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fmtlegacy/include/fmt/format-inl.h
Victor Zverovich 75765bfad5 Avoid unnecessary unsigned overflows (#1515)
2020-01-18 08:19:27 -08:00

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// Formatting library for C++ - implementation
//
// Copyright (c) 2012 - 2016, Victor Zverovich
// All rights reserved.
//
// For the license information refer to format.h.
#ifndef FMT_FORMAT_INL_H_
#define FMT_FORMAT_INL_H_
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <cstdarg>
#include <cstring> // for std::memmove
#include <cwchar>
#include "format.h"
#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
# include <locale>
#endif
#ifdef _WIN32
# include <io.h>
# include <windows.h>
#endif
#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable : 4702) // unreachable code
#endif
// Dummy implementations of strerror_r and strerror_s called if corresponding
// system functions are not available.
inline fmt::internal::null<> strerror_r(int, char*, ...) { return {}; }
inline fmt::internal::null<> strerror_s(char*, std::size_t, ...) { return {}; }
FMT_BEGIN_NAMESPACE
namespace internal {
FMT_FUNC void assert_fail(const char* file, int line, const char* message) {
print(stderr, "{}:{}: assertion failed: {}", file, line, message);
std::abort();
}
#ifndef _MSC_VER
# define FMT_SNPRINTF snprintf
#else // _MSC_VER
inline int fmt_snprintf(char* buffer, size_t size, const char* format, ...) {
va_list args;
va_start(args, format);
int result = vsnprintf_s(buffer, size, _TRUNCATE, format, args);
va_end(args);
return result;
}
# define FMT_SNPRINTF fmt_snprintf
#endif // _MSC_VER
// A portable thread-safe version of strerror.
// Sets buffer to point to a string describing the error code.
// This can be either a pointer to a string stored in buffer,
// or a pointer to some static immutable string.
// Returns one of the following values:
// 0 - success
// ERANGE - buffer is not large enough to store the error message
// other - failure
// Buffer should be at least of size 1.
FMT_FUNC int safe_strerror(int error_code, char*& buffer,
std::size_t buffer_size) FMT_NOEXCEPT {
FMT_ASSERT(buffer != nullptr && buffer_size != 0, "invalid buffer");
class dispatcher {
private:
int error_code_;
char*& buffer_;
std::size_t buffer_size_;
// A noop assignment operator to avoid bogus warnings.
void operator=(const dispatcher&) {}
// Handle the result of XSI-compliant version of strerror_r.
int handle(int result) {
// glibc versions before 2.13 return result in errno.
return result == -1 ? errno : result;
}
// Handle the result of GNU-specific version of strerror_r.
int handle(char* message) {
// If the buffer is full then the message is probably truncated.
if (message == buffer_ && strlen(buffer_) == buffer_size_ - 1)
return ERANGE;
buffer_ = message;
return 0;
}
// Handle the case when strerror_r is not available.
int handle(internal::null<>) {
return fallback(strerror_s(buffer_, buffer_size_, error_code_));
}
// Fallback to strerror_s when strerror_r is not available.
int fallback(int result) {
// If the buffer is full then the message is probably truncated.
return result == 0 && strlen(buffer_) == buffer_size_ - 1 ? ERANGE
: result;
}
#if !FMT_MSC_VER
// Fallback to strerror if strerror_r and strerror_s are not available.
int fallback(internal::null<>) {
errno = 0;
buffer_ = strerror(error_code_);
return errno;
}
#endif
public:
dispatcher(int err_code, char*& buf, std::size_t buf_size)
: error_code_(err_code), buffer_(buf), buffer_size_(buf_size) {}
int run() { return handle(strerror_r(error_code_, buffer_, buffer_size_)); }
};
return dispatcher(error_code, buffer, buffer_size).run();
}
FMT_FUNC void format_error_code(internal::buffer<char>& out, int error_code,
string_view message) FMT_NOEXCEPT {
// Report error code making sure that the output fits into
// inline_buffer_size to avoid dynamic memory allocation and potential
// bad_alloc.
out.resize(0);
static const char SEP[] = ": ";
static const char ERROR_STR[] = "error ";
// Subtract 2 to account for terminating null characters in SEP and ERROR_STR.
std::size_t error_code_size = sizeof(SEP) + sizeof(ERROR_STR) - 2;
auto abs_value = static_cast<uint32_or_64_or_128_t<int>>(error_code);
if (internal::is_negative(error_code)) {
abs_value = 0 - abs_value;
++error_code_size;
}
error_code_size += internal::to_unsigned(internal::count_digits(abs_value));
internal::writer w(out);
if (message.size() <= inline_buffer_size - error_code_size) {
w.write(message);
w.write(SEP);
}
w.write(ERROR_STR);
w.write(error_code);
assert(out.size() <= inline_buffer_size);
}
FMT_FUNC void report_error(format_func func, int error_code,
string_view message) FMT_NOEXCEPT {
memory_buffer full_message;
func(full_message, error_code, message);
// Don't use fwrite_fully because the latter may throw.
(void)std::fwrite(full_message.data(), full_message.size(), 1, stderr);
std::fputc('\n', stderr);
}
// A wrapper around fwrite that throws on error.
FMT_FUNC void fwrite_fully(const void* ptr, size_t size, size_t count,
FILE* stream) {
size_t written = std::fwrite(ptr, size, count, stream);
if (written < count) FMT_THROW(system_error(errno, "cannot write to file"));
}
} // namespace internal
#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
namespace internal {
template <typename Locale>
locale_ref::locale_ref(const Locale& loc) : locale_(&loc) {
static_assert(std::is_same<Locale, std::locale>::value, "");
}
template <typename Locale> Locale locale_ref::get() const {
static_assert(std::is_same<Locale, std::locale>::value, "");
return locale_ ? *static_cast<const std::locale*>(locale_) : std::locale();
}
template <typename Char> FMT_FUNC std::string grouping_impl(locale_ref loc) {
return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>()).grouping();
}
template <typename Char> FMT_FUNC Char thousands_sep_impl(locale_ref loc) {
return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>())
.thousands_sep();
}
template <typename Char> FMT_FUNC Char decimal_point_impl(locale_ref loc) {
return std::use_facet<std::numpunct<Char>>(loc.get<std::locale>())
.decimal_point();
}
} // namespace internal
#else
template <typename Char>
FMT_FUNC std::string internal::grouping_impl(locale_ref) {
return "\03";
}
template <typename Char>
FMT_FUNC Char internal::thousands_sep_impl(locale_ref) {
return FMT_STATIC_THOUSANDS_SEPARATOR;
}
template <typename Char>
FMT_FUNC Char internal::decimal_point_impl(locale_ref) {
return '.';
}
#endif
FMT_API FMT_FUNC format_error::~format_error() FMT_NOEXCEPT = default;
FMT_API FMT_FUNC system_error::~system_error() FMT_NOEXCEPT = default;
FMT_FUNC void system_error::init(int err_code, string_view format_str,
format_args args) {
error_code_ = err_code;
memory_buffer buffer;
format_system_error(buffer, err_code, vformat(format_str, args));
std::runtime_error& base = *this;
base = std::runtime_error(to_string(buffer));
}
namespace internal {
template <> FMT_FUNC int count_digits<4>(internal::fallback_uintptr n) {
// fallback_uintptr is always stored in little endian.
int i = static_cast<int>(sizeof(void*)) - 1;
while (i > 0 && n.value[i] == 0) --i;
auto char_digits = std::numeric_limits<unsigned char>::digits / 4;
return i >= 0 ? i * char_digits + count_digits<4, unsigned>(n.value[i]) : 1;
}
template <typename T>
const char basic_data<T>::digits[] =
"0001020304050607080910111213141516171819"
"2021222324252627282930313233343536373839"
"4041424344454647484950515253545556575859"
"6061626364656667686970717273747576777879"
"8081828384858687888990919293949596979899";
template <typename T>
const char basic_data<T>::hex_digits[] = "0123456789abcdef";
#define FMT_POWERS_OF_10(factor) \
factor * 10, (factor)*100, (factor)*1000, (factor)*10000, (factor)*100000, \
(factor)*1000000, (factor)*10000000, (factor)*100000000, \
(factor)*1000000000
template <typename T>
const uint64_t basic_data<T>::powers_of_10_64[] = {
1, FMT_POWERS_OF_10(1), FMT_POWERS_OF_10(1000000000ULL),
10000000000000000000ULL};
template <typename T>
const uint32_t basic_data<T>::zero_or_powers_of_10_32[] = {0,
FMT_POWERS_OF_10(1)};
template <typename T>
const uint64_t basic_data<T>::zero_or_powers_of_10_64[] = {
0, FMT_POWERS_OF_10(1), FMT_POWERS_OF_10(1000000000ULL),
10000000000000000000ULL};
// Normalized 64-bit significands of pow(10, k), for k = -348, -340, ..., 340.
// These are generated by support/compute-powers.py.
template <typename T>
const uint64_t basic_data<T>::pow10_significands[] = {
0xfa8fd5a0081c0288, 0xbaaee17fa23ebf76, 0x8b16fb203055ac76,
0xcf42894a5dce35ea, 0x9a6bb0aa55653b2d, 0xe61acf033d1a45df,
0xab70fe17c79ac6ca, 0xff77b1fcbebcdc4f, 0xbe5691ef416bd60c,
0x8dd01fad907ffc3c, 0xd3515c2831559a83, 0x9d71ac8fada6c9b5,
0xea9c227723ee8bcb, 0xaecc49914078536d, 0x823c12795db6ce57,
0xc21094364dfb5637, 0x9096ea6f3848984f, 0xd77485cb25823ac7,
0xa086cfcd97bf97f4, 0xef340a98172aace5, 0xb23867fb2a35b28e,
0x84c8d4dfd2c63f3b, 0xc5dd44271ad3cdba, 0x936b9fcebb25c996,
0xdbac6c247d62a584, 0xa3ab66580d5fdaf6, 0xf3e2f893dec3f126,
0xb5b5ada8aaff80b8, 0x87625f056c7c4a8b, 0xc9bcff6034c13053,
0x964e858c91ba2655, 0xdff9772470297ebd, 0xa6dfbd9fb8e5b88f,
0xf8a95fcf88747d94, 0xb94470938fa89bcf, 0x8a08f0f8bf0f156b,
0xcdb02555653131b6, 0x993fe2c6d07b7fac, 0xe45c10c42a2b3b06,
0xaa242499697392d3, 0xfd87b5f28300ca0e, 0xbce5086492111aeb,
0x8cbccc096f5088cc, 0xd1b71758e219652c, 0x9c40000000000000,
0xe8d4a51000000000, 0xad78ebc5ac620000, 0x813f3978f8940984,
0xc097ce7bc90715b3, 0x8f7e32ce7bea5c70, 0xd5d238a4abe98068,
0x9f4f2726179a2245, 0xed63a231d4c4fb27, 0xb0de65388cc8ada8,
0x83c7088e1aab65db, 0xc45d1df942711d9a, 0x924d692ca61be758,
0xda01ee641a708dea, 0xa26da3999aef774a, 0xf209787bb47d6b85,
0xb454e4a179dd1877, 0x865b86925b9bc5c2, 0xc83553c5c8965d3d,
0x952ab45cfa97a0b3, 0xde469fbd99a05fe3, 0xa59bc234db398c25,
0xf6c69a72a3989f5c, 0xb7dcbf5354e9bece, 0x88fcf317f22241e2,
0xcc20ce9bd35c78a5, 0x98165af37b2153df, 0xe2a0b5dc971f303a,
0xa8d9d1535ce3b396, 0xfb9b7cd9a4a7443c, 0xbb764c4ca7a44410,
0x8bab8eefb6409c1a, 0xd01fef10a657842c, 0x9b10a4e5e9913129,
0xe7109bfba19c0c9d, 0xac2820d9623bf429, 0x80444b5e7aa7cf85,
0xbf21e44003acdd2d, 0x8e679c2f5e44ff8f, 0xd433179d9c8cb841,
0x9e19db92b4e31ba9, 0xeb96bf6ebadf77d9, 0xaf87023b9bf0ee6b,
};
// Binary exponents of pow(10, k), for k = -348, -340, ..., 340, corresponding
// to significands above.
template <typename T>
const int16_t basic_data<T>::pow10_exponents[] = {
-1220, -1193, -1166, -1140, -1113, -1087, -1060, -1034, -1007, -980, -954,
-927, -901, -874, -847, -821, -794, -768, -741, -715, -688, -661,
-635, -608, -582, -555, -529, -502, -475, -449, -422, -396, -369,
-343, -316, -289, -263, -236, -210, -183, -157, -130, -103, -77,
-50, -24, 3, 30, 56, 83, 109, 136, 162, 189, 216,
242, 269, 295, 322, 348, 375, 402, 428, 455, 481, 508,
534, 561, 588, 614, 641, 667, 694, 720, 747, 774, 800,
827, 853, 880, 907, 933, 960, 986, 1013, 1039, 1066};
template <typename T>
const char basic_data<T>::foreground_color[] = "\x1b[38;2;";
template <typename T>
const char basic_data<T>::background_color[] = "\x1b[48;2;";
template <typename T> const char basic_data<T>::reset_color[] = "\x1b[0m";
template <typename T> const wchar_t basic_data<T>::wreset_color[] = L"\x1b[0m";
template <typename T> const char basic_data<T>::signs[] = {0, '-', '+', ' '};
template <typename T> struct bits {
static FMT_CONSTEXPR_DECL const int value =
static_cast<int>(sizeof(T) * std::numeric_limits<unsigned char>::digits);
};
class fp;
template <int SHIFT = 0> fp normalize(fp value);
// Lower (upper) boundary is a value half way between a floating-point value
// and its predecessor (successor). Boundaries have the same exponent as the
// value so only significands are stored.
struct boundaries {
uint64_t lower;
uint64_t upper;
};
// A handmade floating-point number f * pow(2, e).
class fp {
private:
using significand_type = uint64_t;
// All sizes are in bits.
// Subtract 1 to account for an implicit most significant bit in the
// normalized form.
static FMT_CONSTEXPR_DECL const int double_significand_size =
std::numeric_limits<double>::digits - 1;
static FMT_CONSTEXPR_DECL const uint64_t implicit_bit =
1ULL << double_significand_size;
public:
significand_type f;
int e;
static FMT_CONSTEXPR_DECL const int significand_size =
bits<significand_type>::value;
fp() : f(0), e(0) {}
fp(uint64_t f_val, int e_val) : f(f_val), e(e_val) {}
// Constructs fp from an IEEE754 double. It is a template to prevent compile
// errors on platforms where double is not IEEE754.
template <typename Double> explicit fp(Double d) { assign(d); }
// Normalizes the value converted from double and multiplied by (1 << SHIFT).
template <int SHIFT> friend fp normalize(fp value) {
// Handle subnormals.
const auto shifted_implicit_bit = fp::implicit_bit << SHIFT;
while ((value.f & shifted_implicit_bit) == 0) {
value.f <<= 1;
--value.e;
}
// Subtract 1 to account for hidden bit.
const auto offset =
fp::significand_size - fp::double_significand_size - SHIFT - 1;
value.f <<= offset;
value.e -= offset;
return value;
}
// Assigns d to this and return true iff predecessor is closer than successor.
template <typename Double, FMT_ENABLE_IF(sizeof(Double) == sizeof(uint64_t))>
bool assign(Double d) {
// Assume double is in the format [sign][exponent][significand].
using limits = std::numeric_limits<Double>;
const int exponent_size =
bits<Double>::value - double_significand_size - 1; // -1 for sign
const uint64_t significand_mask = implicit_bit - 1;
const uint64_t exponent_mask = (~0ULL >> 1) & ~significand_mask;
const int exponent_bias = (1 << exponent_size) - limits::max_exponent - 1;
auto u = bit_cast<uint64_t>(d);
f = u & significand_mask;
int biased_e =
static_cast<int>((u & exponent_mask) >> double_significand_size);
// Predecessor is closer if d is a normalized power of 2 (f == 0) other than
// the smallest normalized number (biased_e > 1).
bool is_predecessor_closer = f == 0 && biased_e > 1;
if (biased_e != 0)
f += implicit_bit;
else
biased_e = 1; // Subnormals use biased exponent 1 (min exponent).
e = biased_e - exponent_bias - double_significand_size;
return is_predecessor_closer;
}
template <typename Double, FMT_ENABLE_IF(sizeof(Double) != sizeof(uint64_t))>
bool assign(Double) {
*this = fp();
return false;
}
// Assigns d to this together with computing lower and upper boundaries,
// where a boundary is a value half way between the number and its predecessor
// (lower) or successor (upper). The upper boundary is normalized and lower
// has the same exponent but may be not normalized.
template <typename Double> boundaries assign_with_boundaries(Double d) {
bool is_lower_closer = assign(d);
fp lower =
is_lower_closer ? fp((f << 2) - 1, e - 2) : fp((f << 1) - 1, e - 1);
// 1 in normalize accounts for the exponent shift above.
fp upper = normalize<1>(fp((f << 1) + 1, e - 1));
lower.f <<= lower.e - upper.e;
return boundaries{lower.f, upper.f};
}
template <typename Double> boundaries assign_float_with_boundaries(Double d) {
assign(d);
constexpr int min_normal_e = std::numeric_limits<float>::min_exponent -
std::numeric_limits<double>::digits;
significand_type half_ulp = 1 << (std::numeric_limits<double>::digits -
std::numeric_limits<float>::digits - 1);
if (min_normal_e > e) half_ulp <<= min_normal_e - e;
fp upper = normalize<0>(fp(f + half_ulp, e));
fp lower = fp(
f - (half_ulp >> ((f == implicit_bit && e > min_normal_e) ? 1 : 0)), e);
lower.f <<= lower.e - upper.e;
return boundaries{lower.f, upper.f};
}
};
inline bool operator==(fp x, fp y) { return x.f == y.f && x.e == y.e; }
// Computes lhs * rhs / pow(2, 64) rounded to nearest with half-up tie breaking.
inline uint64_t multiply(uint64_t lhs, uint64_t rhs) {
#if FMT_USE_INT128
auto product = static_cast<__uint128_t>(lhs) * rhs;
auto f = static_cast<uint64_t>(product >> 64);
return (static_cast<uint64_t>(product) & (1ULL << 63)) != 0 ? f + 1 : f;
#else
// Multiply 32-bit parts of significands.
uint64_t mask = (1ULL << 32) - 1;
uint64_t a = lhs >> 32, b = lhs & mask;
uint64_t c = rhs >> 32, d = rhs & mask;
uint64_t ac = a * c, bc = b * c, ad = a * d, bd = b * d;
// Compute mid 64-bit of result and round.
uint64_t mid = (bd >> 32) + (ad & mask) + (bc & mask) + (1U << 31);
return ac + (ad >> 32) + (bc >> 32) + (mid >> 32);
#endif
}
inline fp operator*(fp x, fp y) { return {multiply(x.f, y.f), x.e + y.e + 64}; }
// Returns a cached power of 10 `c_k = c_k.f * pow(2, c_k.e)` such that its
// (binary) exponent satisfies `min_exponent <= c_k.e <= min_exponent + 28`.
inline fp get_cached_power(int min_exponent, int& pow10_exponent) {
const int64_t one_over_log2_10 = 0x4d104d42; // round(pow(2, 32) / log2(10))
int index = static_cast<int>(
((min_exponent + fp::significand_size - 1) * one_over_log2_10 +
((int64_t(1) << 32) - 1)) // ceil
>> 32 // arithmetic shift
);
// Decimal exponent of the first (smallest) cached power of 10.
const int first_dec_exp = -348;
// Difference between 2 consecutive decimal exponents in cached powers of 10.
const int dec_exp_step = 8;
index = (index - first_dec_exp - 1) / dec_exp_step + 1;
pow10_exponent = first_dec_exp + index * dec_exp_step;
return {data::pow10_significands[index], data::pow10_exponents[index]};
}
// A simple accumulator to hold the sums of terms in bigint::square if uint128_t
// is not available.
struct accumulator {
uint64_t lower;
uint64_t upper;
accumulator() : lower(0), upper(0) {}
explicit operator uint32_t() const { return static_cast<uint32_t>(lower); }
void operator+=(uint64_t n) {
lower += n;
if (lower < n) ++upper;
}
void operator>>=(int shift) {
assert(shift == 32);
(void)shift;
lower = (upper << 32) | (lower >> 32);
upper >>= 32;
}
};
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;
using double_bigit = uint64_t;
enum { bigits_capacity = 32 };
basic_memory_buffer<bigit, bigits_capacity> bigits_;
int exp_;
static FMT_CONSTEXPR_DECL const int bigit_bits = bits<bigit>::value;
friend struct formatter<bigint>;
void subtract_bigits(int index, bigit other, bigit& borrow) {
auto result = static_cast<double_bigit>(bigits_[index]) - other - borrow;
bigits_[index] = static_cast<bigit>(result);
borrow = static_cast<bigit>(result >> (bigit_bits * 2 - 1));
}
void remove_leading_zeros() {
int num_bigits = static_cast<int>(bigits_.size()) - 1;
while (num_bigits > 0 && bigits_[num_bigits] == 0) --num_bigits;
bigits_.resize(num_bigits + 1);
}
// Computes *this -= other assuming aligned bigints and *this >= other.
void subtract_aligned(const bigint& other) {
FMT_ASSERT(other.exp_ >= exp_, "unaligned bigints");
FMT_ASSERT(compare(*this, other) >= 0, "");
bigit borrow = 0;
int i = other.exp_ - exp_;
for (int j = 0, n = static_cast<int>(other.bigits_.size()); j != n;
++i, ++j) {
subtract_bigits(i, other.bigits_[j], borrow);
}
while (borrow > 0) subtract_bigits(i, 0, borrow);
remove_leading_zeros();
}
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) {
double_bigit result = bigits_[i] * wide_value + carry;
bigits_[i] = static_cast<bigit>(result);
carry = static_cast<bigit>(result >> bigit_bits);
}
if (carry != 0) bigits_.push_back(carry);
}
void multiply(uint64_t value) {
const bigit mask = ~bigit(0);
const double_bigit lower = value & mask;
const double_bigit upper = value >> bigit_bits;
double_bigit carry = 0;
for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
double_bigit result = bigits_[i] * lower + (carry & mask);
carry =
bigits_[i] * upper + (result >> bigit_bits) + (carry >> bigit_bits);
bigits_[i] = static_cast<bigit>(result);
}
while (carry != 0) {
bigits_.push_back(carry & mask);
carry >>= bigit_bits;
}
}
public:
bigint() : exp_(0) {}
explicit bigint(uint64_t n) { assign(n); }
~bigint() { assert(bigits_.capacity() <= bigits_capacity); }
bigint(const bigint&) = delete;
void operator=(const bigint&) = delete;
void assign(const bigint& other) {
bigits_.resize(other.bigits_.size());
auto data = other.bigits_.data();
std::copy(data, data + other.bigits_.size(), bigits_.data());
exp_ = other.exp_;
}
void assign(uint64_t n) {
int num_bigits = 0;
do {
bigits_[num_bigits++] = n & ~bigit(0);
n >>= bigit_bits;
} while (n != 0);
bigits_.resize(num_bigits);
exp_ = 0;
}
int num_bigits() const { return static_cast<int>(bigits_.size()) + exp_; }
bigint& operator<<=(int shift) {
assert(shift >= 0);
exp_ += shift / bigit_bits;
shift %= bigit_bits;
if (shift == 0) return *this;
bigit carry = 0;
for (size_t i = 0, n = bigits_.size(); i < n; ++i) {
bigit c = bigits_[i] >> (bigit_bits - shift);
bigits_[i] = (bigits_[i] << shift) + carry;
carry = c;
}
if (carry != 0) bigits_.push_back(carry);
return *this;
}
template <typename Int> bigint& operator*=(Int value) {
FMT_ASSERT(value > 0, "");
multiply(uint32_or_64_or_128_t<Int>(value));
return *this;
}
friend int compare(const bigint& lhs, const bigint& rhs) {
int num_lhs_bigits = lhs.num_bigits(), num_rhs_bigits = rhs.num_bigits();
if (num_lhs_bigits != num_rhs_bigits)
return num_lhs_bigits > num_rhs_bigits ? 1 : -1;
int i = static_cast<int>(lhs.bigits_.size()) - 1;
int j = static_cast<int>(rhs.bigits_.size()) - 1;
int end = i - j;
if (end < 0) end = 0;
for (; i >= end; --i, --j) {
bigit lhs_bigit = lhs.bigits_[i], rhs_bigit = rhs.bigits_[j];
if (lhs_bigit != rhs_bigit) return lhs_bigit > rhs_bigit ? 1 : -1;
}
if (i != j) return i > j ? 1 : -1;
return 0;
}
// Returns compare(lhs1 + lhs2, rhs).
friend int add_compare(const bigint& lhs1, const bigint& lhs2,
const bigint& rhs) {
int max_lhs_bigits = (std::max)(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.bigits_[i - n.exp_] : 0;
};
double_bigit borrow = 0;
int min_exp = (std::min)((std::min)(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);
if (sum > rhs_bigit + borrow) return 1;
borrow = rhs_bigit + borrow - sum;
if (borrow > 1) return -1;
borrow <<= bigit_bits;
}
return borrow != 0 ? -1 : 0;
}
// Assigns pow(10, exp) to this bigint.
void assign_pow10(int exp) {
assert(exp >= 0);
if (exp == 0) return assign(1);
// Find the top bit.
int bitmask = 1;
while (exp >= bitmask) bitmask <<= 1;
bitmask >>= 1;
// pow(10, exp) = pow(5, exp) * pow(2, exp). First compute pow(5, exp) by
// repeated squaring and multiplication.
assign(5);
bitmask >>= 1;
while (bitmask != 0) {
square();
if ((exp & bitmask) != 0) *this *= 5;
bitmask >>= 1;
}
*this <<= exp; // Multiply by pow(2, exp) by shifting.
}
void square() {
basic_memory_buffer<bigit, bigits_capacity> n(std::move(bigits_));
int num_bigits = static_cast<int>(bigits_.size());
int num_result_bigits = 2 * num_bigits;
bigits_.resize(num_result_bigits);
using accumulator_t = conditional_t<FMT_USE_INT128, uint128_t, accumulator>;
auto sum = accumulator_t();
for (int bigit_index = 0; bigit_index < num_bigits; ++bigit_index) {
// Compute bigit at position bigit_index of the result by adding
// cross-product terms n[i] * n[j] such that i + j == bigit_index.
for (int i = 0, j = bigit_index; j >= 0; ++i, --j) {
// Most terms are multiplied twice which can be optimized in the future.
sum += static_cast<double_bigit>(n[i]) * n[j];
}
bigits_[bigit_index] = static_cast<bigit>(sum);
sum >>= bits<bigit>::value; // Compute the carry.
}
// Do the same for the top half.
for (int bigit_index = num_bigits; bigit_index < num_result_bigits;
++bigit_index) {
for (int j = num_bigits - 1, i = bigit_index - j; i < num_bigits;)
sum += static_cast<double_bigit>(n[i++]) * n[j--];
bigits_[bigit_index] = static_cast<bigit>(sum);
sum >>= bits<bigit>::value;
}
--num_result_bigits;
remove_leading_zeros();
exp_ *= 2;
}
// Divides this bignum by divisor, assigning the remainder to this and
// returning the quotient.
int divmod_assign(const bigint& divisor) {
FMT_ASSERT(this != &divisor, "");
if (compare(*this, divisor) < 0) return 0;
int num_bigits = static_cast<int>(bigits_.size());
FMT_ASSERT(divisor.bigits_[divisor.bigits_.size() - 1] != 0, "");
int exp_difference = exp_ - divisor.exp_;
if (exp_difference > 0) {
// Align bigints by adding trailing zeros to simplify subtraction.
bigits_.resize(num_bigits + exp_difference);
for (int i = num_bigits - 1, j = i + exp_difference; i >= 0; --i, --j)
bigits_[j] = bigits_[i];
std::uninitialized_fill_n(bigits_.data(), exp_difference, 0);
exp_ -= exp_difference;
}
int quotient = 0;
do {
subtract_aligned(divisor);
++quotient;
} while (compare(*this, divisor) >= 0);
return quotient;
}
};
enum class round_direction { unknown, up, down };
// Given the divisor (normally a power of 10), the remainder = v % divisor for
// some number v and the error, returns whether v should be rounded up, down, or
// whether the rounding direction can't be determined due to error.
// error should be less than divisor / 2.
inline round_direction get_round_direction(uint64_t divisor, uint64_t remainder,
uint64_t error) {
FMT_ASSERT(remainder < divisor, ""); // divisor - remainder won't overflow.
FMT_ASSERT(error < divisor, ""); // divisor - error won't overflow.
FMT_ASSERT(error < divisor - error, ""); // error * 2 won't overflow.
// Round down if (remainder + error) * 2 <= divisor.
if (remainder <= divisor - remainder && error * 2 <= divisor - remainder * 2)
return round_direction::down;
// Round up if (remainder - error) * 2 >= divisor.
if (remainder >= error &&
remainder - error >= divisor - (remainder - error)) {
return round_direction::up;
}
return round_direction::unknown;
}
namespace digits {
enum result {
more, // Generate more digits.
done, // Done generating digits.
error // Digit generation cancelled due to an error.
};
}
// A version of count_digits optimized for grisu_gen_digits.
inline unsigned grisu_count_digits(uint32_t n) {
if (n < 10) return 1;
if (n < 100) return 2;
if (n < 1000) return 3;
if (n < 10000) return 4;
if (n < 100000) return 5;
if (n < 1000000) return 6;
if (n < 10000000) return 7;
if (n < 100000000) return 8;
if (n < 1000000000) return 9;
return 10;
}
// Generates output using the Grisu digit-gen algorithm.
// error: the size of the region (lower, upper) outside of which numbers
// definitely do not round to value (Delta in Grisu3).
template <typename Handler>
FMT_ALWAYS_INLINE digits::result grisu_gen_digits(fp value, uint64_t error,
int& exp, Handler& handler) {
const fp one(1ULL << -value.e, value.e);
// The integral part of scaled value (p1 in Grisu) = value / one. It cannot be
// zero because it contains a product of two 64-bit numbers with MSB set (due
// to normalization) - 1, shifted right by at most 60 bits.
auto integral = static_cast<uint32_t>(value.f >> -one.e);
FMT_ASSERT(integral != 0, "");
FMT_ASSERT(integral == value.f >> -one.e, "");
// The fractional part of scaled value (p2 in Grisu) c = value % one.
uint64_t fractional = value.f & (one.f - 1);
exp = grisu_count_digits(integral); // kappa in Grisu.
// Divide by 10 to prevent overflow.
auto result = handler.on_start(data::powers_of_10_64[exp - 1] << -one.e,
value.f / 10, error * 10, exp);
if (result != digits::more) return result;
// Generate digits for the integral part. This can produce up to 10 digits.
do {
uint32_t digit = 0;
auto divmod_integral = [&](uint32_t divisor) {
digit = integral / divisor;
integral %= divisor;
};
// This optimization by Milo Yip reduces the number of integer divisions by
// one per iteration.
switch (exp) {
case 10:
divmod_integral(1000000000);
break;
case 9:
divmod_integral(100000000);
break;
case 8:
divmod_integral(10000000);
break;
case 7:
divmod_integral(1000000);
break;
case 6:
divmod_integral(100000);
break;
case 5:
divmod_integral(10000);
break;
case 4:
divmod_integral(1000);
break;
case 3:
divmod_integral(100);
break;
case 2:
divmod_integral(10);
break;
case 1:
digit = integral;
integral = 0;
break;
default:
FMT_ASSERT(false, "invalid number of digits");
}
--exp;
uint64_t remainder =
(static_cast<uint64_t>(integral) << -one.e) + fractional;
result = handler.on_digit(static_cast<char>('0' + digit),
data::powers_of_10_64[exp] << -one.e, remainder,
error, exp, true);
if (result != digits::more) return result;
} while (exp > 0);
// Generate digits for the fractional part.
for (;;) {
fractional *= 10;
error *= 10;
char digit =
static_cast<char>('0' + static_cast<char>(fractional >> -one.e));
fractional &= one.f - 1;
--exp;
result = handler.on_digit(digit, one.f, fractional, error, exp, false);
if (result != digits::more) return result;
}
}
// The fixed precision digit handler.
struct fixed_handler {
char* buf;
int size;
int precision;
int exp10;
bool fixed;
digits::result on_start(uint64_t divisor, uint64_t remainder, uint64_t error,
int& exp) {
// Non-fixed formats require at least one digit and no precision adjustment.
if (!fixed) return digits::more;
// Adjust fixed precision by exponent because it is relative to decimal
// point.
precision += exp + exp10;
// Check if precision is satisfied just by leading zeros, e.g.
// format("{:.2f}", 0.001) gives "0.00" without generating any digits.
if (precision > 0) return digits::more;
if (precision < 0) return digits::done;
auto dir = get_round_direction(divisor, remainder, error);
if (dir == round_direction::unknown) return digits::error;
buf[size++] = dir == round_direction::up ? '1' : '0';
return digits::done;
}
digits::result on_digit(char digit, uint64_t divisor, uint64_t remainder,
uint64_t error, int, bool integral) {
FMT_ASSERT(remainder < divisor, "");
buf[size++] = digit;
if (size < precision) return digits::more;
if (!integral) {
// Check if error * 2 < divisor with overflow prevention.
// The check is not needed for the integral part because error = 1
// and divisor > (1 << 32) there.
if (error >= divisor || error >= divisor - error) return digits::error;
} else {
FMT_ASSERT(error == 1 && divisor > 2, "");
}
auto dir = get_round_direction(divisor, remainder, error);
if (dir != round_direction::up)
return dir == round_direction::down ? digits::done : digits::error;
++buf[size - 1];
for (int i = size - 1; i > 0 && buf[i] > '9'; --i) {
buf[i] = '0';
++buf[i - 1];
}
if (buf[0] > '9') {
buf[0] = '1';
buf[size++] = '0';
}
return digits::done;
}
};
// The shortest representation digit handler.
struct grisu_shortest_handler {
char* buf;
int size;
// Distance between scaled value and upper bound (wp_W in Grisu3).
uint64_t diff;
digits::result on_start(uint64_t, uint64_t, uint64_t, int&) {
return digits::more;
}
// Decrement the generated number approaching value from above.
void round(uint64_t d, uint64_t divisor, uint64_t& remainder,
uint64_t error) {
while (
remainder < d && error - remainder >= divisor &&
(remainder + divisor < d || d - remainder >= remainder + divisor - d)) {
--buf[size - 1];
remainder += divisor;
}
}
// Implements Grisu's round_weed.
digits::result on_digit(char digit, uint64_t divisor, uint64_t remainder,
uint64_t error, int exp, bool integral) {
buf[size++] = digit;
if (remainder >= error) return digits::more;
uint64_t unit = integral ? 1 : data::powers_of_10_64[-exp];
uint64_t up = (diff - 1) * unit; // wp_Wup
round(up, divisor, remainder, error);
uint64_t down = (diff + 1) * unit; // wp_Wdown
if (remainder < down && error - remainder >= divisor &&
(remainder + divisor < down ||
down - remainder > remainder + divisor - down)) {
return digits::error;
}
return 2 * unit <= remainder && remainder <= error - 4 * unit
? digits::done
: digits::error;
}
};
// Formats value using a variation of the Fixed-Precision Positive
// Floating-Point Printout ((FPP)^2) algorithm by Steele & White:
// https://fmt.dev/p372-steele.pdf.
template <typename Double>
void fallback_format(Double d, buffer<char>& buf, int& exp10) {
bigint numerator; // 2 * R in (FPP)^2.
bigint denominator; // 2 * S in (FPP)^2.
// lower and upper are differences between value and corresponding boundaries.
bigint lower; // (M^- in (FPP)^2).
bigint upper_store; // upper's value if different from lower.
bigint* upper = nullptr; // (M^+ in (FPP)^2).
fp value;
// Shift numerator and denominator by an extra bit or two (if lower boundary
// is closer) to make lower and upper integers. This eliminates multiplication
// by 2 during later computations.
// TODO: handle float
int shift = value.assign(d) ? 2 : 1;
uint64_t significand = value.f << shift;
if (value.e >= 0) {
numerator.assign(significand);
numerator <<= value.e;
lower.assign(1);
lower <<= value.e;
if (shift != 1) {
upper_store.assign(1);
upper_store <<= value.e + 1;
upper = &upper_store;
}
denominator.assign_pow10(exp10);
denominator <<= 1;
} else if (exp10 < 0) {
numerator.assign_pow10(-exp10);
lower.assign(numerator);
if (shift != 1) {
upper_store.assign(numerator);
upper_store <<= 1;
upper = &upper_store;
}
numerator *= significand;
denominator.assign(1);
denominator <<= shift - value.e;
} else {
numerator.assign(significand);
denominator.assign_pow10(exp10);
denominator <<= shift - value.e;
lower.assign(1);
if (shift != 1) {
upper_store.assign(1ULL << 1);
upper = &upper_store;
}
}
if (!upper) upper = &lower;
// Invariant: value == (numerator / denominator) * pow(10, exp10).
bool even = (value.f & 1) == 0;
int num_digits = 0;
char* data = buf.data();
for (;;) {
int digit = numerator.divmod_assign(denominator);
bool low = compare(numerator, lower) - even < 0; // numerator <[=] lower.
// numerator + upper >[=] pow10:
bool high = add_compare(numerator, *upper, denominator) + even > 0;
data[num_digits++] = static_cast<char>('0' + digit);
if (low || high) {
if (!low) {
++data[num_digits - 1];
} else if (high) {
int result = add_compare(numerator, numerator, denominator);
// Round half to even.
if (result > 0 || (result == 0 && (digit % 2) != 0))
++data[num_digits - 1];
}
buf.resize(num_digits);
exp10 -= num_digits - 1;
return;
}
numerator *= 10;
lower *= 10;
if (upper != &lower) *upper *= 10;
}
}
// Formats value using the Grisu algorithm
// (https://www.cs.tufts.edu/~nr/cs257/archive/florian-loitsch/printf.pdf)
// if T is a IEEE754 binary32 or binary64 and snprintf otherwise.
template <typename T>
int format_float(T value, int precision, float_specs specs, buffer<char>& buf) {
static_assert(!std::is_same<T, float>::value, "");
FMT_ASSERT(value >= 0, "value is negative");
const bool fixed = specs.format == float_format::fixed;
if (value <= 0) { // <= instead of == to silence a warning.
if (precision <= 0 || !fixed) {
buf.push_back('0');
return 0;
}
buf.resize(to_unsigned(precision));
std::uninitialized_fill_n(buf.data(), precision, '0');
return -precision;
}
if (!specs.use_grisu) return snprintf_float(value, precision, specs, buf);
int exp = 0;
const int min_exp = -60; // alpha in Grisu.
int cached_exp10 = 0; // K in Grisu.
if (precision < 0) {
fp fp_value;
auto boundaries = specs.binary32
? fp_value.assign_float_with_boundaries(value)
: fp_value.assign_with_boundaries(value);
fp_value = normalize(fp_value);
// Find a cached power of 10 such that multiplying value by it will bring
// the exponent in the range [min_exp, -32].
const fp cached_pow = get_cached_power(
min_exp - (fp_value.e + fp::significand_size), cached_exp10);
// Multiply value and boundaries by the cached power of 10.
fp_value = fp_value * cached_pow;
boundaries.lower = multiply(boundaries.lower, cached_pow.f);
boundaries.upper = multiply(boundaries.upper, cached_pow.f);
assert(min_exp <= fp_value.e && fp_value.e <= -32);
--boundaries.lower; // \tilde{M}^- - 1 ulp -> M^-_{\downarrow}.
++boundaries.upper; // \tilde{M}^+ + 1 ulp -> M^+_{\uparrow}.
// Numbers outside of (lower, upper) definitely do not round to value.
grisu_shortest_handler handler{buf.data(), 0,
boundaries.upper - fp_value.f};
auto result =
grisu_gen_digits(fp(boundaries.upper, fp_value.e),
boundaries.upper - boundaries.lower, exp, handler);
if (result == digits::error) {
exp += handler.size - cached_exp10 - 1;
fallback_format(value, buf, exp);
return exp;
}
buf.resize(to_unsigned(handler.size));
} else {
if (precision > 17) return snprintf_float(value, precision, specs, buf);
fp normalized = normalize(fp(value));
const auto cached_pow = get_cached_power(
min_exp - (normalized.e + fp::significand_size), cached_exp10);
normalized = normalized * cached_pow;
fixed_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
if (grisu_gen_digits(normalized, 1, exp, handler) == digits::error)
return snprintf_float(value, precision, specs, buf);
int num_digits = handler.size;
if (!fixed) {
// Remove trailing zeros.
while (num_digits > 0 && buf[num_digits - 1] == '0') {
--num_digits;
++exp;
}
}
buf.resize(to_unsigned(num_digits));
}
return exp - cached_exp10;
}
template <typename T>
int snprintf_float(T value, int precision, float_specs specs,
buffer<char>& buf) {
// Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
FMT_ASSERT(buf.capacity() > buf.size(), "empty buffer");
static_assert(!std::is_same<T, float>::value, "");
// Subtract 1 to account for the difference in precision since we use %e for
// both general and exponent format.
if (specs.format == float_format::general ||
specs.format == float_format::exp)
precision = (precision >= 0 ? precision : 6) - 1;
// Build the format string.
enum { max_format_size = 7 }; // Ths longest format is "%#.*Le".
char format[max_format_size];
char* format_ptr = format;
*format_ptr++ = '%';
if (specs.showpoint && specs.format == float_format::hex) *format_ptr++ = '#';
if (precision >= 0) {
*format_ptr++ = '.';
*format_ptr++ = '*';
}
if (std::is_same<T, long double>()) *format_ptr++ = 'L';
*format_ptr++ = specs.format != float_format::hex
? (specs.format == float_format::fixed ? 'f' : 'e')
: (specs.upper ? 'A' : 'a');
*format_ptr = '\0';
// Format using snprintf.
auto offset = buf.size();
for (;;) {
auto begin = buf.data() + offset;
auto capacity = buf.capacity() - offset;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
if (precision > 100000)
throw std::runtime_error(
"fuzz mode - avoid large allocation inside snprintf");
#endif
// Suppress the warning about a nonliteral format string.
auto snprintf_ptr = FMT_SNPRINTF;
int result = precision >= 0
? snprintf_ptr(begin, capacity, format, precision, value)
: snprintf_ptr(begin, capacity, format, value);
if (result < 0) {
buf.reserve(buf.capacity() + 1); // The buffer will grow exponentially.
continue;
}
unsigned size = to_unsigned(result);
// Size equal to capacity means that the last character was truncated.
if (size >= capacity) {
buf.reserve(size + offset + 1); // Add 1 for the terminating '\0'.
continue;
}
auto is_digit = [](char c) { return c >= '0' && c <= '9'; };
if (specs.format == float_format::fixed) {
if (precision == 0) {
buf.resize(size);
return 0;
}
// Find and remove the decimal point.
auto end = begin + size, p = end;
do {
--p;
} while (is_digit(*p));
int fraction_size = static_cast<int>(end - p - 1);
std::memmove(p, p + 1, fraction_size);
buf.resize(size - 1);
return -fraction_size;
}
if (specs.format == float_format::hex) {
buf.resize(size + offset);
return 0;
}
// Find and parse the exponent.
auto end = begin + size, exp_pos = end;
do {
--exp_pos;
} while (*exp_pos != 'e');
char sign = exp_pos[1];
assert(sign == '+' || sign == '-');
int exp = 0;
auto p = exp_pos + 2; // Skip 'e' and sign.
do {
assert(is_digit(*p));
exp = exp * 10 + (*p++ - '0');
} while (p != end);
if (sign == '-') exp = -exp;
int fraction_size = 0;
if (exp_pos != begin + 1) {
// Remove trailing zeros.
auto fraction_end = exp_pos - 1;
while (*fraction_end == '0') --fraction_end;
// Move the fractional part left to get rid of the decimal point.
fraction_size = static_cast<int>(fraction_end - begin - 1);
std::memmove(begin + 1, begin + 2, fraction_size);
}
buf.resize(fraction_size + offset + 1);
return exp - fraction_size;
}
}
// A public domain branchless UTF-8 decoder by Christopher Wellons:
// https://github.com/skeeto/branchless-utf8
/* Decode the next character, c, from buf, reporting errors in e.
*
* Since this is a branchless decoder, four bytes will be read from the
* buffer regardless of the actual length of the next character. This
* means the buffer _must_ have at least three bytes of zero padding
* following the end of the data stream.
*
* Errors are reported in e, which will be non-zero if the parsed
* character was somehow invalid: invalid byte sequence, non-canonical
* encoding, or a surrogate half.
*
* The function returns a pointer to the next character. When an error
* occurs, this pointer will be a guess that depends on the particular
* error, but it will always advance at least one byte.
*/
FMT_FUNC const char* utf8_decode(const char* buf, uint32_t* c, int* e) {
static const char lengths[] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0,
0, 0, 2, 2, 2, 2, 3, 3, 4, 0};
static const int masks[] = {0x00, 0x7f, 0x1f, 0x0f, 0x07};
static const uint32_t mins[] = {4194304, 0, 128, 2048, 65536};
static const int shiftc[] = {0, 18, 12, 6, 0};
static const int shifte[] = {0, 6, 4, 2, 0};
auto s = reinterpret_cast<const unsigned char*>(buf);
int len = lengths[s[0] >> 3];
// Compute the pointer to the next character early so that the next
// iteration can start working on the next character. Neither Clang
// nor GCC figure out this reordering on their own.
const char* next = buf + len + !len;
// Assume a four-byte character and load four bytes. Unused bits are
// shifted out.
*c = uint32_t(s[0] & masks[len]) << 18;
*c |= uint32_t(s[1] & 0x3f) << 12;
*c |= uint32_t(s[2] & 0x3f) << 6;
*c |= uint32_t(s[3] & 0x3f) << 0;
*c >>= shiftc[len];
// Accumulate the various error conditions.
*e = (*c < mins[len]) << 6; // non-canonical encoding
*e |= ((*c >> 11) == 0x1b) << 7; // surrogate half?
*e |= (*c > 0x10FFFF) << 8; // out of range?
*e |= (s[1] & 0xc0) >> 2;
*e |= (s[2] & 0xc0) >> 4;
*e |= (s[3]) >> 6;
*e ^= 0x2a; // top two bits of each tail byte correct?
*e >>= shifte[len];
return next;
}
} // namespace internal
template <> struct formatter<internal::bigint> {
format_parse_context::iterator parse(format_parse_context& ctx) {
return ctx.begin();
}
format_context::iterator format(const internal::bigint& n,
format_context& ctx) {
auto out = ctx.out();
bool first = true;
for (auto i = n.bigits_.size(); i > 0; --i) {
auto value = n.bigits_[i - 1];
if (first) {
out = format_to(out, "{:x}", value);
first = false;
continue;
}
out = format_to(out, "{:08x}", value);
}
if (n.exp_ > 0)
out = format_to(out, "p{}", n.exp_ * internal::bigint::bigit_bits);
return out;
}
};
FMT_FUNC internal::utf8_to_utf16::utf8_to_utf16(string_view s) {
auto transcode = [this](const char* p) {
auto cp = uint32_t();
auto error = 0;
p = utf8_decode(p, &cp, &error);
if (error != 0) FMT_THROW(std::runtime_error("invalid utf8"));
if (cp <= 0xFFFF) {
buffer_.push_back(static_cast<wchar_t>(cp));
} else {
cp -= 0x10000;
buffer_.push_back(static_cast<wchar_t>(0xD800 + (cp >> 10)));
buffer_.push_back(static_cast<wchar_t>(0xDC00 + (cp & 0x3FF)));
}
return p;
};
auto p = s.data();
const size_t block_size = 4; // utf8_decode always reads blocks of 4 chars.
if (s.size() >= block_size) {
for (auto end = p + s.size() - block_size + 1; p < end;) p = transcode(p);
}
if (auto num_chars_left = s.data() + s.size() - p) {
char buf[2 * block_size - 1] = {};
memcpy(buf, p, num_chars_left);
p = buf;
do {
p = transcode(p);
} while (p - buf < num_chars_left);
}
buffer_.push_back(0);
}
FMT_FUNC void format_system_error(internal::buffer<char>& out, int error_code,
string_view message) FMT_NOEXCEPT {
FMT_TRY {
memory_buffer buf;
buf.resize(inline_buffer_size);
for (;;) {
char* system_message = &buf[0];
int result =
internal::safe_strerror(error_code, system_message, buf.size());
if (result == 0) {
internal::writer w(out);
w.write(message);
w.write(": ");
w.write(system_message);
return;
}
if (result != ERANGE)
break; // Can't get error message, report error code instead.
buf.resize(buf.size() * 2);
}
}
FMT_CATCH(...) {}
format_error_code(out, error_code, message);
}
FMT_FUNC void internal::error_handler::on_error(const char* message) {
FMT_THROW(format_error(message));
}
FMT_FUNC void report_system_error(int error_code,
fmt::string_view message) FMT_NOEXCEPT {
report_error(format_system_error, error_code, message);
}
FMT_FUNC void vprint(std::FILE* f, string_view format_str, format_args args) {
memory_buffer buffer;
internal::vformat_to(buffer, format_str,
basic_format_args<buffer_context<char>>(args));
#ifdef _WIN32
auto fd = _fileno(f);
if (_isatty(fd)) {
internal::utf8_to_utf16 u16(string_view(buffer.data(), buffer.size()));
auto written = DWORD();
if (!WriteConsoleW(reinterpret_cast<HANDLE>(_get_osfhandle(fd)),
u16.c_str(), static_cast<DWORD>(u16.size()), &written,
nullptr)) {
throw format_error("failed to write to console");
}
return;
}
#endif
internal::fwrite_fully(buffer.data(), 1, buffer.size(), f);
}
#ifdef _WIN32
// Print assuming legacy (non-Unicode) encoding.
FMT_FUNC void internal::vprint_mojibake(std::FILE* f, string_view format_str,
format_args args) {
memory_buffer buffer;
internal::vformat_to(buffer, format_str,
basic_format_args<buffer_context<char>>(args));
fwrite_fully(buffer.data(), 1, buffer.size(), f);
}
#endif
FMT_FUNC void vprint(string_view format_str, format_args args) {
vprint(stdout, format_str, args);
}
FMT_END_NAMESPACE
#ifdef _MSC_VER
# pragma warning(pop)
#endif
#endif // FMT_FORMAT_INL_H_
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