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Diffstat (limited to 'third-party/fmt/format-inl.h')
| -rw-r--r-- | third-party/fmt/format-inl.h | 1451 |
1 files changed, 1451 insertions, 0 deletions
diff --git a/third-party/fmt/format-inl.h b/third-party/fmt/format-inl.h new file mode 100644 index 0000000000..d3970d47fa --- /dev/null +++ b/third-party/fmt/format-inl.h @@ -0,0 +1,1451 @@ +// 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 <exception> + +#include "format.h" +#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) +# include <locale> +#endif + +#ifdef _WIN32 +# if !defined(NOMINMAX) && !defined(WIN32_LEAN_AND_MEAN) +# define NOMINMAX +# define WIN32_LEAN_AND_MEAN +# include <windows.h> +# undef WIN32_LEAN_AND_MEAN +# undef NOMINMAX +# else +# include <windows.h> +# endif +# include <io.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::detail::null<> strerror_r(int, char*, ...) { return {}; } +inline fmt::detail::null<> strerror_s(char*, size_t, ...) { return {}; } + +FMT_BEGIN_NAMESPACE +namespace detail { + +FMT_FUNC void assert_fail(const char* file, int line, const char* message) { + // Use unchecked std::fprintf to avoid triggering another assertion when + // writing to stderr fails + std::fprintf(stderr, "%s:%d: assertion failed: %s", file, line, message); + // Chosen instead of std::abort to satisfy Clang in CUDA mode during device + // code pass. + std::terminate(); +} + +#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, + size_t buffer_size) FMT_NOEXCEPT { + FMT_ASSERT(buffer != nullptr && buffer_size != 0, "invalid buffer"); + + class dispatcher { + private: + int error_code_; + char*& buffer_; + 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. + FMT_MAYBE_UNUSED + 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. + FMT_MAYBE_UNUSED + int handle(detail::null<>) { + return fallback(strerror_s(buffer_, buffer_size_, error_code_)); + } + + // Fallback to strerror_s when strerror_r is not available. + FMT_MAYBE_UNUSED + 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(detail::null<>) { + errno = 0; + buffer_ = strerror(error_code_); + return errno; + } +#endif + + public: + dispatcher(int err_code, char*& buf, 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(detail::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.try_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. + 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 (detail::is_negative(error_code)) { + abs_value = 0 - abs_value; + ++error_code_size; + } + error_code_size += detail::to_unsigned(detail::count_digits(abs_value)); + auto it = buffer_appender<char>(out); + if (message.size() <= inline_buffer_size - error_code_size) + format_to(it, "{}{}", message, SEP); + format_to(it, "{}{}", ERROR_STR, 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 detail + +#if !defined(FMT_STATIC_THOUSANDS_SEPARATOR) +namespace detail { + +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 detail +#else +template <typename Char> +FMT_FUNC std::string detail::grouping_impl(locale_ref) { + return "\03"; +} +template <typename Char> FMT_FUNC Char detail::thousands_sep_impl(locale_ref) { + return FMT_STATIC_THOUSANDS_SEPARATOR; +} +template <typename Char> FMT_FUNC Char detail::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 detail { + +template <> FMT_FUNC int count_digits<4>(detail::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 typename basic_data<T>::digit_pair basic_data<T>::digits[] = { + {'0', '0'}, {'0', '1'}, {'0', '2'}, {'0', '3'}, {'0', '4'}, {'0', '5'}, + {'0', '6'}, {'0', '7'}, {'0', '8'}, {'0', '9'}, {'1', '0'}, {'1', '1'}, + {'1', '2'}, {'1', '3'}, {'1', '4'}, {'1', '5'}, {'1', '6'}, {'1', '7'}, + {'1', '8'}, {'1', '9'}, {'2', '0'}, {'2', '1'}, {'2', '2'}, {'2', '3'}, + {'2', '4'}, {'2', '5'}, {'2', '6'}, {'2', '7'}, {'2', '8'}, {'2', '9'}, + {'3', '0'}, {'3', '1'}, {'3', '2'}, {'3', '3'}, {'3', '4'}, {'3', '5'}, + {'3', '6'}, {'3', '7'}, {'3', '8'}, {'3', '9'}, {'4', '0'}, {'4', '1'}, + {'4', '2'}, {'4', '3'}, {'4', '4'}, {'4', '5'}, {'4', '6'}, {'4', '7'}, + {'4', '8'}, {'4', '9'}, {'5', '0'}, {'5', '1'}, {'5', '2'}, {'5', '3'}, + {'5', '4'}, {'5', '5'}, {'5', '6'}, {'5', '7'}, {'5', '8'}, {'5', '9'}, + {'6', '0'}, {'6', '1'}, {'6', '2'}, {'6', '3'}, {'6', '4'}, {'6', '5'}, + {'6', '6'}, {'6', '7'}, {'6', '8'}, {'6', '9'}, {'7', '0'}, {'7', '1'}, + {'7', '2'}, {'7', '3'}, {'7', '4'}, {'7', '5'}, {'7', '6'}, {'7', '7'}, + {'7', '8'}, {'7', '9'}, {'8', '0'}, {'8', '1'}, {'8', '2'}, {'8', '3'}, + {'8', '4'}, {'8', '5'}, {'8', '6'}, {'8', '7'}, {'8', '8'}, {'8', '9'}, + {'9', '0'}, {'9', '1'}, {'9', '2'}, {'9', '3'}, {'9', '4'}, {'9', '5'}, + {'9', '6'}, {'9', '7'}, {'9', '8'}, {'9', '9'}}; + +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> +const char basic_data<T>::left_padding_shifts[] = {31, 31, 0, 1, 0}; +template <typename T> +const char basic_data<T>::right_padding_shifts[] = {0, 31, 0, 1, 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; + + public: + significand_type f; + int e; + + // 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; + 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); } + + // 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}; + } +}; + +// Normalizes the value converted from double and multiplied by (1 << SHIFT). +template <int SHIFT> 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; +} + +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_; + + bigit operator[](int index) const { return bigits_[to_unsigned(index)]; } + bigit& operator[](int index) { return bigits_[to_unsigned(index)]; } + + 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>((*this)[index]) - other - borrow; + (*this)[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 && (*this)[num_bigits] == 0) --num_bigits; + bigits_.resize(to_unsigned(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 (size_t j = 0, n = 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) { + auto size = other.bigits_.size(); + bigits_.resize(size); + auto data = other.bigits_.data(); + std::copy(data, data + size, make_checked(bigits_.data(), size)); + exp_ = other.exp_; + } + + void assign(uint64_t n) { + size_t 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_; } + + FMT_NOINLINE 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[i], rhs_bigit = rhs[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[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(to_unsigned(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]; + } + (*this)[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--]; + (*this)[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() - 1u] != 0, ""); + int exp_difference = exp_ - divisor.exp_; + if (exp_difference > 0) { + // Align bigints by adding trailing zeros to simplify subtraction. + bigits_.resize(to_unsigned(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 int 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.try_resize(to_unsigned(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.try_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.try_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.try_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 }; // The 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 FMT_FUZZ + if (precision > 100000) + throw std::runtime_error( + "fuzz mode - avoid large allocation inside snprintf"); +#endif + // Suppress the warning about a nonliteral format string. + // Cannot use auto because of a bug in MinGW (#1532). + int (*snprintf_ptr)(char*, size_t, const char*, ...) = FMT_SNPRINTF; + int result = precision >= 0 + ? snprintf_ptr(begin, capacity, format, precision, value) + : snprintf_ptr(begin, capacity, format, value); + if (result < 0) { + // The buffer will grow exponentially. + buf.try_reserve(buf.capacity() + 1); + continue; + } + auto size = to_unsigned(result); + // Size equal to capacity means that the last character was truncated. + if (size >= capacity) { + buf.try_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.try_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, to_unsigned(fraction_size)); + buf.try_resize(size - 1); + return -fraction_size; + } + if (specs.format == float_format::hex) { + buf.try_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, to_unsigned(fraction_size)); + } + buf.try_resize(to_unsigned(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; +} + +struct stringifier { + template <typename T> FMT_INLINE std::string operator()(T value) const { + return to_string(value); + } + std::string operator()(basic_format_arg<format_context>::handle h) const { + memory_buffer buf; + format_parse_context parse_ctx({}); + format_context format_ctx(buffer_appender<char>(buf), {}, {}); + h.format(parse_ctx, format_ctx); + return to_string(buf); + } +}; +} // namespace detail + +template <> struct formatter<detail::bigint> { + format_parse_context::iterator parse(format_parse_context& ctx) { + return ctx.begin(); + } + + format_context::iterator format(const detail::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 - 1u]; + 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_ * detail::bigint::bigit_bits); + return out; + } +}; + +FMT_FUNC detail::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, to_unsigned(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(detail::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 = + detail::safe_strerror(error_code, system_message, buf.size()); + if (result == 0) { + format_to(detail::buffer_appender<char>(out), "{}: {}", message, + 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 detail::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 std::string detail::vformat(string_view format_str, format_args args) { + if (format_str.size() == 2 && equal2(format_str.data(), "{}")) { + auto arg = args.get(0); + if (!arg) error_handler().on_error("argument not found"); + return visit_format_arg(stringifier(), arg); + } + memory_buffer buffer; + detail::vformat_to(buffer, format_str, args); + return to_string(buffer); +} + +FMT_FUNC void vprint(std::FILE* f, string_view format_str, format_args args) { + memory_buffer buffer; + detail::vformat_to(buffer, format_str, + basic_format_args<buffer_context<char>>(args)); +#ifdef _WIN32 + auto fd = _fileno(f); + if (_isatty(fd)) { + detail::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)) { + FMT_THROW(format_error("failed to write to console")); + } + return; + } +#endif + detail::fwrite_fully(buffer.data(), 1, buffer.size(), f); +} + +#ifdef _WIN32 +// Print assuming legacy (non-Unicode) encoding. +FMT_FUNC void detail::vprint_mojibake(std::FILE* f, string_view format_str, + format_args args) { + memory_buffer buffer; + detail::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_ |