/*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2016 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* @author Andrei Alexandrescu (andrei.alexandrescu@fb.com)
*/
-#ifndef FOLLY_BASE_CONV_H_
-#define FOLLY_BASE_CONV_H_
+#pragma once
-#include <folly/FBString.h>
-#include <folly/Likely.h>
-#include <folly/Preprocessor.h>
-#include <folly/Range.h>
-
-#include <boost/implicit_cast.hpp>
#include <algorithm>
-#include <type_traits>
+#include <cctype>
+#include <climits>
+#include <cstddef>
#include <limits>
+#include <stdexcept>
#include <string>
#include <tuple>
-#include <stdexcept>
+#include <type_traits>
#include <typeinfo>
+#include <utility>
-#include <limits.h>
+#include <boost/implicit_cast.hpp>
+#include <double-conversion/double-conversion.h> // V8 JavaScript implementation
-// V8 JavaScript implementation
-#include <double-conversion/double-conversion.h>
+#include <folly/Demangle.h>
+#include <folly/FBString.h>
+#include <folly/Likely.h>
+#include <folly/Range.h>
+#include <folly/portability/Math.h>
-#define FOLLY_RANGE_CHECK_STRINGIZE(x) #x
-#define FOLLY_RANGE_CHECK_STRINGIZE2(x) FOLLY_RANGE_CHECK_STRINGIZE(x)
+namespace folly {
-// Android doesn't support std::to_string so just use a placeholder there.
-#ifdef __ANDROID__
-#define FOLLY_RANGE_CHECK_TO_STRING(x) std::string("N/A")
-#else
-#define FOLLY_RANGE_CHECK_TO_STRING(x) std::to_string(x)
-#endif
+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
+ };
-#define FOLLY_RANGE_CHECK(condition, message, src) \
- ((condition) ? (void)0 : throw std::range_error( \
- (std::string(__FILE__ "(" FOLLY_RANGE_CHECK_STRINGIZE2(__LINE__) "): ") \
- + (message) + ": '" + (src) + "'").c_str()))
+ ConversionError(const std::string& str, Code code)
+ : std::range_error(str), code_(code) {}
-#define FOLLY_RANGE_CHECK_BEGIN_END(condition, message, b, e) \
- FOLLY_RANGE_CHECK(condition, message, std::string((b), (e) - (b)))
+ ConversionError(const char* str, Code code)
+ : std::range_error(str), code_(code) {}
-#define FOLLY_RANGE_CHECK_STRINGPIECE(condition, message, sp) \
- FOLLY_RANGE_CHECK(condition, message, std::string((sp).data(), (sp).size()))
+ Code errorCode() const { return code_; }
-namespace folly {
+ private:
+ Code 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());
+}
/**
- * The identity conversion function.
- * to<T>(T) returns itself for all types T.
+ * Enforce that the suffix following a number is made up only of whitespace.
*/
-template <class Tgt, class Src>
-typename std::enable_if<std::is_same<Tgt, Src>::value, Tgt>::type
-to(const Src & value) {
- return value;
+inline ConversionError::Code enforceWhitespaceErr(StringPiece sp) {
+ for (auto c : sp) {
+ if (!std::isspace(c)) {
+ return ConversionError::NON_WHITESPACE_AFTER_END;
+ }
+ }
+ return ConversionError::SUCCESS;
}
-template <class Tgt, class Src>
-typename std::enable_if<std::is_same<Tgt, Src>::value, Tgt>::type
-to(Src && value) {
- return std::move(value);
+/**
+ * Keep this implementation around for prettyToDouble().
+ */
+inline void enforceWhitespace(StringPiece sp) {
+ auto err = enforceWhitespaceErr(sp);
+ if (err != ConversionError::SUCCESS) {
+ throw detail::makeConversionError(err, sp);
+ }
}
-/*******************************************************************************
- * Integral to integral
- ******************************************************************************/
-
/**
- * Unchecked conversion from integral to boolean. This is different from the
- * other integral conversions because we use the C convention of treating any
- * non-zero value as true, instead of range checking.
+ * A simple std::pair-like wrapper to wrap both a value and an error
*/
-template <class Tgt, class Src>
-typename std::enable_if<
- std::is_integral<Src>::value
- && !std::is_same<Tgt, Src>::value
- && std::is_same<Tgt, bool>::value,
- Tgt>::type
-to(const Src & value) {
- return value != 0;
+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;
+ }
+
+ T value;
+ ConversionError::Code error{ConversionError::SUCCESS};
+};
}
/**
- * Checked conversion from integral to integral. The checks are only
- * performed when meaningful, e.g. conversion from int to long goes
- * unchecked.
+ * The identity conversion function.
+ * to<T>(T) returns itself for all types T.
*/
template <class Tgt, class Src>
-typename std::enable_if<
- std::is_integral<Src>::value
- && !std::is_same<Tgt, Src>::value
- && !std::is_same<Tgt, bool>::value
- && std::is_integral<Tgt>::value,
- Tgt>::type
+typename std::enable_if<std::is_same<Tgt, Src>::value, Tgt>::type
to(const Src & value) {
- /* static */ if (std::numeric_limits<Tgt>::max()
- < std::numeric_limits<Src>::max()) {
- FOLLY_RANGE_CHECK(
- (!greater_than<Tgt, std::numeric_limits<Tgt>::max()>(value)),
- "Overflow",
- FOLLY_RANGE_CHECK_TO_STRING(value));
- }
- /* static */ if (std::is_signed<Src>::value &&
- (!std::is_signed<Tgt>::value || sizeof(Src) > sizeof(Tgt))) {
- FOLLY_RANGE_CHECK(
- (!less_than<Tgt, std::numeric_limits<Tgt>::min()>(value)),
- "Negative overflow",
- FOLLY_RANGE_CHECK_TO_STRING(value));
- }
- return static_cast<Tgt>(value);
+ return value;
}
-/*******************************************************************************
- * Floating point to floating point
- ******************************************************************************/
-
template <class Tgt, class Src>
-typename std::enable_if<
- std::is_floating_point<Tgt>::value
- && std::is_floating_point<Src>::value
- && !std::is_same<Tgt, Src>::value,
- Tgt>::type
-to(const Src & value) {
- /* static */ if (std::numeric_limits<Tgt>::max() <
- std::numeric_limits<Src>::max()) {
- FOLLY_RANGE_CHECK(value <= std::numeric_limits<Tgt>::max(),
- "Overflow",
- FOLLY_RANGE_CHECK_TO_STRING(value));
- FOLLY_RANGE_CHECK(value >= -std::numeric_limits<Tgt>::max(),
- "Negative overflow",
- FOLLY_RANGE_CHECK_TO_STRING(value));
- }
- return boost::implicit_cast<Tgt>(value);
+typename std::enable_if<std::is_same<Tgt, Src>::value, Tgt>::type
+to(Src && value) {
+ return std::forward<Src>(value);
}
/*******************************************************************************
template <typename IntegerType>
constexpr unsigned int
digitsEnough() {
- return ceil((double(sizeof(IntegerType) * CHAR_BIT) * M_LN2) / M_LN10);
+ return (unsigned int)(ceil(sizeof(IntegerType) * CHAR_BIT * M_LN2 / M_LN10));
}
inline size_t
// This is 20 * 8 == 160 bytes, which fits neatly into 5 cache lines
// (assuming a cache line size of 64).
static const uint64_t powersOf10[20] FOLLY_ALIGNED(64) = {
- 1, 10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000,
- 10000000000, 100000000000, 1000000000000, 10000000000000, 100000000000000,
- 1000000000000000, 10000000000000000, 100000000000000000,
- 1000000000000000000, 10000000000000000000UL
+ 1,
+ 10,
+ 100,
+ 1000,
+ 10000,
+ 100000,
+ 1000000,
+ 10000000,
+ 100000000,
+ 1000000000,
+ 10000000000,
+ 100000000000,
+ 1000000000000,
+ 10000000000000,
+ 100000000000000,
+ 1000000000000000,
+ 10000000000000000,
+ 100000000000000000,
+ 1000000000000000000,
+ 10000000000000000000UL,
};
// "count leading zeroes" operation not valid; for 0; special case this.
return 1;
}
-/**
- * Ubiquitous helper template for writing string appenders
- */
-template <class T> struct IsSomeString {
- enum { value = std::is_same<T, std::string>::value
- || std::is_same<T, fbstring>::value };
-};
-
/**
* Everything implicitly convertible to const char* gets appended.
*/
return folly::StringPiece(value).size();
}
+template <>
+inline size_t estimateSpaceNeeded(std::nullptr_t /* value */) {
+ return 0;
+}
+
template<class Src>
typename std::enable_if<
std::is_pointer<Src>::value &&
size_t p;
if (value < 0) {
- p = detail::unsafeTelescope128(buffer, sizeof(buffer), Usrc(-value));
+ p = detail::unsafeTelescope128(buffer, sizeof(buffer), -Usrc(value));
buffer[--p] = '-';
} else {
p = detail::unsafeTelescope128(buffer, sizeof(buffer), value);
size_t>::type
estimateSpaceNeeded(Src value) {
if (value < 0) {
- return 1 + digits10(static_cast<uint64_t>(-value));
+ // When "value" is the smallest negative, negating it would evoke
+ // undefined behavior, so, instead of writing "-value" below, we write
+ // "~static_cast<uint64_t>(value) + 1"
+ return 1 + digits10(~static_cast<uint64_t>(value) + 1);
}
return digits10(static_cast<uint64_t>(value));
&& IsSomeString<Tgt>::value && sizeof(Src) >= 4>::type
toAppend(Src value, Tgt * result) {
char buffer[20];
- result->append(buffer, buffer + uint64ToBufferUnsafe(value, buffer));
+ result->append(buffer, uint64ToBufferUnsafe(value, buffer));
}
template <class Src>
template <class Src>
constexpr typename std::enable_if<
!std::is_fundamental<Src>::value
-#ifdef FOLLY_HAVE_INT128_T
+#if FOLLY_HAVE_INT128_T
// On OSX 10.10, is_fundamental<__int128> is false :-O
&& !std::is_same<__int128, Src>::value
&& !std::is_same<unsigned __int128, Src>::value
namespace detail {
-inline size_t estimateSpaceToReserve(size_t sofar) {
+template <class Tgt>
+typename std::enable_if<IsSomeString<Tgt>::value, size_t>::type
+estimateSpaceToReserve(size_t sofar, Tgt*) {
return sofar;
}
return estimateSpaceToReserve(sofar + estimateSpaceNeeded(v), vs...);
}
-template<class T>
-size_t estimateSpaceToReserve(size_t sofar, const T& v) {
- return sofar + estimateSpaceNeeded(v);
-}
-
template<class...Ts>
void reserveInTarget(const Ts&...vs) {
getLastElement(vs...)->reserve(estimateSpaceToReserve(0, vs...));
template<class Delimiter, class...Ts>
void reserveInTargetDelim(const Delimiter& d, const Ts&...vs) {
static_assert(sizeof...(vs) >= 2, "Needs at least 2 args");
- size_t fordelim = (sizeof...(vs) - 2) * estimateSpaceToReserve(0, d);
+ size_t fordelim = (sizeof...(vs) - 2) *
+ estimateSpaceToReserve(0, d, static_cast<std::string*>(nullptr));
getLastElement(vs...)->reserve(estimateSpaceToReserve(fordelim, vs...));
}
template <class Delimiter, class T, class Tgt>
typename std::enable_if<
- IsSomeString<typename std::remove_pointer<Tgt>::type>
- ::value>::type
-toAppendDelimStrImpl(const Delimiter& delim, const T& v, Tgt result) {
+ IsSomeString<typename std::remove_pointer<Tgt>::type>::value>::type
+toAppendDelimStrImpl(const Delimiter& /* delim */, const T& v, Tgt result) {
toAppend(v, result);
}
* the space for them and will depend on strings exponential growth.
* If you just append once consider using toAppendFit which reserves
* the space needed (but does not have exponential as a result).
+ *
+ * Custom implementations of toAppend() can be provided in the same namespace as
+ * the type to customize printing. estimateSpaceNeed() may also be provided to
+ * avoid reallocations in toAppendFit():
+ *
+ * namespace other_namespace {
+ *
+ * template <class String>
+ * void toAppend(const OtherType&, String* out);
+ *
+ * // optional
+ * size_t estimateSpaceNeeded(const OtherType&);
+ *
+ * }
*/
template <class... Ts>
typename std::enable_if<sizeof...(Ts) >= 3
::folly::detail::toAppendStrImpl(vs...);
}
+#ifdef _MSC_VER
+// Special case pid_t on MSVC, because it's a void* rather than an
+// integral type. We can't do a global special case because this is already
+// dangerous enough (as most pointers will implicitly convert to a void*)
+// just doing it for MSVC.
+template <class Tgt>
+void toAppend(const pid_t a, Tgt* res) {
+ toAppend(uint64_t(a), res);
+}
+#endif
+
/**
* Special version of the call that preallocates exaclty as much memory
* as need for arguments to be stored in target. This means we are
* Variadic base case: do nothing.
*/
template <class Tgt>
-typename std::enable_if<IsSomeString<Tgt>::value>::type
-toAppend(Tgt* result) {
-}
+typename std::enable_if<IsSomeString<Tgt>::value>::type toAppend(
+ Tgt* /* result */) {}
/**
* Variadic base case: do nothing.
*/
template <class Delimiter, class Tgt>
-typename std::enable_if<IsSomeString<Tgt>::value>::type
-toAppendDelim(const Delimiter& delim, Tgt* result) {
-}
+typename std::enable_if<IsSomeString<Tgt>::value>::type toAppendDelim(
+ const Delimiter& /* delim */, Tgt* /* result */) {}
/**
* 1 element: same as toAppend.
*/
template <class Delimiter, class T, class Tgt>
-typename std::enable_if<IsSomeString<Tgt>::value>::type
-toAppendDelim(const Delimiter& delim, const T& v, Tgt* tgt) {
+typename std::enable_if<IsSomeString<Tgt>::value>::type toAppendDelim(
+ const Delimiter& /* delim */, const T& v, Tgt* tgt) {
toAppend(v, tgt);
}
* 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) {
+typename std::enable_if<IsSomeString<Tgt>::value &&
+ std::is_same<Tgt, Src>::value,
+ Tgt>::type
+toDelim(const Delim& /* delim */, const Src& value) {
return value;
}
namespace detail {
-/**
- * Finds the first non-digit in a string. The number of digits
- * searched depends on the precision of the Tgt integral. Assumes the
- * string starts with NO whitespace and NO sign.
- *
- * The semantics of the routine is:
- * for (;; ++b) {
- * if (b >= e || !isdigit(*b)) return b;
- * }
- *
- * Complete unrolling marks bottom-line (i.e. entire conversion)
- * improvements of 20%.
- */
- template <class Tgt>
- const char* findFirstNonDigit(const char* b, const char* e) {
- for (; b < e; ++b) {
- auto const c = static_cast<unsigned>(*b) - '0';
- if (c >= 10) break;
- }
- return b;
- }
+ConversionResult<bool> str_to_bool(StringPiece* src);
- // Maximum value of number when represented as a string
- template <class T> struct MaxString {
- static const char*const value;
- };
+template <typename T>
+ConversionResult<T> str_to_floating(StringPiece* src);
+
+extern template ConversionResult<float> str_to_floating<float>(
+ StringPiece* src);
+extern template ConversionResult<double> str_to_floating<double>(
+ StringPiece* src);
+
+template <class Tgt>
+ConversionResult<Tgt> digits_to(const char* b, const char* e);
+
+extern template ConversionResult<char> digits_to<char>(
+ const char*,
+ const char*);
+extern template ConversionResult<signed char> digits_to<signed char>(
+ const char*,
+ const char*);
+extern template ConversionResult<unsigned char> digits_to<unsigned char>(
+ const char*,
+ const char*);
+
+extern template ConversionResult<short> digits_to<short>(
+ const char*,
+ const char*);
+extern template ConversionResult<unsigned short> digits_to<unsigned short>(
+ const char*,
+ const char*);
+
+extern template ConversionResult<int> digits_to<int>(const char*, const char*);
+extern template ConversionResult<unsigned int> digits_to<unsigned int>(
+ const char*,
+ const char*);
+
+extern template ConversionResult<long> digits_to<long>(
+ const char*,
+ const char*);
+extern template ConversionResult<unsigned long> digits_to<unsigned long>(
+ const char*,
+ const char*);
+
+extern template ConversionResult<long long> digits_to<long long>(
+ const char*,
+ const char*);
+extern template ConversionResult<unsigned long long>
+digits_to<unsigned long long>(const char*, const char*);
- bool str_to_bool(StringPiece* src);
-
- template <class Tgt>
- Tgt digits_to(const char* b, const char* e);
-
- extern template unsigned char digits_to<unsigned char>(const char* b,
- const char* e);
- extern template unsigned short digits_to<unsigned short>(const char* b,
- const char* e);
- extern template unsigned int digits_to<unsigned int>(const char* b,
- const char* e);
- extern template unsigned long digits_to<unsigned long>(const char* b,
- const char* e);
- extern template unsigned long long digits_to<unsigned long long>(
- const char* b, const char* e);
#if FOLLY_HAVE_INT128_T
- extern template unsigned __int128 digits_to<unsigned __int128>(const char* b,
- const char* e);
+extern template ConversionResult<__int128> digits_to<__int128>(
+ const char*,
+ const char*);
+extern template ConversionResult<unsigned __int128>
+digits_to<unsigned __int128>(const char*, const char*);
#endif
-} // namespace detail
+template <class T>
+ConversionResult<T> str_to_integral(StringPiece* src);
-/**
- * String represented as a pair of pointers to char to unsigned
- * integrals. Assumes NO whitespace before or after.
- */
-template <class Tgt>
+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);
+
+#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);
+#endif
+
+template <typename T>
+typename std::enable_if<std::is_same<T, bool>::value, ConversionResult<T>>::type
+convertTo(StringPiece* src) {
+ return str_to_bool(src);
+}
+
+template <typename T>
typename std::enable_if<
- std::is_integral<Tgt>::value && !std::is_signed<Tgt>::value
- && !std::is_same<typename std::remove_cv<Tgt>::type, bool>::value,
- Tgt>::type
-to(const char * b, const char * e) {
- return detail::digits_to<Tgt>(b, e);
+ std::is_floating_point<T>::value, ConversionResult<T>>::type
+convertTo(StringPiece* src) {
+ return str_to_floating<T>(src);
}
-/**
- * String represented as a pair of pointers to char to signed
- * integrals. Assumes NO whitespace before or after. Allows an
- * optional leading sign.
- */
-template <class Tgt>
+template <typename T>
typename std::enable_if<
- std::is_integral<Tgt>::value && std::is_signed<Tgt>::value,
- Tgt>::type
-to(const char * b, const char * e) {
- FOLLY_RANGE_CHECK(b < e, "Empty input string in conversion to integral",
- to<std::string>("b: ", intptr_t(b), " e: ", intptr_t(e)));
- if (!isdigit(*b)) {
- if (*b == '-') {
- Tgt result = -to<typename std::make_unsigned<Tgt>::type>(b + 1, e);
- FOLLY_RANGE_CHECK_BEGIN_END(result <= 0, "Negative overflow.", b, e);
- return result;
- }
- FOLLY_RANGE_CHECK_BEGIN_END(*b == '+', "Invalid lead character", b, e);
- ++b;
+ std::is_integral<T>::value && !std::is_same<T, bool>::value,
+ ConversionResult<T>>::type
+convertTo(StringPiece* src) {
+ 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;
}
- Tgt result = to<typename std::make_unsigned<Tgt>::type>(b, e);
- FOLLY_RANGE_CHECK_BEGIN_END(result >= 0, "Overflow", b, e);
- return result;
+ throw detail::makeConversionError(res.error, gen());
}
-/**
- * Parsing strings to integrals. These routines differ from
- * to<integral>(string) in that they take a POINTER TO a StringPiece
- * and alter that StringPiece to reflect progress information.
- */
+} // namespace detail
/**
- * StringPiece to integrals, with progress information. Alters the
- * StringPiece parameter to munch the already-parsed characters.
+ * String represented as a pair of pointers to char to unsigned
+ * integrals. Assumes NO whitespace before or after.
*/
-template <class Tgt>
+template <typename Tgt>
typename std::enable_if<
- std::is_integral<Tgt>::value
- && !std::is_same<typename std::remove_cv<Tgt>::type, bool>::value,
- Tgt>::type
-to(StringPiece * src) {
+ std::is_integral<typename detail::WrapperInfo<Tgt>::type>::value &&
+ !std::is_same<typename detail::WrapperInfo<Tgt>::type, 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); });
+}
- auto b = src->data(), past = src->data() + src->size();
- for (;; ++b) {
- FOLLY_RANGE_CHECK_STRINGPIECE(b < past,
- "No digits found in input string", *src);
- if (!isspace(*b)) break;
- }
+/*******************************************************************************
+ * Conversions from string types to arithmetic types.
+ ******************************************************************************/
- auto m = b;
-
- // First digit is customized because we test for sign
- bool negative = false;
- /* static */ if (std::is_signed<Tgt>::value) {
- if (!isdigit(*m)) {
- if (*m == '-') {
- negative = true;
- } else {
- FOLLY_RANGE_CHECK_STRINGPIECE(*m == '+', "Invalid leading character in "
- "conversion to integral", *src);
- }
- ++b;
- ++m;
- }
- }
- FOLLY_RANGE_CHECK_STRINGPIECE(m < past, "No digits found in input string",
- *src);
- FOLLY_RANGE_CHECK_STRINGPIECE(isdigit(*m), "Non-digit character found", *src);
- m = detail::findFirstNonDigit<Tgt>(m + 1, past);
+/**
+ * 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.
+ */
+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; });
+}
- Tgt result;
- /* static */ if (!std::is_signed<Tgt>::value) {
- result = detail::digits_to<typename std::make_unsigned<Tgt>::type>(b, m);
- } else {
- auto t = detail::digits_to<typename std::make_unsigned<Tgt>::type>(b, m);
- if (negative) {
- result = -t;
- FOLLY_RANGE_CHECK_STRINGPIECE(is_non_positive(result),
- "Negative overflow", *src);
- } else {
- result = t;
- FOLLY_RANGE_CHECK_STRINGPIECE(is_non_negative(result), "Overflow", *src);
- }
+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);
+ if (LIKELY(res.success())) {
+ res.error = detail::enforceWhitespaceErr(src);
}
- src->advance(m - src->data());
- return result;
+ out = detail::wrap<Tgt>(res, [&] { return src; });
}
+/*******************************************************************************
+ * Integral / Floating Point to integral / Floating Point
+ ******************************************************************************/
+
/**
- * StringPiece to bool, with progress information. Alters the
- * StringPiece parameter to munch the already-parsed characters.
+ * 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>
+template <class Tgt, class Src>
typename std::enable_if<
- std::is_same<typename std::remove_cv<Tgt>::type, bool>::value,
- Tgt>::type
-to(StringPiece * src) {
- return detail::str_to_bool(src);
+ 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 {
/**
- * Enforce that the suffix following a number is made up only of whitespace.
+ * Checked conversion from integral to integral. The checks are only
+ * performed when meaningful, e.g. conversion from int to long goes
+ * unchecked.
*/
-inline void enforceWhitespace(const char* b, const char* e) {
- for (; b != e; ++b) {
- FOLLY_RANGE_CHECK_BEGIN_END(isspace(*b),
- to<std::string>("Non-whitespace: ", *b),
- b, e);
+template <class Tgt, class Src>
+typename std::enable_if<
+ 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) {
+ /* static */ if (
+ std::numeric_limits<Tgt>::max() < std::numeric_limits<Src>::max()) {
+ if (greater_than<Tgt, std::numeric_limits<Tgt>::max()>(value)) {
+ return ConversionResult<Tgt>(ConversionError::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 ConversionResult<Tgt>(static_cast<Tgt>(value));
}
-} // namespace detail
-
/**
- * String or StringPiece to integrals. Accepts leading and trailing
- * whitespace, but no non-space trailing characters.
+ * Checked conversion from floating to floating. The checks are only
+ * performed when meaningful, e.g. conversion from float to double goes
+ * unchecked.
*/
-template <class Tgt>
+template <class Tgt, class Src>
typename std::enable_if<
- std::is_integral<Tgt>::value,
- Tgt>::type
-to(StringPiece src) {
- Tgt result = to<Tgt>(&src);
- detail::enforceWhitespace(src.data(), src.data() + src.size());
- return result;
+ 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) {
+ /* 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);
+ }
+ if (value < std::numeric_limits<Tgt>::lowest()) {
+ return ConversionResult<Tgt>(ConversionError::ARITH_NEGATIVE_OVERFLOW);
+ }
+ }
+ return ConversionResult<Tgt>(boost::implicit_cast<Tgt>(value));
}
-/*******************************************************************************
- * Conversions from string types to floating-point types.
- ******************************************************************************/
-
/**
- * StringPiece to double, with progress information. Alters the
- * StringPiece parameter to munch the already-parsed characters.
+ * Check if a floating point value can safely be converted to an
+ * integer value without triggering undefined behaviour.
*/
-template <class Tgt>
+template <typename Tgt, typename Src>
inline typename std::enable_if<
- std::is_floating_point<Tgt>::value,
- Tgt>::type
-to(StringPiece *const src) {
- using namespace double_conversion;
- static StringToDoubleConverter
- conv(StringToDoubleConverter::ALLOW_TRAILING_JUNK
- | StringToDoubleConverter::ALLOW_LEADING_SPACES,
- 0.0,
- // return this for junk input string
- std::numeric_limits<double>::quiet_NaN(),
- nullptr, nullptr);
-
- FOLLY_RANGE_CHECK_STRINGPIECE(!src->empty(),
- "No digits found in input string", *src);
-
- int length;
- auto result = conv.StringToDouble(src->data(),
- static_cast<int>(src->size()),
- &length); // processed char count
-
- if (!std::isnan(result)) {
- src->advance(length);
- return result;
- }
-
- for (;; src->advance(1)) {
- if (src->empty()) {
- throw std::range_error("Unable to convert an empty string"
- " to a floating point value.");
+ std::is_floating_point<Src>::value && std::is_integral<Tgt>::value &&
+ !std::is_same<Tgt, bool>::value,
+ bool>::type
+checkConversion(const Src& value) {
+ constexpr Src tgtMaxAsSrc = static_cast<Src>(std::numeric_limits<Tgt>::max());
+ constexpr Src tgtMinAsSrc = static_cast<Src>(std::numeric_limits<Tgt>::min());
+ if (value >= tgtMaxAsSrc) {
+ if (value > tgtMaxAsSrc) {
+ return false;
}
- if (!isspace(src->front())) {
- break;
+ const Src mmax = folly::nextafter(tgtMaxAsSrc, Src());
+ if (static_cast<Tgt>(value - mmax) >
+ std::numeric_limits<Tgt>::max() - static_cast<Tgt>(mmax)) {
+ return false;
}
- }
-
- // Was that "inf[inity]"?
- if (src->size() >= 3 && toupper((*src)[0]) == 'I'
- && toupper((*src)[1]) == 'N' && toupper((*src)[2]) == 'F') {
- if (src->size() >= 8 &&
- toupper((*src)[3]) == 'I' &&
- toupper((*src)[4]) == 'N' &&
- toupper((*src)[5]) == 'I' &&
- toupper((*src)[6]) == 'T' &&
- toupper((*src)[7]) == 'Y') {
- src->advance(8);
- } else {
- src->advance(3);
+ } else if (std::is_signed<Tgt>::value && value <= tgtMinAsSrc) {
+ if (value < tgtMinAsSrc) {
+ return false;
}
- return std::numeric_limits<Tgt>::infinity();
- }
-
- // Was that "-inf[inity]"?
- if (src->size() >= 4 && toupper((*src)[0]) == '-'
- && toupper((*src)[1]) == 'I' && toupper((*src)[2]) == 'N'
- && toupper((*src)[3]) == 'F') {
- if (src->size() >= 9 &&
- toupper((*src)[4]) == 'I' &&
- toupper((*src)[5]) == 'N' &&
- toupper((*src)[6]) == 'I' &&
- toupper((*src)[7]) == 'T' &&
- toupper((*src)[8]) == 'Y') {
- src->advance(9);
- } else {
- src->advance(4);
+ const Src mmin = folly::nextafter(tgtMinAsSrc, Src());
+ if (static_cast<Tgt>(value - mmin) <
+ std::numeric_limits<Tgt>::min() - static_cast<Tgt>(mmin)) {
+ return false;
}
- return -std::numeric_limits<Tgt>::infinity();
}
-
- // "nan"?
- if (src->size() >= 3 && toupper((*src)[0]) == 'N'
- && toupper((*src)[1]) == 'A' && toupper((*src)[2]) == 'N') {
- src->advance(3);
- return std::numeric_limits<Tgt>::quiet_NaN();
- }
-
- // "-nan"?
- if (src->size() >= 4 &&
- toupper((*src)[0]) == '-' &&
- toupper((*src)[1]) == 'N' &&
- toupper((*src)[2]) == 'A' &&
- toupper((*src)[3]) == 'N') {
- src->advance(4);
- return -std::numeric_limits<Tgt>::quiet_NaN();
- }
-
- // All bets are off
- throw std::range_error("Unable to convert \"" + src->toString()
- + "\" to a floating point value.");
+ return true;
}
-/**
- * Any string, const char*, or StringPiece to double.
- */
-template <class Tgt>
-typename std::enable_if<
- std::is_floating_point<Tgt>::value,
- Tgt>::type
-to(StringPiece src) {
- Tgt result = to<double>(&src);
- detail::enforceWhitespace(src.data(), src.data() + src.size());
- return result;
+// Integers can always safely be converted to floating point values
+template <typename Tgt, typename Src>
+constexpr typename std::enable_if<
+ std::is_integral<Src>::value && std::is_floating_point<Tgt>::value,
+ bool>::type
+checkConversion(const Src&) {
+ return true;
}
-/*******************************************************************************
- * Integral to floating point and back
- ******************************************************************************/
+// Also, floating point values can always be safely converted to bool
+// Per the standard, any floating point value that is not zero will yield true
+template <typename Tgt, typename Src>
+constexpr typename std::enable_if<
+ std::is_floating_point<Src>::value && std::is_same<Tgt, bool>::value,
+ bool>::type
+checkConversion(const Src&) {
+ return true;
+}
/**
- * Checked conversion from integral to flating point and back. The
+ * Checked conversion from integral to floating point and back. The
* result must be convertible back to the source type without loss of
* precision. This seems Draconian but sometimes is what's needed, and
* complements existing routines nicely. For various rounding
* routines, see <math>.
*/
-template <class Tgt, class Src>
+template <typename Tgt, typename Src>
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),
- Tgt>::type
-to(const Src & value) {
- Tgt result = value;
- auto witness = static_cast<Src>(result);
- if (value != witness) {
- throw std::range_error(
- to<std::string>("to<>: loss of precision when converting ", value,
+ (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) {
+ 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 ConversionResult<Tgt>(ConversionError::ARITH_LOSS_OF_PRECISION);
+}
+
+template <typename Tgt, typename Src>
+inline std::string errorValue(const Src& value) {
#ifdef FOLLY_HAS_RTTI
- " to type ", typeid(Tgt).name()
+ return to<std::string>("(", demangle(typeid(Tgt)), ") ", value);
#else
- " to other type"
+ return to<std::string>(value);
#endif
- ).c_str());
- }
+}
+
+template <typename Tgt, typename Src>
+using IsArithToArith = std::integral_constant<
+ bool,
+ !std::is_same<Tgt, Src>::value && !std::is_same<Tgt, bool>::value &&
+ std::is_arithmetic<Src>::value &&
+ std::is_arithmetic<Tgt>::value>;
+
+} // namespace detail
+
+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);
+ });
+}
+
+/*******************************************************************************
+ * Custom Conversions
+ *
+ * Any type can be used with folly::to by implementing parseTo. The
+ * implementation should be provided in the namespace of the type to facilitate
+ * argument-dependent lookup:
+ *
+ * namespace other_namespace {
+ * void parseTo(::folly::StringPiece, OtherType&);
+ * }
+ ******************************************************************************/
+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) {
+ out = in;
+}
+
+inline void parseTo(StringPiece in, std::string& out) {
+ out.clear();
+ out.append(in.data(), in.size());
+}
+
+inline void parseTo(StringPiece in, fbstring& out) {
+ out.clear();
+ out.append(in.data(), in.size());
+}
+
+/**
+ * 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) {
+ Tgt result;
+ parseTo(src, result);
+ return result;
+}
+
+template <class Tgt>
+Tgt to(StringPiece* src) {
+ Tgt result;
+ parseTo(src, result);
return result;
}
}
} // namespace folly
-
-// FOLLY_CONV_INTERNAL is defined by Conv.cpp. Keep the FOLLY_RANGE_CHECK
-// macro for use in Conv.cpp, but #undefine it everywhere else we are included,
-// to avoid defining this global macro name in other files that include Conv.h.
-#ifndef FOLLY_CONV_INTERNAL
-#undef FOLLY_RANGE_CHECK
-#undef FOLLY_RANGE_CHECK_BEGIN_END
-#undef FOLLY_RANGE_CHECK_STRINGPIECE
-#undef FOLLY_RANGE_CHECK_STRINGIZE
-#undef FOLLY_RANGE_CHECK_STRINGIZE2
-#endif
-
-#endif /* FOLLY_BASE_CONV_H_ */
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