/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * RemoteFX Codec Library - DWT

 *

 * Copyright 2011 Vic Lee

 *

 * 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.

 */

#include <winpr/assert.h>

#include <winpr/cast.h>

#include <freerdp/config.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "rfx_dwt.h"

static INLINE void rfx_dwt_2d_decode_block(INT16* WINPR_RESTRICT buffer, INT16* WINPR_RESTRICT idwt,

                                           size_t subband_width)

{

  const size_t total_width = subband_width << 1;

  /* Inverse DWT in horizontal direction, results in 2 sub-bands in L, H order in tmp buffer idwt.

   */

  /* The 4 sub-bands are stored in HL(0), LH(1), HH(2), LL(3) order. */

  /* The lower part L uses LL(3) and HL(0). */

  /* The higher part H uses LH(1) and HH(2). */

  const INT16* ll = buffer + subband_width * subband_width * 3;

  const INT16* hl = buffer;

  INT16* l_dst = idwt;

  const INT16* lh = buffer + subband_width * subband_width;

  const INT16* hh = buffer + subband_width * subband_width * 2;

  INT16* h_dst = idwt + subband_width * subband_width * 2;

  for (size_t y = 0; y < subband_width; y++)

  {

    /* Even coefficients */

    l_dst[0] = WINPR_ASSERTING_INT_CAST(int16_t, ll[0] - ((hl[0] + hl[0] + 1) >> 1));

    h_dst[0] = WINPR_ASSERTING_INT_CAST(int16_t, lh[0] - ((hh[0] + hh[0] + 1) >> 1));

    for (size_t n = 1; n < subband_width; n++)

    {

      const size_t x = n << 1;

      l_dst[x] = WINPR_ASSERTING_INT_CAST(int16_t, ll[n] - ((hl[n - 1] + hl[n] + 1) >> 1));

      h_dst[x] = WINPR_ASSERTING_INT_CAST(int16_t, lh[n] - ((hh[n - 1] + hh[n] + 1) >> 1));

    }

    /* Odd coefficients */

    size_t n = 0;

    for (; n < subband_width - 1; n++)

    {

      const size_t x = n << 1;

      const int ld = (hl[n] << 1) + ((l_dst[x] + l_dst[x + 2]) >> 1);

      const int hd = (hh[n] << 1) + ((h_dst[x] + h_dst[x + 2]) >> 1);

      l_dst[x + 1] = WINPR_ASSERTING_INT_CAST(INT16, ld);

      h_dst[x + 1] = WINPR_ASSERTING_INT_CAST(INT16, hd);

    }

    const size_t x = n << 1;

    const int ld = (hl[n] << 1) + (l_dst[x]);

    const int hd = (hh[n] << 1) + (h_dst[x]);

    l_dst[x + 1] = WINPR_ASSERTING_INT_CAST(INT16, ld);

    h_dst[x + 1] = WINPR_ASSERTING_INT_CAST(INT16, hd);

    ll += subband_width;

    hl += subband_width;

    l_dst += total_width;

    lh += subband_width;

    hh += subband_width;

    h_dst += total_width;

  }

  /* Inverse DWT in vertical direction, results are stored in original buffer. */

  for (size_t x = 0; x < total_width; x++)

  {

    const INT16* l = idwt + x;

    const INT16* h = idwt + x + subband_width * total_width;

    INT16* dst = buffer + x;

    const int dd = *l - ((*h * 2 + 1) >> 1);

    *dst = WINPR_ASSERTING_INT_CAST(INT16, dd);

    for (size_t n = 1; n < subband_width; n++)

    {

      l += total_width;

      h += total_width;

      /* Even coefficients */

      const int d2 = *l - ((*(h - total_width) + *h + 1) >> 1);

      dst[2 * total_width] = WINPR_ASSERTING_INT_CAST(INT16, d2);

      /* Odd coefficients */

      const int d = (*(h - total_width) << 1) + ((*dst + dst[2 * total_width]) >> 1);

      dst[total_width] = WINPR_ASSERTING_INT_CAST(INT16, d);

      dst += 2 * total_width;

    }

    const int d = (*h << 1) + ((*dst * 2) >> 1);

    dst[total_width] = WINPR_ASSERTING_INT_CAST(INT16, d);

  }

}

void rfx_dwt_2d_decode(INT16* WINPR_RESTRICT buffer, INT16* WINPR_RESTRICT dwt_buffer)

{

  WINPR_ASSERT(buffer);

  WINPR_ASSERT(dwt_buffer);

  rfx_dwt_2d_decode_block(&buffer[3840], dwt_buffer, 8);

  rfx_dwt_2d_decode_block(&buffer[3072], dwt_buffer, 16);

  rfx_dwt_2d_decode_block(&buffer[0], dwt_buffer, 32);

}

static void rfx_dwt_2d_encode_block(INT16* WINPR_RESTRICT buffer, INT16* WINPR_RESTRICT dwt,

                                    UINT32 subband_width)

{

  INT16* src = NULL;

  INT16* l = NULL;

  INT16* h = NULL;

  INT16* l_src = NULL;

  INT16* h_src = NULL;

  INT16* hl = NULL;

  INT16* lh = NULL;

  INT16* hh = NULL;

  INT16* ll = NULL;

  const UINT32 total_width = subband_width << 1;

  /* DWT in vertical direction, results in 2 sub-bands in L, H order in tmp buffer dwt. */

  for (UINT32 x = 0; x < total_width; x++)

  {

    for (UINT32 n = 0; n < subband_width; n++)

    {

      UINT32 y = n << 1;

      l = dwt + 1ULL * n * total_width + x;

      h = l + 1ULL * subband_width * total_width;

      src = buffer + 1ULL * y * total_width + x;

      /* H */

      *h = WINPR_ASSERTING_INT_CAST(

          int16_t, (src[total_width] -

                    ((src[0] + src[n < subband_width - 1 ? 2 * total_width : 0]) >> 1)) >>

                       1);

      /* L */

      *l = WINPR_ASSERTING_INT_CAST(int16_t,

                                    src[0] + (n == 0 ? *h : (*(h - total_width) + *h) >> 1));

    }

  }

  /* DWT in horizontal direction, results in 4 sub-bands in HL(0), LH(1), HH(2), LL(3) order,

   * stored in original buffer. */

  /* The lower part L generates LL(3) and HL(0). */

  /* The higher part H generates LH(1) and HH(2). */

  ll = buffer + 3ULL * subband_width * subband_width;

  hl = buffer;

  l_src = dwt;

  lh = buffer + 1ULL * subband_width * subband_width;

  hh = buffer + 2ULL * subband_width * subband_width;

  h_src = dwt + 2ULL * subband_width * subband_width;

  for (size_t y = 0; y < subband_width; y++)

  {

    /* L */

    for (UINT32 n = 0; n < subband_width; n++)

    {

      UINT32 x = n << 1;

      /* HL */

      hl[n] = WINPR_ASSERTING_INT_CAST(

          int16_t,

          (l_src[x + 1] - ((l_src[x] + l_src[n < subband_width - 1 ? x + 2 : x]) >> 1)) >> 1);

      /* LL */

      ll[n] = WINPR_ASSERTING_INT_CAST(

          int16_t, l_src[x] + (n == 0 ? hl[n] : (hl[n - 1] + hl[n]) >> 1));

    }

    /* H */

    for (UINT32 n = 0; n < subband_width; n++)

    {

      UINT32 x = n << 1;

      /* HH */

      hh[n] = WINPR_ASSERTING_INT_CAST(

          int16_t,

          (h_src[x + 1] - ((h_src[x] + h_src[n < subband_width - 1 ? x + 2 : x]) >> 1)) >> 1);

      /* LH */

      lh[n] = WINPR_ASSERTING_INT_CAST(

          int16_t, h_src[x] + (n == 0 ? hh[n] : (hh[n - 1] + hh[n]) >> 1));

    }

    ll += subband_width;

    hl += subband_width;

    l_src += total_width;

    lh += subband_width;

    hh += subband_width;

    h_src += total_width;

  }

}

void rfx_dwt_2d_encode(INT16* WINPR_RESTRICT buffer, INT16* WINPR_RESTRICT dwt_buffer)

{

  WINPR_ASSERT(buffer);

  WINPR_ASSERT(dwt_buffer);

  rfx_dwt_2d_encode_block(&buffer[0], dwt_buffer, 32);

  rfx_dwt_2d_encode_block(&buffer[3072], dwt_buffer, 16);

  rfx_dwt_2d_encode_block(&buffer[3840], dwt_buffer, 8);

}