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fmtlegacy/include/fmt/format-inl.h
Victor Zverovich 8d8ea21c69 Partially implement Grisu3
2019-04-27 12:17:21 -07:00

990 lines
35 KiB
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// Formatting library for C++
//
// 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 "format.h"
#include <string.h>
#include <cctype>
#include <cerrno>
#include <climits>
#include <cmath>
#include <cstdarg>
#include <cstddef> // for std::ptrdiff_t
#include <cstring> // for std::memmove
#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR)
# include <locale>
#endif
#if FMT_USE_WINDOWS_H
# if !defined(FMT_HEADER_ONLY) && !defined(WIN32_LEAN_AND_MEAN)
# define WIN32_LEAN_AND_MEAN
# endif
# if defined(NOMINMAX) || defined(FMT_WIN_MINMAX)
# include <windows.h>
# else
# define NOMINMAX
# include <windows.h>
# undef NOMINMAX
# endif
#endif
#if FMT_EXCEPTIONS
# define FMT_TRY try
# define FMT_CATCH(x) catch (x)
#else
# define FMT_TRY if (true)
# define FMT_CATCH(x) if (false)
#endif
#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable : 4127) // conditional expression is constant
# pragma warning(disable : 4702) // unreachable code
// Disable deprecation warning for strerror. The latter is not called but
// MSVC fails to detect it.
# pragma warning(disable : 4996)
#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 fmt::internal::null<>();
}
inline fmt::internal::null<> strerror_s(char*, std::size_t, ...) {
return fmt::internal::null<>();
}
FMT_BEGIN_NAMESPACE
namespace {
#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
#if defined(_WIN32) && defined(__MINGW32__) && !defined(__NO_ISOCEXT)
# define FMT_SWPRINTF snwprintf
#else
# define FMT_SWPRINTF swprintf
#endif // defined(_WIN32) && defined(__MINGW32__) && !defined(__NO_ISOCEXT)
typedef void (*FormatFunc)(internal::buffer<char>&, int, string_view);
// 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.
int safe_strerror(int error_code, char*& buffer,
std::size_t buffer_size) FMT_NOEXCEPT {
FMT_ASSERT(buffer != FMT_NULL && 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();
}
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;
typedef internal::int_traits<int>::main_type main_type;
main_type abs_value = static_cast<main_type>(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));
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);
}
// try an fwrite, FMT_THROW on failure
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"));
}
}
void report_error(FormatFunc func, int error_code,
string_view message) FMT_NOEXCEPT {
memory_buffer full_message;
func(full_message, error_code, message);
// Use Writer::data instead of Writer::c_str to avoid potential memory
// allocation.
fwrite_fully(full_message.data(), 1, full_message.size(), stderr);
std::fputc('\n', stderr);
}
} // namespace
FMT_FUNC size_t internal::count_code_points(basic_string_view<char8_t> s) {
const char8_t* data = s.data();
size_t num_code_points = 0;
for (size_t i = 0, size = s.size(); i != size; ++i) {
if ((data[i] & 0xc0) != 0x80) ++num_code_points;
}
return num_code_points;
}
#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 Char thousands_sep_impl(locale_ref loc) {
return std::use_facet<std::numpunct<Char> >(loc.get<std::locale>())
.thousands_sep();
}
} // namespace internal
#else
template <typename Char>
FMT_FUNC Char internal::thousands_sep_impl(locale_ref) {
return FMT_STATIC_THOUSANDS_SEPARATOR;
}
#endif
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::uintptr_t n) {
// Assume little endian; pointer formatting is implementation-defined anyway.
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>
int format_float(char* buf, std::size_t size, const char* format, int precision,
T value) {
return precision < 0 ? FMT_SNPRINTF(buf, size, format, value)
: FMT_SNPRINTF(buf, size, format, precision, value);
}
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> struct bits {
static FMT_CONSTEXPR_DECL const int value =
static_cast<int>(sizeof(T) * std::numeric_limits<unsigned char>::digits);
};
// A handmade floating-point number f * pow(2, e).
class fp {
private:
typedef uint64_t significand_type;
// 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) {
// Assume double is in the format [sign][exponent][significand].
typedef std::numeric_limits<Double> limits;
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);
auto biased_e = (u & exponent_mask) >> double_significand_size;
f = u & significand_mask;
if (biased_e != 0)
f += implicit_bit;
else
biased_e = 1; // Subnormals use biased exponent 1 (min exponent).
e = static_cast<int>(biased_e - exponent_bias - double_significand_size);
}
// Normalizes the value converted from double and multiplied by (1 << SHIFT).
template <int SHIFT = 0> void normalize() {
// Handle subnormals.
auto shifted_implicit_bit = implicit_bit << SHIFT;
while ((f & shifted_implicit_bit) == 0) {
f <<= 1;
--e;
}
// Subtract 1 to account for hidden bit.
auto offset = significand_size - double_significand_size - SHIFT - 1;
f <<= offset;
e -= offset;
}
// Compute lower and upper boundaries (m^- and m^+ in the Grisu paper), 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.
void compute_boundaries(fp& lower, fp& upper) const {
lower =
f == implicit_bit ? fp((f << 2) - 1, e - 2) : fp((f << 1) - 1, e - 1);
upper = fp((f << 1) + 1, e - 1);
upper.normalize<1>(); // 1 is to account for the exponent shift above.
lower.f <<= lower.e - upper.e;
lower.e = upper.e;
}
};
// Returns an fp number representing x - y. Result may not be normalized.
inline fp operator-(fp x, fp y) {
FMT_ASSERT(x.f >= y.f && x.e == y.e, "invalid operands");
return fp(x.f - y.f, x.e);
}
// Computes an fp number r with r.f = x.f * y.f / pow(2, 64) rounded to nearest
// with half-up tie breaking, r.e = x.e + y.e + 64. Result may not be
// normalized.
FMT_FUNC fp operator*(fp x, fp y) {
int exp = x.e + y.e + 64;
#if FMT_USE_INT128
auto product = static_cast<__uint128_t>(x.f) * y.f;
auto f = static_cast<uint64_t>(product >> 64);
if ((static_cast<uint64_t>(product) & (1ULL << 63)) != 0) ++f;
return fp(f, exp);
#else
// Multiply 32-bit parts of significands.
uint64_t mask = (1ULL << 32) - 1;
uint64_t a = x.f >> 32, b = x.f & mask;
uint64_t c = y.f >> 32, d = y.f & 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 fp(ac + (ad >> 32) + (bc >> 32) + (mid >> 32), exp);
#endif
}
// Returns 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.
FMT_FUNC fp get_cached_power(int min_exponent, int& pow10_exponent) {
const double one_over_log2_10 = 0.30102999566398114; // 1 / log2(10)
int index = static_cast<int>(
std::ceil((min_exponent + fp::significand_size - 1) * one_over_log2_10));
// 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 fp(data::POW10_SIGNIFICANDS[index], data::POW10_EXPONENTS[index]);
}
enum 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 down;
// Round up if (remainder - error) * 2 >= divisor.
if (remainder >= error &&
remainder - error >= divisor - (remainder - error)) {
return up;
}
return unknown;
}
namespace digits {
enum result {
more, // Generate more digits.
done, // Done generating digits.
error // Digit generation cancelled due to an error.
};
}
// 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>
digits::result grisu_gen_digits(fp value, uint64_t error, int& exp,
Handler& handler) {
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.
uint32_t 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 = 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;
// This optimization by miloyip reduces the number of integer divisions by
// one per iteration.
switch (exp) {
case 10:
digit = integral / 1000000000;
integral %= 1000000000;
break;
case 9:
digit = integral / 100000000;
integral %= 100000000;
break;
case 8:
digit = integral / 10000000;
integral %= 10000000;
break;
case 7:
digit = integral / 1000000;
integral %= 1000000;
break;
case 6:
digit = integral / 100000;
integral %= 100000;
break;
case 5:
digit = integral / 10000;
integral %= 10000;
break;
case 4:
digit = integral / 1000;
integral %= 1000;
break;
case 3:
digit = integral / 100;
integral %= 100;
break;
case 2:
digit = integral / 10;
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;
auto dir = get_round_direction(divisor, remainder, error);
if (dir == unknown) return digits::error;
buf[size++] = dir == 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 != up) return dir == 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.
template <int GRISU_VERSION> 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;
}
// This implements Grisu3'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;
if (GRISU_VERSION != 3) {
uint64_t d = integral ? diff : diff * data::POWERS_OF_10_64[-exp];
while (remainder < d && error - remainder >= divisor &&
(remainder + divisor < d ||
d - remainder > remainder + divisor - d)) {
--buf[size - 1];
remainder += divisor;
}
return digits::done;
}
uint64_t unit = integral ? 1 : data::POWERS_OF_10_64[-exp];
uint64_t up = diff + unit; // wp_Wup
while (remainder < up && error - remainder >= divisor &&
(remainder + divisor < up ||
up - remainder > remainder + divisor - up)) {
--buf[size - 1];
remainder += divisor;
}
uint64_t down = diff - 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;
}
};
template <typename Double, typename std::enable_if<
sizeof(Double) == sizeof(uint64_t), int>::type>
FMT_FUNC bool grisu_format(Double value, buffer<char>& buf, int precision,
unsigned options, int& exp) {
FMT_ASSERT(value >= 0, "value is negative");
bool fixed = (options & grisu_options::fixed) != 0;
if (value <= 0) { // <= instead of == to silence a warning.
if (precision < 0 || !fixed) {
exp = 0;
buf.push_back('0');
} else {
exp = -precision;
buf.resize(precision);
std::uninitialized_fill_n(buf.data(), precision, '0');
}
return true;
}
fp fp_value(value);
const int min_exp = -60; // alpha in Grisu.
int cached_exp10 = 0; // K in Grisu.
if (precision != -1) {
if (precision > 17) return false;
fp_value.normalize();
auto cached_pow = get_cached_power(
min_exp - (fp_value.e + fp::significand_size), cached_exp10);
fp_value = fp_value * cached_pow;
fixed_handler handler{buf.data(), 0, precision, -cached_exp10, fixed};
if (grisu_gen_digits(fp_value, 1, exp, handler) == digits::error)
return false;
buf.resize(to_unsigned(handler.size));
} else {
fp lower, upper; // w^- and w^+ in the Grisu paper.
fp_value.compute_boundaries(lower, upper);
// Find a cached power of 10 such that multiplying upper by it will bring
// the exponent in the range [min_exp, -32].
auto cached_pow = get_cached_power( // \tilde{c}_{-k} in Grisu.
min_exp - (upper.e + fp::significand_size), cached_exp10);
fp_value.normalize();
fp_value = fp_value * cached_pow;
lower = lower * cached_pow; // \tilde{M}^- in Grisu.
upper = upper * cached_pow; // \tilde{M}^+ in Grisu.
assert(min_exp <= upper.e && upper.e <= -32);
auto result = digits::result();
int size = 0;
if ((options & grisu_options::grisu3) != 0) {
--lower.f; // \tilde{M}^- - 1 ulp -> M^-_{\downarrow}.
++upper.f; // \tilde{M}^+ + 1 ulp -> M^+_{\uparrow}.
// Numbers outside of (lower, upper) definitely do not round to value.
grisu_shortest_handler<3> handler{buf.data(), 0, (upper - fp_value).f};
result = grisu_gen_digits(upper, upper.f - lower.f, exp, handler);
size = handler.size;
} else {
++lower.f; // \tilde{M}^- + 1 ulp -> M^-_{\uparrow}.
--upper.f; // \tilde{M}^+ - 1 ulp -> M^+_{\downarrow}.
grisu_shortest_handler<2> handler{buf.data(), 0, (upper - fp_value).f};
result = grisu_gen_digits(upper, upper.f - lower.f, exp, handler);
size = handler.size;
}
if (result == digits::error) return false;
buf.resize(to_unsigned(size));
}
exp -= cached_exp10;
return true;
}
template <typename Double>
void sprintf_format(Double value, internal::buffer<char>& buf,
core_format_specs spec) {
// Buffer capacity must be non-zero, otherwise MSVC's vsnprintf_s will fail.
FMT_ASSERT(buf.capacity() != 0, "empty buffer");
// Build format string.
enum { max_format_size = 10 }; // longest format: %#-*.*Lg
char format[max_format_size];
char* format_ptr = format;
*format_ptr++ = '%';
if (spec.has(HASH_FLAG) || !spec.type) *format_ptr++ = '#';
if (spec.precision >= 0) {
*format_ptr++ = '.';
*format_ptr++ = '*';
}
if (std::is_same<Double, long double>::value) *format_ptr++ = 'L';
char type = spec.type;
if (type == '%')
type = 'f';
else if (type == 0)
type = 'g';
#if FMT_MSC_VER
if (type == 'F') {
// MSVC's printf doesn't support 'F'.
type = 'f';
}
#endif
*format_ptr++ = type;
*format_ptr = '\0';
// Format using snprintf.
char* start = FMT_NULL;
for (;;) {
std::size_t buffer_size = buf.capacity();
start = &buf[0];
int result =
format_float(start, buffer_size, format, spec.precision, value);
if (result >= 0) {
unsigned n = internal::to_unsigned(result);
if (n < buf.capacity()) {
// Find the decimal point.
auto p = buf.data(), end = p + n;
if (*p == '+' || *p == '-') ++p;
if (spec.type == 'a' || spec.type == 'A') p += 2; // Skip "0x".
while (p < end && *p >= '0' && *p <= '9') ++p;
if (p < end && *p != 'e' && *p != 'E') {
if (*p != '.') *p = '.';
if (!spec.type) {
// Keep only one trailing zero after the decimal point.
++p;
if (*p == '0') ++p;
while (p != end && *p >= '1' && *p <= '9') ++p;
char* where = p;
while (p != end && *p == '0') ++p;
if (p == end || *p < '0' || *p > '9') {
if (p != end) std::memmove(where, p, to_unsigned(end - p));
n -= static_cast<unsigned>(p - where);
}
}
}
buf.resize(n);
break; // The buffer is large enough - continue with formatting.
}
buf.reserve(n + 1);
} else {
// If result is negative we ask to increase the capacity by at least 1,
// but as std::vector, the buffer grows exponentially.
buf.reserve(buf.capacity() + 1);
}
}
}
} // namespace internal
#if FMT_USE_WINDOWS_H
FMT_FUNC internal::utf8_to_utf16::utf8_to_utf16(string_view s) {
static const char ERROR_MSG[] = "cannot convert string from UTF-8 to UTF-16";
if (s.size() > INT_MAX)
FMT_THROW(windows_error(ERROR_INVALID_PARAMETER, ERROR_MSG));
int s_size = static_cast<int>(s.size());
if (s_size == 0) {
// MultiByteToWideChar does not support zero length, handle separately.
buffer_.resize(1);
buffer_[0] = 0;
return;
}
int length = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, s.data(),
s_size, FMT_NULL, 0);
if (length == 0) FMT_THROW(windows_error(GetLastError(), ERROR_MSG));
buffer_.resize(length + 1);
length = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, s.data(), s_size,
&buffer_[0], length);
if (length == 0) FMT_THROW(windows_error(GetLastError(), ERROR_MSG));
buffer_[length] = 0;
}
FMT_FUNC internal::utf16_to_utf8::utf16_to_utf8(wstring_view s) {
if (int error_code = convert(s)) {
FMT_THROW(windows_error(error_code,
"cannot convert string from UTF-16 to UTF-8"));
}
}
FMT_FUNC int internal::utf16_to_utf8::convert(wstring_view s) {
if (s.size() > INT_MAX) return ERROR_INVALID_PARAMETER;
int s_size = static_cast<int>(s.size());
if (s_size == 0) {
// WideCharToMultiByte does not support zero length, handle separately.
buffer_.resize(1);
buffer_[0] = 0;
return 0;
}
int length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, FMT_NULL, 0,
FMT_NULL, FMT_NULL);
if (length == 0) return GetLastError();
buffer_.resize(length + 1);
length = WideCharToMultiByte(CP_UTF8, 0, s.data(), s_size, &buffer_[0],
length, FMT_NULL, FMT_NULL);
if (length == 0) return GetLastError();
buffer_[length] = 0;
return 0;
}
FMT_FUNC void windows_error::init(int err_code, string_view format_str,
format_args args) {
error_code_ = err_code;
memory_buffer buffer;
internal::format_windows_error(buffer, err_code, vformat(format_str, args));
std::runtime_error& base = *this;
base = std::runtime_error(to_string(buffer));
}
FMT_FUNC void internal::format_windows_error(internal::buffer<char>& out,
int error_code,
string_view message) FMT_NOEXCEPT {
FMT_TRY {
wmemory_buffer buf;
buf.resize(inline_buffer_size);
for (;;) {
wchar_t* system_message = &buf[0];
int result = FormatMessageW(
FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, FMT_NULL,
error_code, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), system_message,
static_cast<uint32_t>(buf.size()), FMT_NULL);
if (result != 0) {
utf16_to_utf8 utf8_message;
if (utf8_message.convert(system_message) == ERROR_SUCCESS) {
writer w(out);
w.write(message);
w.write(": ");
w.write(utf8_message);
return;
}
break;
}
if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
break; // Can't get error message, report error code instead.
buf.resize(buf.size() * 2);
}
}
FMT_CATCH(...) {}
format_error_code(out, error_code, message);
}
#endif // FMT_USE_WINDOWS_H
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 = safe_strerror(error_code, system_message, buf.size());
if (result == 0) {
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);
}
#if FMT_USE_WINDOWS_H
FMT_FUNC void report_windows_error(int error_code,
fmt::string_view message) FMT_NOEXCEPT {
report_error(internal::format_windows_error, error_code, message);
}
#endif
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>::type>(args));
fwrite_fully(buffer.data(), 1, buffer.size(), f);
}
FMT_FUNC void vprint(std::FILE* f, wstring_view format_str, wformat_args args) {
wmemory_buffer buffer;
internal::vformat_to(buffer, format_str, args);
fwrite_fully(buffer.data(), sizeof(wchar_t), buffer.size(), f);
}
FMT_FUNC void vprint(string_view format_str, format_args args) {
vprint(stdout, format_str, args);
}
FMT_FUNC void vprint(wstring_view format_str, wformat_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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