/src/libwebp/src/dsp/lossless.c

Source
// Copyright 2012 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.
// -----------------------------------------------------------------------------
//
// Image transforms and color space conversion methods for lossless decoder.
//
// Authors: Vikas Arora (vikaas.arora@gmail.com)
//          Jyrki Alakuijala (jyrki@google.com)
//          Urvang Joshi (urvang@google.com)

#include "src/dsp/lossless.h"

#include <assert.h>
#include <stdlib.h>
#include <string.h>

#include "src/dec/vp8li_dec.h"
#include "src/dsp/cpu.h"
#include "src/dsp/dsp.h"
#include "src/dsp/lossless_common.h"
#include "src/utils/endian_inl_utils.h"
#include "src/utils/utils.h"
#include "src/webp/decode.h"
#include "src/webp/format_constants.h"
#include "src/webp/types.h"

//------------------------------------------------------------------------------
// Image transforms.

static WEBP_INLINE uint32_t Average2(uint32_t a0, uint32_t a1) {
  return (((a0 ^ a1) & 0xfefefefeu) >> 1) + (a0 & a1);
}

static WEBP_INLINE uint32_t Average3(uint32_t a0, uint32_t a1, uint32_t a2) {
  return Average2(Average2(a0, a2), a1);
}

static WEBP_INLINE uint32_t Average4(uint32_t a0, uint32_t a1, uint32_t a2,
                                     uint32_t a3) {
  return Average2(Average2(a0, a1), Average2(a2, a3));
}

static WEBP_INLINE uint32_t Clip255(uint32_t a) {
  if (a < 256) {
    return a;
  }
  // return 0, when a is a negative integer.
  // return 255, when a is positive.
  return ~a >> 24;
}

static WEBP_INLINE int AddSubtractComponentFull(int a, int b, int c) {
  return Clip255((uint32_t)(a + b - c));
}

static WEBP_INLINE uint32_t ClampedAddSubtractFull(uint32_t c0, uint32_t c1,
                                                   uint32_t c2) {
  const int a = AddSubtractComponentFull(c0 >> 24, c1 >> 24, c2 >> 24);
  const int r = AddSubtractComponentFull((c0 >> 16) & 0xff, (c1 >> 16) & 0xff,
                                         (c2 >> 16) & 0xff);
  const int g = AddSubtractComponentFull((c0 >> 8) & 0xff, (c1 >> 8) & 0xff,
                                         (c2 >> 8) & 0xff);
  const int b = AddSubtractComponentFull(c0 & 0xff, c1 & 0xff, c2 & 0xff);
  return ((uint32_t)a << 24) | (r << 16) | (g << 8) | b;
}

static WEBP_INLINE int AddSubtractComponentHalf(int a, int b) {
  return Clip255((uint32_t)(a + (a - b) / 2));
}

static WEBP_INLINE uint32_t ClampedAddSubtractHalf(uint32_t c0, uint32_t c1,
                                                   uint32_t c2) {
  const uint32_t ave = Average2(c0, c1);
  const int a = AddSubtractComponentHalf(ave >> 24, c2 >> 24);
  const int r = AddSubtractComponentHalf((ave >> 16) & 0xff, (c2 >> 16) & 0xff);
  const int g = AddSubtractComponentHalf((ave >> 8) & 0xff, (c2 >> 8) & 0xff);
  const int b = AddSubtractComponentHalf((ave >> 0) & 0xff, (c2 >> 0) & 0xff);
  return ((uint32_t)a << 24) | (r << 16) | (g << 8) | b;
}

// gcc <= 4.9 on ARM generates incorrect code in Select() when Sub3() is
// inlined.
#if defined(__arm__) && defined(__GNUC__) && LOCAL_GCC_VERSION <= 0x409
#define LOCAL_INLINE __attribute__((noinline))
#else
#define LOCAL_INLINE WEBP_INLINE
#endif

static LOCAL_INLINE int Sub3(int a, int b, int c) {
  const int pb = b - c;
  const int pa = a - c;
  return abs(pb) - abs(pa);
}

#undef LOCAL_INLINE

static WEBP_INLINE uint32_t Select(uint32_t a, uint32_t b, uint32_t c) {
  const int pa_minus_pb =
      Sub3((a >> 24), (b >> 24), (c >> 24)) +
      Sub3((a >> 16) & 0xff, (b >> 16) & 0xff, (c >> 16) & 0xff) +
      Sub3((a >> 8) & 0xff, (b >> 8) & 0xff, (c >> 8) & 0xff) +
      Sub3((a) & 0xff, (b) & 0xff, (c) & 0xff);
  return (pa_minus_pb <= 0) ? a : b;
}

//------------------------------------------------------------------------------
// Predictors

static uint32_t VP8LPredictor0_C(const uint32_t* const left,
                                 const uint32_t* const top) {
  (void)top;
  (void)left;
  return ARGB_BLACK;
}
static uint32_t VP8LPredictor1_C(const uint32_t* const left,
                                 const uint32_t* const top) {
  (void)top;
  return *left;
}
uint32_t VP8LPredictor2_C(const uint32_t* const left,
                          const uint32_t* const top) {
  (void)left;
  return top[0];
}
uint32_t VP8LPredictor3_C(const uint32_t* const left,
                          const uint32_t* const top) {
  (void)left;
  return top[1];
}
uint32_t VP8LPredictor4_C(const uint32_t* const left,
                          const uint32_t* const top) {
  (void)left;
  return top[-1];
}
uint32_t VP8LPredictor5_C(const uint32_t* const left,
                          const uint32_t* const top) {
  const uint32_t pred = Average3(*left, top[0], top[1]);
  return pred;
}
uint32_t VP8LPredictor6_C(const uint32_t* const left,
                          const uint32_t* const top) {
  const uint32_t pred = Average2(*left, top[-1]);
  return pred;
}
uint32_t VP8LPredictor7_C(const uint32_t* const left,
                          const uint32_t* const top) {
  const uint32_t pred = Average2(*left, top[0]);
  return pred;
}
uint32_t VP8LPredictor8_C(const uint32_t* const left,
                          const uint32_t* const top) {
  const uint32_t pred = Average2(top[-1], top[0]);
  (void)left;
  return pred;
}
uint32_t VP8LPredictor9_C(const uint32_t* const left,
                          const uint32_t* const top) {
  const uint32_t pred = Average2(top[0], top[1]);
  (void)left;
  return pred;
}
uint32_t VP8LPredictor10_C(const uint32_t* const left,
                           const uint32_t* const top) {
  const uint32_t pred = Average4(*left, top[-1], top[0], top[1]);
  return pred;
}
uint32_t VP8LPredictor11_C(const uint32_t* const left,
                           const uint32_t* const top) {
  const uint32_t pred = Select(top[0], *left, top[-1]);
  return pred;
}
uint32_t VP8LPredictor12_C(const uint32_t* const left,
                           const uint32_t* const top) {
  const uint32_t pred = ClampedAddSubtractFull(*left, top[0], top[-1]);
  return pred;
}
uint32_t VP8LPredictor13_C(const uint32_t* const left,
                           const uint32_t* const top) {
  const uint32_t pred = ClampedAddSubtractHalf(*left, top[0], top[-1]);
  return pred;
}

static void PredictorAdd0_C(const uint32_t* in, const uint32_t* upper,
                            int num_pixels, uint32_t* WEBP_RESTRICT out) {
  int x;
  (void)upper;
  for (x = 0; x < num_pixels; ++x) out[x] = VP8LAddPixels(in[x], ARGB_BLACK);
}
static void PredictorAdd1_C(const uint32_t* in, const uint32_t* upper,
                            int num_pixels, uint32_t* WEBP_RESTRICT out) {
  int i;
  uint32_t left = out[-1];
  (void)upper;
  for (i = 0; i < num_pixels; ++i) {
    out[i] = left = VP8LAddPixels(in[i], left);
  }
}
GENERATE_PREDICTOR_ADD(VP8LPredictor2_C, PredictorAdd2_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor3_C, PredictorAdd3_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor4_C, PredictorAdd4_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor5_C, PredictorAdd5_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor6_C, PredictorAdd6_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor7_C, PredictorAdd7_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor8_C, PredictorAdd8_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor9_C, PredictorAdd9_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor10_C, PredictorAdd10_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor11_C, PredictorAdd11_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor12_C, PredictorAdd12_C)
GENERATE_PREDICTOR_ADD(VP8LPredictor13_C, PredictorAdd13_C)

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

// Inverse prediction.
static void PredictorInverseTransform_C(const VP8LTransform* const transform,
                                        int y_start, int y_end,
                                        const uint32_t* in, uint32_t* out) {
  const int width = transform->xsize;
  if (y_start == 0) {  // First Row follows the L (mode=1) mode.
    PredictorAdd0_C(in, NULL, 1, out);
    PredictorAdd1_C(in + 1, NULL, width - 1, out + 1);
    in += width;
    out += width;
    ++y_start;
  }

  {
    int y = y_start;
    const int tile_width = 1 << transform->bits;
    const int mask = tile_width - 1;
    const int tiles_per_row = VP8LSubSampleSize(width, transform->bits);
    const uint32_t* pred_mode_base =
        transform->data + (y >> transform->bits) * tiles_per_row;

    while (y < y_end) {
      const uint32_t* pred_mode_src = pred_mode_base;
      int x = 1;
      // First pixel follows the T (mode=2) mode.
      PredictorAdd2_C(in, out - width, 1, out);
      // .. the rest:
      while (x < width) {
        const VP8LPredictorAddSubFunc pred_func =
            VP8LPredictorsAdd[((*pred_mode_src++) >> 8) & 0xf];
        int x_end = (x & ~mask) + tile_width;
        if (x_end > width) x_end = width;
        pred_func(in + x, out + x - width, x_end - x, out + x);
        x = x_end;
      }
      in += width;
      out += width;
      ++y;
      if ((y & mask) == 0) {  // Use the same mask, since tiles are squares.
        pred_mode_base += tiles_per_row;
      }
    }
  }
}

// Add green to blue and red channels (i.e. perform the inverse transform of
// 'subtract green').
void VP8LAddGreenToBlueAndRed_C(const uint32_t* src, int num_pixels,
                                uint32_t* dst) {
  int i;
  for (i = 0; i < num_pixels; ++i) {
    const uint32_t argb = src[i];
    const uint32_t green = ((argb >> 8) & 0xff);
    uint32_t red_blue = (argb & 0x00ff00ffu);
    red_blue += (green << 16) | green;
    red_blue &= 0x00ff00ffu;
    dst[i] = (argb & 0xff00ff00u) | red_blue;
  }
}

static WEBP_INLINE int ColorTransformDelta(int8_t color_pred, int8_t color) {
  return ((int)color_pred * color) >> 5;
}

static WEBP_INLINE void ColorCodeToMultipliers(uint32_t color_code,
                                               VP8LMultipliers* const m) {
  m->green_to_red = (color_code >> 0) & 0xff;
  m->green_to_blue = (color_code >> 8) & 0xff;
  m->red_to_blue = (color_code >> 16) & 0xff;
}

void VP8LTransformColorInverse_C(const VP8LMultipliers* const m,
                                 const uint32_t* src, int num_pixels,
                                 uint32_t* dst) {
  int i;
  for (i = 0; i < num_pixels; ++i) {
    const uint32_t argb = src[i];
    const int8_t green = (int8_t)(argb >> 8);
    const uint32_t red = argb >> 16;
    int new_red = red & 0xff;
    int new_blue = argb & 0xff;
    new_red += ColorTransformDelta((int8_t)m->green_to_red, green);
    new_red &= 0xff;
    new_blue += ColorTransformDelta((int8_t)m->green_to_blue, green);
    new_blue += ColorTransformDelta((int8_t)m->red_to_blue, (int8_t)new_red);
    new_blue &= 0xff;
    dst[i] = (argb & 0xff00ff00u) | (new_red << 16) | (new_blue);
  }
}

// Color space inverse transform.
static void ColorSpaceInverseTransform_C(const VP8LTransform* const transform,
                                         int y_start, int y_end,
                                         const uint32_t* src, uint32_t* dst) {
  const int width = transform->xsize;
  const int tile_width = 1 << transform->bits;
  const int mask = tile_width - 1;
  const int safe_width = width & ~mask;
  const int remaining_width = width - safe_width;
  const int tiles_per_row = VP8LSubSampleSize(width, transform->bits);
  int y = y_start;
  const uint32_t* pred_row =
      transform->data + (y >> transform->bits) * tiles_per_row;

  while (y < y_end) {
    const uint32_t* pred = pred_row;
    VP8LMultipliers m = {0, 0, 0};
    const uint32_t* const src_safe_end = src + safe_width;
    const uint32_t* const src_end = src + width;
    while (src < src_safe_end) {
      ColorCodeToMultipliers(*pred++, &m);
      VP8LTransformColorInverse(&m, src, tile_width, dst);
      src += tile_width;
      dst += tile_width;
    }
    if (src < src_end) {  // Left-overs using C-version.
      ColorCodeToMultipliers(*pred++, &m);
      VP8LTransformColorInverse(&m, src, remaining_width, dst);
      src += remaining_width;
      dst += remaining_width;
    }
    ++y;
    if ((y & mask) == 0) pred_row += tiles_per_row;
  }
}

// Separate out pixels packed together using pixel-bundling.
// We define two methods for ARGB data (uint32_t) and alpha-only data (uint8_t).
// clang-format off
#define COLOR_INDEX_INVERSE(FUNC_NAME, F_NAME, STATIC_DECL, TYPE, BIT_SUFFIX,  \
                            GET_INDEX, GET_VALUE)                              \
static void F_NAME(const TYPE* src, const uint32_t* const color_map,           \
                   TYPE* dst, int y_start, int y_end, int width) {             \
  int y;                                                                       \
  for (y = y_start; y < y_end; ++y) {                                          \
    int x;                                                                     \
    for (x = 0; x < width; ++x) {                                              \
      *dst++ = GET_VALUE(color_map[GET_INDEX(*src++)]);                        \
    }                                                                          \
  }                                                                            \
}                                                                              \
STATIC_DECL void FUNC_NAME(const VP8LTransform* const transform,               \
                           int y_start, int y_end, const TYPE* src,            \
                           TYPE* dst) {                                        \
  int y;                                                                       \
  const int bits_per_pixel = 8 >> transform->bits;                             \
  const int width = transform->xsize;                                          \
  const uint32_t* const color_map = transform->data;                           \
  if (bits_per_pixel < 8) {                                                    \
    const int pixels_per_byte = 1 << transform->bits;                          \
    const uint32_t bit_mask = (1 << bits_per_pixel) - 1;                       \
    for (y = y_start; y < y_end; ++y) {                                        \
      int x;                                                                   \
      for (x = 0; x + pixels_per_byte <= width; x += pixels_per_byte) {        \
        uint32_t packed = GET_INDEX(*src++);                                   \
        if (bits_per_pixel == 1) {                                             \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
          packed >>= 1;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 1]);                           \
        } else if (bits_per_pixel == 2) {                                      \
          *dst++ = GET_VALUE(color_map[packed & 3]);                           \
          packed >>= 2;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 3]);                           \
          packed >>= 2;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 3]);                           \
          packed >>= 2;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 3]);                           \
        } else {                                                               \
          *dst++ = GET_VALUE(color_map[packed & 15]);                          \
          packed >>= 4;                                                        \
          *dst++ = GET_VALUE(color_map[packed & 15]);                          \
        }                                                                      \
      }                                                                        \
      if (x < width) {                                                         \
        uint32_t packed = GET_INDEX(*src++);                                   \
        for (; x < width; ++x) {                                               \
          *dst++ = GET_VALUE(color_map[packed & bit_mask]);                    \
          packed >>= bits_per_pixel;                                           \
        }                                                                      \
      }                                                                        \
    }                                                                          \
  } else {                                                                     \
    VP8LMapColor##BIT_SUFFIX(src, color_map, dst, y_start, y_end, width);      \
  }                                                                            \
}
// clang-format on

COLOR_INDEX_INVERSE(ColorIndexInverseTransform_C, MapARGB_C, static, uint32_t,
                    32b, VP8GetARGBIndex, VP8GetARGBValue)
COLOR_INDEX_INVERSE(VP8LColorIndexInverseTransformAlpha, MapAlpha_C, , uint8_t,
                    8b, VP8GetAlphaIndex, VP8GetAlphaValue)

#undef COLOR_INDEX_INVERSE

void VP8LInverseTransform(const VP8LTransform* const transform, int row_start,
                          int row_end, const uint32_t* const in,
                          uint32_t* const out) {
  const int width = transform->xsize;
  assert(row_start < row_end);
  assert(row_end <= transform->ysize);
  switch (transform->type) {
    case SUBTRACT_GREEN_TRANSFORM:
      VP8LAddGreenToBlueAndRed(in, (row_end - row_start) * width, out);
      break;
    case PREDICTOR_TRANSFORM:
      PredictorInverseTransform_C(transform, row_start, row_end, in, out);
      if (row_end != transform->ysize) {
        // The last predicted row in this iteration will be the top-pred row
        // for the first row in next iteration.
        memcpy(out - width, out + (row_end - row_start - 1) * width,
               width * sizeof(*out));
      }
      break;
    case CROSS_COLOR_TRANSFORM:
      ColorSpaceInverseTransform_C(transform, row_start, row_end, in, out);
      break;
    case COLOR_INDEXING_TRANSFORM:
      if (in == out && transform->bits > 0) {
        // Move packed pixels to the end of unpacked region, so that unpacking
        // can occur seamlessly.
        // Also, note that this is the only transform that applies on
        // the effective width of VP8LSubSampleSize(xsize, bits). All other
        // transforms work on effective width of 'xsize'.
        const int out_stride = (row_end - row_start) * width;
        const int in_stride =
            (row_end - row_start) *
            VP8LSubSampleSize(transform->xsize, transform->bits);
        uint32_t* const src = out + out_stride - in_stride;
        memmove(src, out, in_stride * sizeof(*src));
        ColorIndexInverseTransform_C(transform, row_start, row_end, src, out);
      } else {
        ColorIndexInverseTransform_C(transform, row_start, row_end, in, out);
      }
      break;
  }
}

//------------------------------------------------------------------------------
// Color space conversion.

static int is_big_endian(void) {
  static const union {
    uint16_t w;
    uint8_t b[2];
  } tmp = {1};
  return (tmp.b[0] != 1);
}

void VP8LConvertBGRAToRGB_C(const uint32_t* WEBP_RESTRICT src, int num_pixels,
                            uint8_t* WEBP_RESTRICT dst) {
  const uint32_t* const src_end = src + num_pixels;
  while (src < src_end) {
    const uint32_t argb = *src++;
    *dst++ = (argb >> 16) & 0xff;
    *dst++ = (argb >> 8) & 0xff;
    *dst++ = (argb >> 0) & 0xff;
  }
}

void VP8LConvertBGRAToRGBA_C(const uint32_t* WEBP_RESTRICT src, int num_pixels,
                             uint8_t* WEBP_RESTRICT dst) {
  const uint32_t* const src_end = src + num_pixels;
  while (src < src_end) {
    const uint32_t argb = *src++;
    *dst++ = (argb >> 16) & 0xff;
    *dst++ = (argb >> 8) & 0xff;
    *dst++ = (argb >> 0) & 0xff;
    *dst++ = (argb >> 24) & 0xff;
  }
}

void VP8LConvertBGRAToRGBA4444_C(const uint32_t* WEBP_RESTRICT src,
                                 int num_pixels, uint8_t* WEBP_RESTRICT dst) {
  const uint32_t* const src_end = src + num_pixels;
  while (src < src_end) {
    const uint32_t argb = *src++;
    const uint8_t rg = ((argb >> 16) & 0xf0) | ((argb >> 12) & 0xf);
    const uint8_t ba = ((argb >> 0) & 0xf0) | ((argb >> 28) & 0xf);
#if (WEBP_SWAP_16BIT_CSP == 1)
    *dst++ = ba;
    *dst++ = rg;
#else
    *dst++ = rg;
    *dst++ = ba;
#endif
  }
}

void VP8LConvertBGRAToRGB565_C(const uint32_t* WEBP_RESTRICT src,
                               int num_pixels, uint8_t* WEBP_RESTRICT dst) {
  const uint32_t* const src_end = src + num_pixels;
  while (src < src_end) {
    const uint32_t argb = *src++;
    const uint8_t rg = ((argb >> 16) & 0xf8) | ((argb >> 13) & 0x7);
    const uint8_t gb = ((argb >> 5) & 0xe0) | ((argb >> 3) & 0x1f);
#if (WEBP_SWAP_16BIT_CSP == 1)
    *dst++ = gb;
    *dst++ = rg;
#else
    *dst++ = rg;
    *dst++ = gb;
#endif
  }
}

void VP8LConvertBGRAToBGR_C(const uint32_t* WEBP_RESTRICT src, int num_pixels,
                            uint8_t* WEBP_RESTRICT dst) {
  const uint32_t* const src_end = src + num_pixels;
  while (src < src_end) {
    const uint32_t argb = *src++;
    *dst++ = (argb >> 0) & 0xff;
    *dst++ = (argb >> 8) & 0xff;
    *dst++ = (argb >> 16) & 0xff;
  }
}

static void CopyOrSwap(const uint32_t* WEBP_RESTRICT src, int num_pixels,
                       uint8_t* WEBP_RESTRICT dst, int swap_on_big_endian) {
  if (is_big_endian() == swap_on_big_endian) {
    const uint32_t* const src_end = src + num_pixels;
    while (src < src_end) {
      const uint32_t argb = *src++;
      WebPUint32ToMem(dst, BSwap32(argb));
      dst += sizeof(argb);
    }
  } else {
    memcpy(dst, src, num_pixels * sizeof(*src));
  }
}

void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels,
                         WEBP_CSP_MODE out_colorspace, uint8_t* const rgba) {
  switch (out_colorspace) {
    case MODE_RGB:
      VP8LConvertBGRAToRGB(in_data, num_pixels, rgba);
      break;
    case MODE_RGBA:
      VP8LConvertBGRAToRGBA(in_data, num_pixels, rgba);
      break;
    case MODE_rgbA:
      VP8LConvertBGRAToRGBA(in_data, num_pixels, rgba);
      WebPApplyAlphaMultiply(rgba, 0, num_pixels, 1, 0);
      break;
    case MODE_BGR:
      VP8LConvertBGRAToBGR(in_data, num_pixels, rgba);
      break;
    case MODE_BGRA:
      CopyOrSwap(in_data, num_pixels, rgba, 1);
      break;
    case MODE_bgrA:
      CopyOrSwap(in_data, num_pixels, rgba, 1);
      WebPApplyAlphaMultiply(rgba, 0, num_pixels, 1, 0);
      break;
    case MODE_ARGB:
      CopyOrSwap(in_data, num_pixels, rgba, 0);
      break;
    case MODE_Argb:
      CopyOrSwap(in_data, num_pixels, rgba, 0);
      WebPApplyAlphaMultiply(rgba, 1, num_pixels, 1, 0);
      break;
    case MODE_RGBA_4444:
      VP8LConvertBGRAToRGBA4444(in_data, num_pixels, rgba);
      break;
    case MODE_rgbA_4444:
      VP8LConvertBGRAToRGBA4444(in_data, num_pixels, rgba);
      WebPApplyAlphaMultiply4444(rgba, num_pixels, 1, 0);
      break;
    case MODE_RGB_565:
      VP8LConvertBGRAToRGB565(in_data, num_pixels, rgba);
      break;
    default:
      assert(0);  // Code flow should not reach here.
  }
}

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

VP8LProcessDecBlueAndRedFunc VP8LAddGreenToBlueAndRed;
VP8LProcessDecBlueAndRedFunc VP8LAddGreenToBlueAndRed_SSE;
VP8LPredictorAddSubFunc VP8LPredictorsAdd[16];
VP8LPredictorAddSubFunc VP8LPredictorsAdd_SSE[16];
VP8LPredictorFunc VP8LPredictors[16];

// exposed plain-C implementations
VP8LPredictorAddSubFunc VP8LPredictorsAdd_C[16];

VP8LTransformColorInverseFunc VP8LTransformColorInverse;
VP8LTransformColorInverseFunc VP8LTransformColorInverse_SSE;

VP8LConvertFunc VP8LConvertBGRAToRGB;
VP8LConvertFunc VP8LConvertBGRAToRGB_SSE;
VP8LConvertFunc VP8LConvertBGRAToRGBA;
VP8LConvertFunc VP8LConvertBGRAToRGBA_SSE;
VP8LConvertFunc VP8LConvertBGRAToRGBA4444;
VP8LConvertFunc VP8LConvertBGRAToRGB565;
VP8LConvertFunc VP8LConvertBGRAToBGR;
VP8LConvertFunc VP8LConvertBGRAToBGR_SSE;

VP8LMapARGBFunc VP8LMapColor32b;
VP8LMapAlphaFunc VP8LMapColor8b;

extern VP8CPUInfo VP8GetCPUInfo;
extern void VP8LDspInitSSE2(void);
extern void VP8LDspInitSSE41(void);
extern void VP8LDspInitAVX2(void);
extern void VP8LDspInitNEON(void);
extern void VP8LDspInitMIPSdspR2(void);
extern void VP8LDspInitMSA(void);

#define COPY_PREDICTOR_ARRAY(IN, OUT)                       \
  do {                                                      \
    (OUT)[0] = IN##0_C;                                     \
    (OUT)[1] = IN##1_C;                                     \
    (OUT)[2] = IN##2_C;                                     \
    (OUT)[3] = IN##3_C;                                     \
    (OUT)[4] = IN##4_C;                                     \
    (OUT)[5] = IN##5_C;                                     \
    (OUT)[6] = IN##6_C;                                     \
    (OUT)[7] = IN##7_C;                                     \
    (OUT)[8] = IN##8_C;                                     \
    (OUT)[9] = IN##9_C;                                     \
    (OUT)[10] = IN##10_C;                                   \
    (OUT)[11] = IN##11_C;                                   \
    (OUT)[12] = IN##12_C;                                   \
    (OUT)[13] = IN##13_C;                                   \
    (OUT)[14] = IN##0_C; /* <- padding security sentinels*/ \
    (OUT)[15] = IN##0_C;                                    \
  } while (0);

WEBP_DSP_INIT_FUNC(VP8LDspInit) {
  COPY_PREDICTOR_ARRAY(VP8LPredictor, VP8LPredictors)
  COPY_PREDICTOR_ARRAY(PredictorAdd, VP8LPredictorsAdd)
  COPY_PREDICTOR_ARRAY(PredictorAdd, VP8LPredictorsAdd_C)

#if !WEBP_NEON_OMIT_C_CODE
  VP8LAddGreenToBlueAndRed = VP8LAddGreenToBlueAndRed_C;

  VP8LTransformColorInverse = VP8LTransformColorInverse_C;

  VP8LConvertBGRAToRGBA = VP8LConvertBGRAToRGBA_C;
  VP8LConvertBGRAToRGB = VP8LConvertBGRAToRGB_C;
  VP8LConvertBGRAToBGR = VP8LConvertBGRAToBGR_C;
#endif

  VP8LConvertBGRAToRGBA4444 = VP8LConvertBGRAToRGBA4444_C;
  VP8LConvertBGRAToRGB565 = VP8LConvertBGRAToRGB565_C;

  VP8LMapColor32b = MapARGB_C;
  VP8LMapColor8b = MapAlpha_C;

  // If defined, use CPUInfo() to overwrite some pointers with faster versions.
  if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_HAVE_SSE2)
    if (VP8GetCPUInfo(kSSE2)) {
      VP8LDspInitSSE2();
#if defined(WEBP_HAVE_SSE41)
      if (VP8GetCPUInfo(kSSE4_1)) {
        VP8LDspInitSSE41();
#if defined(WEBP_HAVE_AVX2)
        if (VP8GetCPUInfo(kAVX2)) {
          VP8LDspInitAVX2();
        }
#endif
      }
#endif
    }
#endif
#if defined(WEBP_USE_MIPS_DSP_R2)
    if (VP8GetCPUInfo(kMIPSdspR2)) {
      VP8LDspInitMIPSdspR2();
    }
#endif
#if defined(WEBP_USE_MSA)
    if (VP8GetCPUInfo(kMSA)) {
      VP8LDspInitMSA();
    }
#endif
  }

#if defined(WEBP_HAVE_NEON)
  if (WEBP_NEON_OMIT_C_CODE ||
      (VP8GetCPUInfo != NULL && VP8GetCPUInfo(kNEON))) {
    VP8LDspInitNEON();
  }
#endif

  assert(VP8LAddGreenToBlueAndRed != NULL);
  assert(VP8LTransformColorInverse != NULL);
  assert(VP8LConvertBGRAToRGBA != NULL);
  assert(VP8LConvertBGRAToRGB != NULL);
  assert(VP8LConvertBGRAToBGR != NULL);
  assert(VP8LConvertBGRAToRGBA4444 != NULL);
  assert(VP8LConvertBGRAToRGB565 != NULL);
  assert(VP8LMapColor32b != NULL);
  assert(VP8LMapColor8b != NULL);
}
#undef COPY_PREDICTOR_ARRAY

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

Coverage Report

Created: 2026-11-12 07:35