// Copyright 2018 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.

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

#ifndef WEBP_DSP_QUANT_H_

#define WEBP_DSP_QUANT_H_

#include <string.h>

#include "src/dsp/dsp.h"

#include "src/webp/types.h"

#if defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) && \

    !defined(WEBP_HAVE_NEON_RTCD)

#include <arm_neon.h>

#define IsFlat IsFlat_NEON

static uint32_t horizontal_add_uint32x4(const uint32x4_t a) {

#if WEBP_AARCH64

  return vaddvq_u32(a);

#else

  const uint64x2_t b = vpaddlq_u32(a);

  const uint32x2_t c = vadd_u32(vreinterpret_u32_u64(vget_low_u64(b)),

                                vreinterpret_u32_u64(vget_high_u64(b)));

  return vget_lane_u32(c, 0);

#endif

}

static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,

                              int thresh) {

  const int16x8_t tst_ones = vdupq_n_s16(-1);

  uint32x4_t sum = vdupq_n_u32(0);

  int i;

  for (i = 0; i < num_blocks; ++i) {

    // Set DC to zero.

    const int16x8_t a_0 = vsetq_lane_s16(0, vld1q_s16(levels), 0);

    const int16x8_t a_1 = vld1q_s16(levels + 8);

    const uint16x8_t b_0 = vshrq_n_u16(vtstq_s16(a_0, tst_ones), 15);

    const uint16x8_t b_1 = vshrq_n_u16(vtstq_s16(a_1, tst_ones), 15);

    sum = vpadalq_u16(sum, b_0);

    sum = vpadalq_u16(sum, b_1);

    levels += 16;

  }

  return thresh >= (int)horizontal_add_uint32x4(sum);

}

#else

#define IsFlat IsFlat_C

static WEBP_INLINE int IsFlat(const int16_t* levels, int num_blocks,

                              int thresh) {

  int score = 0;

  while (num_blocks-- > 0) {      // TODO(skal): refine positional scoring?

    int i;

    for (i = 1; i < 16; ++i) {    // omit DC, we're only interested in AC

      score += (levels[i] != 0);

      if (score > thresh) return 0;

    }

    levels += 16;

  }

  return 1;

}

#endif  // defined(WEBP_USE_NEON) && !defined(WEBP_ANDROID_NEON) &&

        // !defined(WEBP_HAVE_NEON_RTCD)

static WEBP_INLINE int IsFlatSource16(const uint8_t* src) {

  const uint32_t v = src[0] * 0x01010101u;

  int i;

  for (i = 0; i < 16; ++i) {

    if (memcmp(src + 0, &v, 4) || memcmp(src +  4, &v, 4) ||

        memcmp(src + 8, &v, 4) || memcmp(src + 12, &v, 4)) {

      return 0;

    }

    src += BPS;

  }

  return 1;

}

#endif  // WEBP_DSP_QUANT_H_