ecency-mobile/ios/Pods/Folly/folly/Format.cpp
2019-05-29 14:32:35 +03:00

428 lines
12 KiB
C++

/*
* Copyright 2012-present Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <folly/Format.h>
#include <folly/ConstexprMath.h>
#include <folly/CppAttributes.h>
#include <folly/container/Array.h>
#include <double-conversion/double-conversion.h>
namespace folly {
namespace detail {
// ctor for items in the align table
struct format_table_align_make_item {
static constexpr std::size_t size = 256;
constexpr FormatArg::Align operator()(std::size_t index) const {
// clang-format off
return
index == '<' ? FormatArg::Align::LEFT:
index == '>' ? FormatArg::Align::RIGHT :
index == '=' ? FormatArg::Align::PAD_AFTER_SIGN :
index == '^' ? FormatArg::Align::CENTER :
FormatArg::Align::INVALID;
// clang-format on
}
};
// ctor for items in the conv tables for representing parts of nonnegative
// integers into ascii digits of length Size, over a given base Base
template <std::size_t Base, std::size_t Size, bool Upper = false>
struct format_table_conv_make_item {
static_assert(Base <= 36, "Base is unrepresentable");
struct make_item {
std::size_t index{};
constexpr explicit make_item(std::size_t index_) : index(index_) {} // gcc49
constexpr char alpha(std::size_t ord) const {
return ord < 10 ? '0' + ord : (Upper ? 'A' : 'a') + (ord - 10);
}
constexpr char operator()(std::size_t offset) const {
return alpha(index / constexpr_pow(Base, Size - offset - 1) % Base);
}
};
constexpr std::array<char, Size> operator()(std::size_t index) const {
return make_array_with<Size>(make_item{index});
}
};
// ctor for items in the sign table
struct format_table_sign_make_item {
static constexpr std::size_t size = 256;
constexpr FormatArg::Sign operator()(std::size_t index) const {
// clang-format off
return
index == '+' ? FormatArg::Sign::PLUS_OR_MINUS :
index == '-' ? FormatArg::Sign::MINUS :
index == ' ' ? FormatArg::Sign::SPACE_OR_MINUS :
FormatArg::Sign::INVALID;
// clang-format on
}
};
// the tables
FOLLY_STORAGE_CONSTEXPR auto formatAlignTable =
make_array_with<256>(format_table_align_make_item{});
FOLLY_STORAGE_CONSTEXPR auto formatSignTable =
make_array_with<256>(format_table_sign_make_item{});
FOLLY_STORAGE_CONSTEXPR decltype(formatHexLower) formatHexLower =
make_array_with<256>(format_table_conv_make_item<16, 2, false>{});
FOLLY_STORAGE_CONSTEXPR decltype(formatHexUpper) formatHexUpper =
make_array_with<256>(format_table_conv_make_item<16, 2, true>{});
FOLLY_STORAGE_CONSTEXPR decltype(formatOctal) formatOctal =
make_array_with<512>(format_table_conv_make_item<8, 3>{});
FOLLY_STORAGE_CONSTEXPR decltype(formatBinary) formatBinary =
make_array_with<256>(format_table_conv_make_item<2, 8>{});
} // namespace detail
using namespace folly::detail;
void FormatValue<double>::formatHelper(
fbstring& piece,
int& prefixLen,
FormatArg& arg) const {
using ::double_conversion::DoubleToStringConverter;
using ::double_conversion::StringBuilder;
arg.validate(FormatArg::Type::FLOAT);
if (arg.presentation == FormatArg::kDefaultPresentation) {
arg.presentation = 'g';
}
const char* infinitySymbol = isupper(arg.presentation) ? "INF" : "inf";
const char* nanSymbol = isupper(arg.presentation) ? "NAN" : "nan";
char exponentSymbol = isupper(arg.presentation) ? 'E' : 'e';
if (arg.precision == FormatArg::kDefaultPrecision) {
arg.precision = 6;
}
// 2+: for null terminator and optional sign shenanigans.
constexpr int bufLen = 2 +
constexpr_max(2 + DoubleToStringConverter::kMaxFixedDigitsBeforePoint +
DoubleToStringConverter::kMaxFixedDigitsAfterPoint,
constexpr_max(
8 + DoubleToStringConverter::kMaxExponentialDigits,
7 + DoubleToStringConverter::kMaxPrecisionDigits));
char buf[bufLen];
StringBuilder builder(buf + 1, bufLen - 1);
char plusSign;
switch (arg.sign) {
case FormatArg::Sign::PLUS_OR_MINUS:
plusSign = '+';
break;
case FormatArg::Sign::SPACE_OR_MINUS:
plusSign = ' ';
break;
default:
plusSign = '\0';
break;
};
auto flags = DoubleToStringConverter::EMIT_POSITIVE_EXPONENT_SIGN |
(arg.trailingDot ? DoubleToStringConverter::EMIT_TRAILING_DECIMAL_POINT
: 0);
double val = val_;
switch (arg.presentation) {
case '%':
val *= 100;
FOLLY_FALLTHROUGH;
case 'f':
case 'F': {
if (arg.precision > DoubleToStringConverter::kMaxFixedDigitsAfterPoint) {
arg.precision = DoubleToStringConverter::kMaxFixedDigitsAfterPoint;
}
DoubleToStringConverter conv(
flags,
infinitySymbol,
nanSymbol,
exponentSymbol,
-4,
arg.precision,
0,
0);
arg.enforce(
conv.ToFixed(val, arg.precision, &builder),
"fixed double conversion failed");
break;
}
case 'e':
case 'E': {
if (arg.precision > DoubleToStringConverter::kMaxExponentialDigits) {
arg.precision = DoubleToStringConverter::kMaxExponentialDigits;
}
DoubleToStringConverter conv(
flags,
infinitySymbol,
nanSymbol,
exponentSymbol,
-4,
arg.precision,
0,
0);
arg.enforce(conv.ToExponential(val, arg.precision, &builder));
break;
}
case 'n': // should be locale-aware, but isn't
case 'g':
case 'G': {
if (arg.precision < DoubleToStringConverter::kMinPrecisionDigits) {
arg.precision = DoubleToStringConverter::kMinPrecisionDigits;
} else if (arg.precision > DoubleToStringConverter::kMaxPrecisionDigits) {
arg.precision = DoubleToStringConverter::kMaxPrecisionDigits;
}
DoubleToStringConverter conv(
flags,
infinitySymbol,
nanSymbol,
exponentSymbol,
-4,
arg.precision,
0,
0);
arg.enforce(conv.ToShortest(val, &builder));
break;
}
default:
arg.error("invalid specifier '", arg.presentation, "'");
}
int len = builder.position();
builder.Finalize();
DCHECK_GT(len, 0);
// Add '+' or ' ' sign if needed
char* p = buf + 1;
// anything that's neither negative nor nan
prefixLen = 0;
if (plusSign && (*p != '-' && *p != 'n' && *p != 'N')) {
*--p = plusSign;
++len;
prefixLen = 1;
} else if (*p == '-') {
prefixLen = 1;
}
piece = fbstring(p, size_t(len));
}
void FormatArg::initSlow() {
auto b = fullArgString.begin();
auto end = fullArgString.end();
// Parse key
auto p = static_cast<const char*>(memchr(b, ':', size_t(end - b)));
if (!p) {
key_ = StringPiece(b, end);
return;
}
key_ = StringPiece(b, p);
if (*p == ':') {
// parse format spec
if (++p == end) {
return;
}
// fill/align, or just align
Align a;
if (p + 1 != end &&
(a = formatAlignTable[static_cast<unsigned char>(p[1])]) !=
Align::INVALID) {
fill = *p;
align = a;
p += 2;
if (p == end) {
return;
}
} else if (
(a = formatAlignTable[static_cast<unsigned char>(*p)]) !=
Align::INVALID) {
align = a;
if (++p == end) {
return;
}
}
Sign s;
unsigned char uSign = static_cast<unsigned char>(*p);
if ((s = formatSignTable[uSign]) != Sign::INVALID) {
sign = s;
if (++p == end) {
return;
}
}
if (*p == '#') {
basePrefix = true;
if (++p == end) {
return;
}
}
if (*p == '0') {
enforce(align == Align::DEFAULT, "alignment specified twice");
fill = '0';
align = Align::PAD_AFTER_SIGN;
if (++p == end) {
return;
}
}
auto readInt = [&] {
auto const c = p;
do {
++p;
} while (p != end && *p >= '0' && *p <= '9');
return to<int>(StringPiece(c, p));
};
if (*p == '*') {
width = kDynamicWidth;
++p;
if (p == end) {
return;
}
if (*p >= '0' && *p <= '9') {
widthIndex = readInt();
}
if (p == end) {
return;
}
} else if (*p >= '0' && *p <= '9') {
width = readInt();
if (p == end) {
return;
}
}
if (*p == ',') {
thousandsSeparator = true;
if (++p == end) {
return;
}
}
if (*p == '.') {
auto d = ++p;
while (p != end && *p >= '0' && *p <= '9') {
++p;
}
if (p != d) {
precision = to<int>(StringPiece(d, p));
if (p != end && *p == '.') {
trailingDot = true;
++p;
}
} else {
trailingDot = true;
}
if (p == end) {
return;
}
}
presentation = *p;
if (++p == end) {
return;
}
}
error("extra characters in format string");
}
void FormatArg::validate(Type type) const {
enforce(keyEmpty(), "index not allowed");
switch (type) {
case Type::INTEGER:
enforce(
precision == kDefaultPrecision, "precision not allowed on integers");
break;
case Type::FLOAT:
enforce(
!basePrefix, "base prefix ('#') specifier only allowed on integers");
enforce(
!thousandsSeparator,
"thousands separator (',') only allowed on integers");
break;
case Type::OTHER:
enforce(
align != Align::PAD_AFTER_SIGN,
"'='alignment only allowed on numbers");
enforce(sign == Sign::DEFAULT, "sign specifier only allowed on numbers");
enforce(
!basePrefix, "base prefix ('#') specifier only allowed on integers");
enforce(
!thousandsSeparator,
"thousands separator (',') only allowed on integers");
break;
}
}
namespace detail {
void insertThousandsGroupingUnsafe(char* start_buffer, char** end_buffer) {
uint32_t remaining_digits = uint32_t(*end_buffer - start_buffer);
uint32_t separator_size = (remaining_digits - 1) / 3;
uint32_t result_size = remaining_digits + separator_size;
*end_buffer = *end_buffer + separator_size;
// get the end of the new string with the separators
uint32_t buffer_write_index = result_size - 1;
uint32_t buffer_read_index = remaining_digits - 1;
start_buffer[buffer_write_index + 1] = 0;
bool done = false;
uint32_t next_group_size = 3;
while (!done) {
uint32_t current_group_size = std::max<uint32_t>(
1, std::min<uint32_t>(remaining_digits, next_group_size));
// write out the current group's digits to the buffer index
for (uint32_t i = 0; i < current_group_size; i++) {
start_buffer[buffer_write_index--] = start_buffer[buffer_read_index--];
}
// if not finished, write the separator before the next group
if (buffer_write_index < buffer_write_index + 1) {
start_buffer[buffer_write_index--] = ',';
} else {
done = true;
}
remaining_digits -= current_group_size;
}
}
} // namespace detail
FormatKeyNotFoundException::FormatKeyNotFoundException(StringPiece key)
: std::out_of_range(kMessagePrefix.str() + key.str()) {}
constexpr StringPiece const FormatKeyNotFoundException::kMessagePrefix;
} // namespace folly