/*
  * TechSmith Screen Codec 2 (aka Dora) decoder
  * Copyright (c) 2012 Konstantin Shishkov
  *

  * 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
  * TechSmith Screen Codec 2 decoder
  */
 
 #define BITSTREAM_READER_LE
 #include "avcodec.h"
 #include "get_bits.h"
 #include "bytestream.h"

 #include "internal.h"

 #include "tscc2data.h"
 
 typedef struct TSCC2Context {
     AVCodecContext *avctx;

     AVFrame       *pic;

     int            mb_width, mb_height;
     uint8_t        *slice_quants;
     int            quant[2];
     int            q[2][3];
     GetBitContext  gb;
 
     VLC            dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
     int            block[16];
 } TSCC2Context;
 
 static av_cold void free_vlcs(TSCC2Context *c)
 {
     int i;
 
     ff_free_vlc(&c->dc_vlc);
     for (i = 0; i < NUM_VLC_SETS; i++) {
         ff_free_vlc(c->nc_vlc + i);
         ff_free_vlc(c->ac_vlc + i);
     }
 }
 
 static av_cold int init_vlcs(TSCC2Context *c)
 {
     int i, ret;
 
     ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,
                              tscc2_dc_vlc_bits,  1, 1,
                              tscc2_dc_vlc_codes, 2, 2,
                              tscc2_dc_vlc_syms,  2, 2, INIT_VLC_LE);
     if (ret)
         return ret;
 
     for (i = 0; i < NUM_VLC_SETS; i++) {
         ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,
                                  tscc2_nc_vlc_bits[i],  1, 1,
                                  tscc2_nc_vlc_codes[i], 2, 2,
                                  tscc2_nc_vlc_syms,     1, 1, INIT_VLC_LE);
         if (ret) {
             free_vlcs(c);
             return ret;
         }
         ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],
                                  tscc2_ac_vlc_bits[i],  1, 1,
                                  tscc2_ac_vlc_codes[i], 2, 2,
                                  tscc2_ac_vlc_syms[i],  2, 2, INIT_VLC_LE);
         if (ret) {
             free_vlcs(c);
             return ret;
         }
     }
 
     return 0;
 }
 
 #define DEQUANT(val, q) ((q * val + 0x80) >> 8)
 #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
     OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3));  \
     OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1));  \

     OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1));  \

     OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3));  \
 
 #define COL_OP(a, b)  a = b

 #define ROW_OP(a, b)  a = ((b) + 0x20) >> 6

 
 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
 {
     int i;
     int tblk[4 * 4];
     int t0, t1, t2, t3;
 
     for (i = 0; i < 4; i++) {
         t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
         t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
         t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
         t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
         DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
               tblk[2 * 4 + i], tblk[3 * 4 + i],
               t0, t1, t2, t3, COL_OP);
     }
     for (i = 0; i < 4; i++) {
         DCT1D(dst[0], dst[1], dst[2], dst[3],
               tblk[i * 4 + 0], tblk[i * 4 + 1],
               tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
         dst += stride;
     }
 }
 
 static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
                            uint8_t *dst, int stride, int plane)
 {
     GetBitContext *gb = &c->gb;
     int prev_dc, dc, nc, ac, bpos, val;
     int i, j, k, l;
 
     if (get_bits1(gb)) {
         if (get_bits1(gb)) {
             val = get_bits(gb, 8);
             for (i = 0; i < 8; i++, dst += stride)
                 memset(dst, val, 16);
         } else {
             if (get_bits_left(gb) < 16 * 8 * 8)
                 return AVERROR_INVALIDDATA;
             for (i = 0; i < 8; i++) {
                 for (j = 0; j < 16; j++)
                     dst[j] = get_bits(gb, 8);
                 dst += stride;
             }
         }
         return 0;
     }
 
     prev_dc = 0;
     for (j = 0; j < 2; j++) {
         for (k = 0; k < 4; k++) {
             if (!(j | k)) {
                 dc = get_bits(gb, 8);
             } else {
                 dc = get_vlc2(gb, c->dc_vlc.table, 9, 2);
                 if (dc == -1)
                     return AVERROR_INVALIDDATA;
                 if (dc == 0x100)
                     dc = get_bits(gb, 8);
             }
             dc          = (dc + prev_dc) & 0xFF;
             prev_dc     = dc;

             c->block[0] = dc;

 
             nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);
             if (nc == -1)
                 return AVERROR_INVALIDDATA;
 
             bpos = 1;
             memset(c->block + 1, 0, 15 * sizeof(*c->block));
             for (l = 0; l < nc; l++) {
                 ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);
                 if (ac == -1)
                     return AVERROR_INVALIDDATA;
                 if (ac == 0x1000)
                     ac = get_bits(gb, 12);
                 bpos += ac & 0xF;

                 if (bpos >= 16)

                     return AVERROR_INVALIDDATA;
                 val = sign_extend(ac >> 4, 8);
                 c->block[tscc2_zigzag[bpos++]] = val;
             }
             tscc2_idct4_put(c->block, q, dst + k * 4, stride);
         }
         dst += 4 * stride;
     }
     return 0;
 }
 
 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
                               const uint8_t *buf, int buf_size)
 {
     int i, mb_x, q, ret;
     int off;
 
     init_get_bits(&c->gb, buf, buf_size * 8);
 
     for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
         q = c->slice_quants[mb_x + c->mb_width * mb_y];
 
         if (q == 0 || q == 3) // skip block
             continue;
         for (i = 0; i < 3; i++) {

             off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];

             ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,

                                   c->pic->data[i] + off, c->pic->linesize[i], i);

             if (ret)
                 return ret;
         }
     }
 
     return 0;
 }
 
 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,

                               int *got_frame, AVPacket *avpkt)

 {
     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;
     TSCC2Context *c = avctx->priv_data;
     GetByteContext gb;
     uint32_t frame_type, size;
     int i, val, len, pos = 0;
     int num_mb = c->mb_width * c->mb_height;
     int ret;
 
     bytestream2_init(&gb, buf, buf_size);
     frame_type = bytestream2_get_byte(&gb);
     if (frame_type > 1) {
         av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %d\n", frame_type);
         return AVERROR_INVALIDDATA;
     }
 

     if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) {

         return ret;
     }
 
     if (frame_type == 0) {

         *got_frame      = 1;

         if ((ret = av_frame_ref(data, c->pic)) < 0)

             return ret;

 
         return buf_size;
     }
 
     if (bytestream2_get_bytes_left(&gb) < 4) {
         av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
         return AVERROR_INVALIDDATA;
     }
 
     c->quant[0] = bytestream2_get_byte(&gb);
     c->quant[1] = bytestream2_get_byte(&gb);
     if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
         c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
         av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
                c->quant[0], c->quant[1]);
         return AVERROR_INVALIDDATA;
     }
 
     for (i = 0; i < 3; i++) {
         c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
         c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
     }
 
     bytestream2_skip(&gb, 1);
 
     size = bytestream2_get_le32(&gb);
     if (size > bytestream2_get_bytes_left(&gb)) {
         av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
         return AVERROR_INVALIDDATA;
     }
 
     for (i = 0; i < size; i++) {
         val   = bytestream2_get_byte(&gb);
         len   = val & 0x3F;
         val >>= 6;
         if (pos + len > num_mb) {
             av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
             return AVERROR_INVALIDDATA;
         }
         memset(c->slice_quants + pos, val, len);
         pos += len;
     }
     if (pos < num_mb) {
         av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
                pos, num_mb);
         return AVERROR_INVALIDDATA;
     }
 
     for (i = 0; i < c->mb_height; i++) {
         size = bytestream2_peek_byte(&gb);
         if (size & 1) {
             size = bytestream2_get_byte(&gb) - 1;
         } else {
             size = bytestream2_get_le32(&gb) >> 1;
         }
         if (!size) {
             int skip_row = 1, j, off = i * c->mb_width;
             for (j = 0; j < c->mb_width; j++) {

                 if (c->slice_quants[off + j] == 1 ||
                     c->slice_quants[off + j] == 2) {

                     skip_row = 0;
                     break;
                 }
             }
             if (!skip_row) {
                 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
                 return AVERROR_INVALIDDATA;
             }
         }
         if (bytestream2_get_bytes_left(&gb) < size) {
             av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%d/%d)\n",
                    size, bytestream2_get_bytes_left(&gb));
             return AVERROR_INVALIDDATA;
         }
         ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
         if (ret) {
             av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
             return ret;
         }
         bytestream2_skip(&gb, size);
     }
 

     *got_frame      = 1;

     if ((ret = av_frame_ref(data, c->pic)) < 0)

         return ret;

 
     /* always report that the buffer was completely consumed */
     return buf_size;
 }
 

 static av_cold int tscc2_decode_end(AVCodecContext *avctx)
 {
     TSCC2Context * const c = avctx->priv_data;
 
     av_frame_free(&c->pic);
     av_freep(&c->slice_quants);
     free_vlcs(c);
 
     return 0;
 }
 

 static av_cold int tscc2_decode_init(AVCodecContext *avctx)
 {
     TSCC2Context * const c = avctx->priv_data;
     int ret;
 
     c->avctx = avctx;
 

     avctx->pix_fmt = AV_PIX_FMT_YUV444P;

 
     if ((ret = init_vlcs(c)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
         return ret;
     }
 
     c->mb_width     = FFALIGN(avctx->width,  16) >> 4;
     c->mb_height    = FFALIGN(avctx->height,  8) >> 3;
     c->slice_quants = av_malloc(c->mb_width * c->mb_height);
     if (!c->slice_quants) {
         av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
         free_vlcs(c);
         return AVERROR(ENOMEM);
     }
 

     c->pic = av_frame_alloc();
     if (!c->pic) {
         tscc2_decode_end(avctx);
         return AVERROR(ENOMEM);
     }

 
     return 0;
 }
 
 AVCodec ff_tscc2_decoder = {
     .name           = "tscc2",

     .long_name      = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),

     .type           = AVMEDIA_TYPE_VIDEO,

     .id             = AV_CODEC_ID_TSCC2,

     .priv_data_size = sizeof(TSCC2Context),
     .init           = tscc2_decode_init,
     .close          = tscc2_decode_end,
     .decode         = tscc2_decode_frame,
     .capabilities   = CODEC_CAP_DR1,
 };