/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE 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.
 */


#include "variance.h"
#include "vp8/common/filter.h"


unsigned int vp8_get_mb_ss_c
(
  const short *src_ptr
) {
  unsigned int i = 0, sum = 0;

  do {
    sum += (src_ptr[i] * src_ptr[i]);
    i++;
  } while (i < 256);

  return sum;
}


static void variance(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  int  w,
  int  h,
  unsigned int *sse,
  int *sum) {
  int i, j;
  int diff;

  *sum = 0;
  *sse = 0;

  for (i = 0; i < h; i++) {
    for (j = 0; j < w; j++) {
      diff = src_ptr[j] - ref_ptr[j];
      *sum += diff;
      *sse += diff * diff;
    }

    src_ptr += source_stride;
    ref_ptr += recon_stride;
  }
}

#if CONFIG_SUPERBLOCKS
unsigned int vp8_variance32x32_c(const unsigned char *src_ptr,
                                 int  source_stride,
                                 const unsigned char *ref_ptr,
                                 int  recon_stride,
                                 unsigned int *sse) {
  unsigned int var;
  int avg;

  variance(src_ptr, source_stride, ref_ptr, recon_stride, 32, 32, &var, &avg);
  *sse = var;
  return (var - ((avg * avg) >> 10));
}
#endif

unsigned int vp8_variance16x16_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  unsigned int var;
  int avg;


  variance(src_ptr, source_stride, ref_ptr, recon_stride, 16, 16, &var, &avg);
  *sse = var;
  return (var - ((avg * avg) >> 8));
}

unsigned int vp8_variance8x16_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  unsigned int var;
  int avg;


  variance(src_ptr, source_stride, ref_ptr, recon_stride, 8, 16, &var, &avg);
  *sse = var;
  return (var - ((avg * avg) >> 7));
}

unsigned int vp8_variance16x8_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  unsigned int var;
  int avg;


  variance(src_ptr, source_stride, ref_ptr, recon_stride, 16, 8, &var, &avg);
  *sse = var;
  return (var - ((avg * avg) >> 7));
}


unsigned int vp8_variance8x8_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  unsigned int var;
  int avg;


  variance(src_ptr, source_stride, ref_ptr, recon_stride, 8, 8, &var, &avg);
  *sse = var;
  return (var - ((avg * avg) >> 6));
}

unsigned int vp8_variance4x4_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  unsigned int var;
  int avg;


  variance(src_ptr, source_stride, ref_ptr, recon_stride, 4, 4, &var, &avg);
  *sse = var;
  return (var - ((avg * avg) >> 4));
}


unsigned int vp8_mse16x16_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  unsigned int var;
  int avg;

  variance(src_ptr, source_stride, ref_ptr, recon_stride, 16, 16, &var, &avg);
  *sse = var;
  return var;
}


/****************************************************************************
 *
 *  ROUTINE       : filter_block2d_bil_first_pass
 *
 *  INPUTS        : UINT8  *src_ptr          : Pointer to source block.
 *                  UINT32 src_pixels_per_line : Stride of input block.
 *                  UINT32 pixel_step        : Offset between filter input samples (see notes).
 *                  UINT32 output_height     : Input block height.
 *                  UINT32 output_width      : Input block width.
 *                  INT32  *vp8_filter          : Array of 2 bi-linear filter taps.
 *
 *  OUTPUTS       : INT32 *output_ptr        : Pointer to filtered block.
 *
 *  RETURNS       : void
 *
 *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block in
 *                  either horizontal or vertical direction to produce the
 *                  filtered output block. Used to implement first-pass
 *                  of 2-D separable filter.
 *
 *  SPECIAL NOTES : Produces INT32 output to retain precision for next pass.
 *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
 *                  pixel_step defines whether the filter is applied
 *                  horizontally (pixel_step=1) or vertically (pixel_step=stride).
 *                  It defines the offset required to move from one input
 *                  to the next.
 *
 ****************************************************************************/
static void var_filter_block2d_bil_first_pass
(
  const unsigned char *src_ptr,
  unsigned short *output_ptr,
  unsigned int src_pixels_per_line,
  int pixel_step,
  unsigned int output_height,
  unsigned int output_width,
  const short *vp8_filter
) {
  unsigned int i, j;

  for (i = 0; i < output_height; i++) {
    for (j = 0; j < output_width; j++) {
      // Apply bilinear filter
      output_ptr[j] = (((int)src_ptr[0]          * vp8_filter[0]) +
                       ((int)src_ptr[pixel_step] * vp8_filter[1]) +
                       (VP8_FILTER_WEIGHT / 2)) >> VP8_FILTER_SHIFT;
      src_ptr++;
    }

    // Next row...
    src_ptr    += src_pixels_per_line - output_width;
    output_ptr += output_width;
  }
}

/****************************************************************************
 *
 *  ROUTINE       : filter_block2d_bil_second_pass
 *
 *  INPUTS        : INT32  *src_ptr          : Pointer to source block.
 *                  UINT32 src_pixels_per_line : Stride of input block.
 *                  UINT32 pixel_step        : Offset between filter input samples (see notes).
 *                  UINT32 output_height     : Input block height.
 *                  UINT32 output_width      : Input block width.
 *                  INT32  *vp8_filter          : Array of 2 bi-linear filter taps.
 *
 *  OUTPUTS       : UINT16 *output_ptr       : Pointer to filtered block.
 *
 *  RETURNS       : void
 *
 *  FUNCTION      : Applies a 1-D 2-tap bi-linear filter to the source block in
 *                  either horizontal or vertical direction to produce the
 *                  filtered output block. Used to implement second-pass
 *                  of 2-D separable filter.
 *
 *  SPECIAL NOTES : Requires 32-bit input as produced by filter_block2d_bil_first_pass.
 *                  Two filter taps should sum to VP8_FILTER_WEIGHT.
 *                  pixel_step defines whether the filter is applied
 *                  horizontally (pixel_step=1) or vertically (pixel_step=stride).
 *                  It defines the offset required to move from one input
 *                  to the next.
 *
 ****************************************************************************/
static void var_filter_block2d_bil_second_pass
(
  const unsigned short *src_ptr,
  unsigned char  *output_ptr,
  unsigned int  src_pixels_per_line,
  unsigned int  pixel_step,
  unsigned int  output_height,
  unsigned int  output_width,
  const short *vp8_filter
) {
  unsigned int  i, j;
  int  Temp;

  for (i = 0; i < output_height; i++) {
    for (j = 0; j < output_width; j++) {
      // Apply filter
      Temp = ((int)src_ptr[0]         * vp8_filter[0]) +
             ((int)src_ptr[pixel_step] * vp8_filter[1]) +
             (VP8_FILTER_WEIGHT / 2);
      output_ptr[j] = (unsigned int)(Temp >> VP8_FILTER_SHIFT);
      src_ptr++;
    }

    // Next row...
    src_ptr    += src_pixels_per_line - output_width;
    output_ptr += output_width;
  }
}


unsigned int vp8_sub_pixel_variance4x4_c
(
  const unsigned char  *src_ptr,
  int  src_pixels_per_line,
  int  xoffset,
  int  yoffset,
  const unsigned char *dst_ptr,
  int dst_pixels_per_line,
  unsigned int *sse
) {
  unsigned char  temp2[20 * 16];
  const short *HFilter, *VFilter;
  unsigned short FData3[5 * 4]; // Temp data bufffer used in filtering

  HFilter = vp8_bilinear_filters[xoffset];
  VFilter = vp8_bilinear_filters[yoffset];

  // First filter 1d Horizontal
  var_filter_block2d_bil_first_pass(src_ptr, FData3, src_pixels_per_line, 1, 5, 4, HFilter);

  // Now filter Verticaly
  var_filter_block2d_bil_second_pass(FData3, temp2, 4,  4,  4,  4, VFilter);

  return vp8_variance4x4_c(temp2, 4, dst_ptr, dst_pixels_per_line, sse);
}


unsigned int vp8_sub_pixel_variance8x8_c
(
  const unsigned char  *src_ptr,
  int  src_pixels_per_line,
  int  xoffset,
  int  yoffset,
  const unsigned char *dst_ptr,
  int dst_pixels_per_line,
  unsigned int *sse
) {
  unsigned short FData3[9 * 8]; // Temp data bufffer used in filtering
  unsigned char  temp2[20 * 16];
  const short *HFilter, *VFilter;

  HFilter = vp8_bilinear_filters[xoffset];
  VFilter = vp8_bilinear_filters[yoffset];

  var_filter_block2d_bil_first_pass(src_ptr, FData3, src_pixels_per_line, 1, 9, 8, HFilter);
  var_filter_block2d_bil_second_pass(FData3, temp2, 8, 8, 8, 8, VFilter);

  return vp8_variance8x8_c(temp2, 8, dst_ptr, dst_pixels_per_line, sse);
}

unsigned int vp8_sub_pixel_variance16x16_c
(
  const unsigned char  *src_ptr,
  int  src_pixels_per_line,
  int  xoffset,
  int  yoffset,
  const unsigned char *dst_ptr,
  int dst_pixels_per_line,
  unsigned int *sse
) {
  unsigned short FData3[17 * 16]; // Temp data bufffer used in filtering
  unsigned char  temp2[20 * 16];
  const short *HFilter, *VFilter;

  HFilter = vp8_bilinear_filters[xoffset];
  VFilter = vp8_bilinear_filters[yoffset];

  var_filter_block2d_bil_first_pass(src_ptr, FData3, src_pixels_per_line, 1, 17, 16, HFilter);
  var_filter_block2d_bil_second_pass(FData3, temp2, 16, 16, 16, 16, VFilter);

  return vp8_variance16x16_c(temp2, 16, dst_ptr, dst_pixels_per_line, sse);
}

#if CONFIG_SUPERBLOCKS
unsigned int vp8_sub_pixel_variance32x32_c(const unsigned char  *src_ptr,
                                           int  src_pixels_per_line,
                                           int  xoffset,
                                           int  yoffset,
                                           const unsigned char *dst_ptr,
                                           int dst_pixels_per_line,
                                           unsigned int *sse) {
  unsigned short FData3[33 * 32]; // Temp data bufffer used in filtering
  unsigned char  temp2[36 * 32];
  const short *HFilter, *VFilter;

  HFilter = vp8_bilinear_filters[xoffset];
  VFilter = vp8_bilinear_filters[yoffset];

  var_filter_block2d_bil_first_pass(src_ptr, FData3, src_pixels_per_line, 1, 33, 32, HFilter);
  var_filter_block2d_bil_second_pass(FData3, temp2, 32, 32, 32, 32, VFilter);

  return vp8_variance32x32_c(temp2, 32, dst_ptr, dst_pixels_per_line, sse);
}
#endif

unsigned int vp8_variance_halfpixvar16x16_h_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  return vp8_sub_pixel_variance16x16_c(src_ptr, source_stride, 8, 0,
                                       ref_ptr, recon_stride, sse);
}

#if CONFIG_SUPERBLOCKS
unsigned int vp8_variance_halfpixvar32x32_h_c(const unsigned char *src_ptr,
                                              int  source_stride,
                                              const unsigned char *ref_ptr,
                                              int  recon_stride,
                                              unsigned int *sse) {
  return vp8_sub_pixel_variance32x32_c(src_ptr, source_stride, 8, 0,
                                       ref_ptr, recon_stride, sse);
}
#endif


unsigned int vp8_variance_halfpixvar16x16_v_c(const unsigned char *src_ptr,
                                              int  source_stride,
                                              const unsigned char *ref_ptr,
                                              int  recon_stride,
                                              unsigned int *sse) {
  return vp8_sub_pixel_variance16x16_c(src_ptr, source_stride, 0, 8,
                                       ref_ptr, recon_stride, sse);
}

#if CONFIG_SUPERBLOCKS
unsigned int vp8_variance_halfpixvar32x32_v_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  return vp8_sub_pixel_variance32x32_c(src_ptr, source_stride, 0, 8,
                                       ref_ptr, recon_stride, sse);
}
#endif

unsigned int vp8_variance_halfpixvar16x16_hv_c(
  const unsigned char *src_ptr,
  int  source_stride,
  const unsigned char *ref_ptr,
  int  recon_stride,
  unsigned int *sse) {
  return vp8_sub_pixel_variance16x16_c(src_ptr, source_stride, 8, 8,
                                       ref_ptr, recon_stride, sse);
}

#if CONFIG_SUPERBLOCKS
unsigned int vp8_variance_halfpixvar32x32_hv_c(const unsigned char *src_ptr,
                                               int  source_stride,
                                               const unsigned char *ref_ptr,
                                               int  recon_stride,
                                               unsigned int *sse) {
  return vp8_sub_pixel_variance32x32_c(src_ptr, source_stride, 8, 8,
                                       ref_ptr, recon_stride, sse);
}
#endif

unsigned int vp8_sub_pixel_mse16x16_c
(
  const unsigned char  *src_ptr,
  int  src_pixels_per_line,
  int  xoffset,
  int  yoffset,
  const unsigned char *dst_ptr,
  int dst_pixels_per_line,
  unsigned int *sse
) {
  vp8_sub_pixel_variance16x16_c(src_ptr, src_pixels_per_line, xoffset, yoffset, dst_ptr, dst_pixels_per_line, sse);
  return *sse;
}

#if CONFIG_SUPERBLOCKS
unsigned int vp8_sub_pixel_mse32x32_c(const unsigned char  *src_ptr,
                                      int  src_pixels_per_line,
                                      int  xoffset,
                                      int  yoffset,
                                      const unsigned char *dst_ptr,
                                      int dst_pixels_per_line,
                                      unsigned int *sse) {
  vp8_sub_pixel_variance32x32_c(src_ptr, src_pixels_per_line, xoffset, yoffset, dst_ptr, dst_pixels_per_line, sse);
  return *sse;
}
#endif

unsigned int vp8_sub_pixel_variance16x8_c
(
  const unsigned char  *src_ptr,
  int  src_pixels_per_line,
  int  xoffset,
  int  yoffset,
  const unsigned char *dst_ptr,
  int dst_pixels_per_line,
  unsigned int *sse
) {
  unsigned short FData3[16 * 9];  // Temp data bufffer used in filtering
  unsigned char  temp2[20 * 16];
  const short *HFilter, *VFilter;

  HFilter = vp8_bilinear_filters[xoffset];
  VFilter = vp8_bilinear_filters[yoffset];

  var_filter_block2d_bil_first_pass(src_ptr, FData3, src_pixels_per_line, 1, 9, 16, HFilter);
  var_filter_block2d_bil_second_pass(FData3, temp2, 16, 16, 8, 16, VFilter);

  return vp8_variance16x8_c(temp2, 16, dst_ptr, dst_pixels_per_line, sse);
}

unsigned int vp8_sub_pixel_variance8x16_c
(
  const unsigned char  *src_ptr,
  int  src_pixels_per_line,
  int  xoffset,
  int  yoffset,
  const unsigned char *dst_ptr,
  int dst_pixels_per_line,
  unsigned int *sse
) {
  unsigned short FData3[9 * 16];  // Temp data bufffer used in filtering
  unsigned char  temp2[20 * 16];
  const short *HFilter, *VFilter;


  HFilter = vp8_bilinear_filters[xoffset];
  VFilter = vp8_bilinear_filters[yoffset];


  var_filter_block2d_bil_first_pass(src_ptr, FData3, src_pixels_per_line, 1, 17, 8, HFilter);
  var_filter_block2d_bil_second_pass(FData3, temp2, 8, 8, 16, 8, VFilter);

  return vp8_variance8x16_c(temp2, 8, dst_ptr, dst_pixels_per_line, sse);
}