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//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2025
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#pragma once
#include "td/utils/bits.h"
#include "td/utils/common.h"
#include <limits>
#include <type_traits>
namespace td {
class uint128_emulated {
public:
using uint128 = uint128_emulated;
uint128_emulated(uint64 hi, uint64 lo) : hi_(hi), lo_(lo) {
}
template <class T, typename = std::enable_if_t<std::is_unsigned<T>::value>>
uint128_emulated(T lo) : uint128_emulated(0, lo) {
}
uint128_emulated() = default;
uint64 hi() const {
return hi_;
}
uint64 lo() const {
return lo_;
}
uint64 rounded_hi() const {
return hi_ + (lo_ >> 63);
}
static uint128 from_signed(int64 x) {
if (x >= 0) {
return uint128(0, x);
}
return uint128(std::numeric_limits<uint64>::max(), static_cast<uint64>(x));
}
static uint128 from_unsigned(uint64 x) {
return uint128(0, x);
}
uint128 add(uint128 other) const {
uint128 res(other.hi() + hi(), other.lo() + lo());
if (res.lo() < lo()) {
res.hi_++;
}
return res;
}
uint128 shl(int cnt) const {
if (cnt == 0) {
return *this;
}
if (cnt < 64) {
return uint128((hi() << cnt) | (lo() >> (64 - cnt)), lo() << cnt);
}
if (cnt < 128) {
return uint128(lo() << (cnt - 64), 0);
}
return uint128();
}
uint128 shr(int cnt) const {
if (cnt == 0) {
return *this;
}
if (cnt < 64) {
return uint128(hi() >> cnt, (lo() >> cnt) | (hi() << (64 - cnt)));
}
if (cnt < 128) {
return uint128(0, hi() >> (cnt - 64));
}
return uint128();
}
uint128 mult(uint128 other) const {
uint64 a_lo = lo() & 0xffffffff;
uint64 a_hi = lo() >> 32;
uint64 b_lo = other.lo() & 0xffffffff;
uint64 b_hi = other.lo() >> 32;
uint128 res(lo() * other.hi() + hi() * other.lo() + a_hi * b_hi, a_lo * b_lo);
uint128 add1(0, a_lo * b_hi);
uint128 add2(0, a_hi * b_lo);
return res.add(add1.shl(32)).add(add2.shl(32));
}
uint128 mult(uint64 other) const {
return mult(uint128(0, other));
}
uint128 mult_signed(int64 other) const {
return mult(uint128::from_signed(other));
}
bool is_zero() const {
return lo() == 0 && hi() == 0;
}
uint128 sub(uint128 other) const {
uint32 carry = 0;
if (other.lo() > lo()) {
carry = 1;
}
return uint128(hi() - other.hi() - carry, lo() - other.lo());
}
void divmod(uint128 other, uint128 *div_res, uint128 *mod_res) const {
CHECK(!other.is_zero());
auto from = *this;
auto ctz = from.count_leading_zeroes();
auto other_ctz = other.count_leading_zeroes();
if (ctz > other_ctz) {
*div_res = uint128();
*mod_res = from;
return;
}
auto shift = other_ctz - ctz;
auto res = uint128();
for (int i = shift; i >= 0; i--) {
auto sub = other.shl(i);
res = res.shl(1);
if (from.greater_or_equal(sub)) {
from = from.sub(sub);
res = res.set_lower_bit();
}
}
*div_res = res;
*mod_res = from;
}
uint128 div(uint128 other) const {
uint128 a;
uint128 b;
divmod(other, &a, &b);
return a;
}
uint128 mod(uint128 other) const {
uint128 a;
uint128 b;
divmod(other, &a, &b);
return b;
}
void divmod_signed(int64 y, int64 *quot, int64 *rem) const {
CHECK(y != 0);
auto x = *this;
int x_sgn = x.is_negative();
int y_sgn = y < 0;
if (x_sgn) {
x = x.negate();
}
uint128 uy = from_signed(y);
if (uy.is_negative()) {
uy = uy.negate();
}
uint128 t_quot;
uint128 t_mod;
x.divmod(uy, &t_quot, &t_mod);
*quot = t_quot.lo();
*rem = t_mod.lo();
if (x_sgn != y_sgn) {
*quot = -*quot;
}
if (x_sgn) {
*rem = -*rem;
}
}
private:
uint64 hi_{0};
uint64 lo_{0};
bool is_negative() const {
return (hi_ >> 63) == 1;
}
int32 count_leading_zeroes() const {
if (hi() == 0) {
return 64 + count_leading_zeroes64(lo());
}
return count_leading_zeroes64(hi());
}
uint128 set_lower_bit() const {
return uint128(hi(), lo() | 1);
}
bool greater_or_equal(uint128 other) const {
return hi() > other.hi() || (hi() == other.hi() && lo() >= other.lo());
}
uint128 negate() const {
uint128 res(~hi(), ~lo() + 1);
if (res.lo() == 0) {
return uint128(res.hi() + 1, 0);
}
return res;
}
};
#if TD_HAVE_INT128
class uint128_intrinsic {
public:
using ValueT = unsigned __int128;
using uint128 = uint128_intrinsic;
explicit uint128_intrinsic(ValueT value) : value_(value) {
}
uint128_intrinsic(uint64 hi, uint64 lo) : value_((ValueT(hi) << 64) | lo) {
}
uint128_intrinsic() = default;
static uint128 from_signed(int64 x) {
return uint128(static_cast<ValueT>(x));
}
static uint128 from_unsigned(uint64 x) {
return uint128(static_cast<ValueT>(x));
}
uint64 hi() const {
return uint64(value() >> 64);
}
uint64 lo() const {
return uint64(value() & std::numeric_limits<uint64>::max());
}
uint64 rounded_hi() const {
return uint64((value() + (1ULL << 63)) >> 64);
}
uint128 add(uint128 other) const {
return uint128(value() + other.value());
}
uint128 sub(uint128 other) const {
return uint128(value() - other.value());
}
uint128 shl(int cnt) const {
if (cnt >= 128) {
return uint128();
}
return uint128(value() << cnt);
}
uint128 shr(int cnt) const {
if (cnt >= 128) {
return uint128();
}
return uint128(value() >> cnt);
}
uint128 mult(uint128 other) const {
return uint128(value() * other.value());
}
uint128 mult(uint64 other) const {
return uint128(value() * other);
}
uint128 mult_signed(int64 other) const {
return uint128(value() * other);
}
bool is_zero() const {
return value() == 0;
}
void divmod(uint128 other, uint128 *div_res, uint128 *mod_res) const {
CHECK(!other.is_zero());
*div_res = uint128(value() / other.value());
*mod_res = uint128(value() % other.value());
}
uint128 div(uint128 other) const {
CHECK(!other.is_zero());
return uint128(value() / other.value());
}
uint128 mod(uint128 other) const {
CHECK(!other.is_zero());
return uint128(value() % other.value());
}
void divmod_signed(int64 y, int64 *quot, int64 *rem) const {
CHECK(y != 0);
*quot = static_cast<int64>(signed_value() / y);
*rem = static_cast<int64>(signed_value() % y);
}
private:
unsigned __int128 value_{0};
ValueT value() const {
return value_;
}
__int128 signed_value() const {
return static_cast<__int128>(value());
}
};
#endif
#if TD_HAVE_INT128
using uint128 = uint128_intrinsic;
#else
using uint128 = uint128_emulated;
#endif
} // namespace td
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