/*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#include <double-conversion/double-conversion.h> // V8 JavaScript implementation
#include <folly/Demangle.h>
+#include <folly/Expected.h>
#include <folly/FBString.h>
#include <folly/Likely.h>
#include <folly/Range.h>
+#include <folly/Traits.h>
+#include <folly/Unit.h>
#include <folly/portability/Math.h>
namespace folly {
-class ConversionError : public std::range_error {
- public:
- // Keep this in sync with kErrorStrings in Conv.cpp
- enum Code {
- SUCCESS,
- EMPTY_INPUT_STRING,
- NO_DIGITS,
- BOOL_OVERFLOW,
- BOOL_INVALID_VALUE,
- NON_DIGIT_CHAR,
- INVALID_LEADING_CHAR,
- POSITIVE_OVERFLOW,
- NEGATIVE_OVERFLOW,
- STRING_TO_FLOAT_ERROR,
- NON_WHITESPACE_AFTER_END,
- ARITH_POSITIVE_OVERFLOW,
- ARITH_NEGATIVE_OVERFLOW,
- ARITH_LOSS_OF_PRECISION,
- NUM_ERROR_CODES, // has to be the last entry
- };
+// Keep this in sync with kErrorStrings in Conv.cpp
+enum class ConversionCode : unsigned char {
+ SUCCESS,
+ EMPTY_INPUT_STRING,
+ NO_DIGITS,
+ BOOL_OVERFLOW,
+ BOOL_INVALID_VALUE,
+ NON_DIGIT_CHAR,
+ INVALID_LEADING_CHAR,
+ POSITIVE_OVERFLOW,
+ NEGATIVE_OVERFLOW,
+ STRING_TO_FLOAT_ERROR,
+ NON_WHITESPACE_AFTER_END,
+ ARITH_POSITIVE_OVERFLOW,
+ ARITH_NEGATIVE_OVERFLOW,
+ ARITH_LOSS_OF_PRECISION,
+ NUM_ERROR_CODES, // has to be the last entry
+};
- ConversionError(const std::string& str, Code code)
- : std::range_error(str), code_(code) {}
+struct ConversionErrorBase : std::range_error {
+ using std::range_error::range_error;
+};
+
+class ConversionError : public ConversionErrorBase {
+ public:
+ ConversionError(const std::string& str, ConversionCode code)
+ : ConversionErrorBase(str), code_(code) {}
- ConversionError(const char* str, Code code)
- : std::range_error(str), code_(code) {}
+ ConversionError(const char* str, ConversionCode code)
+ : ConversionErrorBase(str), code_(code) {}
- Code errorCode() const { return code_; }
+ ConversionCode errorCode() const {
+ return code_;
+ }
private:
- Code code_;
+ ConversionCode code_;
};
-namespace detail {
-
-ConversionError makeConversionError(
- ConversionError::Code code,
- const char* input,
- size_t inputLen);
-
-inline ConversionError makeConversionError(
- ConversionError::Code code,
- const std::string& str) {
- return makeConversionError(code, str.data(), str.size());
-}
-
-inline ConversionError makeConversionError(
- ConversionError::Code code,
- StringPiece sp) {
- return makeConversionError(code, sp.data(), sp.size());
-}
+/*******************************************************************************
+ * Custom Error Translation
+ *
+ * Your overloaded parseTo() function can return a custom error code on failure.
+ * ::folly::to() will call makeConversionError to translate that error code into
+ * an object to throw. makeConversionError is found by argument-dependent
+ * lookup. It should have this signature:
+ *
+ * namespace other_namespace {
+ * enum YourErrorCode { BAD_ERROR, WORSE_ERROR };
+ *
+ * struct YourConversionError : ConversionErrorBase {
+ * YourConversionError(const char* what) : ConversionErrorBase(what) {}
+ * };
+ *
+ * YourConversionError
+ * makeConversionError(YourErrorCode code, ::folly::StringPiece sp) {
+ * ...
+ * return YourConversionError(messageString);
+ * }
+ ******************************************************************************/
+ConversionError makeConversionError(ConversionCode code, StringPiece sp);
+namespace detail {
/**
* Enforce that the suffix following a number is made up only of whitespace.
*/
-inline ConversionError::Code enforceWhitespaceErr(StringPiece sp) {
+inline ConversionCode enforceWhitespaceErr(StringPiece sp) {
for (auto c : sp) {
- if (!std::isspace(c)) {
- return ConversionError::NON_WHITESPACE_AFTER_END;
+ if (UNLIKELY(!std::isspace(c))) {
+ return ConversionCode::NON_WHITESPACE_AFTER_END;
}
}
- return ConversionError::SUCCESS;
+ return ConversionCode::SUCCESS;
}
/**
*/
inline void enforceWhitespace(StringPiece sp) {
auto err = enforceWhitespaceErr(sp);
- if (err != ConversionError::SUCCESS) {
- throw detail::makeConversionError(err, sp);
+ if (err != ConversionCode::SUCCESS) {
+ throw makeConversionError(err, sp);
}
}
+}
/**
- * A simple std::pair-like wrapper to wrap both a value and an error
+ * The identity conversion function.
+ * tryTo<T>(T) returns itself for all types T.
*/
-template <typename T>
-struct ConversionResult {
- explicit ConversionResult(T v) : value(v) {}
- explicit ConversionResult(ConversionError::Code e) : error(e) {}
-
- bool success() const {
- return error == ConversionError::SUCCESS;
- }
+template <class Tgt, class Src>
+typename std::enable_if<
+ std::is_same<Tgt, typename std::decay<Src>::type>::value,
+ Expected<Tgt, ConversionCode>>::type
+tryTo(Src&& value) {
+ return std::forward<Src>(value);
+}
- T value;
- ConversionError::Code error{ConversionError::SUCCESS};
-};
+template <class Tgt, class Src>
+typename std::enable_if<
+ std::is_same<Tgt, typename std::decay<Src>::type>::value,
+ Tgt>::type
+to(Src&& value) {
+ return std::forward<Src>(value);
}
+/*******************************************************************************
+ * Arithmetic to boolean
+ ******************************************************************************/
+
/**
- * The identity conversion function.
- * to<T>(T) returns itself for all types T.
+ * Unchecked conversion from arithmetic to boolean. This is different from the
+ * other arithmetic conversions because we use the C convention of treating any
+ * non-zero value as true, instead of range checking.
*/
template <class Tgt, class Src>
-typename std::enable_if<std::is_same<Tgt, Src>::value, Tgt>::type
-to(const Src & value) {
- return value;
+typename std::enable_if<
+ std::is_arithmetic<Src>::value && !std::is_same<Tgt, Src>::value &&
+ std::is_same<Tgt, bool>::value,
+ Expected<Tgt, ConversionCode>>::type
+tryTo(const Src& value) {
+ return value != Src();
}
template <class Tgt, class Src>
-typename std::enable_if<std::is_same<Tgt, Src>::value, Tgt>::type
-to(Src && value) {
- return std::forward<Src>(value);
+typename std::enable_if<
+ std::is_arithmetic<Src>::value && !std::is_same<Tgt, Src>::value &&
+ std::is_same<Tgt, bool>::value,
+ Tgt>::type
+to(const Src& value) {
+ return value != Src();
}
/*******************************************************************************
namespace detail {
-template <class T>
-const T& getLastElement(const T & v) {
- return v;
-}
+#ifdef _MSC_VER
+// MSVC can't quite figure out the LastElementImpl::call() stuff
+// in the base implementation, so we have to use tuples instead,
+// which result in significantly more templates being compiled,
+// though the runtime performance is the same.
-template <class T, class... Ts>
-typename std::tuple_element<
- sizeof...(Ts),
- std::tuple<T, Ts...> >::type const&
- getLastElement(const T&, const Ts&... vs) {
- return getLastElement(vs...);
+template <typename... Ts>
+auto getLastElement(Ts&&... ts) -> decltype(
+ std::get<sizeof...(Ts)-1>(std::forward_as_tuple(std::forward<Ts>(ts)...))) {
+ return std::get<sizeof...(Ts)-1>(
+ std::forward_as_tuple(std::forward<Ts>(ts)...));
}
-// This class exists to specialize away std::tuple_element in the case where we
-// have 0 template arguments. Without this, Clang/libc++ will blow a
-// static_assert even if tuple_element is protected by an enable_if.
+inline void getLastElement() {}
+
+template <size_t size, typename... Ts>
+struct LastElementType : std::tuple_element<size - 1, std::tuple<Ts...>> {};
+
+template <>
+struct LastElementType<0> {
+ using type = void;
+};
+
template <class... Ts>
-struct last_element {
- typedef typename std::enable_if<
- sizeof...(Ts) >= 1,
- typename std::tuple_element<
- sizeof...(Ts) - 1, std::tuple<Ts...>
- >::type>::type type;
+struct LastElement
+ : std::decay<typename LastElementType<sizeof...(Ts), Ts...>::type> {};
+#else
+template <typename... Ts>
+struct LastElementImpl {
+ static void call(Ignored<Ts>...) {}
};
-template <>
-struct last_element<> {
- typedef void type;
+template <typename Head, typename... Ts>
+struct LastElementImpl<Head, Ts...> {
+ template <typename Last>
+ static Last call(Ignored<Ts>..., Last&& last) {
+ return std::forward<Last>(last);
+ }
+};
+
+template <typename... Ts>
+auto getLastElement(const Ts&... ts)
+ -> decltype(LastElementImpl<Ts...>::call(ts...)) {
+ return LastElementImpl<Ts...>::call(ts...);
+}
+
+template <class... Ts>
+struct LastElement : std::decay<decltype(
+ LastElementImpl<Ts...>::call(std::declval<Ts>()...))> {
};
+#endif
} // namespace detail
// Keep these together so a peephole optimization "sees" them and
// computes them in one shot.
auto const q = v / 10;
- auto const r = static_cast<uint32_t>(v % 10);
+ auto const r = static_cast<char>(v % 10);
buffer[pos--] = '0' + r;
v = q;
}
// Last digit is trivial to handle
- buffer[pos] = static_cast<uint32_t>(v) + '0';
+ buffer[pos] = static_cast<char>(v) + '0';
return result;
}
}
}
-template<class Src>
-typename std::enable_if<
- std::is_convertible<Src, const char*>::value,
- size_t>::type
-estimateSpaceNeeded(Src value) {
+template <class Src>
+typename std::enable_if<std::is_convertible<Src, const char*>::value, size_t>::
+ type
+ estimateSpaceNeeded(Src value) {
const char *c = value;
if (c) {
return folly::StringPiece(value).size();
char buffer[20];
if (value < 0) {
result->push_back('-');
- result->append(buffer, uint64ToBufferUnsafe(-uint64_t(value), buffer));
+ result->append(
+ buffer,
+ uint64ToBufferUnsafe(~static_cast<uint64_t>(value) + 1, buffer));
} else {
- result->append(buffer, uint64ToBufferUnsafe(value, buffer));
+ result->append(buffer, uint64ToBufferUnsafe(uint64_t(value), buffer));
}
}
conv.ToShortest(value, &builder);
break;
case DoubleToStringConverter::FIXED:
- conv.ToFixed(value, numDigits, &builder);
+ conv.ToFixed(value, int(numDigits), &builder);
break;
default:
CHECK(mode == DoubleToStringConverter::PRECISION);
- conv.ToPrecision(value, numDigits, &builder);
+ conv.ToPrecision(value, int(numDigits), &builder);
break;
}
- const size_t length = builder.position();
+ const size_t length = size_t(builder.position());
builder.Finalize();
result->append(buffer, length);
}
// so 21 is the longest non-exponential number > 1.
detail::kConvMaxDecimalInShortestHigh
});
- return kMaxPositiveSpace + (value < 0); // +1 for minus sign, if negative
+ return size_t(
+ kMaxPositiveSpace +
+ (value < 0 ? 1 : 0)); // +1 for minus sign, if negative
}
/**
}
template <class T, class... Ts>
-typename std::enable_if<sizeof...(Ts) >= 2
- && IsSomeString<
- typename std::remove_pointer<
- typename detail::last_element<Ts...>::type
- >::type>::value>::type
+typename std::enable_if<
+ sizeof...(Ts) >= 2 &&
+ IsSomeString<typename std::remove_pointer<
+ typename detail::LastElement<const Ts&...>::type>::type>::value>::type
toAppendStrImpl(const T& v, const Ts&... vs) {
toAppend(v, getLastElement(vs...));
toAppendStrImpl(vs...);
}
template <class Delimiter, class T, class... Ts>
-typename std::enable_if<sizeof...(Ts) >= 2
- && IsSomeString<
- typename std::remove_pointer<
- typename detail::last_element<Ts...>::type
- >::type>::value>::type
+typename std::enable_if<
+ sizeof...(Ts) >= 2 &&
+ IsSomeString<typename std::remove_pointer<
+ typename detail::LastElement<const Ts&...>::type>::type>::value>::type
toAppendDelimStrImpl(const Delimiter& delim, const T& v, const Ts&... vs) {
// we are really careful here, calling toAppend with just one element does
// not try to estimate space needed (as we already did that). If we call
* }
*/
template <class... Ts>
-typename std::enable_if<sizeof...(Ts) >= 3
- && IsSomeString<
- typename std::remove_pointer<
- typename detail::last_element<Ts...>::type
- >::type>::value>::type
+typename std::enable_if<
+ sizeof...(Ts) >= 3 &&
+ IsSomeString<typename std::remove_pointer<
+ typename detail::LastElement<const Ts&...>::type>::type>::value>::type
toAppend(const Ts&... vs) {
::folly::detail::toAppendStrImpl(vs...);
}
* will probably save a few calls to malloc.
*/
template <class... Ts>
-typename std::enable_if<
- IsSomeString<
- typename std::remove_pointer<
- typename detail::last_element<Ts...>::type
- >::type>::value>::type
+typename std::enable_if<IsSomeString<typename std::remove_pointer<
+ typename detail::LastElement<const Ts&...>::type>::type>::value>::type
toAppendFit(const Ts&... vs) {
::folly::detail::reserveInTarget(vs...);
toAppend(vs...);
* comments for toAppend for details about memory allocation.
*/
template <class Delimiter, class... Ts>
-typename std::enable_if<sizeof...(Ts) >= 3
- && IsSomeString<
- typename std::remove_pointer<
- typename detail::last_element<Ts...>::type
- >::type>::value>::type
+typename std::enable_if<
+ sizeof...(Ts) >= 3 &&
+ IsSomeString<typename std::remove_pointer<
+ typename detail::LastElement<const Ts&...>::type>::type>::value>::type
toAppendDelim(const Delimiter& delim, const Ts&... vs) {
detail::toAppendDelimStrImpl(delim, vs...);
}
* Detail in comment for toAppendFit
*/
template <class Delimiter, class... Ts>
-typename std::enable_if<
- IsSomeString<
- typename std::remove_pointer<
- typename detail::last_element<Ts...>::type
- >::type>::value>::type
+typename std::enable_if<IsSomeString<typename std::remove_pointer<
+ typename detail::LastElement<const Ts&...>::type>::type>::value>::type
toAppendDelimFit(const Delimiter& delim, const Ts&... vs) {
detail::reserveInTargetDelim(delim, vs...);
toAppendDelim(delim, vs...);
*/
template <class Tgt, class... Ts>
typename std::enable_if<
- IsSomeString<Tgt>::value && (
- sizeof...(Ts) != 1 ||
- !std::is_same<Tgt, typename detail::last_element<Ts...>::type>::value),
- Tgt>::type
+ IsSomeString<Tgt>::value &&
+ (sizeof...(Ts) != 1 ||
+ !std::is_same<Tgt, typename detail::LastElement<const Ts&...>::type>::
+ value),
+ Tgt>::type
to(const Ts&... vs) {
Tgt result;
toAppendFit(vs..., &result);
return result;
}
+/**
+ * Special version of to<SomeString> for floating point. When calling
+ * folly::to<SomeString>(double), generic implementation above will
+ * firstly reserve 24 (or 25 when negative value) bytes. This will
+ * introduce a malloc call for most mainstream string implementations.
+ *
+ * But for most cases, a floating point doesn't need 24 (or 25) bytes to
+ * be converted as a string.
+ *
+ * This special version will not do string reserve.
+ */
+template <class Tgt, class Src>
+typename std::enable_if<
+ IsSomeString<Tgt>::value && std::is_floating_point<Src>::value,
+ Tgt>::type
+to(Src value) {
+ Tgt result;
+ toAppend(value, &result);
+ return result;
+}
+
/**
* toDelim<SomeString>(SomeString str) returns itself.
*/
template <class Tgt, class Delim, class Src>
-typename std::enable_if<IsSomeString<Tgt>::value &&
- std::is_same<Tgt, Src>::value,
- Tgt>::type
-toDelim(const Delim& /* delim */, const Src& value) {
- return value;
+typename std::enable_if<
+ IsSomeString<Tgt>::value &&
+ std::is_same<Tgt, typename std::decay<Src>::type>::value,
+ Tgt>::type
+toDelim(const Delim& /* delim */, Src&& value) {
+ return std::forward<Src>(value);
}
/**
*/
template <class Tgt, class Delim, class... Ts>
typename std::enable_if<
- IsSomeString<Tgt>::value && (
- sizeof...(Ts) != 1 ||
- !std::is_same<Tgt, typename detail::last_element<Ts...>::type>::value),
- Tgt>::type
+ IsSomeString<Tgt>::value &&
+ (sizeof...(Ts) != 1 ||
+ !std::is_same<Tgt, typename detail::LastElement<const Ts&...>::type>::
+ value),
+ Tgt>::type
toDelim(const Delim& delim, const Ts&... vs) {
Tgt result;
toAppendDelimFit(delim, vs..., &result);
namespace detail {
-ConversionResult<bool> str_to_bool(StringPiece* src);
+Expected<bool, ConversionCode> str_to_bool(StringPiece* src) noexcept;
template <typename T>
-ConversionResult<T> str_to_floating(StringPiece* src);
+Expected<T, ConversionCode> str_to_floating(StringPiece* src) noexcept;
-extern template ConversionResult<float> str_to_floating<float>(
- StringPiece* src);
-extern template ConversionResult<double> str_to_floating<double>(
- StringPiece* src);
+extern template Expected<float, ConversionCode> str_to_floating<float>(
+ StringPiece* src) noexcept;
+extern template Expected<double, ConversionCode> str_to_floating<double>(
+ StringPiece* src) noexcept;
template <class Tgt>
-ConversionResult<Tgt> digits_to(const char* b, const char* e);
+Expected<Tgt, ConversionCode> digits_to(const char* b, const char* e) noexcept;
-extern template ConversionResult<char> digits_to<char>(
- const char*,
- const char*);
-extern template ConversionResult<signed char> digits_to<signed char>(
+extern template Expected<char, ConversionCode> digits_to<char>(
const char*,
- const char*);
-extern template ConversionResult<unsigned char> digits_to<unsigned char>(
+ const char*) noexcept;
+extern template Expected<signed char, ConversionCode> digits_to<signed char>(
const char*,
- const char*);
+ const char*) noexcept;
+extern template Expected<unsigned char, ConversionCode>
+digits_to<unsigned char>(const char*, const char*) noexcept;
-extern template ConversionResult<short> digits_to<short>(
- const char*,
- const char*);
-extern template ConversionResult<unsigned short> digits_to<unsigned short>(
+extern template Expected<short, ConversionCode> digits_to<short>(
const char*,
- const char*);
+ const char*) noexcept;
+extern template Expected<unsigned short, ConversionCode>
+digits_to<unsigned short>(const char*, const char*) noexcept;
-extern template ConversionResult<int> digits_to<int>(const char*, const char*);
-extern template ConversionResult<unsigned int> digits_to<unsigned int>(
+extern template Expected<int, ConversionCode> digits_to<int>(
const char*,
- const char*);
-
-extern template ConversionResult<long> digits_to<long>(
+ const char*) noexcept;
+extern template Expected<unsigned int, ConversionCode> digits_to<unsigned int>(
const char*,
- const char*);
-extern template ConversionResult<unsigned long> digits_to<unsigned long>(
+ const char*) noexcept;
+
+extern template Expected<long, ConversionCode> digits_to<long>(
const char*,
- const char*);
+ const char*) noexcept;
+extern template Expected<unsigned long, ConversionCode>
+digits_to<unsigned long>(const char*, const char*) noexcept;
-extern template ConversionResult<long long> digits_to<long long>(
+extern template Expected<long long, ConversionCode> digits_to<long long>(
const char*,
- const char*);
-extern template ConversionResult<unsigned long long>
-digits_to<unsigned long long>(const char*, const char*);
+ const char*) noexcept;
+extern template Expected<unsigned long long, ConversionCode>
+digits_to<unsigned long long>(const char*, const char*) noexcept;
#if FOLLY_HAVE_INT128_T
-extern template ConversionResult<__int128> digits_to<__int128>(
+extern template Expected<__int128, ConversionCode> digits_to<__int128>(
const char*,
- const char*);
-extern template ConversionResult<unsigned __int128>
-digits_to<unsigned __int128>(const char*, const char*);
+ const char*) noexcept;
+extern template Expected<unsigned __int128, ConversionCode>
+digits_to<unsigned __int128>(const char*, const char*) noexcept;
#endif
template <class T>
-ConversionResult<T> str_to_integral(StringPiece* src);
-
-extern template ConversionResult<char> str_to_integral<char>(StringPiece* src);
-extern template ConversionResult<signed char> str_to_integral<signed char>(
- StringPiece* src);
-extern template ConversionResult<unsigned char> str_to_integral<unsigned char>(
- StringPiece* src);
-
-extern template ConversionResult<short> str_to_integral<short>(
- StringPiece* src);
-extern template ConversionResult<unsigned short>
-str_to_integral<unsigned short>(StringPiece* src);
-
-extern template ConversionResult<int> str_to_integral<int>(StringPiece* src);
-extern template ConversionResult<unsigned int> str_to_integral<unsigned int>(
- StringPiece* src);
-
-extern template ConversionResult<long> str_to_integral<long>(StringPiece* src);
-extern template ConversionResult<unsigned long> str_to_integral<unsigned long>(
- StringPiece* src);
-
-extern template ConversionResult<long long> str_to_integral<long long>(
- StringPiece* src);
-extern template ConversionResult<unsigned long long>
-str_to_integral<unsigned long long>(StringPiece* src);
+Expected<T, ConversionCode> str_to_integral(StringPiece* src) noexcept;
+
+extern template Expected<char, ConversionCode> str_to_integral<char>(
+ StringPiece* src) noexcept;
+extern template Expected<signed char, ConversionCode>
+str_to_integral<signed char>(StringPiece* src) noexcept;
+extern template Expected<unsigned char, ConversionCode>
+str_to_integral<unsigned char>(StringPiece* src) noexcept;
+
+extern template Expected<short, ConversionCode> str_to_integral<short>(
+ StringPiece* src) noexcept;
+extern template Expected<unsigned short, ConversionCode>
+str_to_integral<unsigned short>(StringPiece* src) noexcept;
+
+extern template Expected<int, ConversionCode> str_to_integral<int>(
+ StringPiece* src) noexcept;
+extern template Expected<unsigned int, ConversionCode>
+str_to_integral<unsigned int>(StringPiece* src) noexcept;
+
+extern template Expected<long, ConversionCode> str_to_integral<long>(
+ StringPiece* src) noexcept;
+extern template Expected<unsigned long, ConversionCode>
+str_to_integral<unsigned long>(StringPiece* src) noexcept;
+
+extern template Expected<long long, ConversionCode> str_to_integral<long long>(
+ StringPiece* src) noexcept;
+extern template Expected<unsigned long long, ConversionCode>
+str_to_integral<unsigned long long>(StringPiece* src) noexcept;
#if FOLLY_HAVE_INT128_T
-extern template ConversionResult<__int128> str_to_integral<__int128>(
- StringPiece* src);
-extern template ConversionResult<unsigned __int128>
-str_to_integral<unsigned __int128>(StringPiece* src);
+extern template Expected<__int128, ConversionCode> str_to_integral<__int128>(
+ StringPiece* src) noexcept;
+extern template Expected<unsigned __int128, ConversionCode>
+str_to_integral<unsigned __int128>(StringPiece* src) noexcept;
#endif
template <typename T>
-typename std::enable_if<std::is_same<T, bool>::value, ConversionResult<T>>::type
-convertTo(StringPiece* src) {
+typename std::
+ enable_if<std::is_same<T, bool>::value, Expected<T, ConversionCode>>::type
+ convertTo(StringPiece* src) noexcept {
return str_to_bool(src);
}
template <typename T>
typename std::enable_if<
- std::is_floating_point<T>::value, ConversionResult<T>>::type
-convertTo(StringPiece* src) {
+ std::is_floating_point<T>::value,
+ Expected<T, ConversionCode>>::type
+convertTo(StringPiece* src) noexcept {
return str_to_floating<T>(src);
}
template <typename T>
typename std::enable_if<
std::is_integral<T>::value && !std::is_same<T, bool>::value,
- ConversionResult<T>>::type
-convertTo(StringPiece* src) {
+ Expected<T, ConversionCode>>::type
+convertTo(StringPiece* src) noexcept {
return str_to_integral<T>(src);
}
-template <typename T>
-struct WrapperInfo { using type = T; };
-
-template <typename T, typename Gen>
-typename std::enable_if<
- std::is_same<typename WrapperInfo<T>::type, T>::value, T>::type
-inline wrap(ConversionResult<typename WrapperInfo<T>::type> res, Gen&& gen) {
- if (LIKELY(res.success())) {
- return res.value;
- }
- throw detail::makeConversionError(res.error, gen());
-}
-
} // namespace detail
/**
*/
template <typename Tgt>
typename std::enable_if<
- std::is_integral<typename detail::WrapperInfo<Tgt>::type>::value &&
- !std::is_same<typename detail::WrapperInfo<Tgt>::type, bool>::value,
+ std::is_integral<Tgt>::value && !std::is_same<Tgt, bool>::value,
+ Expected<Tgt, ConversionCode>>::type
+tryTo(const char* b, const char* e) {
+ return detail::digits_to<Tgt>(b, e);
+}
+
+template <typename Tgt>
+typename std::enable_if<
+ std::is_integral<Tgt>::value && !std::is_same<Tgt, bool>::value,
Tgt>::type
to(const char* b, const char* e) {
- auto res = detail::digits_to<typename detail::WrapperInfo<Tgt>::type>(b, e);
- return detail::wrap<Tgt>(res, [&] { return StringPiece(b, e); });
+ return tryTo<Tgt>(b, e).thenOrThrow(
+ [](Tgt res) { return res; },
+ [=](ConversionCode code) {
+ return makeConversionError(code, StringPiece(b, e));
+ });
}
/*******************************************************************************
******************************************************************************/
/**
- * Parsing strings to numeric types. These routines differ from
- * parseTo(str, numeric) routines in that they take a POINTER TO a StringPiece
- * and alter that StringPiece to reflect progress information.
+ * Parsing strings to numeric types.
*/
template <typename Tgt>
-typename std::enable_if<
- std::is_arithmetic<typename detail::WrapperInfo<Tgt>::type>::value>::type
-parseTo(StringPiece* src, Tgt& out) {
- auto res = detail::convertTo<typename detail::WrapperInfo<Tgt>::type>(src);
- out = detail::wrap<Tgt>(res, [&] { return *src; });
-}
-
-template <typename Tgt>
-typename std::enable_if<
- std::is_arithmetic<typename detail::WrapperInfo<Tgt>::type>::value>::type
+FOLLY_NODISCARD inline typename std::enable_if<
+ std::is_arithmetic<Tgt>::value,
+ Expected<StringPiece, ConversionCode>>::type
parseTo(StringPiece src, Tgt& out) {
- auto res = detail::convertTo<typename detail::WrapperInfo<Tgt>::type>(&src);
- if (LIKELY(res.success())) {
- res.error = detail::enforceWhitespaceErr(src);
- }
- out = detail::wrap<Tgt>(res, [&] { return src; });
+ return detail::convertTo<Tgt>(&src).then(
+ [&](Tgt res) { return void(out = res), src; });
}
/*******************************************************************************
* Integral / Floating Point to integral / Floating Point
******************************************************************************/
+namespace detail {
+
/**
- * Unchecked conversion from arithmetic to boolean. This is different from the
- * other arithmetic conversions because we use the C convention of treating any
- * non-zero value as true, instead of range checking.
+ * Bool to integral/float doesn't need any special checks, and this
+ * overload means we aren't trying to see if a bool is less than
+ * an integer.
*/
-template <class Tgt, class Src>
+template <class Tgt>
typename std::enable_if<
- std::is_arithmetic<Src>::value && !std::is_same<Tgt, Src>::value &&
- std::is_same<Tgt, bool>::value,
- Tgt>::type
-to(const Src& value) {
- return value != Src();
+ !std::is_same<Tgt, bool>::value &&
+ (std::is_integral<Tgt>::value || std::is_floating_point<Tgt>::value),
+ Expected<Tgt, ConversionCode>>::type
+convertTo(const bool& value) noexcept {
+ return static_cast<Tgt>(value ? 1 : 0);
}
-namespace detail {
-
/**
* Checked conversion from integral to integral. The checks are only
* performed when meaningful, e.g. conversion from int to long goes
std::is_integral<Src>::value && !std::is_same<Tgt, Src>::value &&
!std::is_same<Tgt, bool>::value &&
std::is_integral<Tgt>::value,
- ConversionResult<Tgt>>::type
-convertTo(const Src& value) {
+ Expected<Tgt, ConversionCode>>::type
+convertTo(const Src& value) noexcept {
/* static */ if (
- std::numeric_limits<Tgt>::max() < std::numeric_limits<Src>::max()) {
+ folly::_t<std::make_unsigned<Tgt>>(std::numeric_limits<Tgt>::max()) <
+ folly::_t<std::make_unsigned<Src>>(std::numeric_limits<Src>::max())) {
if (greater_than<Tgt, std::numeric_limits<Tgt>::max()>(value)) {
- return ConversionResult<Tgt>(ConversionError::ARITH_POSITIVE_OVERFLOW);
+ return makeUnexpected(ConversionCode::ARITH_POSITIVE_OVERFLOW);
}
}
/* static */ if (
std::is_signed<Src>::value &&
(!std::is_signed<Tgt>::value || sizeof(Src) > sizeof(Tgt))) {
if (less_than<Tgt, std::numeric_limits<Tgt>::min()>(value)) {
- return ConversionResult<Tgt>(ConversionError::ARITH_NEGATIVE_OVERFLOW);
+ return makeUnexpected(ConversionCode::ARITH_NEGATIVE_OVERFLOW);
}
}
- return ConversionResult<Tgt>(static_cast<Tgt>(value));
+ return static_cast<Tgt>(value);
}
/**
typename std::enable_if<
std::is_floating_point<Tgt>::value && std::is_floating_point<Src>::value &&
!std::is_same<Tgt, Src>::value,
- ConversionResult<Tgt>>::type
-convertTo(const Src& value) {
+ Expected<Tgt, ConversionCode>>::type
+convertTo(const Src& value) noexcept {
/* static */ if (
std::numeric_limits<Tgt>::max() < std::numeric_limits<Src>::max()) {
if (value > std::numeric_limits<Tgt>::max()) {
- return ConversionResult<Tgt>(ConversionError::ARITH_POSITIVE_OVERFLOW);
+ return makeUnexpected(ConversionCode::ARITH_POSITIVE_OVERFLOW);
}
if (value < std::numeric_limits<Tgt>::lowest()) {
- return ConversionResult<Tgt>(ConversionError::ARITH_NEGATIVE_OVERFLOW);
+ return makeUnexpected(ConversionCode::ARITH_NEGATIVE_OVERFLOW);
}
}
- return ConversionResult<Tgt>(boost::implicit_cast<Tgt>(value));
+ return static_cast<Tgt>(value);
}
/**
typename std::enable_if<
(std::is_integral<Src>::value && std::is_floating_point<Tgt>::value) ||
(std::is_floating_point<Src>::value && std::is_integral<Tgt>::value),
- ConversionResult<Tgt>>::type
-convertTo(const Src& value) {
+ Expected<Tgt, ConversionCode>>::type
+convertTo(const Src& value) noexcept {
if (LIKELY(checkConversion<Tgt>(value))) {
Tgt result = static_cast<Tgt>(value);
if (LIKELY(checkConversion<Src>(result))) {
Src witness = static_cast<Src>(result);
if (LIKELY(value == witness)) {
- return ConversionResult<Tgt>(result);
+ return result;
}
}
}
- return ConversionResult<Tgt>(ConversionError::ARITH_LOSS_OF_PRECISION);
+ return makeUnexpected(ConversionCode::ARITH_LOSS_OF_PRECISION);
}
template <typename Tgt, typename Src>
template <typename Tgt, typename Src>
typename std::enable_if<
- detail::IsArithToArith<
- typename detail::WrapperInfo<Tgt>::type, Src>::value, Tgt>::type
-to(const Src& value) {
- auto res = detail::convertTo<typename detail::WrapperInfo<Tgt>::type>(value);
- return detail::wrap<Tgt>(res, [&] {
- return detail::errorValue<typename detail::WrapperInfo<Tgt>::type>(value);
- });
+ detail::IsArithToArith<Tgt, Src>::value,
+ Expected<Tgt, ConversionCode>>::type
+tryTo(const Src& value) noexcept {
+ return detail::convertTo<Tgt>(value);
+}
+
+template <typename Tgt, typename Src>
+typename std::enable_if<detail::IsArithToArith<Tgt, Src>::value, Tgt>::type to(
+ const Src& value) {
+ return tryTo<Tgt>(value).thenOrThrow(
+ [](Tgt res) { return res; },
+ [&](ConversionCode e) {
+ return makeConversionError(e, detail::errorValue<Tgt>(value));
+ });
}
/*******************************************************************************
* argument-dependent lookup:
*
* namespace other_namespace {
- * void parseTo(::folly::StringPiece, OtherType&);
+ * ::folly::Expected<::folly::StringPiece, SomeErrorCode>
+ * parseTo(::folly::StringPiece, OtherType&) noexcept;
* }
******************************************************************************/
template <class T>
-typename std::enable_if<std::is_enum<T>::value>::type
-parseTo(StringPiece in, T& out) {
- typename std::underlying_type<T>::type tmp;
- parseTo(in, tmp);
- out = static_cast<T>(tmp);
-}
-
-inline void parseTo(StringPiece in, StringPiece& out) {
+FOLLY_NODISCARD typename std::enable_if<
+ std::is_enum<T>::value,
+ Expected<StringPiece, ConversionCode>>::type
+parseTo(StringPiece in, T& out) noexcept {
+ typename std::underlying_type<T>::type tmp{};
+ auto restOrError = parseTo(in, tmp);
+ out = static_cast<T>(tmp); // Harmless if parseTo fails
+ return restOrError;
+}
+
+FOLLY_NODISCARD
+inline Expected<StringPiece, ConversionCode> parseTo(
+ StringPiece in,
+ StringPiece& out) noexcept {
out = in;
+ return StringPiece{in.end(), in.end()};
}
-inline void parseTo(StringPiece in, std::string& out) {
+FOLLY_NODISCARD
+inline Expected<StringPiece, ConversionCode> parseTo(
+ StringPiece in,
+ std::string& out) {
out.clear();
- out.append(in.data(), in.size());
+ out.append(in.data(), in.size()); // TODO try/catch?
+ return StringPiece{in.end(), in.end()};
}
-inline void parseTo(StringPiece in, fbstring& out) {
+FOLLY_NODISCARD
+inline Expected<StringPiece, ConversionCode> parseTo(
+ StringPiece in,
+ fbstring& out) {
out.clear();
- out.append(in.data(), in.size());
+ out.append(in.data(), in.size()); // TODO try/catch?
+ return StringPiece{in.end(), in.end()};
+}
+
+namespace detail {
+template <typename Tgt>
+using ParseToResult = decltype(parseTo(StringPiece{}, std::declval<Tgt&>()));
+
+struct CheckTrailingSpace {
+ Expected<Unit, ConversionCode> operator()(StringPiece sp) const {
+ auto e = enforceWhitespaceErr(sp);
+ if (UNLIKELY(e != ConversionCode::SUCCESS))
+ return makeUnexpected(e);
+ return unit;
+ }
+};
+
+template <class Error>
+struct ReturnUnit {
+ template <class T>
+ constexpr Expected<Unit, Error> operator()(T&&) const {
+ return unit;
+ }
+};
+
+// Older versions of the parseTo customization point threw on error and
+// returned void. Handle that.
+template <class Tgt>
+inline typename std::enable_if<
+ std::is_void<ParseToResult<Tgt>>::value,
+ Expected<StringPiece, ConversionCode>>::type
+parseToWrap(StringPiece sp, Tgt& out) {
+ parseTo(sp, out);
+ return StringPiece(sp.end(), sp.end());
+}
+
+template <class Tgt>
+inline typename std::enable_if<
+ !std::is_void<ParseToResult<Tgt>>::value,
+ ParseToResult<Tgt>>::type
+parseToWrap(StringPiece sp, Tgt& out) {
+ return parseTo(sp, out);
}
+template <typename Tgt>
+using ParseToError = ExpectedErrorType<decltype(
+ detail::parseToWrap(StringPiece{}, std::declval<Tgt&>()))>;
+
+} // namespace detail
+
/**
* String or StringPiece to target conversion. Accepts leading and trailing
* whitespace, but no non-space trailing characters.
*/
template <class Tgt>
-typename std::enable_if<!std::is_same<StringPiece, Tgt>::value, Tgt>::type
-to(StringPiece src) {
+inline typename std::enable_if<
+ !std::is_same<StringPiece, Tgt>::value,
+ Expected<Tgt, detail::ParseToError<Tgt>>>::type
+tryTo(StringPiece src) {
+ Tgt result{};
+ using Error = detail::ParseToError<Tgt>;
+ using Check = typename std::conditional<
+ std::is_arithmetic<Tgt>::value,
+ detail::CheckTrailingSpace,
+ detail::ReturnUnit<Error>>::type;
+ return parseTo(src, result).then(Check(), [&](Unit) {
+ return std::move(result);
+ });
+}
+
+template <class Tgt>
+inline
+ typename std::enable_if<!std::is_same<StringPiece, Tgt>::value, Tgt>::type
+ to(StringPiece src) {
+ Tgt result{};
+ using Error = detail::ParseToError<Tgt>;
+ using Check = typename std::conditional<
+ std::is_arithmetic<Tgt>::value,
+ detail::CheckTrailingSpace,
+ detail::ReturnUnit<Error>>::type;
+ auto tmp = detail::parseToWrap(src, result);
+ return tmp
+ .thenOrThrow(Check(), [&](Error e) { throw makeConversionError(e, src); })
+ .thenOrThrow(
+ [&](Unit) { return std::move(result); },
+ [&](Error e) { throw makeConversionError(e, tmp.value()); });
+}
+
+/**
+ * tryTo/to that take the strings by pointer so the caller gets information
+ * about how much of the string was consumed by the conversion. These do not
+ * check for trailing whitepsace.
+ */
+template <class Tgt>
+Expected<Tgt, detail::ParseToError<Tgt>> tryTo(StringPiece* src) {
Tgt result;
- parseTo(src, result);
- return result;
+ return parseTo(*src, result).then([&, src](StringPiece sp) -> Tgt {
+ *src = sp;
+ return std::move(result);
+ });
}
template <class Tgt>
Tgt to(StringPiece* src) {
- Tgt result;
- parseTo(src, result);
- return result;
+ Tgt result{};
+ using Error = detail::ParseToError<Tgt>;
+ return parseTo(*src, result)
+ .thenOrThrow(
+ [&, src](StringPiece sp) -> Tgt {
+ *src = sp;
+ return std::move(result);
+ },
+ [=](Error e) { return makeConversionError(e, *src); });
}
/*******************************************************************************
template <class Tgt, class Src>
typename std::enable_if<
- std::is_enum<Src>::value && !std::is_same<Src, Tgt>::value, Tgt>::type
-to(const Src & value) {
+ std::is_enum<Src>::value && !std::is_same<Src, Tgt>::value,
+ Expected<Tgt, ConversionCode>>::type
+tryTo(const Src& value) {
+ using I = typename std::underlying_type<Src>::type;
+ return tryTo<Tgt>(static_cast<I>(value));
+}
+
+template <class Tgt, class Src>
+typename std::enable_if<
+ std::is_enum<Tgt>::value && !std::is_same<Src, Tgt>::value,
+ Expected<Tgt, ConversionCode>>::type
+tryTo(const Src& value) {
+ using I = typename std::underlying_type<Tgt>::type;
+ return tryTo<I>(value).then([](I i) { return static_cast<Tgt>(i); });
+}
+
+template <class Tgt, class Src>
+typename std::enable_if<
+ std::is_enum<Src>::value && !std::is_same<Src, Tgt>::value,
+ Tgt>::type
+to(const Src& value) {
return to<Tgt>(static_cast<typename std::underlying_type<Src>::type>(value));
}
projects / folly.git / blobdiff