/*
  Copyright 2019-2021 David Robillard <d@drobilla.net>

  Permission to use, copy, modify, and/or distribute this software for any
  purpose with or without fee is hereby granted, provided that the above
  copyright notice and this permission notice appear in all copies.

  THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

#ifndef EXESS_INTMATH_H
#define EXESS_INTMATH_H

#include "attributes.h"

#include <stdint.h>

static const int uint64_digits10 = 19;

static const uint64_t POW10[] = {1ull,
                                 10ull,
                                 100ull,
                                 1000ull,
                                 10000ull,
                                 100000ull,
                                 1000000ull,
                                 10000000ull,
                                 100000000ull,
                                 1000000000ull,
                                 10000000000ull,
                                 100000000000ull,
                                 1000000000000ull,
                                 10000000000000ull,
                                 100000000000000ull,
                                 1000000000000000ull,
                                 10000000000000000ull,
                                 100000000000000000ull,
                                 1000000000000000000ull,
                                 10000000000000000000ull};

/// Return the number of leading zeros in `i`
EXESS_I_CONST_FUNC
unsigned
exess_clz32(uint32_t i);

/// Return the number of leading zeros in `i`
EXESS_I_CONST_FUNC
unsigned
exess_clz64(uint64_t i);

/// Return the log base 2 of `i`
EXESS_I_CONST_FUNC
uint64_t
exess_ilog2(uint64_t i);

/// Return the log base 10 of `i`
EXESS_I_CONST_FUNC
uint64_t
exess_ilog10(uint64_t i);

/// Return the number of decimal digits required to represent `i`
EXESS_I_CONST_FUNC
uint8_t
exess_num_digits(uint64_t i);

#endif // EXESS_INTMATH_H