qt/qtbase/src/corelib/text/qlocale_tools.cpp

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// Copyright (C) 2021 The Qt Company Ltd.
// Copyright (C) 2016 Intel Corporation.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:critical reason:data-parser
#include "qlocale_tools_p.h"
#include "qdoublescanprint_p.h"
#include "qlocale_p.h"
#include "qstring.h"
#include <private/qtools_p.h>
#include <private/qnumeric_p.h>
#include <cstdio>
#include <ctype.h>
#include <errno.h>
#include <float.h>
#include <limits.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#include <limits>
#include <charconv>
#if defined(Q_OS_LINUX) && !defined(__UCLIBC__)
# include <fenv.h>
#endif
// Sizes as defined by the ISO C99 standard - fallback
#ifndef LLONG_MAX
# define LLONG_MAX Q_INT64_C(0x7fffffffffffffff)
#endif
#ifndef LLONG_MIN
# define LLONG_MIN (-LLONG_MAX - Q_INT64_C(1))
#endif
#ifndef ULLONG_MAX
# define ULLONG_MAX Q_UINT64_C(0xffffffffffffffff)
#endif
QT_BEGIN_NAMESPACE
using namespace QtMiscUtils;
QT_CLOCALE_HOLDER
void qt_doubleToAscii(double d, QLocaleData::DoubleForm form, int precision,
char *buf, qsizetype bufSize,
bool &sign, int &length, int &decpt)
{
if (bufSize == 0) {
decpt = 0;
sign = d < 0;
length = 0;
return;
}
// Detect special numbers (nan, +/-inf)
// We cannot use the high-level API of libdouble-conversion as we need to
// apply locale-specific formatting, such as decimal points, grouping
// separators, etc. Because of this, we have to check for infinity and NaN
// before calling DoubleToAscii.
if (qt_is_inf(d)) {
sign = d < 0;
if (bufSize >= 3) {
buf[0] = 'i';
buf[1] = 'n';
buf[2] = 'f';
length = 3;
} else {
length = 0;
}
return;
} else if (qt_is_nan(d)) {
if (bufSize >= 3) {
buf[0] = 'n';
buf[1] = 'a';
buf[2] = 'n';
length = 3;
} else {
length = 0;
}
return;
}
if (form == QLocaleData::DFSignificantDigits && precision == 0)
precision = 1; // 0 significant digits is silently converted to 1
#if !defined(QT_NO_DOUBLECONVERSION) && !defined(QT_BOOTSTRAPPED)
// one digit before the decimal dot, counts as significant digit for DoubleToStringConverter
if (form == QLocaleData::DFExponent && precision >= 0)
++precision;
double_conversion::DoubleToStringConverter::DtoaMode mode;
if (precision == QLocale::FloatingPointShortest) {
mode = double_conversion::DoubleToStringConverter::SHORTEST;
} else if (form == QLocaleData::DFSignificantDigits || form == QLocaleData::DFExponent) {
mode = double_conversion::DoubleToStringConverter::PRECISION;
} else {
mode = double_conversion::DoubleToStringConverter::FIXED;
}
// libDoubleConversion is limited to 32-bit lengths. It's ok to cap the buffer size,
// though, because the library will never write 2GiB of chars as output
// (the length out-parameter is just an int, too).
const auto boundedBufferSize = static_cast<int>((std::min)(bufSize, qsizetype(INT_MAX)));
double_conversion::DoubleToStringConverter::DoubleToAscii(d, mode, precision, buf,
boundedBufferSize,
&sign, &length, &decpt);
#else // QT_NO_DOUBLECONVERSION || QT_BOOTSTRAPPED
// Cut the precision at 999, to fit it into the format string. We can't get more than 17
// significant digits, so anything after that is mostly noise. You do get closer to the "middle"
// of the range covered by the given double with more digits, so to a degree it does make sense
// to honor higher precisions. We define that at more than 999 digits that is not the case.
if (precision > 999)
precision = 999;
else if (precision == QLocale::FloatingPointShortest)
precision = std::numeric_limits<double>::max_digits10; // snprintf lacks "shortest" mode
if (qIsNull(d)) {
// Negative zero is expected as simple "0", not "-0". We cannot do d < 0, though.
sign = false;
buf[0] = '0';
length = 1;
decpt = 1;
return;
} else if (d < 0) {
sign = true;
d = -d;
} else {
sign = false;
}
const int formatLength = 7; // '%', '.', 3 digits precision, 'f', '\0'
char format[formatLength];
format[formatLength - 1] = '\0';
format[0] = '%';
format[1] = '.';
format[2] = char((precision / 100) % 10) + '0';
format[3] = char((precision / 10) % 10) + '0';
format[4] = char(precision % 10) + '0';
int extraChars;
switch (form) {
case QLocaleData::DFDecimal:
format[formatLength - 2] = 'f';
// <anything> '.' <precision> '\0'
extraChars = wholePartSpace(d) + 2;
break;
case QLocaleData::DFExponent:
format[formatLength - 2] = 'e';
// '.', 'e', '-', <exponent> '\0'
extraChars = 7;
break;
case QLocaleData::DFSignificantDigits:
format[formatLength - 2] = 'g';
// either the same as in the 'e' case, or '.' and '\0'
// precision covers part before '.'
extraChars = 7;
break;
default:
Q_UNREACHABLE();
}
QVarLengthArray<char> target(precision + extraChars);
length = qDoubleSnprintf(target.data(), target.size(), QT_CLOCALE, format, d);
int firstSignificant = 0;
int decptInTarget = length;
// Find the first significant digit (not 0), and note any '.' we encounter.
// There is no '-' at the front of target because we made sure d > 0 above.
while (firstSignificant < length) {
if (target[firstSignificant] == '.')
decptInTarget = firstSignificant;
else if (target[firstSignificant] != '0')
break;
++firstSignificant;
}
// If no '.' found so far, search the rest of the target buffer for it.
if (decptInTarget == length)
decptInTarget = std::find(target.data() + firstSignificant, target.data() + length, '.') -
target.data();
int eSign = length;
if (form != QLocaleData::DFDecimal) {
// In 'e' or 'g' form, look for the 'e'.
eSign = std::find(target.data() + firstSignificant, target.data() + length, 'e') -
target.data();
if (eSign < length) {
// If 'e' is found, the final decimal point is determined by the number after 'e'.
// Mind that the final decimal point, decpt, is the offset of the decimal point from the
// start of the resulting string in buf. It may be negative or larger than bufSize, in
// which case the missing digits are zeroes. In the 'e' case decptInTarget is always 1,
// as variants of snprintf always generate numbers with one digit before the '.' then.
// This is why the final decimal point is offset by 1, relative to the number after 'e'.
auto r = qstrntoll(target.data() + eSign + 1, length - eSign - 1, 10);
decpt = r.result + 1;
Q_ASSERT(r.ok());
Q_ASSERT(r.used + eSign + 1 <= length);
} else {
// No 'e' found, so it's the 'f' form. Variants of snprintf generate numbers with
// potentially multiple digits before the '.', but without decimal exponent then. So we
// get the final decimal point from the position of the '.'. The '.' itself takes up one
// character. We adjust by 1 below if that gets in the way.
decpt = decptInTarget - firstSignificant;
}
} else {
// In 'f' form, there can not be an 'e', so it's enough to look for the '.'
// (and possibly adjust by 1 below)
decpt = decptInTarget - firstSignificant;
}
// Move the actual digits from the snprintf target to the actual buffer.
if (decptInTarget > firstSignificant) {
// First move the digits before the '.', if any
int lengthBeforeDecpt = decptInTarget - firstSignificant;
memcpy(buf, target.data() + firstSignificant, qMin(lengthBeforeDecpt, bufSize));
if (eSign > decptInTarget && lengthBeforeDecpt < bufSize) {
// Then move any remaining digits, until 'e'
memcpy(buf + lengthBeforeDecpt, target.data() + decptInTarget + 1,
qMin(eSign - decptInTarget - 1, bufSize - lengthBeforeDecpt));
// The final length of the output is the distance between the first significant digit
// and 'e' minus 1, for the '.', except if the buffer is smaller.
length = qMin(eSign - firstSignificant - 1, bufSize);
} else {
// 'e' was before the decpt or things didn't fit. Don't subtract the '.' from the length.
length = qMin(eSign - firstSignificant, bufSize);
}
} else {
if (eSign > firstSignificant) {
// If there are any significant digits at all, they are all after the '.' now.
// Just copy them straight away.
memcpy(buf, target.data() + firstSignificant, qMin(eSign - firstSignificant, bufSize));
// The decimal point was before the first significant digit, so we were one off above.
// Consider 0.1 - buf will be just '1', and decpt should be 0. But
// "decptInTarget - firstSignificant" will yield -1.
++decpt;
length = qMin(eSign - firstSignificant, bufSize);
} else {
// No significant digits means the number is just 0.
buf[0] = '0';
length = 1;
decpt = 1;
}
}
#endif // QT_NO_DOUBLECONVERSION || QT_BOOTSTRAPPED
while (length > 1 && buf[length - 1] == '0') // drop trailing zeroes
--length;
}
QSimpleParsedNumber<double> qt_asciiToDouble(const char *num, qsizetype numLen,
StrayCharacterMode strayCharMode)
{
if (numLen <= 0)
return {};
// We have to catch NaN before because we need NaN as marker for "garbage" in the
// libdouble-conversion case and, in contrast to libdouble-conversion or sscanf, we don't allow
// "-nan" or "+nan"
if (char c = *num; numLen >= 3
&& (c == '-' || c == '+' || c == 'I' || c == 'i' || c == 'N' || c == 'n')) {
bool negative = (c == '-');
bool hasSign = negative || (c == '+');
qptrdiff offset = 0;
if (hasSign) {
offset = 1;
c = num[offset];
}
if (c > '9') {
auto lowered = [](char c) {
// this will mangle non-letters, but none can become a letter
return c | 0x20;
};
// Found a non-digit, so this MUST be either "inf", "+inf", "-inf"
// or "nan". Anything else is an invalid parse and we don't need to
// feed it to the converter below.
if (numLen != offset + 3)
return {};
c = lowered(c);
char c2 = lowered(num[offset + 1]);
char c3 = lowered(num[offset + 2]);
if (c == 'i' && c2 == 'n' && c3 == 'f')
return { negative ? -qt_inf() : qt_inf(), offset + 3 };
else if (c == 'n' && c2 == 'a' && c3 == 'n' && !hasSign)
return { qt_qnan(), 3 };
return {};
}
}
double d = 0.0;
int processed;
#if !defined(QT_NO_DOUBLECONVERSION) && !defined(QT_BOOTSTRAPPED)
int conv_flags = double_conversion::StringToDoubleConverter::NO_FLAGS;
if (strayCharMode == TrailingJunkAllowed) {
conv_flags = double_conversion::StringToDoubleConverter::ALLOW_TRAILING_JUNK;
}
double_conversion::StringToDoubleConverter conv(conv_flags, 0.0, qt_qnan(), nullptr, nullptr);
if (int(numLen) != numLen) {
// a number over 2 GB in length is silly, just assume it isn't valid
return {};
} else {
d = conv.StringToDouble(num, int(numLen), &processed);
}
if (!qt_is_finite(d)) {
if (qt_is_nan(d)) {
// Garbage found. We don't accept it and return 0.
return {};
} else {
// Overflow. That's not OK, but we still return infinity.
return { d, -processed };
}
}
#else
// ::digits10 is 19, but ::max() is 18'446'744'073'709'551'615ULL - go, figure...
constexpr auto maxDigitsForULongLong = 1 + std::numeric_limits<unsigned long long>::digits10;
// need to ensure that we don't read more than numLen of input:
char fmt[1 + maxDigitsForULongLong + 4 + 1];
std::snprintf(fmt, sizeof fmt, "%s%llu%s",
"%", static_cast<unsigned long long>(numLen), "lf%n");
if (qDoubleSscanf(num, QT_CLOCALE, fmt, &d, &processed) < 1)
processed = 0;
if ((strayCharMode == TrailingJunkProhibited && processed != numLen) || qt_is_nan(d)) {
// Implementation defined nan symbol or garbage found. We don't accept it.
return {};
}
if (!qt_is_finite(d)) {
// Overflow. Check for implementation-defined infinity symbols and reject them.
// We assume that any infinity symbol has to contain a character that cannot be part of a
// "normal" number (that is 0-9, ., -, +, e).
for (int i = 0; i < processed; ++i) {
char c = num[i];
if ((c < '0' || c > '9') && c != '.' && c != '-' && c != '+' && c != 'e' && c != 'E') {
// Garbage found
return {};
}
}
return { d, -processed };
}
#endif // !defined(QT_NO_DOUBLECONVERSION) && !defined(QT_BOOTSTRAPPED)
// Otherwise we would have gotten NaN or sorted it out above.
Q_ASSERT(strayCharMode == TrailingJunkAllowed || processed == numLen);
// Check if underflow has occurred.
if (qIsNull(d)) {
for (int i = 0; i < processed; ++i) {
if (num[i] >= '1' && num[i] <= '9') {
// if a digit before any 'e' is not 0, then a non-zero number was intended.
return {d, -processed};
} else if (num[i] == 'e' || num[i] == 'E') {
break;
}
}
}
return { d, processed };
}
/* Detect base if 0 and, if base is hex or bin, skip over 0x/0b prefixes */
static auto scanPrefix(const char *p, const char *stop, int base)
{
struct R
{
const char *next;
int base;
};
if (p < stop && isAsciiDigit(*p)) {
if (*p == '0') {
const char *x_or_b = p + 1;
if (x_or_b < stop) {
switch (*x_or_b) {
case 'b':
case 'B':
if (base == 0)
base = 2;
if (base == 2)
p += 2;
return R{p, base};
case 'x':
case 'X':
if (base == 0)
base = 16;
if (base == 16)
p += 2;
return R{p, base};
}
}
if (base == 0)
base = 8;
} else if (base == 0) {
base = 10;
}
Q_ASSERT(base);
}
return R{p, base};
}
static bool isDigitForBase(char d, int base)
{
if (d < '0')
return false;
if (d - '0' < qMin(base, 10))
return true;
if (base > 10) {
d |= 0x20; // tolower
return d >= 'a' && d < 'a' + base - 10;
}
return false;
}
QSimpleParsedNumber<qulonglong> qstrntoull(const char *begin, qsizetype size, int base)
{
const char *p = begin, *const stop = begin + size;
while (p < stop && ascii_isspace(*p))
++p;
unsigned long long result = 0;
if (p >= stop || *p == '-')
return { };
const auto prefix = scanPrefix(*p == '+' ? p + 1 : p, stop, base);
if (!prefix.base || prefix.next >= stop)
return { };
const auto res = std::from_chars(prefix.next, stop, result, prefix.base);
if (res.ec != std::errc{})
return { };
return { result, res.ptr == prefix.next ? 0 : res.ptr - begin };
}
QSimpleParsedNumber<qlonglong> qstrntoll(const char *begin, qsizetype size, int base)
{
const char *p = begin, *const stop = begin + size;
while (p < stop && ascii_isspace(*p))
++p;
// Frustratingly, std::from_chars() doesn't cope with a 0x prefix that might
// be between the sign and digits, so we have to handle that for it, which
// means we can't use its ability to read LLONG_MIN directly; see below.
const bool negate = p < stop && *p == '-';
if (negate || (p < stop && *p == '+'))
++p;
const auto prefix = scanPrefix(p, stop, base);
// Must check for digit, as from_chars() will accept a sign, which would be
// a second sign, that we should reject.
if (!prefix.base || prefix.next >= stop || !isDigitForBase(*prefix.next, prefix.base))
return { };
long long result = 0;
auto res = std::from_chars(prefix.next, stop, result, prefix.base);
if (negate && res.ec == std::errc::result_out_of_range) {
// Maybe LLONG_MIN:
unsigned long long check = 0;
res = std::from_chars(prefix.next, stop, check, prefix.base);
if (res.ec == std::errc{} && check + std::numeric_limits<long long>::min() == 0)
return { std::numeric_limits<long long>::min(), res.ptr - begin };
return { };
}
if (res.ec != std::errc{})
return { };
return { negate ? -result : result, res.ptr - begin };
}
template <typename Char>
Q_ALWAYS_INLINE static void qulltoString_helper(qulonglong number, int base, Char *&p)
{
// Performance-optimized code. Compiler can generate faster code when base is known.
switch (base) {
#define BIG_BASE_LOOP(b) \
do { \
const int r = number % b; \
*--p = Char((r < 10 ? '0' : 'a' - 10) + r); \
number /= b; \
} while (number)
#ifndef __OPTIMIZE_SIZE__
# define SMALL_BASE_LOOP(b) \
do { \
*--p = Char('0' + number % b); \
number /= b; \
} while (number)
case 2: SMALL_BASE_LOOP(2); break;
case 8: SMALL_BASE_LOOP(8); break;
case 10: SMALL_BASE_LOOP(10); break;
case 16: BIG_BASE_LOOP(16); break;
#undef SMALL_BASE_LOOP
#endif
default: BIG_BASE_LOOP(base); break;
#undef BIG_BASE_LOOP
}
}
// This is technically "qulonglong to ascii", but that name's taken
QString qulltoBasicLatin(qulonglong number, int base, bool negative)
{
if (number == 0)
return QStringLiteral("0");
// Length of MIN_LLONG with the sign in front is 65; we never need surrogate pairs.
// We do not need a terminator.
const unsigned maxlen = 65;
static_assert(CHAR_BIT * sizeof(number) + 1 <= maxlen);
Q_DECL_UNINITIALIZED char16_t buff[maxlen];
char16_t *const end = buff + maxlen, *p = end;
qulltoString_helper<char16_t>(number, base, p);
if (negative)
*--p = u'-';
return QString(reinterpret_cast<QChar *>(p), end - p);
}
QString qulltoa(qulonglong number, int base, const QStringView zero)
{
// Length of MAX_ULLONG in base 2 is 64; and we may need a surrogate pair
// per digit. We do not need a terminator.
const unsigned maxlen = 128;
static_assert(CHAR_BIT * sizeof(number) <= maxlen);
Q_DECL_UNINITIALIZED char16_t buff[maxlen];
char16_t *const end = buff + maxlen, *p = end;
if (base != 10 || zero == u"0") {
qulltoString_helper<char16_t>(number, base, p);
} else if (zero.size() && !zero.at(0).isSurrogate()) {
const char16_t zeroUcs2 = zero.at(0).unicode();
while (number != 0) {
*(--p) = unicodeForDigit(number % base, zeroUcs2);
number /= base;
}
} else if (zero.size() == 2 && zero.at(0).isHighSurrogate()) {
const char32_t zeroUcs4 = QChar::surrogateToUcs4(zero.at(0), zero.at(1));
while (number != 0) {
const char32_t digit = unicodeForDigit(number % base, zeroUcs4);
*(--p) = QChar::lowSurrogate(digit);
*(--p) = QChar::highSurrogate(digit);
number /= base;
}
} else { // zero should always be either a non-surrogate or a surrogate pair:
Q_UNREACHABLE_RETURN(QString());
}
return QString(reinterpret_cast<QChar *>(p), end - p);
}
char *qulltoa2(char *p, qulonglong n, int base)
{
#if defined(QT_CHECK_RANGE)
if (base < 2 || base > 36) {
qWarning("QByteArray::setNum: Invalid base %d", base);
base = 10;
}
#endif
qulltoString_helper(n, base, p);
return p;
}
/*!
\internal
Converts the initial portion of the string pointed to by \a s00 to a double,
using the 'C' locale. The function sets the pointer pointed to by \a se to
point to the character past the last character converted.
*/
double qstrntod(const char *s00, qsizetype len, const char **se, bool *ok)
{
auto r = qt_asciiToDouble(s00, len, TrailingJunkAllowed);
if (se)
*se = s00 + (r.used < 0 ? -r.used : r.used);
if (ok)
*ok = r.ok();
return r.result;
}
QString qdtoa(qreal d, int *decpt, int *sign)
{
bool nonNullSign = false;
int nonNullDecpt = 0;
int length = 0;
// Some versions of libdouble-conversion like an extra digit, probably for '\0'
constexpr qsizetype digits = std::numeric_limits<double>::max_digits10 + 1;
char result[digits];
qt_doubleToAscii(d, QLocaleData::DFSignificantDigits, QLocale::FloatingPointShortest,
result, digits, nonNullSign, length, nonNullDecpt);
if (sign)
*sign = nonNullSign ? 1 : 0;
if (decpt)
*decpt = nonNullDecpt;
return QLatin1StringView(result, length);
}
static QLocaleData::DoubleForm resolveFormat(int precision, int decpt, qsizetype length)
{
bool useDecimal;
if (precision == QLocale::FloatingPointShortest) {
// Find out which representation is shorter.
// Set bias to everything added to exponent form but not
// decimal, minus the converse.
// Exponent adds separator, sign and two exponents:
int bias = 2 + 2;
if (length <= decpt && length > 1)
++bias;
else if (length == 1 && decpt <= 0)
--bias;
// When 0 < decpt <= length, the forms have equal digit
// counts, plus things bias has taken into account;
// otherwise decimal form's digit count is right-padded with
// zeros to decpt, when decpt is positive, otherwise it's
// left-padded with 1 - decpt zeros.
if (decpt <= 0)
useDecimal = 1 - decpt <= bias;
else if (decpt <= length)
useDecimal = true;
else
useDecimal = decpt <= length + bias;
} else {
// X == decpt - 1, POSIX's P; -4 <= X < P iff -4 < decpt <= P
Q_ASSERT(precision >= 0);
useDecimal = decpt > -4 && decpt <= (precision ? precision : 1);
}
return useDecimal ? QLocaleData::DFDecimal : QLocaleData::DFExponent;
}
static constexpr int digits(int number)
{
Q_ASSERT(number >= 0);
if (Q_LIKELY(number < 1000))
return number < 10 ? 1 : number < 100 ? 2 : 3;
int i = 3;
for (number /= 1000; number; number /= 10)
++i;
return i;
}
// Used generically for both QString and QByteArray
template <typename T>
static T dtoString(double d, QLocaleData::DoubleForm form, int precision, bool uppercase)
{
// Undocumented: aside from F.P.Shortest, precision < 0 is treated as
// default, 6 - same as printf().
if (precision != QLocale::FloatingPointShortest && precision < 0)
precision = 6;
using D = std::numeric_limits<double>;
// 1 is for the null-terminator
constexpr int MaxDigits = 1 + qMax(D::max_exponent10, D::digits10 - D::min_exponent10);
// "maxDigits" above is a reasonable estimate, though we may need more due to extra precision
int bufSize = 1;
if (precision == QLocale::FloatingPointShortest)
bufSize += D::max_digits10;
else if (form == QLocaleData::DFDecimal && qt_is_finite(d))
bufSize += wholePartSpace(qAbs(d)) + precision;
else // Add extra digit due to different interpretations of precision.
bufSize += qMax(2, precision) + 1; // Must also be big enough for "nan" or "inf"
// Reserve `MaxDigits` on the stack, which is a reasonable estimate;
// but we may need more due to extra precision, which we cannot know at compile-time.
QVarLengthArray<char, MaxDigits> buffer(bufSize);
bool negative = false;
int length = 0;
int decpt = 0;
qt_doubleToAscii(d, form, precision, buffer.data(), buffer.size(), negative, length, decpt);
QLatin1StringView view(buffer.data(), length);
const bool succinct = form == QLocaleData::DFSignificantDigits;
qsizetype total = (negative ? 1 : 0) + length;
if (qt_is_finite(d)) {
if (succinct)
form = resolveFormat(precision, decpt, view.size());
switch (form) {
case QLocaleData::DFExponent:
total += 3; // (.e+) The '.' may not be needed, but we would only overestimate by 1 char
// Exponents: we guarantee at least 2
total += std::max(2, digits(std::abs(decpt - 1)));
// "length - 1" because one of the digits will always be before the decimal point
if (int extraPrecision = precision - (length - 1); extraPrecision > 0 && !succinct)
total += extraPrecision; // some requested zero-padding
break;
case QLocaleData::DFDecimal:
if (decpt <= 0) // leading "0." and zeros
total += 2 - decpt;
else if (decpt < length) // just the dot
total += 1;
else // trailing zeros (and no dot, unless we require extra precision):
total += decpt - length;
if (precision > 0 && !succinct) {
// May need trailing zeros to satisfy precision:
if (decpt < length)
total += std::max(0, precision - length + decpt);
else // and a dot to separate them:
total += 1 + precision;
}
break;
case QLocaleData::DFSignificantDigits:
Q_UNREACHABLE(); // Handled earlier
}
}
constexpr bool IsQString = std::is_same_v<T, QString>;
using Char = std::conditional_t<IsQString, char16_t, char>;
T result;
result.reserve(total);
if (negative && !qIsNull(d)) // We don't return "-0"
result.append(Char('-'));
if (!qt_is_finite(d)) {
result.append(view);
if (uppercase)
result = std::move(result).toUpper();
} else {
switch (form) {
case QLocaleData::DFExponent: {
result.append(view.first(1));
view = view.sliced(1);
if (!view.isEmpty() || (!succinct && precision > 0)) {
result.append(Char('.'));
result.append(view);
if (qsizetype pad = precision - view.size(); !succinct && pad > 0) {
for (int i = 0; i < pad; ++i)
result.append(Char('0'));
}
}
int exponent = decpt - 1;
result.append(Char(uppercase ? 'E' : 'e'));
result.append(Char(exponent < 0 ? '-' : '+'));
exponent = std::abs(exponent);
Q_ASSERT(exponent <= D::max_exponent10 + D::max_digits10);
int exponentDigits = digits(exponent);
// C's printf guarantees a two-digit exponent, and so do we:
if (exponentDigits == 1)
result.append(Char('0'));
result.resize(result.size() + exponentDigits);
auto location = reinterpret_cast<Char *>(result.end());
qulltoString_helper<Char>(exponent, 10, location);
break;
}
case QLocaleData::DFDecimal:
if (decpt < 0) {
if constexpr (IsQString)
result.append(u"0.0");
else
result.append("0.0");
while (++decpt < 0)
result.append(Char('0'));
result.append(view);
if (!succinct) {
auto numDecimals = result.size() - 2 - (negative ? 1 : 0);
for (qsizetype i = numDecimals; i < precision; ++i)
result.append(Char('0'));
}
} else {
if (decpt > view.size()) {
result.append(view);
const int sign = negative ? 1 : 0;
while (result.size() - sign < decpt)
result.append(Char('0'));
view = {};
} else if (decpt) {
result.append(view.first(decpt));
view = view.sliced(decpt);
} else {
result.append(Char('0'));
}
if (!view.isEmpty() || (!succinct && view.size() < precision)) {
result.append(Char('.'));
result.append(view);
if (!succinct) {
for (qsizetype i = view.size(); i < precision; ++i)
result.append(Char('0'));
}
}
}
break;
case QLocaleData::DFSignificantDigits:
Q_UNREACHABLE(); // taken care of earlier
break;
}
}
Q_ASSERT(total >= result.size()); // No reallocations are needed
return result;
}
QString qdtoBasicLatin(double d, QLocaleData::DoubleForm form, int precision, bool uppercase)
{
return dtoString<QString>(d, form, precision, uppercase);
}
QByteArray qdtoAscii(double d, QLocaleData::DoubleForm form, int precision, bool uppercase)
{
return dtoString<QByteArray>(d, form, precision, uppercase);
}
#if defined(QT_SUPPORTS_INT128) || defined(QT_USE_MSVC_INT128)
static inline quint64 toUInt64(qinternaluint128 v)
{
#if defined(QT_USE_MSVC_INT128)
return quint64(v._Word[0]);
#else
return quint64(v);
#endif
}
QString quint128toBasicLatin(qinternaluint128 number, int base)
{
// We divide our 128-bit number into parts that we can do text
// concatenation with. This list is the maximum power of the
// base that is less than 2^64.
static constexpr auto dividers = []() constexpr {
std::array<quint64, 35> bases {};
for (int base = 2; base <= 36; ++base) {
quint64 v = base;
while (v * base > v)
v *= base;
bases[base - 2] = v;
}
return bases;
}();
static constexpr auto digitCounts = []() constexpr {
std::array<quint8, 35> digits{};
for (int base = 2; base <= 36; ++base) {
quint64 v = base;
int i = 0;
for (i = 0; v * base > v; ++i)
v *= base;
// v == divider == base^(i + 1), so a chunk (< divider) has up to
// i + 1 digits, all of which must be kept when zero-padding.
digits[base - 2] = i + 1;
}
return digits;
}();
QString result;
constexpr unsigned flags = QLocaleData::NoFlags;
const QLocaleData *dd = QLocaleData::c();
// special base cases:
constexpr int Width = -1;
if (base == 2 || base == 4 || base == 16) {
// 2^64 is a power of 2, 4 and 16, taking 64, 32 and 16 digits
const int digitsPerWord = base == 2 ? 64 : base == 4 ? 32 : 16;
if (const quint64 high = quint64(number >> 64)) {
result = dd->unsLongLongToString(quint64(number), digitsPerWord, base, Width, flags);
result.prepend(dd->unsLongLongToString(high, -1, base, Width, flags));
} else {
result = dd->unsLongLongToString(quint64(number), -1, base, Width, flags);
}
} else {
int digitCount = digitCounts[base - 2];
quint64 divider = dividers[base - 2];
quint64 lower = toUInt64(number % divider);
number /= divider;
while (number) {
result.prepend(dd->unsLongLongToString(lower, digitCount, base, Width, flags));
lower = toUInt64(number % divider);
number /= divider;
}
result.prepend(dd->unsLongLongToString(lower, -1, base, Width, flags));
}
return result;
}
QString qint128toBasicLatin(qinternalint128 number, int base)
{
const bool negative = number < 0;
// Take the magnitude in the unsigned type: negating the minimum value in
// the signed one would overflow.
qinternaluint128 magnitude = qinternaluint128(number);
if (negative)
magnitude = qinternaluint128(0) - magnitude;
QString result = quint128toBasicLatin(magnitude, base);
if (negative)
result.prepend(u'-');
return result;
}
#endif // defined(QT_SUPPORTS_INT128) || defined(QT_USE_MSVC_INT128)
QT_END_NAMESPACE