#ifndef UTIL64BITS32BITS_H
#define UTIL64BITS32BITS_H

#include <stdlib.h>
#include <stdint.h>

#ifdef _MSC_VER
// reverse the order of the bytes
static inline uint32_t bytereverse32(uint32_t value) {
  return ::_byteswap_ulong(value);
}

// reverse the order of the bytes
static inline uint64_t bytereverse64(uint64_t value) {
  return ::_byteswap_uint64(value);
}
#else

// reverse the order of the bytes
static inline uint32_t bytereverse32(uint32_t value) {
  return __builtin_bswap32(value);
}

// reverse the order of the bytes
static inline uint64_t bytereverse64(uint64_t value) {
  return __builtin_bswap64(value);
}
#endif

uint32_t lsb64(uint64_t x) { return (uint32_t)x; }

uint32_t msb64(uint64_t x) { return (uint32_t)(x >> 32); }

// https://stackoverflow.com/questions/746171/best-algorithm-for-bit-reversal-from-msb-lsb-to-lsb-msb-in-c
static const unsigned char BitReverseTable256[] = {
    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};

static inline uint32_t bitreverse32(uint32_t v) {
  return ((uint32_t)BitReverseTable256[v & 0xff] << 24) |
         ((uint32_t)BitReverseTable256[(v >> 8) & 0xff] << 16) |
         ((uint32_t)BitReverseTable256[(v >> 16) & 0xff] << 8) |
         ((uint32_t)BitReverseTable256[(v >> 24) & 0xff]);
}

static inline uint16_t bitreverse16(uint16_t v) {
  return ((uint16_t)BitReverseTable256[v & 0xff] << 8) |
         ((uint16_t)BitReverseTable256[(v >> 8) & 0xff]);
}

static inline uint64_t factorial(uint64_t n) { return (n == 1 || n == 0) ? 1 : factorial(n - 1) * n; }

#endif // UTIL64BITS32BITS_H