/*
  * Mirillis FIC decoder
  *
  * Copyright (c) 2014 Konstantin Shishkov
  * Copyright (c) 2014 Derek Buitenhuis
  *

  * 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/common.h"

 #include "libavutil/opt.h"

 #include "avcodec.h"
 #include "internal.h"
 #include "get_bits.h"
 #include "golomb.h"
 
 typedef struct FICThreadContext {
     DECLARE_ALIGNED(16, int16_t, block)[64];
     uint8_t *src;
     int slice_h;
     int src_size;
     int y_off;

     int p_frame;

 } FICThreadContext;
 
 typedef struct FICContext {

     AVClass *class;

     AVCodecContext *avctx;
     AVFrame *frame;

     AVFrame *final_frame;

 
     FICThreadContext *slice_data;
     int slice_data_size;
 
     const uint8_t *qmat;
 
     enum AVPictureType cur_frame_type;
 
     int aligned_width, aligned_height;
     int num_slices, slice_h;

 
     uint8_t cursor_buf[4096];

     int skip_cursor;

 } FICContext;
 
 static const uint8_t fic_qmat_hq[64] = {
     1, 2, 2, 2, 3, 3, 3, 4,
     2, 2, 2, 3, 3, 3, 4, 4,
     2, 2, 3, 3, 3, 4, 4, 4,
     2, 2, 3, 3, 3, 4, 4, 5,
     2, 3, 3, 3, 4, 4, 5, 6,
     3, 3, 3, 4, 4, 5, 6, 7,
     3, 3, 3, 4, 4, 5, 7, 7,
     3, 3, 4, 4, 5, 7, 7, 7,
 };
 
 static const uint8_t fic_qmat_lq[64] = {
     1,  5,  6,  7,  8,  9,  9, 11,
     5,  5,  7,  8,  9,  9, 11, 12,
     6,  7,  8,  9,  9, 11, 11, 12,
     7,  7,  8,  9,  9, 11, 12, 13,
     7,  8,  9,  9, 10, 11, 13, 16,
     8,  9,  9, 10, 11, 13, 16, 19,
     8,  9,  9, 11, 12, 15, 18, 23,
     9,  9, 11, 12, 15, 18, 23, 27
 };
 
 static const uint8_t fic_header[7] = { 0, 0, 1, 'F', 'I', 'C', 'V' };
 
 #define FIC_HEADER_SIZE 27

 #define CURSOR_OFFSET 59

 static av_always_inline void fic_idct(int16_t *blk, int step, int shift, int rnd)

 {

     const unsigned t0 =  27246 * blk[3 * step] + 18405 * blk[5 * step];
     const unsigned t1 =  27246 * blk[5 * step] - 18405 * blk[3 * step];
     const unsigned t2 =   6393 * blk[7 * step] + 32139 * blk[1 * step];
     const unsigned t3 =   6393 * blk[1 * step] - 32139 * blk[7 * step];
     const unsigned t4 = 5793U * ((int)(t2 + t0 + 0x800) >> 12);
     const unsigned t5 = 5793U * ((int)(t3 + t1 + 0x800) >> 12);

     const unsigned t6 = t2 - t0;
     const unsigned t7 = t3 - t1;
     const unsigned t8 =  17734 * blk[2 * step] - 42813 * blk[6 * step];
     const unsigned t9 =  17734 * blk[6 * step] + 42814 * blk[2 * step];
     const unsigned tA = (blk[0 * step] - blk[4 * step]) * 32768 + rnd;
     const unsigned tB = (blk[0 * step] + blk[4 * step]) * 32768 + rnd;
     blk[0 * step] = (int)(  t4       + t9 + tB) >> shift;
     blk[1 * step] = (int)(  t6 + t7  + t8 + tA) >> shift;
     blk[2 * step] = (int)(  t6 - t7  - t8 + tA) >> shift;
     blk[3 * step] = (int)(  t5       - t9 + tB) >> shift;
     blk[4 * step] = (int)( -t5       - t9 + tB) >> shift;
     blk[5 * step] = (int)(-(t6 - t7) - t8 + tA) >> shift;
     blk[6 * step] = (int)(-(t6 + t7) + t8 + tA) >> shift;
     blk[7 * step] = (int)( -t4       + t9 + tB) >> shift;

 }
 
 static void fic_idct_put(uint8_t *dst, int stride, int16_t *block)
 {
     int i, j;
     int16_t *ptr;
 
     ptr = block;

     fic_idct(ptr++, 8, 13, (1 << 12) + (1 << 17));
     for (i = 1; i < 8; i++) {
         fic_idct(ptr, 8, 13, 1 << 12);

         ptr++;
     }
 
     ptr = block;
     for (i = 0; i < 8; i++) {

         fic_idct(ptr, 1, 20, 0);

         ptr += 8;
     }
 
     ptr = block;
     for (j = 0; j < 8; j++) {
         for (i = 0; i < 8; i++)
             dst[i] = av_clip_uint8(ptr[i]);
         dst += stride;
         ptr += 8;
     }
 }

 static int fic_decode_block(FICContext *ctx, GetBitContext *gb,

                             uint8_t *dst, int stride, int16_t *block, int *is_p)

 {
     int i, num_coeff;
 

     if (get_bits_left(gb) < 8)
         return AVERROR_INVALIDDATA;
 

     /* Is it a skip block? */
     if (get_bits1(gb)) {

         *is_p = 1;

         return 0;
     }
 

     memset(block, 0, sizeof(*block) * 64);

 
     num_coeff = get_bits(gb, 7);
     if (num_coeff > 64)
         return AVERROR_INVALIDDATA;
 

     for (i = 0; i < num_coeff; i++) {
         int v = get_se_golomb(gb);
         if (v < -2048 || v > 2048)
              return AVERROR_INVALIDDATA;
         block[ff_zigzag_direct[i]] = v *

                                      ctx->qmat[ff_zigzag_direct[i]];

     }

     fic_idct_put(dst, stride, block);

 
     return 0;
 }
 
 static int fic_decode_slice(AVCodecContext *avctx, void *tdata)
 {
     FICContext *ctx        = avctx->priv_data;
     FICThreadContext *tctx = tdata;
     GetBitContext gb;
     uint8_t *src = tctx->src;
     int slice_h  = tctx->slice_h;
     int src_size = tctx->src_size;
     int y_off    = tctx->y_off;
     int x, y, p;
 
     init_get_bits(&gb, src, src_size * 8);
 
     for (p = 0; p < 3; p++) {
         int stride   = ctx->frame->linesize[p];
         uint8_t* dst = ctx->frame->data[p] + (y_off >> !!p) * stride;
 
         for (y = 0; y < (slice_h >> !!p); y += 8) {
             for (x = 0; x < (ctx->aligned_width >> !!p); x += 8) {
                 int ret;
 

                 if ((ret = fic_decode_block(ctx, &gb, dst + x, stride,
                                             tctx->block, &tctx->p_frame)) != 0)

                     return ret;
             }
 
             dst += 8 * stride;
         }
     }
 
     return 0;
 }
 

 static av_always_inline void fic_alpha_blend(uint8_t *dst, uint8_t *src,
                                              int size, uint8_t *alpha)
 {
     int i;
 
     for (i = 0; i < size; i++)
         dst[i] += ((src[i] - dst[i]) * alpha[i]) >> 8;
 }
 
 static void fic_draw_cursor(AVCodecContext *avctx, int cur_x, int cur_y)
 {
     FICContext *ctx = avctx->priv_data;
     uint8_t *ptr    = ctx->cursor_buf;
     uint8_t *dstptr[3];
     uint8_t planes[4][1024];
     uint8_t chroma[3][256];
     int i, j, p;
 
     /* Convert to YUVA444. */
     for (i = 0; i < 1024; i++) {
         planes[0][i] = (( 25 * ptr[0] + 129 * ptr[1] +  66 * ptr[2]) / 255) + 16;
         planes[1][i] = ((-38 * ptr[0] + 112 * ptr[1] + -74 * ptr[2]) / 255) + 128;
         planes[2][i] = ((-18 * ptr[0] + 112 * ptr[1] + -94 * ptr[2]) / 255) + 128;
         planes[3][i] = ptr[3];
 
         ptr += 4;
     }
 
     /* Subsample chroma. */
     for (i = 0; i < 32; i += 2)
         for (j = 0; j < 32; j += 2)
             for (p = 0; p < 3; p++)
                 chroma[p][16 * (i / 2) + j / 2] = (planes[p + 1][32 *  i      + j    ] +
                                                    planes[p + 1][32 *  i      + j + 1] +
                                                    planes[p + 1][32 * (i + 1) + j    ] +
                                                    planes[p + 1][32 * (i + 1) + j + 1]) / 4;
 
     /* Seek to x/y pos of cursor. */
     for (i = 0; i < 3; i++)
         dstptr[i] = ctx->final_frame->data[i]                        +
                     (ctx->final_frame->linesize[i] * (cur_y >> !!i)) +
                     (cur_x >> !!i) + !!i;
 
     /* Copy. */
     for (i = 0; i < FFMIN(32, avctx->height - cur_y) - 1; i += 2) {
         int lsize = FFMIN(32, avctx->width - cur_x);
         int csize = lsize / 2;
 
         fic_alpha_blend(dstptr[0],
                         planes[0] + i * 32, lsize, planes[3] + i * 32);
         fic_alpha_blend(dstptr[0] + ctx->final_frame->linesize[0],
                         planes[0] + (i + 1) * 32, lsize, planes[3] + (i + 1) * 32);
         fic_alpha_blend(dstptr[1],
                         chroma[0] + (i / 2) * 16, csize, chroma[2] + (i / 2) * 16);
         fic_alpha_blend(dstptr[2],
                         chroma[1] + (i / 2) * 16, csize, chroma[2] + (i / 2) * 16);
 
         dstptr[0] += ctx->final_frame->linesize[0] * 2;
         dstptr[1] += ctx->final_frame->linesize[1];
         dstptr[2] += ctx->final_frame->linesize[2];
     }
 }
 

 static int fic_decode_frame(AVCodecContext *avctx, void *data,
                             int *got_frame, AVPacket *avpkt)
 {
     FICContext *ctx = avctx->priv_data;
     uint8_t *src = avpkt->data;
     int ret;
     int slice, nslices;
     int msize;
     int tsize;

     int cur_x, cur_y;

     int skip_cursor = ctx->skip_cursor;

     uint8_t *sdata;
 

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

         return ret;
 
     /* Header + at least one slice (4) */
     if (avpkt->size < FIC_HEADER_SIZE + 4) {
         av_log(avctx, AV_LOG_ERROR, "Frame data is too small.\n");
         return AVERROR_INVALIDDATA;
     }
 
     /* Check for header. */
     if (memcmp(src, fic_header, 7))
         av_log(avctx, AV_LOG_WARNING, "Invalid FIC Header.\n");
 

     /* Is it a skip frame? */

     if (src[17]) {
         if (!ctx->final_frame) {
             av_log(avctx, AV_LOG_WARNING, "Initial frame is skipped\n");
             return AVERROR_INVALIDDATA;
         }

         goto skip;

     }

     nslices = src[13];
     if (!nslices) {
         av_log(avctx, AV_LOG_ERROR, "Zero slices found.\n");
         return AVERROR_INVALIDDATA;
     }
 
     /* High or Low Quality Matrix? */
     ctx->qmat = src[23] ? fic_qmat_hq : fic_qmat_lq;
 
     /* Skip cursor data. */
     tsize = AV_RB24(src + 24);
     if (tsize > avpkt->size - FIC_HEADER_SIZE) {

         av_log(avctx, AV_LOG_ERROR,
                "Packet is too small to contain cursor (%d vs %d bytes).\n",
                tsize, avpkt->size - FIC_HEADER_SIZE);

         return AVERROR_INVALIDDATA;
     }
 

     if (!tsize || !AV_RL16(src + 37) || !AV_RL16(src + 39))

         skip_cursor = 1;
 
     if (!skip_cursor && tsize < 32) {

         av_log(avctx, AV_LOG_WARNING,
                "Cursor data too small. Skipping cursor.\n");
         skip_cursor = 1;
     }
 
     /* Cursor position. */
     cur_x = AV_RL16(src + 33);
     cur_y = AV_RL16(src + 35);

     if (!skip_cursor && (cur_x > avctx->width || cur_y > avctx->height)) {

         av_log(avctx, AV_LOG_DEBUG,

                "Invalid cursor position: (%d,%d). Skipping cursor.\n",

                cur_x, cur_y);
         skip_cursor = 1;
     }
 

     if (!skip_cursor && (AV_RL16(src + 37) != 32 || AV_RL16(src + 39) != 32)) {

         av_log(avctx, AV_LOG_WARNING,
                "Invalid cursor size. Skipping cursor.\n");
         skip_cursor = 1;
     }
 

     if (!skip_cursor && avpkt->size < CURSOR_OFFSET + sizeof(ctx->cursor_buf)) {
         skip_cursor = 1;
     }
 

     /* Slice height for all but the last slice. */
     ctx->slice_h = 16 * (ctx->aligned_height >> 4) / nslices;
     if (ctx->slice_h % 16)
         ctx->slice_h = FFALIGN(ctx->slice_h - 16, 16);
 
     /* First slice offset and remaining data. */
     sdata = src + tsize + FIC_HEADER_SIZE + 4 * nslices;
     msize = avpkt->size - nslices * 4 - tsize - FIC_HEADER_SIZE;
 
     if (msize <= 0) {
         av_log(avctx, AV_LOG_ERROR, "Not enough frame data to decode.\n");
         return AVERROR_INVALIDDATA;
     }
 
     /* Allocate slice data. */
     av_fast_malloc(&ctx->slice_data, &ctx->slice_data_size,
                    nslices * sizeof(ctx->slice_data[0]));
     if (!ctx->slice_data_size) {
         av_log(avctx, AV_LOG_ERROR, "Could not allocate slice data.\n");
         return AVERROR(ENOMEM);
     }

     memset(ctx->slice_data, 0, nslices * sizeof(ctx->slice_data[0]));

 
     for (slice = 0; slice < nslices; slice++) {

         unsigned slice_off = AV_RB32(src + tsize + FIC_HEADER_SIZE + slice * 4);
         unsigned slice_size;

         int y_off   = ctx->slice_h * slice;
         int slice_h = ctx->slice_h;
 
         /*
          * Either read the slice size, or consume all data left.
          * Also, special case the last slight height.
          */
         if (slice == nslices - 1) {
             slice_size   = msize;
             slice_h      = FFALIGN(avctx->height - ctx->slice_h * (nslices - 1), 16);
         } else {
             slice_size = AV_RB32(src + tsize + FIC_HEADER_SIZE + slice * 4 + 4);

             if (slice_size < slice_off)
                 return AVERROR_INVALIDDATA;

         }
 

         if (slice_size < slice_off || slice_size > msize)

             continue;
 

         slice_size -= slice_off;
 

         ctx->slice_data[slice].src      = sdata + slice_off;
         ctx->slice_data[slice].src_size = slice_size;
         ctx->slice_data[slice].slice_h  = slice_h;
         ctx->slice_data[slice].y_off    = y_off;
     }
 

     if ((ret = avctx->execute(avctx, fic_decode_slice, ctx->slice_data,
                               NULL, nslices, sizeof(ctx->slice_data[0]))) < 0)

         return ret;
 

     ctx->frame->key_frame = 1;
     ctx->frame->pict_type = AV_PICTURE_TYPE_I;
     for (slice = 0; slice < nslices; slice++) {
         if (ctx->slice_data[slice].p_frame) {
             ctx->frame->key_frame = 0;
             ctx->frame->pict_type = AV_PICTURE_TYPE_P;
             break;
         }
     }

     av_frame_free(&ctx->final_frame);
     ctx->final_frame = av_frame_clone(ctx->frame);
     if (!ctx->final_frame) {
         av_log(avctx, AV_LOG_ERROR, "Could not clone frame buffer.\n");
         return AVERROR(ENOMEM);
     }
 
     /* Make sure we use a user-supplied buffer. */
     if ((ret = ff_reget_buffer(avctx, ctx->final_frame)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "Could not make frame writable.\n");
         return ret;
     }
 
     /* Draw cursor. */
     if (!skip_cursor) {

         memcpy(ctx->cursor_buf, src + CURSOR_OFFSET, sizeof(ctx->cursor_buf));

         fic_draw_cursor(avctx, cur_x, cur_y);
     }
 

 skip:

     *got_frame = 1;

     if ((ret = av_frame_ref(data, ctx->final_frame)) < 0)

         return ret;
 
     return avpkt->size;
 }
 
 static av_cold int fic_decode_close(AVCodecContext *avctx)
 {
     FICContext *ctx = avctx->priv_data;
 
     av_freep(&ctx->slice_data);

     av_frame_free(&ctx->final_frame);

     av_frame_free(&ctx->frame);
 
     return 0;
 }
 
 static av_cold int fic_decode_init(AVCodecContext *avctx)
 {
     FICContext *ctx = avctx->priv_data;
 
     /* Initialize various context values */
     ctx->avctx            = avctx;
     ctx->aligned_width    = FFALIGN(avctx->width,  16);
     ctx->aligned_height   = FFALIGN(avctx->height, 16);
 
     avctx->pix_fmt             = AV_PIX_FMT_YUV420P;
     avctx->bits_per_raw_sample = 8;
 
     ctx->frame = av_frame_alloc();
     if (!ctx->frame)
         return AVERROR(ENOMEM);
 
     return 0;
 }
 

 static const AVOption options[] = {

 { "skip_cursor", "skip the cursor", offsetof(FICContext, skip_cursor), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_VIDEO_PARAM },

 { NULL },
 };
 
 static const AVClass fic_decoder_class = {
     .class_name = "FIC encoder",
     .item_name  = av_default_item_name,
     .option     = options,
     .version    = LIBAVUTIL_VERSION_INT,
 };
 

 AVCodec ff_fic_decoder = {
     .name           = "fic",
     .long_name      = NULL_IF_CONFIG_SMALL("Mirillis FIC"),
     .type           = AVMEDIA_TYPE_VIDEO,
     .id             = AV_CODEC_ID_FIC,
     .priv_data_size = sizeof(FICContext),
     .init           = fic_decode_init,
     .decode         = fic_decode_frame,
     .close          = fic_decode_close,

     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_SLICE_THREADS,

     .priv_class     = &fic_decoder_class,

 };