/* -*- c++ -*- */
/*
 * gr-satnogs: SatNOGS GNU Radio Out-Of-Tree Module
 *
 *  Copyright (C) 2016,2018,2019 Libre Space Foundation <http://libre.space>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDE_SATNOGS_UTILS_H_
#define INCLUDE_SATNOGS_UTILS_H_

#include <cstdint>
#include <cmath>
#include <arpa/inet.h>

namespace gr {

namespace satnogs {

#define htonll(x) ((1==htonl(1)) ? (x) : ((uint64_t)htonl((x) & 0xFFFFFFFF) << 32) | htonl((x) >> 32))
#define ntohll(x) ((1==ntohl(1)) ? (x) : ((uint64_t)ntohl((x) & 0xFFFFFFFF) << 32) | ntohl((x) >> 32))
/**
 * Computes the Mean Absolute Percentage Error
 * @param ref the reference value
 * @param estimation the estimated value
 * @return the mean absolute percentage error
 */
static inline double
mape(double ref, double estimation)
{
  return std::abs(ref - estimation) / ref;
}

/**
 * Counts the number of active bits in x
 */
static inline unsigned int
bit_count(unsigned int x)
{
  /*
   * Some more magic from
   * http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
   */
  x = x - ((x >> 1) & 0x55555555);
  x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
  return (((x + (x >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24;
}

static const uint8_t _bytes_reversed[256] = {
  0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0,
  0x30, 0xB0, 0x70, 0xF0, 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68,
  0xE8, 0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, 0x04, 0x84,
  0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34,
  0xB4, 0x74, 0xF4, 0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
  0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC, 0x02, 0x82, 0x42,
  0xC2, 0x22, 0xA2, 0x62, 0xE2, 0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2,
  0x72, 0xF2, 0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA, 0x1A,
  0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA, 0x06, 0x86, 0x46, 0xC6,
  0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76,
  0xF6, 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE, 0x1E, 0x9E,
  0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, 0x01, 0x81, 0x41, 0xC1, 0x21,
  0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
  0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59,
  0xD9, 0x39, 0xB9, 0x79, 0xF9, 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5,
  0x65, 0xE5, 0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, 0x0D,
  0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD,
  0x3D, 0xBD, 0x7D, 0xFD, 0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63,
  0xE3, 0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3, 0x0B, 0x8B,
  0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB, 0x1B, 0x9B, 0x5B, 0xDB, 0x3B,
  0xBB, 0x7B, 0xFB, 0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
  0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7, 0x0F, 0x8F, 0x4F,
  0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF,
  0x7F, 0xFF
};

/**
 * Reverse the bits of the byte b.
 * @param b the byte to be mirrored.
 */
static inline uint8_t
reverse_byte(uint8_t b)
{
  return _bytes_reversed[b];
}

static inline uint32_t
reverse_uint32_bytes(uint32_t i)
{
  return (_bytes_reversed[i & 0xff] << 24)
         | (_bytes_reversed[(i >> 8) & 0xff] << 16)
         | (_bytes_reversed[(i >> 16) & 0xff] << 8)
         | (_bytes_reversed[(i >> 24) & 0xff]);
}

static inline uint64_t
reverse_uint64_bytes(uint64_t x)
{
  x = (x & 0x00000000FFFFFFFF) << 32 | (x & 0xFFFFFFFF00000000) >> 32;
  x = (x & 0x0000FFFF0000FFFF) << 16 | (x & 0xFFFF0000FFFF0000) >> 16;
  x = (x & 0x00FF00FF00FF00FF) << 8 | (x & 0xFF00FF00FF00FF00) >> 8;
  return x;
}

/**
 * CRC-32 calculation using lookup tables, supporting progressive CRC calculation
 * polynomial: 0x104C11DB7
 *
 * @param crc the initial feed
 * @param data the buffer containing the data
 * @param len the length of the buffer
 * @return the CRC-32 result
 */
static inline uint32_t
update_crc32(uint32_t crc, const uint8_t *data, size_t len)
{
  static const uint32_t crc32_lut[256] = {
    0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL, 0x076DC419L,
    0x706AF48FL, 0xE963A535L, 0x9E6495A3L, 0x0EDB8832L, 0x79DCB8A4L,
    0xE0D5E91EL, 0x97D2D988L, 0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L,
    0x90BF1D91L, 0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL,
    0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L, 0x136C9856L,
    0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL, 0x14015C4FL, 0x63066CD9L,
    0xFA0F3D63L, 0x8D080DF5L, 0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L,
    0xA2677172L, 0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL,
    0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L, 0x32D86CE3L,
    0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L, 0x26D930ACL, 0x51DE003AL,
    0xC8D75180L, 0xBFD06116L, 0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L,
    0xB8BDA50FL, 0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L,
    0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL, 0x76DC4190L,
    0x01DB7106L, 0x98D220BCL, 0xEFD5102AL, 0x71B18589L, 0x06B6B51FL,
    0x9FBFE4A5L, 0xE8B8D433L, 0x7807C9A2L, 0x0F00F934L, 0x9609A88EL,
    0xE10E9818L, 0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L,
    0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL, 0x6C0695EDL,
    0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L, 0x65B0D9C6L, 0x12B7E950L,
    0x8BBEB8EAL, 0xFCB9887CL, 0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L,
    0xFBD44C65L, 0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L,
    0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL, 0x4369E96AL,
    0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L, 0x44042D73L, 0x33031DE5L,
    0xAA0A4C5FL, 0xDD0D7CC9L, 0x5005713CL, 0x270241AAL, 0xBE0B1010L,
    0xC90C2086L, 0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL,
    0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L, 0x59B33D17L,
    0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL, 0xEDB88320L, 0x9ABFB3B6L,
    0x03B6E20CL, 0x74B1D29AL, 0xEAD54739L, 0x9DD277AFL, 0x04DB2615L,
    0x73DC1683L, 0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L,
    0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L, 0xF00F9344L,
    0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL, 0xF762575DL, 0x806567CBL,
    0x196C3671L, 0x6E6B06E7L, 0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL,
    0x67DD4ACCL, 0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L,
    0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L, 0xD1BB67F1L,
    0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL, 0xD80D2BDAL, 0xAF0A1B4CL,
    0x36034AF6L, 0x41047A60L, 0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL,
    0x4669BE79L, 0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L,
    0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL, 0xC5BA3BBEL,
    0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L, 0xC2D7FFA7L, 0xB5D0CF31L,
    0x2CD99E8BL, 0x5BDEAE1DL, 0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL,
    0x026D930AL, 0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L,
    0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L, 0x92D28E9BL,
    0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L, 0x86D3D2D4L, 0xF1D4E242L,
    0x68DDB3F8L, 0x1FDA836EL, 0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L,
    0x18B74777L, 0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL,
    0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L, 0xA00AE278L,
    0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L, 0xA7672661L, 0xD06016F7L,
    0x4969474DL, 0x3E6E77DBL, 0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L,
    0x37D83BF0L, 0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L,
    0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L, 0xBAD03605L,
    0xCDD70693L, 0x54DE5729L, 0x23D967BFL, 0xB3667A2EL, 0xC4614AB8L,
    0x5D681B02L, 0x2A6F2B94L, 0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL,
    0x2D02EF8DL
  };

  register uint32_t i;
  for (i = 0; i < len; i++) {
    crc = (crc >> 8) ^ crc32_lut[(crc ^ data[i]) & 0xff];
  }
  return crc;
}

/**
 * Calculates the CRC-32 of the buffer buf.
 * @param buf The buffer containing the data
 * @param len the size of the buffer
 * @return the CRC-32 of the buffer
 */
static inline uint32_t
crc32(const uint8_t *buf, size_t len)
{
  unsigned int crc = update_crc32(0xffffffff, buf, len) ^ 0xffffffff;
  return crc;
}

static void
print_pdu(const uint8_t *buf, size_t len)
{
  for (size_t i = 0; i < len; i++) {
    printf("0x%02x ", buf[i]);
  }
  printf("\n");
}

}  // namespace satnogs

}  // namespace gr

#endif /* INCLUDE_SATNOGS_UTILS_H_ */