/*
 *  Copyright (c) 2013 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 <assert.h>

#include "./vpx_dsp_rtcd.h"
#include "vpx_dsp/vpx_dsp_common.h"
#include "vpx_dsp/vpx_filter.h"
#include "vpx_ports/mem.h"

void vpx_convolve8_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
                        ptrdiff_t dst_stride, const InterpKernel *filter,
                        int x0_q4, int x_step_q4, int y0_q4, int y_step_q4,
                        int w, int h) {
  // Given our constraints: w <= 64, h <= 64, taps <= 8 we can reduce the
  // maximum buffer size to 64 * (64 + 7) (+1 row to make it divisible by 4).
  DECLARE_ALIGNED(32, uint8_t, im_block[64 * 72]);
  const int im_stride = 64;

  const int vert_filter_taps = vpx_get_filter_taps(filter[y0_q4]) <= 4 ? 4 : 8;
  // Account for the vertical phase needing vert_filter_taps / 2 - 1 lines prior
  // and vert_filter_taps / 2 lines post. (+1 to make total divisible by 4.)
  const int im_height = h + vert_filter_taps;
  const ptrdiff_t border_offset = vert_filter_taps / 2 - 1;

  assert(y_step_q4 == 16);
  assert(x_step_q4 == 16);

  // Filter starting border_offset rows back. The Neon implementation will
  // ignore the given height and filter a multiple of 4 lines. Since this goes
  // into the temporary buffer which has lots of extra room and is subsequently
  // discarded this is safe if somewhat less than ideal.
  vpx_convolve8_horiz_neon(src - src_stride * border_offset, src_stride,
                           im_block, im_stride, filter, x0_q4, x_step_q4, y0_q4,
                           y_step_q4, w, im_height);

  // Step into the temporary buffer border_offset rows to get actual frame data.
  vpx_convolve8_vert_neon(im_block + im_stride * border_offset, im_stride, dst,
                          dst_stride, filter, x0_q4, x_step_q4, y0_q4,
                          y_step_q4, w, h);
}

void vpx_convolve8_avg_neon(const uint8_t *src, ptrdiff_t src_stride,
                            uint8_t *dst, ptrdiff_t dst_stride,
                            const InterpKernel *filter, int x0_q4,
                            int x_step_q4, int y0_q4, int y_step_q4, int w,
                            int h) {
  DECLARE_ALIGNED(32, uint8_t, im_block[64 * 72]);
  const int im_stride = 64;
  const int im_height = h + SUBPEL_TAPS;
  const ptrdiff_t border_offset = SUBPEL_TAPS / 2 - 1;

  assert(y_step_q4 == 16);
  assert(x_step_q4 == 16);

  // This implementation has the same issues as above. In addition, we only want
  // to average the values after both passes.
  vpx_convolve8_horiz_neon(src - src_stride * border_offset, src_stride,
                           im_block, im_stride, filter, x0_q4, x_step_q4, y0_q4,
                           y_step_q4, w, im_height);

  vpx_convolve8_avg_vert_neon(im_block + im_stride * border_offset, im_stride,
                              dst, dst_stride, filter, x0_q4, x_step_q4, y0_q4,
                              y_step_q4, w, h);
}