Relax constexpr

This commit is contained in:
Victor Zverovich 2024-09-29 09:16:29 -07:00
parent ff9ee0461a
commit d64b100a30
3 changed files with 40 additions and 42 deletions

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@ -1694,7 +1694,7 @@ template <typename T> class buffer {
protected:
// Don't initialize ptr_ since it is not accessed to save a few cycles.
FMT_MSC_WARNING(suppress : 26495)
FMT_CONSTEXPR20 buffer(grow_fun grow, size_t sz) noexcept
FMT_CONSTEXPR buffer(grow_fun grow, size_t sz) noexcept
: size_(sz), capacity_(sz), grow_(grow) {}
constexpr buffer(grow_fun grow, T* p = nullptr, size_t sz = 0,

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@ -876,7 +876,7 @@ class basic_memory_buffer : public detail::buffer<T> {
using value_type = T;
using const_reference = const T&;
FMT_CONSTEXPR20 explicit basic_memory_buffer(
FMT_CONSTEXPR explicit basic_memory_buffer(
const Allocator& alloc = Allocator())
: detail::buffer<T>(grow), alloc_(alloc) {
this->set(store_, SIZE);
@ -924,7 +924,7 @@ class basic_memory_buffer : public detail::buffer<T> {
/// Resizes the buffer to contain `count` elements. If T is a POD type new
/// elements may not be initialized.
FMT_CONSTEXPR20 void resize(size_t count) { this->try_resize(count); }
FMT_CONSTEXPR void resize(size_t count) { this->try_resize(count); }
/// Increases the buffer capacity to `new_capacity`.
void reserve(size_t new_capacity) { this->try_reserve(new_capacity); }
@ -2663,39 +2663,44 @@ inline FMT_CONSTEXPR20 void adjust_precision(int& precision, int exp10) {
class bigint {
private:
// A bigint is stored as an array of bigits (big digits), with bigit at index
// 0 being the least significant one.
using bigit = uint32_t;
// A bigint is a number in the form bigit_[N - 1] ... bigit_[0] * 32^exp_.
using bigit = uint32_t; // A big digit.
using double_bigit = uint64_t;
enum { bigit_bits = num_bits<bigit>() };
enum { bigits_capacity = 32 };
basic_memory_buffer<bigit, bigits_capacity> bigits_;
int exp_;
FMT_CONSTEXPR20 auto operator[](int index) const -> bigit {
return bigits_[to_unsigned(index)];
}
FMT_CONSTEXPR20 auto operator[](int index) -> bigit& {
return bigits_[to_unsigned(index)];
}
static constexpr const int bigit_bits = num_bits<bigit>();
friend struct formatter<bigint>;
FMT_CONSTEXPR20 void subtract_bigits(int index, bigit other, bigit& borrow) {
FMT_CONSTEXPR auto operator[](int index) const -> bigit {
return bigits_[to_unsigned(index)];
}
FMT_CONSTEXPR auto operator[](int index) -> bigit& {
return bigits_[to_unsigned(index)];
}
static constexpr auto minimum(int a, int b) -> int { return a < b ? a : b; }
static constexpr auto maximum(int a, int b) -> int { return a > b ? a : b; }
FMT_CONSTEXPR auto get_bigit(int i) const -> bigit {
return i >= exp_ && i < num_bigits() ? bigits_[i - exp_] : 0;
};
FMT_CONSTEXPR void subtract_bigits(int index, bigit other, bigit& borrow) {
auto result = static_cast<double_bigit>((*this)[index]) - other - borrow;
(*this)[index] = static_cast<bigit>(result);
borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
}
FMT_CONSTEXPR20 void remove_leading_zeros() {
FMT_CONSTEXPR void remove_leading_zeros() {
int num_bigits = static_cast<int>(bigits_.size()) - 1;
while (num_bigits > 0 && (*this)[num_bigits] == 0) --num_bigits;
bigits_.resize(to_unsigned(num_bigits + 1));
}
// Computes *this -= other assuming aligned bigints and *this >= other.
FMT_CONSTEXPR20 void subtract_aligned(const bigint& other) {
FMT_CONSTEXPR void subtract_aligned(const bigint& other) {
FMT_ASSERT(other.exp_ >= exp_, "unaligned bigints");
FMT_ASSERT(compare(*this, other) >= 0, "");
bigit borrow = 0;
@ -2706,7 +2711,7 @@ class bigint {
remove_leading_zeros();
}
FMT_CONSTEXPR20 void multiply(uint32_t value) {
FMT_CONSTEXPR void multiply(uint32_t value) {
const double_bigit wide_value = value;
bigit carry = 0;
for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
@ -2719,7 +2724,7 @@ class bigint {
template <typename UInt, FMT_ENABLE_IF(std::is_same<UInt, uint64_t>::value ||
std::is_same<UInt, uint128_t>::value)>
FMT_CONSTEXPR20 void multiply(UInt value) {
FMT_CONSTEXPR void multiply(UInt value) {
using half_uint =
conditional_t<std::is_same<UInt, uint128_t>::value, uint64_t, uint32_t>;
const int shift = num_bits<half_uint>() - bigit_bits;
@ -2740,7 +2745,7 @@ class bigint {
template <typename UInt, FMT_ENABLE_IF(std::is_same<UInt, uint64_t>::value ||
std::is_same<UInt, uint128_t>::value)>
FMT_CONSTEXPR20 void assign(UInt n) {
FMT_CONSTEXPR void assign(UInt n) {
size_t num_bigits = 0;
do {
bigits_[num_bigits++] = static_cast<bigit>(n);
@ -2751,13 +2756,13 @@ class bigint {
}
public:
FMT_CONSTEXPR20 bigint() : exp_(0) {}
FMT_CONSTEXPR bigint() : exp_(0) {}
explicit bigint(uint64_t n) { assign(n); }
bigint(const bigint&) = delete;
void operator=(const bigint&) = delete;
FMT_CONSTEXPR20 void assign(const bigint& other) {
FMT_CONSTEXPR void assign(const bigint& other) {
auto size = other.bigits_.size();
bigits_.resize(size);
auto data = other.bigits_.data();
@ -2765,16 +2770,16 @@ class bigint {
exp_ = other.exp_;
}
template <typename Int> FMT_CONSTEXPR20 void operator=(Int n) {
template <typename Int> FMT_CONSTEXPR void operator=(Int n) {
FMT_ASSERT(n > 0, "");
assign(uint64_or_128_t<Int>(n));
}
FMT_CONSTEXPR20 auto num_bigits() const -> int {
FMT_CONSTEXPR auto num_bigits() const -> int {
return static_cast<int>(bigits_.size()) + exp_;
}
FMT_NOINLINE FMT_CONSTEXPR20 auto operator<<=(int shift) -> bigint& {
FMT_CONSTEXPR auto operator<<=(int shift) -> bigint& {
FMT_ASSERT(shift >= 0, "");
exp_ += shift / bigit_bits;
shift %= bigit_bits;
@ -2789,14 +2794,13 @@ class bigint {
return *this;
}
template <typename Int>
FMT_CONSTEXPR20 auto operator*=(Int value) -> bigint& {
template <typename Int> FMT_CONSTEXPR auto operator*=(Int value) -> bigint& {
FMT_ASSERT(value > 0, "");
multiply(uint32_or_64_or_128_t<Int>(value));
return *this;
}
friend FMT_CONSTEXPR20 auto compare(const bigint& lhs, const bigint& rhs)
friend FMT_CONSTEXPR auto compare(const bigint& lhs, const bigint& rhs)
-> int {
int num_lhs_bigits = lhs.num_bigits(), num_rhs_bigits = rhs.num_bigits();
if (num_lhs_bigits != num_rhs_bigits)
@ -2814,24 +2818,18 @@ class bigint {
}
// Returns compare(lhs1 + lhs2, rhs).
friend FMT_CONSTEXPR20 auto add_compare(const bigint& lhs1,
const bigint& lhs2, const bigint& rhs)
-> int {
auto minimum = [](int a, int b) { return a < b ? a : b; };
auto maximum = [](int a, int b) { return a > b ? a : b; };
friend FMT_CONSTEXPR auto add_compare(const bigint& lhs1, const bigint& lhs2,
const bigint& rhs) -> int {
int max_lhs_bigits = maximum(lhs1.num_bigits(), lhs2.num_bigits());
int num_rhs_bigits = rhs.num_bigits();
if (max_lhs_bigits + 1 < num_rhs_bigits) return -1;
if (max_lhs_bigits > num_rhs_bigits) return 1;
auto get_bigit = [](const bigint& n, int i) -> bigit {
return i >= n.exp_ && i < n.num_bigits() ? n[i - n.exp_] : 0;
};
double_bigit borrow = 0;
int min_exp = minimum(minimum(lhs1.exp_, lhs2.exp_), rhs.exp_);
for (int i = num_rhs_bigits - 1; i >= min_exp; --i) {
double_bigit sum =
static_cast<double_bigit>(get_bigit(lhs1, i)) + get_bigit(lhs2, i);
bigit rhs_bigit = get_bigit(rhs, i);
static_cast<double_bigit>(lhs1.get_bigit(i)) + lhs2.get_bigit(i);
bigit rhs_bigit = rhs.get_bigit(i);
if (sum > rhs_bigit + borrow) return 1;
borrow = rhs_bigit + borrow - sum;
if (borrow > 1) return -1;
@ -2890,7 +2888,7 @@ class bigint {
// If this bigint has a bigger exponent than other, adds trailing zero to make
// exponents equal. This simplifies some operations such as subtraction.
FMT_CONSTEXPR20 void align(const bigint& other) {
FMT_CONSTEXPR void align(const bigint& other) {
int exp_difference = exp_ - other.exp_;
if (exp_difference <= 0) return;
int num_bigits = static_cast<int>(bigits_.size());
@ -2903,7 +2901,7 @@ class bigint {
// Divides this bignum by divisor, assigning the remainder to this and
// returning the quotient.
FMT_CONSTEXPR20 auto divmod_assign(const bigint& divisor) -> int {
FMT_CONSTEXPR auto divmod_assign(const bigint& divisor) -> int {
FMT_ASSERT(this != &divisor, "");
if (compare(*this, divisor) < 0) return 0;
FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1u] != 0, "");

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@ -12,7 +12,7 @@
void throw_assertion_failure(const char* message);
#define FMT_ASSERT(condition, message) \
if (!(condition)) throw_assertion_failure(message);
((condition) ? (void)0 : throw_assertion_failure(message))
#include "gtest/gtest.h"