/******************************************************************************
 *
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *****************************************************************************
 * Originally developed and contributed by Ittiam Systems Pvt. Ltd, Bangalore
*/

#include "iv_datatypedef.h"
#include "impeg2_defs.h"
#include "impeg2_globals.h"
#include "impeg2_platform_macros.h"
#include "impeg2_inter_pred.h"
#include "impeg2_idct.h"
#include "impeg2_mem_func.h"
#include "impeg2_format_conv.h"
#include "impeg2_disp_mgr.h"
#include "impeg2_buf_mgr.h"

#include "impeg2d.h"
#include "impeg2d_bitstream.h"
#include "impeg2d_structs.h"
#include "impeg2d_vld.h"
#include "impeg2d_vld_tables.h"

#define BLK_SIZE 8
#define LUMA_BLK_SIZE (2 * (BLK_SIZE))
#define CHROMA_BLK_SIZE (BLK_SIZE)
/*****************************************************************************/
/*                                                                           */
/*  Function Name : impeg2d_get_luma_dc_diff                                         */
/*                                                                           */
/*  Description   : Decode the DC differential value from the bitstream for  */
/*                  luma block                                               */
/*                                                                           */
/*  Inputs        : stream - Input stream                                    */
/*                                                                           */
/*  Globals       : None                                                     */
/*                                                                           */
/*  Processing    : Decode the vlc for dc_diff                               */
/*                                                                           */
/*  Outputs       : dc_diff - dc differential used in dc prediction          */
/*                                                                           */
/*  Returns       : dc_diff - dc differential used in dc prediction          */
/*                                                                           */
/*  Issues        : None                                                     */
/*                                                                           */
/*  Revision History:                                                        */
/*                                                                           */
/*         DD MM YYYY   Author(s)       Changes                              */
/*         14 09 2005   Harish M        First Version                        */
/*                                                                           */
/*****************************************************************************/
WORD16  impeg2d_get_luma_dc_diff(stream_t *ps_stream)
{
    UWORD16 u2_dc_size;
    WORD16  i2_dc_diff;

    u2_dc_size = impeg2d_dec_vld_symbol(ps_stream,gai2_impeg2d_dct_dc_size[0],
                        MPEG2_DCT_DC_LUMA_SIZE_LEN) +
                        MPEG2_DCT_DC_SIZE_OFFSET;
    if (u2_dc_size != 0)
    {
        i2_dc_diff = impeg2d_bit_stream_get(ps_stream,u2_dc_size);
        if ((i2_dc_diff & (1 << (u2_dc_size - 1))) == 0)
            i2_dc_diff -= (1 << u2_dc_size) - 1;
    }
    else
    {
        i2_dc_diff = 0;
    }
    return i2_dc_diff;
}

/*****************************************************************************/
/*                                                                           */
/*  Function Name : impeg2d_get_chroma_dc_diff                                       */
/*                                                                           */
/*  Description   : Decode the DC differential value from the bitstream for  */
/*                  chroma block                                             */
/*                                                                           */
/*  Inputs        : stream - Input stream                                    */
/*                                                                           */
/*  Globals       : None                                                     */
/*                                                                           */
/*  Processing    : Decode the vlc for dc_diff                               */
/*                                                                           */
/*  Outputs       : dc_diff - dc differential used in dc prediction          */
/*                                                                           */
/*  Returns       : dc_diff - dc differential used in dc prediction          */
/*                                                                           */
/*  Issues        : None                                                     */
/*                                                                           */
/*  Revision History:                                                        */
/*                                                                           */
/*         DD MM YYYY   Author(s)       Changes                              */
/*         14 09 2005   Harish M        First Version                        */
/*                                                                           */
/*****************************************************************************/
WORD16  impeg2d_get_chroma_dc_diff(stream_t *ps_stream)
{
    UWORD16 u2_dc_size;
    WORD16  i2_dc_diff;
    u2_dc_size = impeg2d_dec_vld_symbol(ps_stream,gai2_impeg2d_dct_dc_size[1],
                        MPEG2_DCT_DC_CHROMA_SIZE_LEN) +
                        MPEG2_DCT_DC_SIZE_OFFSET;
    if (u2_dc_size != 0)
    {
        i2_dc_diff = impeg2d_bit_stream_get(ps_stream,u2_dc_size);
        if ((i2_dc_diff & (1 << (u2_dc_size - 1))) == 0)
            i2_dc_diff -= (1 << u2_dc_size) - 1;
    }
    else
    {
        i2_dc_diff = 0;
    }
    return i2_dc_diff;
}
/*******************************************************************************
*  Function Name   : impeg2d_dec_d_slice
*
*  Description     : Decodes I slice
*
*  Arguments       :
*  dec             : Decoder state
*
*  Values Returned : None
*******************************************************************************/
IMPEG2D_ERROR_CODES_T impeg2d_dec_d_slice(dec_state_t *ps_dec)
{
    UWORD32 i;
    yuv_buf_t *ps_cur_frm_buf  = &ps_dec->s_cur_frm_buf;

    stream_t   *ps_stream       = &ps_dec->s_bit_stream;
    UWORD8   *pu1_vld_buf;

    WORD16 i2_dc_diff;
    UWORD32 u4_frame_width = ps_dec->u2_frame_width;
    UWORD32 u4_frm_offset = 0;
    if(ps_dec->u2_picture_structure != FRAME_PICTURE)
    {
        u4_frame_width <<= 1;
        if(ps_dec->u2_picture_structure == BOTTOM_FIELD)
        {
            u4_frm_offset = ps_dec->u2_frame_width;
        }
    }

    do
    {

        UWORD32 u4_x_offset, u4_y_offset;
        UWORD32 u4_blk_pos;
        WORD16 i2_dc_val;

        UWORD32 u4_dst_x_offset     = u4_frm_offset + (ps_dec->u2_mb_x << 4);
        UWORD32 u4_dst_y_offset     = (ps_dec->u2_mb_y << 4) * u4_frame_width;
        UWORD8 *pu1_vld_buf8        = ps_cur_frm_buf->pu1_y + u4_dst_x_offset + u4_dst_y_offset;
        UWORD32 u4_dst_wd           = u4_frame_width;
        /*------------------------------------------------------------------*/
        /* Discard the Macroblock stuffing in case of MPEG-1 stream         */
        /*------------------------------------------------------------------*/
        while(impeg2d_bit_stream_nxt(ps_stream,MB_STUFFING_CODE_LEN) == MB_STUFFING_CODE &&
                ps_stream->u4_offset < ps_stream->u4_max_offset)
            impeg2d_bit_stream_flush(ps_stream,MB_STUFFING_CODE_LEN);

        /*------------------------------------------------------------------*/
        /* Flush 2 bits from bitstream [MB_Type and MacroBlockAddrIncrement]*/
        /*------------------------------------------------------------------*/
        impeg2d_bit_stream_flush(ps_stream,1);

        if(impeg2d_bit_stream_get(ps_stream, 1) != 0x01)
        {
            /* Ignore and continue decoding. */
        }

        /* Process LUMA blocks of the MB */
        for(i = 0; i < NUM_LUMA_BLKS; ++i)
        {

            u4_x_offset    = gai2_impeg2_blk_x_off[i];
            u4_y_offset    = gai2_impeg2_blk_y_off_frm[i] ;
            u4_blk_pos     = (u4_y_offset * u4_dst_wd) + u4_x_offset;
            pu1_vld_buf     = pu1_vld_buf8 + u4_blk_pos;

            i2_dc_diff = impeg2d_get_luma_dc_diff(ps_stream);
            i2_dc_val = ps_dec->u2_def_dc_pred[Y_LUMA] + i2_dc_diff;
            ps_dec->u2_def_dc_pred[Y_LUMA] = i2_dc_val;
            i2_dc_val = CLIP_U8(i2_dc_val);

            ps_dec->pf_memset_8bit_8x8_block(pu1_vld_buf, i2_dc_val, u4_dst_wd);
        }


        /* Process U block of the MB */

        u4_dst_x_offset                >>= 1;
        u4_dst_y_offset                >>= 2;
        u4_dst_wd                      >>= 1;
        pu1_vld_buf                     = ps_cur_frm_buf->pu1_u + u4_dst_x_offset + u4_dst_y_offset;
        i2_dc_diff                     = impeg2d_get_chroma_dc_diff(ps_stream);
        i2_dc_val                      = ps_dec->u2_def_dc_pred[U_CHROMA] + i2_dc_diff;
        ps_dec->u2_def_dc_pred[U_CHROMA]    = i2_dc_val;
        i2_dc_val = CLIP_U8(i2_dc_val);
        ps_dec->pf_memset_8bit_8x8_block(pu1_vld_buf, i2_dc_val, u4_dst_wd);


        /* Process V block of the MB */

        pu1_vld_buf                     = ps_cur_frm_buf->pu1_v + u4_dst_x_offset + u4_dst_y_offset;
        i2_dc_diff                     = impeg2d_get_chroma_dc_diff(ps_stream);
        i2_dc_val                      = ps_dec->u2_def_dc_pred[V_CHROMA] + i2_dc_diff;
        ps_dec->u2_def_dc_pred[V_CHROMA]    = i2_dc_val;
        i2_dc_val = CLIP_U8(i2_dc_val);
        ps_dec->pf_memset_8bit_8x8_block(pu1_vld_buf, i2_dc_val, u4_dst_wd);

        /* Common MB processing Steps */


        ps_dec->u2_num_mbs_left--;
        ps_dec->u2_mb_x++;

        if(ps_dec->s_bit_stream.u4_offset > ps_dec->s_bit_stream.u4_max_offset)
        {
            return IMPEG2D_BITSTREAM_BUFF_EXCEEDED_ERR;
        }
        else if (ps_dec->u2_mb_x == ps_dec->u2_num_horiz_mb)
        {
            ps_dec->u2_mb_x = 0;
            ps_dec->u2_mb_y++;

        }

        /* Flush end of macro block */
        impeg2d_bit_stream_flush(ps_stream,1);
    }
    while(ps_dec->u2_num_mbs_left != 0 && impeg2d_bit_stream_nxt(&ps_dec->s_bit_stream,23) != 0x0);
    return (IMPEG2D_ERROR_CODES_T)IVD_ERROR_NONE;
}/* End of impeg2d_dec_d_slice() */