/*

  * Copyright (C) 2005  Ole André Vadla Ravnås <oleavr@gmail.com>

  * Copyright (C) 2008  Ramiro Polla

  *
  * 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 <stdlib.h>
 #include <string.h>
 #include <stdint.h>
 
 #include "avcodec.h"

 #include "internal.h"

 #include "get_bits.h"

 #include "bytestream.h"

 #include "dsputil.h"

 #include "thread.h"

 
 #define MIMIC_HEADER_SIZE   20
 
 typedef struct {
     AVCodecContext *avctx;
 
     int             num_vblocks[3];
     int             num_hblocks[3];
 

     void           *swap_buf;

     int             swap_buf_size;
 
     int             cur_index;
     int             prev_index;
 
     AVFrame         buf_ptrs    [16];
     AVPicture       flipped_ptrs[16];
 

     DECLARE_ALIGNED(16, DCTELEM, dct_block)[64];

 
     GetBitContext   gb;
     ScanTable       scantable;
     DSPContext      dsp;

     VLC             vlc;

 
     /* Kept in the context so multithreading can have a constant to read from */
     int             next_cur_index;
     int             next_prev_index;

 } MimicContext;
 
 static const uint32_t huffcodes[] = {
     0x0000000a, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
     0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
     0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x0000000b,
     0x0000001b, 0x00000038, 0x00000078, 0x00000079, 0x0000007a, 0x000000f9,
     0x000000fa, 0x000003fb, 0x000007f8, 0x000007f9, 0x000007fa, 0x000007fb,
     0x00000ff8, 0x00000ff9, 0x00000001, 0x00000039, 0x0000007b, 0x000000fb,
     0x000001f8, 0x000001f9, 0x00000ffa, 0x00000ffb, 0x00001ff8, 0x00001ff9,
     0x00001ffa, 0x00001ffb, 0x00003ff8, 0x00003ff9, 0x00003ffa, 0x00000000,
     0x00000004, 0x0000003a, 0x000001fa, 0x00003ffb, 0x00007ff8, 0x00007ff9,
     0x00007ffa, 0x00007ffb, 0x0000fff8, 0x0000fff9, 0x0000fffa, 0x0000fffb,
     0x0001fff8, 0x0001fff9, 0x0001fffa, 0x00000000, 0x0000000c, 0x000000f8,
     0x000001fb, 0x0001fffb, 0x0003fff8, 0x0003fff9, 0x0003fffa, 0x0003fffb,
     0x0007fff8, 0x0007fff9, 0x0007fffa, 0x0007fffb, 0x000ffff8, 0x000ffff9,
     0x000ffffa, 0x00000000, 0x0000001a, 0x000003f8, 0x000ffffb, 0x001ffff8,
     0x001ffff9, 0x001ffffa, 0x001ffffb, 0x003ffff8, 0x003ffff9, 0x003ffffa,
     0x003ffffb, 0x007ffff8, 0x007ffff9, 0x007ffffa, 0x007ffffb, 0x00000000,
     0x0000003b, 0x000003f9, 0x00fffff8, 0x00fffff9, 0x00fffffa, 0x00fffffb,
     0x01fffff8, 0x01fffff9, 0x01fffffa, 0x01fffffb, 0x03fffff8, 0x03fffff9,
     0x03fffffa, 0x03fffffb, 0x07fffff8, 0x00000000, 0x000003fa, 0x07fffff9,
     0x07fffffa, 0x07fffffb, 0x0ffffff8, 0x0ffffff9, 0x0ffffffa, 0x0ffffffb,
     0x1ffffff8, 0x1ffffff9, 0x1ffffffa, 0x1ffffffb, 0x3ffffff8, 0x3ffffff9,
     0x3ffffffa,
 };
 
 static const uint8_t huffbits[] = {
      4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
      0,  0,  0,  0,  2,  4,  5,  6,  7,  7,  7,  8,
      8, 10, 11, 11, 11, 11, 12, 12,  2,  6,  7,  8,
      9,  9, 12, 12, 13, 13, 13, 13, 14, 14, 14,  0,
      3,  6,  9, 14, 15, 15, 15, 15, 16, 16, 16, 16,
     17, 17, 17,  0,  4,  8,  9, 17, 18, 18, 18, 18,
     19, 19, 19, 19, 20, 20, 20,  0,  5, 10, 20, 21,
     21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,  0,
      6, 10, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26,
     26, 26, 27,  0, 10, 27, 27, 27, 28, 28, 28, 28,
     29, 29, 29, 29, 30, 30, 30,
 };
 
 static const uint8_t col_zag[64] = {
      0,  8,  1,  2,  9, 16, 24, 17,
     10,  3,  4, 11, 18, 25, 32, 40,
     33, 26, 19, 12,  5,  6, 13, 20,
     27, 34, 41, 48, 56, 49, 42, 35,
     28, 21, 14,  7, 15, 22, 29, 36,
     43, 50, 57, 58, 51, 44, 37, 30,
     23, 31, 38, 45, 52, 59, 39, 46,

     53, 60, 61, 54, 47, 55, 62, 63,

 };
 

 static av_cold int mimic_decode_init(AVCodecContext *avctx)

 {
     MimicContext *ctx = avctx->priv_data;
 
     ctx->prev_index = 0;
     ctx->cur_index = 15;
 

     if(init_vlc(&ctx->vlc, 11, FF_ARRAY_ELEMS(huffbits),

                  huffbits, 1, 1, huffcodes, 4, 4, 0)) {
         av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
         return -1;
     }

     ff_dsputil_init(&ctx->dsp, avctx);

     ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable, col_zag);
 
     return 0;
 }
 

 static int mimic_decode_update_thread_context(AVCodecContext *avctx, const AVCodecContext *avctx_from)
 {
     MimicContext *dst = avctx->priv_data, *src = avctx_from->priv_data;
 
     if (avctx == avctx_from) return 0;
 
     dst->cur_index  = src->next_cur_index;
     dst->prev_index = src->next_prev_index;
 
     memcpy(dst->buf_ptrs, src->buf_ptrs, sizeof(src->buf_ptrs));
     memcpy(dst->flipped_ptrs, src->flipped_ptrs, sizeof(src->flipped_ptrs));
 
     memset(&dst->buf_ptrs[dst->cur_index], 0, sizeof(AVFrame));
 
     return 0;
 }
 

 static const int8_t vlcdec_lookup[9][64] = {

     {    0, },
     {   -1,   1, },
     {   -3,   3,   -2,   2, },
     {   -7,   7,   -6,   6,   -5,   5,   -4,   4, },
     {  -15,  15,  -14,  14,  -13,  13,  -12,  12,
        -11,  11,  -10,  10,   -9,   9,   -8,   8, },
     {  -31,  31,  -30,  30,  -29,  29,  -28,  28,
        -27,  27,  -26,  26,  -25,  25,  -24,  24,
        -23,  23,  -22,  22,  -21,  21,  -20,  20,
        -19,  19,  -18,  18,  -17,  17,  -16,  16, },
     {  -63,  63,  -62,  62,  -61,  61,  -60,  60,
        -59,  59,  -58,  58,  -57,  57,  -56,  56,
        -55,  55,  -54,  54,  -53,  53,  -52,  52,
        -51,  51,  -50,  50,  -49,  49,  -48,  48,
        -47,  47,  -46,  46,  -45,  45,  -44,  44,
        -43,  43,  -42,  42,  -41,  41,  -40,  40,
        -39,  39,  -38,  38,  -37,  37,  -36,  36,
        -35,  35,  -34,  34,  -33,  33,  -32,  32, },
     { -127, 127, -126, 126, -125, 125, -124, 124,
       -123, 123, -122, 122, -121, 121, -120, 120,
       -119, 119, -118, 118, -117, 117, -116, 116,
       -115, 115, -114, 114, -113, 113, -112, 112,
       -111, 111, -110, 110, -109, 109, -108, 108,
       -107, 107, -106, 106, -105, 105, -104, 104,
       -103, 103, -102, 102, -101, 101, -100, 100,
        -99,  99,  -98,  98,  -97,  97,  -96,  96, },
     {  -95,  95,  -94,  94,  -93,  93,  -92,  92,
        -91,  91,  -90,  90,  -89,  89,  -88,  88,
        -87,  87,  -86,  86,  -85,  85,  -84,  84,
        -83,  83,  -82,  82,  -81,  81,  -80,  80,
        -79,  79,  -78,  78,  -77,  77,  -76,  76,
        -75,  75,  -74,  74,  -73,  73,  -72,  72,
        -71,  71,  -70,  70,  -69,  69,  -68,  68,
        -67,  67,  -66,  66,  -65,  65,  -64,  64, },
 };
 

 static int vlc_decode_block(MimicContext *ctx, int num_coeffs, int qscale)

 {

     DCTELEM *block = ctx->dct_block;

     unsigned int pos;
 

     ctx->dsp.clear_block(block);

 
     block[0] = get_bits(&ctx->gb, 8) << 3;
 
     for(pos = 1; pos < num_coeffs; pos++) {
         uint32_t vlc, num_bits;
         int value;
         int coeff;
 

         vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 3);

         if(!vlc) /* end-of-block code */
             return 1;
         if(vlc == -1)
             return 0;
 
         /* pos_add and num_bits are coded in the vlc code */
         pos +=     vlc&15; // pos_add
         num_bits = vlc>>4; // num_bits
 
         if(pos >= 64)
             return 0;
 
         value = get_bits(&ctx->gb, num_bits);
 

         /* FFmpeg's IDCT behaves somewhat different from the original code, so

          * a factor of 4 was added to the input */
 
         coeff = vlcdec_lookup[num_bits][value];
         if(pos<3)
             coeff <<= 4;
         else /* TODO Use >> 10 instead of / 1001 */
             coeff = (coeff * qscale) / 1001;
 
         block[ctx->scantable.permutated[pos]] = coeff;
     }
 
     return 1;
 }
 
 static int decode(MimicContext *ctx, int quality, int num_coeffs,
                   int is_iframe)
 {

     int y, x, plane, cur_row = 0;

 
     for(plane = 0; plane < 3; plane++) {
         const int is_chroma = !!plane;
         const int qscale = av_clip(10000-quality,is_chroma?1000:2000,10000)<<2;
         const int stride = ctx->flipped_ptrs[ctx->cur_index].linesize[plane];
         const uint8_t *src = ctx->flipped_ptrs[ctx->prev_index].data[plane];
         uint8_t       *dst = ctx->flipped_ptrs[ctx->cur_index ].data[plane];
 

         for(y = 0; y < ctx->num_vblocks[plane]; y++) {

             for(x = 0; x < ctx->num_hblocks[plane]; x++) {
 
                 /* Check for a change condition in the current block.
                  * - iframes always change.
                  * - Luma plane changes on get_bits1 == 0
                  * - Chroma planes change on get_bits1 == 1 */
                 if(is_iframe || get_bits1(&ctx->gb) == is_chroma) {
 
                     /* Luma planes may use a backreference from the 15 last
                      * frames preceding the previous. (get_bits1 == 1)
                      * Chroma planes don't use backreferences. */
                     if(is_chroma || is_iframe || !get_bits1(&ctx->gb)) {
 

                         if(!vlc_decode_block(ctx, num_coeffs, qscale))

                             return 0;
                         ctx->dsp.idct_put(dst, stride, ctx->dct_block);
                     } else {
                         unsigned int backref = get_bits(&ctx->gb, 4);
                         int index = (ctx->cur_index+backref)&15;
                         uint8_t *p = ctx->flipped_ptrs[index].data[0];
 

                         if (index != ctx->cur_index && p) {
                             ff_thread_await_progress(&ctx->buf_ptrs[index], cur_row, 0);

                             p += src -
                                 ctx->flipped_ptrs[ctx->prev_index].data[plane];
                             ctx->dsp.put_pixels_tab[1][0](dst, p, stride, 8);
                         } else {
                             av_log(ctx->avctx, AV_LOG_ERROR,
                                      "No such backreference! Buggy sample.\n");
                         }
                     }
                 } else {

                     ff_thread_await_progress(&ctx->buf_ptrs[ctx->prev_index], cur_row, 0);

                     ctx->dsp.put_pixels_tab[1][0](dst, src, stride, 8);
                 }
                 src += 8;
                 dst += 8;
             }
             src += (stride - ctx->num_hblocks[plane])<<3;
             dst += (stride - ctx->num_hblocks[plane])<<3;

 
             ff_thread_report_progress(&ctx->buf_ptrs[ctx->cur_index], cur_row++, 0);

         }
     }
 
     return 1;
 }
 
 /**
  * Flip the buffer upside-down and put it in the YVU order to match the
  * way Mimic encodes frames.
  */
 static void prepare_avpic(MimicContext *ctx, AVPicture *dst, AVPicture *src)
 {
     int i;
     dst->data[0] = src->data[0]+( ctx->avctx->height    -1)*src->linesize[0];
     dst->data[1] = src->data[2]+((ctx->avctx->height>>1)-1)*src->linesize[2];
     dst->data[2] = src->data[1]+((ctx->avctx->height>>1)-1)*src->linesize[1];

     for(i = 0; i < 3; i++)

         dst->linesize[i] = -src->linesize[i];
 }
 
 static int mimic_decode_frame(AVCodecContext *avctx, void *data,

                               int *data_size, AVPacket *avpkt)

 {

     const uint8_t *buf = avpkt->data;
     int buf_size = avpkt->size;

     MimicContext *ctx = avctx->priv_data;

     GetByteContext gb;

     int is_pframe;
     int width, height;
     int quality, num_coeffs;
     int swap_buf_size = buf_size - MIMIC_HEADER_SIZE;

     int res;

     if (buf_size <= MIMIC_HEADER_SIZE) {

         av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
         return -1;
     }
 

     bytestream2_init(&gb, buf, MIMIC_HEADER_SIZE);
     bytestream2_skip(&gb, 2); /* some constant (always 256) */
     quality    = bytestream2_get_le16u(&gb);
     width      = bytestream2_get_le16u(&gb);
     height     = bytestream2_get_le16u(&gb);
     bytestream2_skip(&gb, 4); /* some constant */
     is_pframe  = bytestream2_get_le32u(&gb);
     num_coeffs = bytestream2_get_byteu(&gb);
     bytestream2_skip(&gb, 3); /* some constant */

 
     if(!ctx->avctx) {
         int i;
 
         if(!(width == 160 && height == 120) &&
            !(width == 320 && height == 240)) {
             av_log(avctx, AV_LOG_ERROR, "invalid width/height!\n");
             return -1;
         }
 
         ctx->avctx     = avctx;
         avctx->width   = width;
         avctx->height  = height;
         avctx->pix_fmt = PIX_FMT_YUV420P;

         for(i = 0; i < 3; i++) {

             ctx->num_vblocks[i] = -((-height) >> (3 + !!i));
             ctx->num_hblocks[i] =     width   >> (3 + !!i) ;
         }
     } else if(width != ctx->avctx->width || height != ctx->avctx->height) {
         av_log(avctx, AV_LOG_ERROR, "resolution changing is not supported\n");
         return -1;
     }
 
     if(is_pframe && !ctx->buf_ptrs[ctx->prev_index].data[0]) {
         av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
         return -1;
     }
 

     ctx->buf_ptrs[ctx->cur_index].reference = 3;

     ctx->buf_ptrs[ctx->cur_index].pict_type = is_pframe ? AV_PICTURE_TYPE_P:AV_PICTURE_TYPE_I;

     if(ff_thread_get_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index])) {

         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return -1;
     }
 

     ctx->next_prev_index = ctx->cur_index;
     ctx->next_cur_index  = (ctx->cur_index - 1) & 15;
 

     prepare_avpic(ctx, &ctx->flipped_ptrs[ctx->cur_index],
                   (AVPicture*) &ctx->buf_ptrs[ctx->cur_index]);
 

     ff_thread_finish_setup(avctx);
 

     av_fast_padded_malloc(&ctx->swap_buf, &ctx->swap_buf_size, swap_buf_size);

     if(!ctx->swap_buf)

         return AVERROR(ENOMEM);

     ctx->dsp.bswap_buf(ctx->swap_buf,

                         (const uint32_t*) (buf + MIMIC_HEADER_SIZE),

                         swap_buf_size>>2);
     init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);
 

     res = decode(ctx, quality, num_coeffs, !is_pframe);
     ff_thread_report_progress(&ctx->buf_ptrs[ctx->cur_index], INT_MAX, 0);
     if (!res) {
         if (!(avctx->active_thread_type & FF_THREAD_FRAME)) {

             ff_thread_release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
             return -1;
         }

     }
 
     *(AVFrame*)data = ctx->buf_ptrs[ctx->cur_index];
     *data_size = sizeof(AVFrame);
 

     ctx->prev_index = ctx->next_prev_index;
     ctx->cur_index  = ctx->next_cur_index;

 
     /* Only release frames that aren't used for backreferences anymore */
     if(ctx->buf_ptrs[ctx->cur_index].data[0])

         ff_thread_release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);

 
     return buf_size;
 }
 

 static av_cold int mimic_decode_end(AVCodecContext *avctx)

 {
     MimicContext *ctx = avctx->priv_data;
     int i;
 
     av_free(ctx->swap_buf);

     if (avctx->internal->is_copy)
         return 0;

     for(i = 0; i < 16; i++)
         if(ctx->buf_ptrs[i].data[0])

             ff_thread_release_buffer(avctx, &ctx->buf_ptrs[i]);

     ff_free_vlc(&ctx->vlc);

 
     return 0;
 }
 

 AVCodec ff_mimic_decoder = {

     .name                  = "mimic",
     .type                  = AVMEDIA_TYPE_VIDEO,
     .id                    = CODEC_ID_MIMIC,
     .priv_data_size        = sizeof(MimicContext),
     .init                  = mimic_decode_init,
     .close                 = mimic_decode_end,
     .decode                = mimic_decode_frame,
     .capabilities          = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
     .long_name             = NULL_IF_CONFIG_SMALL("Mimic"),

     .update_thread_context = ONLY_IF_THREADS_ENABLED(mimic_decode_update_thread_context)

 };