tvl-depot/absl/strings/internal/str_format/arg.h
Abseil Team 4491d606df Export of internal Abseil changes.
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70f43a482d7d4ae4a255f17ca02b0106653dd600 by Shaindel Schwartz <shaindel@google.com>:

Internal change

PiperOrigin-RevId: 201571193

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93e6e9c2e683158be49d9dd1f5cb1a91d0c0f556 by Abseil Team <absl-team@google.com>:

Internal change.

PiperOrigin-RevId: 201567108

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fbd8ee94fbe9f2448e5adf5e88706f9c8216048f by Juemin Yang <jueminyang@google.com>:

str_format release

PiperOrigin-RevId: 201565129

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387faa301555a8a888c4429df52734aa806dca46 by Abseil Team <absl-team@google.com>:

Adds a defaulted allocator parameter to the size_type constructor of InlinedVector

PiperOrigin-RevId: 201558711

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39b15ea2c68d7129d70cbde7e71af900032595ec by Matt Calabrese <calabrese@google.com>:

Update the variant implementation to eliminate unnecessary checking on alternative access when the index is known or required to be correct.

PiperOrigin-RevId: 201529535

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adab77f1f7bb363aa534297f22aae2b0f08889ea by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 201458388

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a701dc0ba62e3cadf0de14203415b91df4ee8151 by Greg Falcon <gfalcon@google.com>:

Internal cleanup

PiperOrigin-RevId: 201394836

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8a7191410b8f440fdfa27f722ff05e451502ab61 by Abseil Team <absl-team@google.com>:

Import of CCTZ from GitHub.

PiperOrigin-RevId: 201369269
GitOrigin-RevId: 70f43a482d7d4ae4a255f17ca02b0106653dd600
Change-Id: I8ab073b30b4e27405a3b6da2c826bb4f3f0b9af6
2018-06-22 08:55:41 -04:00

434 lines
16 KiB
C++

#ifndef ABSL_STRINGS_INTERNAL_STR_FORMAT_ARG_H_
#define ABSL_STRINGS_INTERNAL_STR_FORMAT_ARG_H_
#include <string.h>
#include <wchar.h>
#include <cstdio>
#include <iomanip>
#include <limits>
#include <sstream>
#include <string>
#include <type_traits>
#include "absl/base/port.h"
#include "absl/meta/type_traits.h"
#include "absl/numeric/int128.h"
#include "absl/strings/internal/str_format/extension.h"
#include "absl/strings/string_view.h"
class Cord;
class CordReader;
namespace absl {
class FormatCountCapture;
class FormatSink;
namespace str_format_internal {
template <typename T, typename = void>
struct HasUserDefinedConvert : std::false_type {};
template <typename T>
struct HasUserDefinedConvert<
T, void_t<decltype(AbslFormatConvert(
std::declval<const T&>(), std::declval<const ConversionSpec&>(),
std::declval<FormatSink*>()))>> : std::true_type {};
template <typename T>
class StreamedWrapper;
// If 'v' can be converted (in the printf sense) according to 'conv',
// then convert it, appending to `sink` and return `true`.
// Otherwise fail and return `false`.
// Raw pointers.
struct VoidPtr {
VoidPtr() = default;
template <typename T,
decltype(reinterpret_cast<uintptr_t>(std::declval<T*>())) = 0>
VoidPtr(T* ptr) // NOLINT
: value(ptr ? reinterpret_cast<uintptr_t>(ptr) : 0) {}
uintptr_t value;
};
ConvertResult<Conv::p> FormatConvertImpl(VoidPtr v, const ConversionSpec& conv,
FormatSinkImpl* sink);
// Strings.
ConvertResult<Conv::s> FormatConvertImpl(const std::string& v,
const ConversionSpec& conv,
FormatSinkImpl* sink);
ConvertResult<Conv::s> FormatConvertImpl(string_view v,
const ConversionSpec& conv,
FormatSinkImpl* sink);
ConvertResult<Conv::s | Conv::p> FormatConvertImpl(const char* v,
const ConversionSpec& conv,
FormatSinkImpl* sink);
template <class AbslCord,
typename std::enable_if<
std::is_same<AbslCord, ::Cord>::value>::type* = nullptr,
class AbslCordReader = ::CordReader>
ConvertResult<Conv::s> FormatConvertImpl(const AbslCord& value,
const ConversionSpec& conv,
FormatSinkImpl* sink) {
if (conv.conv().id() != ConversionChar::s) return {false};
bool is_left = conv.flags().left;
size_t space_remaining = 0;
int width = conv.width();
if (width >= 0) space_remaining = width;
size_t to_write = value.size();
int precision = conv.precision();
if (precision >= 0)
to_write = std::min(to_write, static_cast<size_t>(precision));
space_remaining = Excess(to_write, space_remaining);
if (space_remaining > 0 && !is_left) sink->Append(space_remaining, ' ');
string_view piece;
for (AbslCordReader reader(value);
to_write > 0 && reader.ReadFragment(&piece); to_write -= piece.size()) {
if (piece.size() > to_write) piece.remove_suffix(piece.size() - to_write);
sink->Append(piece);
}
if (space_remaining > 0 && is_left) sink->Append(space_remaining, ' ');
return {true};
}
using IntegralConvertResult =
ConvertResult<Conv::c | Conv::numeric | Conv::star>;
using FloatingConvertResult = ConvertResult<Conv::floating>;
// Floats.
FloatingConvertResult FormatConvertImpl(float v, const ConversionSpec& conv,
FormatSinkImpl* sink);
FloatingConvertResult FormatConvertImpl(double v, const ConversionSpec& conv,
FormatSinkImpl* sink);
FloatingConvertResult FormatConvertImpl(long double v,
const ConversionSpec& conv,
FormatSinkImpl* sink);
// Chars.
IntegralConvertResult FormatConvertImpl(char v, const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(signed char v,
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned char v,
const ConversionSpec& conv,
FormatSinkImpl* sink);
// Ints.
IntegralConvertResult FormatConvertImpl(short v, // NOLINT
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned short v, // NOLINT
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(int v, const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned v, const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(long v, // NOLINT
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned long v, // NOLINT
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(long long v, // NOLINT
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(unsigned long long v, // NOLINT
const ConversionSpec& conv,
FormatSinkImpl* sink);
IntegralConvertResult FormatConvertImpl(uint128 v, const ConversionSpec& conv,
FormatSinkImpl* sink);
template <typename T, enable_if_t<std::is_same<T, bool>::value, int> = 0>
IntegralConvertResult FormatConvertImpl(T v, const ConversionSpec& conv,
FormatSinkImpl* sink) {
return FormatConvertImpl(static_cast<int>(v), conv, sink);
}
// We provide this function to help the checker, but it is never defined.
// FormatArgImpl will use the underlying Convert functions instead.
template <typename T>
typename std::enable_if<std::is_enum<T>::value &&
!HasUserDefinedConvert<T>::value,
IntegralConvertResult>::type
FormatConvertImpl(T v, const ConversionSpec& conv, FormatSinkImpl* sink);
template <typename T>
ConvertResult<Conv::s> FormatConvertImpl(const StreamedWrapper<T>& v,
const ConversionSpec& conv,
FormatSinkImpl* out) {
std::ostringstream oss;
oss << v.v_;
if (!oss) return {false};
return str_format_internal::FormatConvertImpl(oss.str(), conv, out);
}
// Use templates and dependent types to delay evaluation of the function
// until after FormatCountCapture is fully defined.
struct FormatCountCaptureHelper {
template <class T = int>
static ConvertResult<Conv::n> ConvertHelper(const FormatCountCapture& v,
const ConversionSpec& conv,
FormatSinkImpl* sink) {
const absl::enable_if_t<sizeof(T) != 0, FormatCountCapture>& v2 = v;
if (conv.conv().id() != str_format_internal::ConversionChar::n)
return {false};
*v2.p_ = static_cast<int>(sink->size());
return {true};
}
};
template <class T = int>
ConvertResult<Conv::n> FormatConvertImpl(const FormatCountCapture& v,
const ConversionSpec& conv,
FormatSinkImpl* sink) {
return FormatCountCaptureHelper::ConvertHelper(v, conv, sink);
}
// Helper friend struct to hide implementation details from the public API of
// FormatArgImpl.
struct FormatArgImplFriend {
template <typename Arg>
static bool ToInt(Arg arg, int* out) {
if (!arg.vtbl_->to_int) return false;
*out = arg.vtbl_->to_int(arg.data_);
return true;
}
template <typename Arg>
static bool Convert(Arg arg, const str_format_internal::ConversionSpec& conv,
FormatSinkImpl* out) {
return arg.vtbl_->convert(arg.data_, conv, out);
}
template <typename Arg>
static const void* GetVTablePtrForTest(Arg arg) {
return arg.vtbl_;
}
};
// A type-erased handle to a format argument.
class FormatArgImpl {
private:
enum { kInlinedSpace = 8 };
using VoidPtr = str_format_internal::VoidPtr;
union Data {
const void* ptr;
const volatile void* volatile_ptr;
char buf[kInlinedSpace];
};
struct VTable {
bool (*convert)(Data, const str_format_internal::ConversionSpec& conv,
FormatSinkImpl* out);
int (*to_int)(Data);
};
template <typename T>
struct store_by_value
: std::integral_constant<bool, (sizeof(T) <= kInlinedSpace) &&
(std::is_integral<T>::value ||
std::is_floating_point<T>::value ||
std::is_pointer<T>::value ||
std::is_same<VoidPtr, T>::value)> {};
enum StoragePolicy { ByPointer, ByVolatilePointer, ByValue };
template <typename T>
struct storage_policy
: std::integral_constant<StoragePolicy,
(std::is_volatile<T>::value
? ByVolatilePointer
: (store_by_value<T>::value ? ByValue
: ByPointer))> {
};
// An instance of an FormatArgImpl::VTable suitable for 'T'.
template <typename T>
struct TypedVTable;
// To reduce the number of vtables we will decay values before hand.
// Anything with a user-defined Convert will get its own vtable.
// For everything else:
// - Decay char* and char arrays into `const char*`
// - Decay any other pointer to `const void*`
// - Decay all enums to their underlying type.
// - Decay function pointers to void*.
template <typename T, typename = void>
struct DecayType {
static constexpr bool kHasUserDefined =
str_format_internal::HasUserDefinedConvert<T>::value;
using type = typename std::conditional<
!kHasUserDefined && std::is_convertible<T, const char*>::value,
const char*,
typename std::conditional<!kHasUserDefined &&
std::is_convertible<T, VoidPtr>::value,
VoidPtr, const T&>::type>::type;
};
template <typename T>
struct DecayType<T,
typename std::enable_if<
!str_format_internal::HasUserDefinedConvert<T>::value &&
std::is_enum<T>::value>::type> {
using type = typename std::underlying_type<T>::type;
};
public:
template <typename T>
explicit FormatArgImpl(const T& value) {
using D = typename DecayType<T>::type;
static_assert(
std::is_same<D, const T&>::value || storage_policy<D>::value == ByValue,
"Decayed types must be stored by value");
Init(static_cast<D>(value));
}
private:
friend struct str_format_internal::FormatArgImplFriend;
template <typename T, StoragePolicy = storage_policy<T>::value>
struct Manager;
template <typename T>
struct Manager<T, ByPointer> {
static Data SetValue(const T& value) {
Data data;
data.ptr = &value;
return data;
}
static const T& Value(Data arg) { return *static_cast<const T*>(arg.ptr); }
};
template <typename T>
struct Manager<T, ByVolatilePointer> {
static Data SetValue(const T& value) {
Data data;
data.volatile_ptr = &value;
return data;
}
static const T& Value(Data arg) {
return *static_cast<const T*>(arg.volatile_ptr);
}
};
template <typename T>
struct Manager<T, ByValue> {
static Data SetValue(const T& value) {
Data data;
memcpy(data.buf, &value, sizeof(value));
return data;
}
static T Value(Data arg) {
T value;
memcpy(&value, arg.buf, sizeof(T));
return value;
}
};
template <typename T>
void Init(const T& value);
template <typename T>
static int ToIntVal(const T& val) {
using CommonType = typename std::conditional<std::is_signed<T>::value,
int64_t, uint64_t>::type;
if (static_cast<CommonType>(val) >
static_cast<CommonType>(std::numeric_limits<int>::max())) {
return std::numeric_limits<int>::max();
} else if (std::is_signed<T>::value &&
static_cast<CommonType>(val) <
static_cast<CommonType>(std::numeric_limits<int>::min())) {
return std::numeric_limits<int>::min();
}
return static_cast<int>(val);
}
Data data_;
const VTable* vtbl_;
};
template <typename T>
struct FormatArgImpl::TypedVTable {
private:
static bool ConvertImpl(Data arg,
const str_format_internal::ConversionSpec& conv,
FormatSinkImpl* out) {
return str_format_internal::FormatConvertImpl(Manager<T>::Value(arg), conv,
out)
.value;
}
template <typename U = T, typename = void>
struct ToIntImpl {
static constexpr int (*value)(Data) = nullptr;
};
template <typename U>
struct ToIntImpl<U,
typename std::enable_if<std::is_integral<U>::value>::type> {
static int Invoke(Data arg) { return ToIntVal(Manager<T>::Value(arg)); }
static constexpr int (*value)(Data) = &Invoke;
};
template <typename U>
struct ToIntImpl<U, typename std::enable_if<std::is_enum<U>::value>::type> {
static int Invoke(Data arg) {
return ToIntVal(static_cast<typename std::underlying_type<T>::type>(
Manager<T>::Value(arg)));
}
static constexpr int (*value)(Data) = &Invoke;
};
public:
static constexpr VTable value{&ConvertImpl, ToIntImpl<>::value};
};
template <typename T>
constexpr FormatArgImpl::VTable FormatArgImpl::TypedVTable<T>::value;
template <typename T>
void FormatArgImpl::Init(const T& value) {
data_ = Manager<T>::SetValue(value);
vtbl_ = &TypedVTable<T>::value;
}
extern template struct FormatArgImpl::TypedVTable<str_format_internal::VoidPtr>;
extern template struct FormatArgImpl::TypedVTable<bool>;
extern template struct FormatArgImpl::TypedVTable<char>;
extern template struct FormatArgImpl::TypedVTable<signed char>;
extern template struct FormatArgImpl::TypedVTable<unsigned char>;
extern template struct FormatArgImpl::TypedVTable<short>; // NOLINT
extern template struct FormatArgImpl::TypedVTable<unsigned short>; // NOLINT
extern template struct FormatArgImpl::TypedVTable<int>;
extern template struct FormatArgImpl::TypedVTable<unsigned>;
extern template struct FormatArgImpl::TypedVTable<long>; // NOLINT
extern template struct FormatArgImpl::TypedVTable<unsigned long>; // NOLINT
extern template struct FormatArgImpl::TypedVTable<long long>; // NOLINT
extern template struct FormatArgImpl::TypedVTable<
unsigned long long>; // NOLINT
extern template struct FormatArgImpl::TypedVTable<uint128>;
extern template struct FormatArgImpl::TypedVTable<float>;
extern template struct FormatArgImpl::TypedVTable<double>;
extern template struct FormatArgImpl::TypedVTable<long double>;
extern template struct FormatArgImpl::TypedVTable<const char*>;
extern template struct FormatArgImpl::TypedVTable<std::string>;
extern template struct FormatArgImpl::TypedVTable<string_view>;
} // namespace str_format_internal
} // namespace absl
#endif // ABSL_STRINGS_INTERNAL_STR_FORMAT_ARG_H_