// Copyright 2014 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.

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

//

// Utilities for processing transparent channel.

//

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

#include "src/dsp/dsp.h"

#if defined(WEBP_USE_SSE2)

#include <emmintrin.h>

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

static int DispatchAlpha_SSE2(const uint8_t* alpha, int alpha_stride,

                              int width, int height,

                              uint8_t* dst, int dst_stride) {

  // alpha_and stores an 'and' operation of all the alpha[] values. The final

  // value is not 0xff if any of the alpha[] is not equal to 0xff.

  uint32_t alpha_and = 0xff;

  int i, j;

  const __m128i zero = _mm_setzero_si128();

  const __m128i rgb_mask = _mm_set1_epi32(0xffffff00u);  // to preserve RGB

  const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);

  __m128i all_alphas = all_0xff;

  // We must be able to access 3 extra bytes after the last written byte

  // 'dst[4 * width - 4]', because we don't know if alpha is the first or the

  // last byte of the quadruplet.

  const int limit = (width - 1) & ~7;

  for (j = 0; j < height; ++j) {

    __m128i* out = (__m128i*)dst;

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

      // load 8 alpha bytes

      const __m128i a0 = _mm_loadl_epi64((const __m128i*)&alpha[i]);

      const __m128i a1 = _mm_unpacklo_epi8(a0, zero);

      const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);

      const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);

      // load 8 dst pixels (32 bytes)

      const __m128i b0_lo = _mm_loadu_si128(out + 0);

      const __m128i b0_hi = _mm_loadu_si128(out + 1);

      // mask dst alpha values

      const __m128i b1_lo = _mm_and_si128(b0_lo, rgb_mask);

      const __m128i b1_hi = _mm_and_si128(b0_hi, rgb_mask);

      // combine

      const __m128i b2_lo = _mm_or_si128(b1_lo, a2_lo);

      const __m128i b2_hi = _mm_or_si128(b1_hi, a2_hi);

      // store

      _mm_storeu_si128(out + 0, b2_lo);

      _mm_storeu_si128(out + 1, b2_hi);

      // accumulate eight alpha 'and' in parallel

      all_alphas = _mm_and_si128(all_alphas, a0);

      out += 2;

    }

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

      const uint32_t alpha_value = alpha[i];

      dst[4 * i] = alpha_value;

      alpha_and &= alpha_value;

    }

    alpha += alpha_stride;

    dst += dst_stride;

  }

  // Combine the eight alpha 'and' into a 8-bit mask.

  alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));

  return (alpha_and != 0xff);

}

static void DispatchAlphaToGreen_SSE2(const uint8_t* alpha, int alpha_stride,

                                      int width, int height,

                                      uint32_t* dst, int dst_stride) {

  int i, j;

  const __m128i zero = _mm_setzero_si128();

  const int limit = width & ~15;

  for (j = 0; j < height; ++j) {

    for (i = 0; i < limit; i += 16) {   // process 16 alpha bytes

      const __m128i a0 = _mm_loadu_si128((const __m128i*)&alpha[i]);

      const __m128i a1 = _mm_unpacklo_epi8(zero, a0);  // note the 'zero' first!

      const __m128i b1 = _mm_unpackhi_epi8(zero, a0);

      const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);

      const __m128i b2_lo = _mm_unpacklo_epi16(b1, zero);

      const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);

      const __m128i b2_hi = _mm_unpackhi_epi16(b1, zero);

      _mm_storeu_si128((__m128i*)&dst[i +  0], a2_lo);

      _mm_storeu_si128((__m128i*)&dst[i +  4], a2_hi);

      _mm_storeu_si128((__m128i*)&dst[i +  8], b2_lo);

      _mm_storeu_si128((__m128i*)&dst[i + 12], b2_hi);

    }

    for (; i < width; ++i) dst[i] = alpha[i] << 8;

    alpha += alpha_stride;

    dst += dst_stride;

  }

}

static int ExtractAlpha_SSE2(const uint8_t* argb, int argb_stride,

                             int width, int height,

                             uint8_t* alpha, int alpha_stride) {

  // alpha_and stores an 'and' operation of all the alpha[] values. The final

  // value is not 0xff if any of the alpha[] is not equal to 0xff.

  uint32_t alpha_and = 0xff;

  int i, j;

  const __m128i a_mask = _mm_set1_epi32(0xffu);  // to preserve alpha

  const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);

  __m128i all_alphas = all_0xff;

  // We must be able to access 3 extra bytes after the last written byte

  // 'src[4 * width - 4]', because we don't know if alpha is the first or the

  // last byte of the quadruplet.

  const int limit = (width - 1) & ~7;

  for (j = 0; j < height; ++j) {

    const __m128i* src = (const __m128i*)argb;

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

      // load 32 argb bytes

      const __m128i a0 = _mm_loadu_si128(src + 0);

      const __m128i a1 = _mm_loadu_si128(src + 1);

      const __m128i b0 = _mm_and_si128(a0, a_mask);

      const __m128i b1 = _mm_and_si128(a1, a_mask);

      const __m128i c0 = _mm_packs_epi32(b0, b1);

      const __m128i d0 = _mm_packus_epi16(c0, c0);

      // store

      _mm_storel_epi64((__m128i*)&alpha[i], d0);

      // accumulate eight alpha 'and' in parallel

      all_alphas = _mm_and_si128(all_alphas, d0);

      src += 2;

    }

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

      const uint32_t alpha_value = argb[4 * i];

      alpha[i] = alpha_value;

      alpha_and &= alpha_value;

    }

    argb += argb_stride;

    alpha += alpha_stride;

  }

  // Combine the eight alpha 'and' into a 8-bit mask.

  alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));

  return (alpha_and == 0xff);

}

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

// Non-dither premultiplied modes

#define MULTIPLIER(a)   ((a) * 0x8081)

#define PREMULTIPLY(x, m) (((x) * (m)) >> 23)

// We can't use a 'const int' for the SHUFFLE value, because it has to be an

// immediate in the _mm_shufflexx_epi16() instruction. We really need a macro.

// We use: v / 255 = (v * 0x8081) >> 23, where v = alpha * {r,g,b} is a 16bit

// value.

#define APPLY_ALPHA(RGBX, SHUFFLE) do {                              \

  const __m128i argb0 = _mm_loadu_si128((const __m128i*)&(RGBX));    \

  const __m128i argb1_lo = _mm_unpacklo_epi8(argb0, zero);           \

  const __m128i argb1_hi = _mm_unpackhi_epi8(argb0, zero);           \

  const __m128i alpha0_lo = _mm_or_si128(argb1_lo, kMask);           \

  const __m128i alpha0_hi = _mm_or_si128(argb1_hi, kMask);           \

  const __m128i alpha1_lo = _mm_shufflelo_epi16(alpha0_lo, SHUFFLE); \

  const __m128i alpha1_hi = _mm_shufflelo_epi16(alpha0_hi, SHUFFLE); \

  const __m128i alpha2_lo = _mm_shufflehi_epi16(alpha1_lo, SHUFFLE); \

  const __m128i alpha2_hi = _mm_shufflehi_epi16(alpha1_hi, SHUFFLE); \

  /* alpha2 = [ff a0 a0 a0][ff a1 a1 a1] */                          \

  const __m128i A0_lo = _mm_mullo_epi16(alpha2_lo, argb1_lo);        \

  const __m128i A0_hi = _mm_mullo_epi16(alpha2_hi, argb1_hi);        \

  const __m128i A1_lo = _mm_mulhi_epu16(A0_lo, kMult);               \

  const __m128i A1_hi = _mm_mulhi_epu16(A0_hi, kMult);               \

  const __m128i A2_lo = _mm_srli_epi16(A1_lo, 7);                    \

  const __m128i A2_hi = _mm_srli_epi16(A1_hi, 7);                    \

  const __m128i A3 = _mm_packus_epi16(A2_lo, A2_hi);                 \

  _mm_storeu_si128((__m128i*)&(RGBX), A3);                           \

} while (0)

static void ApplyAlphaMultiply_SSE2(uint8_t* rgba, int alpha_first,

                                    int w, int h, int stride) {

  const __m128i zero = _mm_setzero_si128();

  const __m128i kMult = _mm_set1_epi16(0x8081u);

  const __m128i kMask = _mm_set_epi16(0, 0xff, 0xff, 0, 0, 0xff, 0xff, 0);

  const int kSpan = 4;

  while (h-- > 0) {

    uint32_t* const rgbx = (uint32_t*)rgba;

    int i;

    if (!alpha_first) {

      for (i = 0; i + kSpan <= w; i += kSpan) {

        APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(2, 3, 3, 3));

      }

    } else {

      for (i = 0; i + kSpan <= w; i += kSpan) {

        APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(0, 0, 0, 1));

      }

    }

    // Finish with left-overs.

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

      uint8_t* const rgb = rgba + (alpha_first ? 1 : 0);

      const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3);

      const uint32_t a = alpha[4 * i];

      if (a != 0xff) {

        const uint32_t mult = MULTIPLIER(a);

        rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult);

        rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult);

        rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult);

      }

    }

    rgba += stride;

  }

}

#undef MULTIPLIER

#undef PREMULTIPLY

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

// Alpha detection

static int HasAlpha8b_SSE2(const uint8_t* src, int length) {

  const __m128i all_0xff = _mm_set1_epi8(0xff);

  int i = 0;

  for (; i + 16 <= length; i += 16) {

    const __m128i v = _mm_loadu_si128((const __m128i*)(src + i));

    const __m128i bits = _mm_cmpeq_epi8(v, all_0xff);

    const int mask = _mm_movemask_epi8(bits);

    if (mask != 0xffff) return 1;

  }

  for (; i < length; ++i) if (src[i] != 0xff) return 1;

  return 0;

}

static int HasAlpha32b_SSE2(const uint8_t* src, int length) {

  const __m128i alpha_mask = _mm_set1_epi32(0xff);

  const __m128i all_0xff = _mm_set1_epi8(0xff);

  int i = 0;

  // We don't know if we can access the last 3 bytes after the last alpha

  // value 'src[4 * length - 4]' (because we don't know if alpha is the first

  // or the last byte of the quadruplet). Hence the '-3' protection below.

  length = length * 4 - 3;   // size in bytes

  for (; i + 64 <= length; i += 64) {

    const __m128i a0 = _mm_loadu_si128((const __m128i*)(src + i +  0));

    const __m128i a1 = _mm_loadu_si128((const __m128i*)(src + i + 16));

    const __m128i a2 = _mm_loadu_si128((const __m128i*)(src + i + 32));

    const __m128i a3 = _mm_loadu_si128((const __m128i*)(src + i + 48));

    const __m128i b0 = _mm_and_si128(a0, alpha_mask);

    const __m128i b1 = _mm_and_si128(a1, alpha_mask);

    const __m128i b2 = _mm_and_si128(a2, alpha_mask);

    const __m128i b3 = _mm_and_si128(a3, alpha_mask);

    const __m128i c0 = _mm_packs_epi32(b0, b1);

    const __m128i c1 = _mm_packs_epi32(b2, b3);

    const __m128i d  = _mm_packus_epi16(c0, c1);

    const __m128i bits = _mm_cmpeq_epi8(d, all_0xff);

    const int mask = _mm_movemask_epi8(bits);

    if (mask != 0xffff) return 1;

  }

  for (; i + 32 <= length; 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_and_si128(a0, alpha_mask);

    const __m128i b1 = _mm_and_si128(a1, alpha_mask);

    const __m128i c  = _mm_packs_epi32(b0, b1);

    const __m128i d  = _mm_packus_epi16(c, c);

    const __m128i bits = _mm_cmpeq_epi8(d, all_0xff);

    const int mask = _mm_movemask_epi8(bits);

    if (mask != 0xffff) return 1;

  }

  for (; i <= length; i += 4) if (src[i] != 0xff) return 1;

  return 0;

}

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

// Apply alpha value to rows

static void MultARGBRow_SSE2(uint32_t* const ptr, int width, int inverse) {

  int x = 0;

  if (!inverse) {

    const int kSpan = 2;

    const __m128i zero = _mm_setzero_si128();

    const __m128i k128 = _mm_set1_epi16(128);

    const __m128i kMult = _mm_set1_epi16(0x0101);

    const __m128i kMask = _mm_set_epi16(0, 0xff, 0, 0, 0, 0xff, 0, 0);

    for (x = 0; x + kSpan <= width; x += kSpan) {

      // To compute 'result = (int)(a * x / 255. + .5)', we use:

      //   tmp = a * v + 128, result = (tmp * 0x0101u) >> 16

      const __m128i A0 = _mm_loadl_epi64((const __m128i*)&ptr[x]);

      const __m128i A1 = _mm_unpacklo_epi8(A0, zero);

      const __m128i A2 = _mm_or_si128(A1, kMask);

      const __m128i A3 = _mm_shufflelo_epi16(A2, _MM_SHUFFLE(2, 3, 3, 3));

      const __m128i A4 = _mm_shufflehi_epi16(A3, _MM_SHUFFLE(2, 3, 3, 3));

      // here, A4 = [ff a0 a0 a0][ff a1 a1 a1]

      const __m128i A5 = _mm_mullo_epi16(A4, A1);

      const __m128i A6 = _mm_add_epi16(A5, k128);

      const __m128i A7 = _mm_mulhi_epu16(A6, kMult);

      const __m128i A10 = _mm_packus_epi16(A7, zero);

      _mm_storel_epi64((__m128i*)&ptr[x], A10);

    }

  }

  width -= x;

  if (width > 0) WebPMultARGBRow_C(ptr + x, width, inverse);

}

static void MultRow_SSE2(uint8_t* const ptr, const uint8_t* const alpha,

                         int width, int inverse) {

  int x = 0;

  if (!inverse) {

    const __m128i zero = _mm_setzero_si128();

    const __m128i k128 = _mm_set1_epi16(128);

    const __m128i kMult = _mm_set1_epi16(0x0101);

    for (x = 0; x + 8 <= width; x += 8) {

      const __m128i v0 = _mm_loadl_epi64((__m128i*)&ptr[x]);

      const __m128i a0 = _mm_loadl_epi64((const __m128i*)&alpha[x]);

      const __m128i v1 = _mm_unpacklo_epi8(v0, zero);

      const __m128i a1 = _mm_unpacklo_epi8(a0, zero);

      const __m128i v2 = _mm_mullo_epi16(v1, a1);

      const __m128i v3 = _mm_add_epi16(v2, k128);

      const __m128i v4 = _mm_mulhi_epu16(v3, kMult);

      const __m128i v5 = _mm_packus_epi16(v4, zero);

      _mm_storel_epi64((__m128i*)&ptr[x], v5);

    }

  }

  width -= x;

  if (width > 0) WebPMultRow_C(ptr + x, alpha + x, width, inverse);

}

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

// Entry point

extern void WebPInitAlphaProcessingSSE2(void);

WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingSSE2(void) {

  WebPMultARGBRow = MultARGBRow_SSE2;

  WebPMultRow = MultRow_SSE2;

  WebPApplyAlphaMultiply = ApplyAlphaMultiply_SSE2;

  WebPDispatchAlpha = DispatchAlpha_SSE2;

  WebPDispatchAlphaToGreen = DispatchAlphaToGreen_SSE2;

  WebPExtractAlpha = ExtractAlpha_SSE2;

  WebPHasAlpha8b = HasAlpha8b_SSE2;

  WebPHasAlpha32b = HasAlpha32b_SSE2;

}

#else  // !WEBP_USE_SSE2

WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingSSE2)

#endif  // WEBP_USE_SSE2