// Copyright 2015 Google Inc. All Rights Reserved.

//

// Use of this source code is governed by a BSD-style license

// that can be found in the COPYING file in the root of the source

// tree. An additional intellectual property rights grant can be found

// in the file PATENTS. All contributing project authors may

// be found in the AUTHORS file in the root of the source tree.

// -----------------------------------------------------------------------------

//

// SSE2 variant of alpha filters

//

// Author: Skal (pascal.massimino@gmail.com)

#include "src/dsp/dsp.h"

#if defined(WEBP_USE_SSE2)

#include <assert.h>

#include <emmintrin.h>

#include <stdlib.h>

#include <string.h>

//------------------------------------------------------------------------------

// Helpful macro.

# define SANITY_CHECK(in, out)                                                 \

  assert((in) != NULL);                                                        \

  assert((out) != NULL);                                                       \

  assert(width > 0);                                                           \

  assert(height > 0);                                                          \

  assert(stride >= width);                                                     \

  assert(row >= 0 && num_rows > 0 && row + num_rows <= height);                \

  (void)height;  // Silence unused warning.

static void PredictLineTop_SSE2(const uint8_t* src, const uint8_t* pred,

                                uint8_t* dst, int length) {

  int i;

  const int max_pos = length & ~31;

  assert(length >= 0);

  for (i = 0; i < max_pos; i += 32) {

    const __m128i A0 = _mm_loadu_si128((const __m128i*)&src[i +  0]);

    const __m128i A1 = _mm_loadu_si128((const __m128i*)&src[i + 16]);

    const __m128i B0 = _mm_loadu_si128((const __m128i*)&pred[i +  0]);

    const __m128i B1 = _mm_loadu_si128((const __m128i*)&pred[i + 16]);

    const __m128i C0 = _mm_sub_epi8(A0, B0);

    const __m128i C1 = _mm_sub_epi8(A1, B1);

    _mm_storeu_si128((__m128i*)&dst[i +  0], C0);

    _mm_storeu_si128((__m128i*)&dst[i + 16], C1);

  }

  for (; i < length; ++i) dst[i] = src[i] - pred[i];

}

// Special case for left-based prediction (when preds==dst-1 or preds==src-1).

static void PredictLineLeft_SSE2(const uint8_t* src, uint8_t* dst, int length) {

  int i;

  const int max_pos = length & ~31;

  assert(length >= 0);

  for (i = 0; i < max_pos; i += 32) {

    const __m128i A0 = _mm_loadu_si128((const __m128i*)(src + i +  0    ));

    const __m128i B0 = _mm_loadu_si128((const __m128i*)(src + i +  0 - 1));

    const __m128i A1 = _mm_loadu_si128((const __m128i*)(src + i + 16    ));

    const __m128i B1 = _mm_loadu_si128((const __m128i*)(src + i + 16 - 1));

    const __m128i C0 = _mm_sub_epi8(A0, B0);

    const __m128i C1 = _mm_sub_epi8(A1, B1);

    _mm_storeu_si128((__m128i*)(dst + i +  0), C0);

    _mm_storeu_si128((__m128i*)(dst + i + 16), C1);

  }

  for (; i < length; ++i) dst[i] = src[i] - src[i - 1];

}

//------------------------------------------------------------------------------

// Horizontal filter.

static WEBP_INLINE void DoHorizontalFilter_SSE2(const uint8_t* in,

                                                int width, int height,

                                                int stride,

                                                int row, int num_rows,

                                                uint8_t* out) {

  const size_t start_offset = row * stride;

  const int last_row = row + num_rows;

  SANITY_CHECK(in, out);

  in += start_offset;

  out += start_offset;

  if (row == 0) {

    // Leftmost pixel is the same as input for topmost scanline.

    out[0] = in[0];

    PredictLineLeft_SSE2(in + 1, out + 1, width - 1);

    row = 1;

    in += stride;

    out += stride;

  }

  // Filter line-by-line.

  while (row < last_row) {

    // Leftmost pixel is predicted from above.

    out[0] = in[0] - in[-stride];

    PredictLineLeft_SSE2(in + 1, out + 1, width - 1);

    ++row;

    in += stride;

    out += stride;

  }

}

//------------------------------------------------------------------------------

// Vertical filter.

static WEBP_INLINE void DoVerticalFilter_SSE2(const uint8_t* in,

                                              int width, int height, int stride,

                                              int row, int num_rows,

                                              uint8_t* out) {

  const size_t start_offset = row * stride;

  const int last_row = row + num_rows;

  SANITY_CHECK(in, out);

  in += start_offset;

  out += start_offset;

  if (row == 0) {

    // Very first top-left pixel is copied.

    out[0] = in[0];

    // Rest of top scan-line is left-predicted.

    PredictLineLeft_SSE2(in + 1, out + 1, width - 1);

    row = 1;

    in += stride;

    out += stride;

  }

  // Filter line-by-line.

  while (row < last_row) {

    PredictLineTop_SSE2(in, in - stride, out, width);

    ++row;

    in += stride;

    out += stride;

  }

}

//------------------------------------------------------------------------------

// Gradient filter.

static WEBP_INLINE int GradientPredictor_SSE2(uint8_t a, uint8_t b, uint8_t c) {

  const int g = a + b - c;

  return ((g & ~0xff) == 0) ? g : (g < 0) ? 0 : 255;  // clip to 8bit

}

static void GradientPredictDirect_SSE2(const uint8_t* const row,

                                       const uint8_t* const top,

                                       uint8_t* const out, int length) {

  const int max_pos = length & ~7;

  int i;

  const __m128i zero = _mm_setzero_si128();

  for (i = 0; i < max_pos; i += 8) {

    const __m128i A0 = _mm_loadl_epi64((const __m128i*)&row[i - 1]);

    const __m128i B0 = _mm_loadl_epi64((const __m128i*)&top[i]);

    const __m128i C0 = _mm_loadl_epi64((const __m128i*)&top[i - 1]);

    const __m128i D = _mm_loadl_epi64((const __m128i*)&row[i]);

    const __m128i A1 = _mm_unpacklo_epi8(A0, zero);

    const __m128i B1 = _mm_unpacklo_epi8(B0, zero);

    const __m128i C1 = _mm_unpacklo_epi8(C0, zero);

    const __m128i E = _mm_add_epi16(A1, B1);

    const __m128i F = _mm_sub_epi16(E, C1);

    const __m128i G = _mm_packus_epi16(F, zero);

    const __m128i H = _mm_sub_epi8(D, G);

    _mm_storel_epi64((__m128i*)(out + i), H);

  }

  for (; i < length; ++i) {

    out[i] = row[i] - GradientPredictor_SSE2(row[i - 1], top[i], top[i - 1]);

  }

}

static WEBP_INLINE void DoGradientFilter_SSE2(const uint8_t* in,

                                              int width, int height, int stride,

                                              int row, int num_rows,

                                              uint8_t* out) {

  const size_t start_offset = row * stride;

  const int last_row = row + num_rows;

  SANITY_CHECK(in, out);

  in += start_offset;

  out += start_offset;

  // left prediction for top scan-line

  if (row == 0) {

    out[0] = in[0];

    PredictLineLeft_SSE2(in + 1, out + 1, width - 1);

    row = 1;

    in += stride;

    out += stride;

  }

  // Filter line-by-line.

  while (row < last_row) {

    out[0] = in[0] - in[-stride];

    GradientPredictDirect_SSE2(in + 1, in + 1 - stride, out + 1, width - 1);

    ++row;

    in += stride;

    out += stride;

  }

}

#undef SANITY_CHECK

//------------------------------------------------------------------------------

static void HorizontalFilter_SSE2(const uint8_t* data, int width, int height,

                                  int stride, uint8_t* filtered_data) {

  DoHorizontalFilter_SSE2(data, width, height, stride, 0, height,

                          filtered_data);

}

static void VerticalFilter_SSE2(const uint8_t* data, int width, int height,

                                int stride, uint8_t* filtered_data) {

  DoVerticalFilter_SSE2(data, width, height, stride, 0, height, filtered_data);

}

static void GradientFilter_SSE2(const uint8_t* data, int width, int height,

                                int stride, uint8_t* filtered_data) {

  DoGradientFilter_SSE2(data, width, height, stride, 0, height, filtered_data);

}

//------------------------------------------------------------------------------

// Inverse transforms

static void HorizontalUnfilter_SSE2(const uint8_t* prev, const uint8_t* in,

                                    uint8_t* out, int width) {

  int i;

  __m128i last;

  out[0] = in[0] + (prev == NULL ? 0 : prev[0]);

  if (width <= 1) return;

  last = _mm_set_epi32(0, 0, 0, out[0]);

  for (i = 1; i + 8 <= width; i += 8) {

    const __m128i A0 = _mm_loadl_epi64((const __m128i*)(in + i));

    const __m128i A1 = _mm_add_epi8(A0, last);

    const __m128i A2 = _mm_slli_si128(A1, 1);

    const __m128i A3 = _mm_add_epi8(A1, A2);

    const __m128i A4 = _mm_slli_si128(A3, 2);

    const __m128i A5 = _mm_add_epi8(A3, A4);

    const __m128i A6 = _mm_slli_si128(A5, 4);

    const __m128i A7 = _mm_add_epi8(A5, A6);

    _mm_storel_epi64((__m128i*)(out + i), A7);

    last = _mm_srli_epi64(A7, 56);

  }

  for (; i < width; ++i) out[i] = in[i] + out[i - 1];

}

static void VerticalUnfilter_SSE2(const uint8_t* prev, const uint8_t* in,

                                  uint8_t* out, int width) {

  if (prev == NULL) {

    HorizontalUnfilter_SSE2(NULL, in, out, width);

  } else {

    int i;

    const int max_pos = width & ~31;

    assert(width >= 0);

    for (i = 0; i < max_pos; i += 32) {

      const __m128i A0 = _mm_loadu_si128((const __m128i*)&in[i +  0]);

      const __m128i A1 = _mm_loadu_si128((const __m128i*)&in[i + 16]);

      const __m128i B0 = _mm_loadu_si128((const __m128i*)&prev[i +  0]);

      const __m128i B1 = _mm_loadu_si128((const __m128i*)&prev[i + 16]);

      const __m128i C0 = _mm_add_epi8(A0, B0);

      const __m128i C1 = _mm_add_epi8(A1, B1);

      _mm_storeu_si128((__m128i*)&out[i +  0], C0);

      _mm_storeu_si128((__m128i*)&out[i + 16], C1);

    }

    for (; i < width; ++i) out[i] = in[i] + prev[i];

  }

}

static void GradientPredictInverse_SSE2(const uint8_t* const in,

                                        const uint8_t* const top,

                                        uint8_t* const row, int length) {

  if (length > 0) {

    int i;

    const int max_pos = length & ~7;

    const __m128i zero = _mm_setzero_si128();

    __m128i A = _mm_set_epi32(0, 0, 0, row[-1]);   // left sample

    for (i = 0; i < max_pos; i += 8) {

      const __m128i tmp0 = _mm_loadl_epi64((const __m128i*)&top[i]);

      const __m128i tmp1 = _mm_loadl_epi64((const __m128i*)&top[i - 1]);

      const __m128i B = _mm_unpacklo_epi8(tmp0, zero);

      const __m128i C = _mm_unpacklo_epi8(tmp1, zero);

      const __m128i D = _mm_loadl_epi64((const __m128i*)&in[i]);  // base input

      const __m128i E = _mm_sub_epi16(B, C);  // unclipped gradient basis B - C

      __m128i out = zero;                     // accumulator for output

      __m128i mask_hi = _mm_set_epi32(0, 0, 0, 0xff);

      int k = 8;

      while (1) {

        const __m128i tmp3 = _mm_add_epi16(A, E);           // delta = A + B - C

        const __m128i tmp4 = _mm_packus_epi16(tmp3, zero);  // saturate delta

        const __m128i tmp5 = _mm_add_epi8(tmp4, D);         // add to in[]

        A = _mm_and_si128(tmp5, mask_hi);                   // 1-complement clip

        out = _mm_or_si128(out, A);                         // accumulate output

        if (--k == 0) break;

        A = _mm_slli_si128(A, 1);                        // rotate left sample

        mask_hi = _mm_slli_si128(mask_hi, 1);            // rotate mask

        A = _mm_unpacklo_epi8(A, zero);                  // convert 8b->16b

      }

      A = _mm_srli_si128(A, 7);       // prepare left sample for next iteration

      _mm_storel_epi64((__m128i*)&row[i], out);

    }

    for (; i < length; ++i) {

      row[i] = in[i] + GradientPredictor_SSE2(row[i - 1], top[i], top[i - 1]);

    }

  }

}

static void GradientUnfilter_SSE2(const uint8_t* prev, const uint8_t* in,

                                  uint8_t* out, int width) {

  if (prev == NULL) {

    HorizontalUnfilter_SSE2(NULL, in, out, width);

  } else {

    out[0] = in[0] + prev[0];  // predict from above

    GradientPredictInverse_SSE2(in + 1, prev + 1, out + 1, width - 1);

  }

}

//------------------------------------------------------------------------------

// Entry point

extern void VP8FiltersInitSSE2(void);

WEBP_TSAN_IGNORE_FUNCTION void VP8FiltersInitSSE2(void) {

  WebPUnfilters[WEBP_FILTER_HORIZONTAL] = HorizontalUnfilter_SSE2;

  WebPUnfilters[WEBP_FILTER_VERTICAL] = VerticalUnfilter_SSE2;

  WebPUnfilters[WEBP_FILTER_GRADIENT] = GradientUnfilter_SSE2;

  WebPFilters[WEBP_FILTER_HORIZONTAL] = HorizontalFilter_SSE2;

  WebPFilters[WEBP_FILTER_VERTICAL] = VerticalFilter_SSE2;

  WebPFilters[WEBP_FILTER_GRADIENT] = GradientFilter_SSE2;

}

#else  // !WEBP_USE_SSE2

WEBP_DSP_INIT_STUB(VP8FiltersInitSSE2)

#endif  // WEBP_USE_SSE2