bits(&b, 8);
 

         dst = p->data[i] + j * sheight * stride;

         if (flags & 1) {
             for (k = 0; k < height; k++) {
                 for (x = 0; x < width; x++) {
                     dst[x] = get_bits(&b, 8);

                 }

                 dst += stride;
             }
         } else {
             for (k = 0; k < height; k++) {
                 for (x = 0; x < width; x++) {
                     int pix;
                     if (get_bits_left(&b) <= 0) {
                         return AVERROR_INVALIDDATA;
                     }
                     pix = get_vlc2(&b, s->vlc[i].table, s->vlc[i].bits, 3);
                     if (pix < 0) {
                         return AVERROR_INVALIDDATA;
                     }
                     dst[x] = 255 - pix;

                 }

                 dst += stride;

             }
         }
 
         if (pred == LEFT) {
             dst = p->data[i] + j * sheight * stride;
             s->hdsp.add_hfyu_left_pred(dst, dst, width, 0);
             dst += stride;
             if (interlaced) {
                 s->hdsp.add_hfyu_left_pred(dst, dst, width, 0);
                 dst += stride;
             }
             for (k = 1 + interlaced; k < height; k++) {
                 s->hdsp.add_hfyu_left_pred(dst, dst, width, dst[-fake_stride]);
                 dst += stride;
             }
         } else if (pred == GRADIENT) {
             int left, lefttop, top;
 
             dst = p->data[i] + j * sheight * stride;
             s->hdsp.add_hfyu_left_pred(dst, dst, width, 0);
             left = lefttop = 0;
             dst += stride;
             if (interlaced) {
                 s->hdsp.add_hfyu_left_pred(dst, dst, width, 0);
                 left = lefttop = 0;
                 dst += stride;
             }
             for (k = 1 + interlaced; k < height; k++) {
                 top = dst[-fake_stride];
                 left = top + dst[0];
                 dst[0] = left;
                 for (x = 1; x < width; x++) {
                     top = dst[x - fake_stride];
                     lefttop = dst[x - (fake_stride + 1)];
                     left += top - lefttop + dst[x];
                     dst[x] = left;
                 }
                 dst += stride;
             }
         } else if (pred == MEDIAN) {
             int left, lefttop;
 
             dst = p->data[i] + j * sheight * stride;
             lefttop = left = dst[0];
             s->hdsp.add_hfyu_left_pred(dst, dst, width, 0);
             dst += stride;
             if (interlaced) {
                 lefttop = left = dst[0];
                 s->hdsp.add_hfyu_left_pred(dst, dst, width, 0);
                 dst += stride;
             }
             for (k = 1 + interlaced; k < height; k++) {
                 s->hdsp.add_hfyu_median_pred(dst, dst - fake_stride, dst, width, &left, &lefttop);
                 lefttop = left = dst[0];
                 dst += stride;
             }
         } else {
             avpriv_request_sample(avctx, "unknown prediction: %d", pred);
         }
     }
 
     if (s->decorrelate) {
         int height = FFMIN(s->slice_height, avctx->coded_height - j * s->slice_height);
         int width = avctx->coded_width;
         uint8_t *b = p->data[0] + j * s->slice_height * p->linesize[0];
         uint8_t *g = p->data[1] + j * s->slice_height * p->linesize[1];
         uint8_t *r = p->data[2] + j * s->slice_height * p->linesize[2];
 
         for (i = 0; i < height; i++) {
             s->hdsp.add_bytes(b, g, width);
             s->hdsp.add_bytes(r, g, width);
             b += p->linesize[0];
             g += p->linesize[1];
             r += p->linesize[2];
         }
     }
 
     return 0;
 }
 
 static int decode_frame(AVCodecContext *avctx,
                         void *data, int *got_frame,
                         AVPacket *avpkt)
 {
     uint32_t first_offset, offset, next_offset, header_size, slice_width;
     int ret, format, version, table_size;
     MagicYUVContext *s = avctx->priv_data;
     ThreadFrame frame = { .f = data };
     AVFrame *p = data;
     GetByteContext gb;
     GetBitContext b;

     int i, j, k, width, height;

 
     bytestream2_init(&gb, avpkt->data, avpkt->size);
     if (bytestream2_get_le32(&gb) != MKTAG('M','A','G','Y'))
         return AVERROR_INVALIDDATA;
 
     header_size = bytestream2_get_le32(&gb);
     if (header_size < 32 || header_size >= avpkt->size)
         return AVERROR_INVALIDDATA;
 
     version = bytestream2_get_byte(&gb);
     if (version != 7) {
         avpriv_request_sample(avctx, "unsupported version: %d", version);
         return AVERROR_PATCHWELCOME;
     }
 
     s->hshift[1] = s->vshift[1] = 0;
     s->hshift[2] = s->vshift[2] = 0;
     s->decorrelate = 0;
 
     format = bytestream2_get_byte(&gb);
     switch (format) {
     case 0x65:
         avctx->pix_fmt = AV_PIX_FMT_GBRP;
         s->decorrelate = 1;
         s->planes = 3;
         break;
     case 0x66:
         avctx->pix_fmt = AV_PIX_FMT_GBRAP;
         s->decorrelate = 1;
         s->planes = 4;
         break;
     case 0x67:
         avctx->pix_fmt = AV_PIX_FMT_YUV444P;
         s->planes = 3;
         break;
     case 0x68:
         avctx->pix_fmt = AV_PIX_FMT_YUV422P;
         s->planes = 3;
         s->hshift[1] = s->hshift[2] = 1;
         break;
     case 0x69:
         avctx->pix_fmt = AV_PIX_FMT_YUV420P;
         s->planes = 3;
         s->hshift[1] = s->vshift[1] = 1;
         s->hshift[2] = s->vshift[2] = 1;
         break;
     case 0x6a:
         avctx->pix_fmt = AV_PIX_FMT_YUVA444P;
         s->planes = 4;
         break;
     case 0x6b:
         avctx->pix_fmt = AV_PIX_FMT_GRAY8;
         s->planes = 1;
         break;
     default:
         avpriv_request_sample(avctx, "unsupported format: 0x%X", format);
         return AVERROR_PATCHWELCOME;
     }
 
     bytestream2_skip(&gb, 2);
     s->interlaced = !!(bytestream2_get_byte(&gb) & 2);
     bytestream2_skip(&gb, 3);
 

     width  = bytestream2_get_le32(&gb);
     height = bytestream2_get_le32(&gb);
     if ((ret = ff_set_dimensions(avctx, width, height)) < 0)

         return ret;
 

     slice_width = bytestream2_get_le32(&gb);
     if (slice_width != avctx->coded_width) {
         avpriv_request_sample(avctx, "unsupported slice width: %d", slice_width);
         return AVERROR_PATCHWELCOME;
     }
     s->slice_height = bytestream2_get_le32(&gb);
     if ((s->slice_height <= 0) || (s->slice_height > INT_MAX - avctx->coded_height)) {
         av_log(avctx, AV_LOG_ERROR, "invalid slice height: %d\n", s->slice_height);
         return AVERROR_INVALIDDATA;
     }
 
     bytestream2_skip(&gb, 4);
 
     s->nb_slices = (avctx->coded_height + s->slice_height - 1) / s->slice_height;
     if (s->nb_slices > INT_MAX / sizeof(Slice)) {
         av_log(avctx, AV_LOG_ERROR, "invalid number of slices: %d\n", s->nb_slices);
         return AVERROR_INVALIDDATA;
     }
 
     for (i = 0; i < s->planes; i++) {
         av_fast_malloc(&s->slices[i], &s->slices_size[i], s->nb_slices * sizeof(Slice));
         if (!s->slices[i])
             return AVERROR(ENOMEM);
 
         offset = bytestream2_get_le32(&gb);
         if (offset >= avpkt->size - header_size)
             return AVERROR_INVALIDDATA;
 
         if (i == 0)
             first_offset = offset;
 
         for (j = 0; j < s->nb_slices - 1; j++) {
             s->slices[i][j].start = offset + header_size;
             next_offset = bytestream2_get_le32(&gb);
             s->slices[i][j].size  = next_offset - offset;
             offset = next_offset;
 
             if (offset >= avpkt->size - header_size)
                 return AVERROR_INVALIDDATA;
         }
 
         s->slices[i][j].start = offset + header_size;

         s->slices[i][j].size  = avpkt->size - s->slices[i][j].start;

     }
 
     if (bytestream2_get_byte(&gb) != s->planes)
         return AVERROR_INVALIDDATA;
 
     bytestream2_skip(&gb, s->nb_slices * s->planes);
 
     table_size = header_size + first_offset - bytestream2_tell(&gb);
     if (table_size < 2)
         return AVERROR_INVALIDDATA;
 
     if ((ret = init_get_bits8(&b, avpkt->data + bytestream2_tell(&gb), table_size)) < 0)
         return ret;
 
     memset(s->len, 0, sizeof(s->len));
     j = i = 0;
     while (get_bits_left(&b) >= 8) {
         int l = get_bits(&b, 4);
         int x = get_bits(&b, 4);
         int L = get_bitsz(&b, l) + 1;
 
         for (k = 0; k < L; k++) {
             if (j + k < 256)
                 s->len[i][j + k] = x;
         }
 
         j += L;
         if (j == 256) {
             j = 0;
             if (build_huff(&s->vlc[i], s->len[i])) {
                 av_log(avctx, AV_LOG_ERROR, "Cannot build Huffman codes\n");
                 return AVERROR_INVALIDDATA;
             }
             i++;
             if (i == s->planes) {
                 break;
             }
         } else if (j > 256) {
             return AVERROR_INVALIDDATA;
         }
     }
 
     if (i != s->planes) {
         av_log(avctx, AV_LOG_ERROR, "Huffman tables too short\n");
         return AVERROR_INVALIDDATA;
     }
 
     p->pict_type = AV_PICTURE_TYPE_I;
     p->key_frame = 1;
 
     if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
         return ret;
 
     s->buf = avpkt->data;
     s->p = p;
     avctx->execute2(avctx, decode_slice, NULL, NULL, s->nb_slices);
 
     if (avctx->pix_fmt == AV_PIX_FMT_GBRP ||
         avctx->pix_fmt == AV_PIX_FMT_GBRAP) {
         FFSWAP(uint8_t*, p->data[0], p->data[1]);
         FFSWAP(int, p->linesize[0], p->linesize[1]);
     }
 
     *got_frame = 1;
 
     if (ret < 0)
         return ret;
     return avpkt->size;
 }
 
 #if HAVE_THREADS
 static int decode_init_thread_copy(AVCodecContext *avctx)
 {
     MagicYUVContext *s = avctx->priv_data;
 
     s->slices[0] = 0;
     s->slices[1] = 0;
     s->slices[2] = 0;
     s->slices[3] = 0;
     s->slices_size[0] = 0;
     s->slices_size[1] = 0;
     s->slices_size[2] = 0;
     s->slices_size[3] = 0;
 
     return 0;
 }
 #endif
 
 static av_cold int decode_end(AVCodecContext *avctx)
 {
     MagicYUVContext * const s = avctx->priv_data;
 
     av_freep(&s->slices[0]);
     av_freep(&s->slices[1]);
     av_freep(&s->slices[2]);
     av_freep(&s->slices[3]);
     s->slices_size[0] = 0;
     s->slices_size[1] = 0;
     s->slices_size[2] = 0;
     s->slices_size[3] = 0;
     ff_free_vlc(&s->vlc[0]);
     ff_free_vlc(&s->vlc[1]);
     ff_free_vlc(&s->vlc[2]);
     ff_free_vlc(&s->vlc[3]);
 
     return 0;
 }
 
 AVCodec ff_magicyuv_decoder = {
     .name             = "magicyuv",
     .long_name        = NULL_IF_CONFIG_SMALL("MagicYUV Lossless Video"),
     .type             = AVMEDIA_TYPE_VIDEO,
     .id               = AV_CODEC_ID_MAGICYUV,
     .priv_data_size   = sizeof(MagicYUVContext),
     .init             = decode_init,
     .init_thread_copy = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy),
     .close            = decode_end,
     .decode           = decode_frame,
     .capabilities     = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS | AV_CODEC_CAP_SLICE_THREADS,
 };