/*****************************************************************************
 * This file is part of Kvazaar HEVC encoder.
 *
 * Copyright (C) 2013-2015 Tampere University of Technology and others (see
 * COPYING file).
 *
 * Kvazaar is free software: you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation; either version 2.1 of the License, or (at your
 * option) any later version.
 *
 * Kvazaar is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with Kvazaar.  If not, see <http://www.gnu.org/licenses/>.
 ****************************************************************************/

/*
 * \file
 */

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

#include "strategyselector.h"
#include "nal.h"


static void array_checksum_generic(const kvz_pixel* data,
                                   const int height, const int width,
                                   const int stride,
                                   unsigned char checksum_out[SEI_HASH_MAX_LENGTH]) {
  int x, y;
  int checksum = 0;
  
  assert(SEI_HASH_MAX_LENGTH >= 4);
  
  for (y = 0; y < height; ++y) {
    for (x = 0; x < width; ++x) {
      const uint8_t mask = (uint8_t)((x & 0xff) ^ (y & 0xff) ^ (x >> 8) ^ (y >> 8));
      checksum += (data[(y * stride) + x] & 0xff) ^ mask;
    }
  }

  // Unpack uint into byte-array.
  checksum_out[0] = (checksum >> 24) & 0xff;
  checksum_out[1] = (checksum >> 16) & 0xff;
  checksum_out[2] = (checksum >> 8) & 0xff;
  checksum_out[3] = (checksum) & 0xff;
}

static void array_checksum_generic4(const kvz_pixel* data,
                                   const int height, const int width,
                                   const int stride,
                                   unsigned char checksum_out[SEI_HASH_MAX_LENGTH]) {
  uint32_t checksum = 0;
  int y, x, xp;
  
  static uint8_t ckmap_initialized = 0;
  static uint32_t ckmap[64*256];
  
  if (!ckmap_initialized) {
    uint8_t * const ckmap_uint8 = (uint8_t*)&ckmap;
    int x, y;
    for (y = 0; y < 256; ++y) {
      for (x = 0; x < 256; ++x) {
        ckmap_uint8[y*256+x] = x^y;
      }
    }
    ckmap_initialized = 1;
  }

  assert(SEI_HASH_MAX_LENGTH >= 4);

  for (y = 0; y < height; ++y) {
    for (xp = 0; xp < width/4; ++xp) {
      const int x = xp * 4;
      const uint32_t mask = ckmap[(xp&63)+64*(y&255)] ^ (((x >> 8) ^ (y >> 8)) * 0x1010101);
      const uint32_t cksumbytes = (*((uint32_t*)(&data[(y * stride) + x]))) ^ mask;
      checksum += ((cksumbytes >> 24) & 0xff) + ((cksumbytes >> 16) & 0xff) + ((cksumbytes >> 8) & 0xff) + (cksumbytes & 0xff);
    }
    for (x = xp*4; x < width; ++x) {
      uint8_t mask = (uint8_t)((x & 0xff) ^ (y & 0xff) ^ (x >> 8) ^ (y >> 8));
      checksum += (data[(y * stride) + x] & 0xff) ^ mask;
    }
  }

  // Unpack uint into byte-array.
  checksum_out[0] = (checksum >> 24) & 0xff;
  checksum_out[1] = (checksum >> 16) & 0xff;
  checksum_out[2] = (checksum >> 8) & 0xff;
  checksum_out[3] = (checksum) & 0xff;
}

static void array_checksum_generic8(const kvz_pixel* data,
                                   const int height, const int width,
                                   const int stride,
                                   unsigned char checksum_out[SEI_HASH_MAX_LENGTH]) {
  uint32_t checksum = 0;
  int y, x, xp;
  
  static uint8_t ckmap_initialized = 0;
  static uint64_t ckmap[32*256];
  
  if (!ckmap_initialized) {
    uint8_t * const ckmap_uint8 = (uint8_t*)&ckmap;
    int x, y;
    for (y = 0; y < 256; ++y) {
      for (x = 0; x < 256; ++x) {
        ckmap_uint8[y*256+x] = x^y;
      }
    }
    ckmap_initialized = 1;
  }

  assert(SEI_HASH_MAX_LENGTH >= 4);

  for (y = 0; y < height; ++y) {
    for (xp = 0; xp < width/8; ++xp) {
      const int x = xp * 8;
      const uint64_t mask = ckmap[(xp&31)+32*(y&255)] ^ ((uint64_t)((x >> 8) ^ (y >> 8)) * 0x101010101010101);
      const uint64_t cksumbytes = (*((uint64_t*)(&data[(y * stride) + x]))) ^ mask;
      checksum += ((cksumbytes >> 56) & 0xff) + ((cksumbytes >> 48) & 0xff) + ((cksumbytes >> 40) & 0xff) + ((cksumbytes >> 32) & 0xff) + ((cksumbytes >> 24) & 0xff) + ((cksumbytes >> 16) & 0xff) + ((cksumbytes >> 8) & 0xff) + (cksumbytes & 0xff);
    }
    for (x = xp*8; x < width; ++x) {
      uint8_t mask = (uint8_t)((x & 0xff) ^ (y & 0xff) ^ (x >> 8) ^ (y >> 8));
      checksum += (data[(y * stride) + x] & 0xff) ^ mask;
    }
  }

  // Unpack uint into byte-array.
  checksum_out[0] = (checksum >> 24) & 0xff;
  checksum_out[1] = (checksum >> 16) & 0xff;
  checksum_out[2] = (checksum >> 8) & 0xff;
  checksum_out[3] = (checksum) & 0xff;
}

int strategy_register_nal_generic(void* opaque) {
  bool success = true;

  success &= strategyselector_register(opaque, "array_checksum", "generic", 0, &array_checksum_generic);
  success &= strategyselector_register(opaque, "array_checksum", "generic4", 1, &array_checksum_generic4);
  success &= strategyselector_register(opaque, "array_checksum", "generic8", 2, &array_checksum_generic8);
  
  return success;
}