[base] Add wide string to number conversions
As a follow-up to r775075 this change introduces a Windows version of
string_number_conversions.h, which contains wide string overloads that
are only exposed on Windows. In order to facilitate code sharing with the
regular string number conversions, this change also adds
string_number_conversions_internal.h.
Furthermore, it performs some small clean-ups to simplify the template
logic and rely on more automatic type deductions.
Bug: 911896
Change-Id: I0ed8f8b73b8b78ccbe3a762b04a021c7b2a60ec2
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231142
Commit-Queue: Jan Wilken Dörrie <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Cr-Commit-Position: refs/heads/master@{#780735}
diff --git a/base/strings/string_number_conversions.cc b/base/strings/string_number_conversions.cc
index bd0a7e4..e2ef8acf 100644
--- a/base/strings/string_number_conversions.cc
+++ b/base/strings/string_number_conversions.cc
@@ -4,458 +4,120 @@
#include "base/strings/string_number_conversions.h"
-#include <ctype.h>
-#include <errno.h>
-#include <stdlib.h>
-#include <wctype.h>
+#include <iterator>
+#include <string>
-#include <limits>
-#include <type_traits>
-
-#include "base/check_op.h"
-#include "base/no_destructor.h"
-#include "base/numerics/safe_math.h"
-#include "base/strings/string_util.h"
-#include "base/strings/utf_string_conversions.h"
-#include "base/third_party/double_conversion/double-conversion/double-conversion.h"
+#include "base/containers/span.h"
+#include "base/logging.h"
+#include "base/strings/string16.h"
+#include "base/strings/string_number_conversions_internal.h"
+#include "base/strings/string_piece.h"
namespace base {
-namespace {
-
-template <typename STR, typename INT>
-struct IntToStringT {
- static STR IntToString(INT value) {
- // log10(2) ~= 0.3 bytes needed per bit or per byte log10(2**8) ~= 2.4.
- // So round up to allocate 3 output characters per byte, plus 1 for '-'.
- const size_t kOutputBufSize =
- 3 * sizeof(INT) + std::numeric_limits<INT>::is_signed;
-
- // Create the string in a temporary buffer, write it back to front, and
- // then return the substr of what we ended up using.
- using CHR = typename STR::value_type;
- CHR outbuf[kOutputBufSize];
-
- // The ValueOrDie call below can never fail, because UnsignedAbs is valid
- // for all valid inputs.
- typename std::make_unsigned<INT>::type res =
- CheckedNumeric<INT>(value).UnsignedAbs().ValueOrDie();
-
- CHR* end = outbuf + kOutputBufSize;
- CHR* i = end;
- do {
- --i;
- DCHECK(i != outbuf);
- *i = static_cast<CHR>((res % 10) + '0');
- res /= 10;
- } while (res != 0);
- if (IsValueNegative(value)) {
- --i;
- DCHECK(i != outbuf);
- *i = static_cast<CHR>('-');
- }
- return STR(i, end);
- }
-};
-
-// Utility to convert a character to a digit in a given base
-template<typename CHAR, int BASE, bool BASE_LTE_10> class BaseCharToDigit {
-};
-
-// Faster specialization for bases <= 10
-template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, true> {
- public:
- static bool Convert(CHAR c, uint8_t* digit) {
- if (c >= '0' && c < '0' + BASE) {
- *digit = static_cast<uint8_t>(c - '0');
- return true;
- }
- return false;
- }
-};
-
-// Specialization for bases where 10 < base <= 36
-template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, false> {
- public:
- static bool Convert(CHAR c, uint8_t* digit) {
- if (c >= '0' && c <= '9') {
- *digit = c - '0';
- } else if (c >= 'a' && c < 'a' + BASE - 10) {
- *digit = c - 'a' + 10;
- } else if (c >= 'A' && c < 'A' + BASE - 10) {
- *digit = c - 'A' + 10;
- } else {
- return false;
- }
- return true;
- }
-};
-
-template <int BASE, typename CHAR>
-bool CharToDigit(CHAR c, uint8_t* digit) {
- return BaseCharToDigit<CHAR, BASE, BASE <= 10>::Convert(c, digit);
-}
-
-// There is an IsUnicodeWhitespace for wchars defined in string_util.h, but it
-// is locale independent, whereas the functions we are replacing were
-// locale-dependent. TBD what is desired, but for the moment let's not
-// introduce a change in behaviour.
-template<typename CHAR> class WhitespaceHelper {
-};
-
-template<> class WhitespaceHelper<char> {
- public:
- static bool Invoke(char c) {
- return 0 != isspace(static_cast<unsigned char>(c));
- }
-};
-
-template<> class WhitespaceHelper<char16> {
- public:
- static bool Invoke(char16 c) {
- return 0 != iswspace(c);
- }
-};
-
-template<typename CHAR> bool LocalIsWhitespace(CHAR c) {
- return WhitespaceHelper<CHAR>::Invoke(c);
-}
-
-// IteratorRangeToNumberTraits should provide:
-// - a typedef for iterator_type, the iterator type used as input.
-// - a typedef for value_type, the target numeric type.
-// - static functions min, max (returning the minimum and maximum permitted
-// values)
-// - constant kBase, the base in which to interpret the input
-template<typename IteratorRangeToNumberTraits>
-class IteratorRangeToNumber {
- public:
- typedef IteratorRangeToNumberTraits traits;
- typedef typename traits::iterator_type const_iterator;
- typedef typename traits::value_type value_type;
-
- // Generalized iterator-range-to-number conversion.
- //
- static bool Invoke(const_iterator begin,
- const_iterator end,
- value_type* output) {
- bool valid = true;
-
- while (begin != end && LocalIsWhitespace(*begin)) {
- valid = false;
- ++begin;
- }
-
- if (begin != end && *begin == '-') {
- if (!std::numeric_limits<value_type>::is_signed) {
- *output = 0;
- valid = false;
- } else if (!Negative::Invoke(begin + 1, end, output)) {
- valid = false;
- }
- } else {
- if (begin != end && *begin == '+') {
- ++begin;
- }
- if (!Positive::Invoke(begin, end, output)) {
- valid = false;
- }
- }
-
- return valid;
- }
-
- private:
- // Sign provides:
- // - a static function, CheckBounds, that determines whether the next digit
- // causes an overflow/underflow
- // - a static function, Increment, that appends the next digit appropriately
- // according to the sign of the number being parsed.
- template<typename Sign>
- class Base {
- public:
- static bool Invoke(const_iterator begin, const_iterator end,
- typename traits::value_type* output) {
- *output = 0;
-
- if (begin == end) {
- return false;
- }
-
- // Note: no performance difference was found when using template
- // specialization to remove this check in bases other than 16
- if (traits::kBase == 16 && end - begin > 2 && *begin == '0' &&
- (*(begin + 1) == 'x' || *(begin + 1) == 'X')) {
- begin += 2;
- }
-
- for (const_iterator current = begin; current != end; ++current) {
- uint8_t new_digit = 0;
-
- if (!CharToDigit<traits::kBase>(*current, &new_digit)) {
- return false;
- }
-
- if (current != begin) {
- if (!Sign::CheckBounds(output, new_digit)) {
- return false;
- }
- *output *= traits::kBase;
- }
-
- Sign::Increment(new_digit, output);
- }
- return true;
- }
- };
-
- class Positive : public Base<Positive> {
- public:
- static bool CheckBounds(value_type* output, uint8_t new_digit) {
- if (*output > static_cast<value_type>(traits::max() / traits::kBase) ||
- (*output == static_cast<value_type>(traits::max() / traits::kBase) &&
- new_digit > traits::max() % traits::kBase)) {
- *output = traits::max();
- return false;
- }
- return true;
- }
- static void Increment(uint8_t increment, value_type* output) {
- *output += increment;
- }
- };
-
- class Negative : public Base<Negative> {
- public:
- static bool CheckBounds(value_type* output, uint8_t new_digit) {
- if (*output < traits::min() / traits::kBase ||
- (*output == traits::min() / traits::kBase &&
- new_digit > 0 - traits::min() % traits::kBase)) {
- *output = traits::min();
- return false;
- }
- return true;
- }
- static void Increment(uint8_t increment, value_type* output) {
- *output -= increment;
- }
- };
-};
-
-template<typename ITERATOR, typename VALUE, int BASE>
-class BaseIteratorRangeToNumberTraits {
- public:
- typedef ITERATOR iterator_type;
- typedef VALUE value_type;
- static value_type min() {
- return std::numeric_limits<value_type>::min();
- }
- static value_type max() {
- return std::numeric_limits<value_type>::max();
- }
- static const int kBase = BASE;
-};
-
-template<typename ITERATOR>
-class BaseHexIteratorRangeToIntTraits
- : public BaseIteratorRangeToNumberTraits<ITERATOR, int, 16> {
-};
-
-template <typename ITERATOR>
-class BaseHexIteratorRangeToUIntTraits
- : public BaseIteratorRangeToNumberTraits<ITERATOR, uint32_t, 16> {};
-
-template <typename ITERATOR>
-class BaseHexIteratorRangeToInt64Traits
- : public BaseIteratorRangeToNumberTraits<ITERATOR, int64_t, 16> {};
-
-template <typename ITERATOR>
-class BaseHexIteratorRangeToUInt64Traits
- : public BaseIteratorRangeToNumberTraits<ITERATOR, uint64_t, 16> {};
-
-typedef BaseHexIteratorRangeToIntTraits<StringPiece::const_iterator>
- HexIteratorRangeToIntTraits;
-
-typedef BaseHexIteratorRangeToUIntTraits<StringPiece::const_iterator>
- HexIteratorRangeToUIntTraits;
-
-typedef BaseHexIteratorRangeToInt64Traits<StringPiece::const_iterator>
- HexIteratorRangeToInt64Traits;
-
-typedef BaseHexIteratorRangeToUInt64Traits<StringPiece::const_iterator>
- HexIteratorRangeToUInt64Traits;
-
-template <typename VALUE, int BASE>
-class StringPieceToNumberTraits
- : public BaseIteratorRangeToNumberTraits<StringPiece::const_iterator,
- VALUE,
- BASE> {
-};
-
-template <typename VALUE>
-bool StringToIntImpl(StringPiece input, VALUE* output) {
- return IteratorRangeToNumber<StringPieceToNumberTraits<VALUE, 10> >::Invoke(
- input.begin(), input.end(), output);
-}
-
-template <typename VALUE, int BASE>
-class StringPiece16ToNumberTraits
- : public BaseIteratorRangeToNumberTraits<StringPiece16::const_iterator,
- VALUE,
- BASE> {
-};
-
-template <typename VALUE>
-bool String16ToIntImpl(StringPiece16 input, VALUE* output) {
- return IteratorRangeToNumber<StringPiece16ToNumberTraits<VALUE, 10> >::Invoke(
- input.begin(), input.end(), output);
-}
-
-} // namespace
-
std::string NumberToString(int value) {
- return IntToStringT<std::string, int>::IntToString(value);
+ return internal::IntToStringT<std::string>(value);
}
string16 NumberToString16(int value) {
- return IntToStringT<string16, int>::IntToString(value);
+ return internal::IntToStringT<string16>(value);
}
std::string NumberToString(unsigned value) {
- return IntToStringT<std::string, unsigned>::IntToString(value);
+ return internal::IntToStringT<std::string>(value);
}
string16 NumberToString16(unsigned value) {
- return IntToStringT<string16, unsigned>::IntToString(value);
+ return internal::IntToStringT<string16>(value);
}
std::string NumberToString(long value) {
- return IntToStringT<std::string, long>::IntToString(value);
+ return internal::IntToStringT<std::string>(value);
}
string16 NumberToString16(long value) {
- return IntToStringT<string16, long>::IntToString(value);
+ return internal::IntToStringT<string16>(value);
}
std::string NumberToString(unsigned long value) {
- return IntToStringT<std::string, unsigned long>::IntToString(value);
+ return internal::IntToStringT<std::string>(value);
}
string16 NumberToString16(unsigned long value) {
- return IntToStringT<string16, unsigned long>::IntToString(value);
+ return internal::IntToStringT<string16>(value);
}
std::string NumberToString(long long value) {
- return IntToStringT<std::string, long long>::IntToString(value);
+ return internal::IntToStringT<std::string>(value);
}
string16 NumberToString16(long long value) {
- return IntToStringT<string16, long long>::IntToString(value);
+ return internal::IntToStringT<string16>(value);
}
std::string NumberToString(unsigned long long value) {
- return IntToStringT<std::string, unsigned long long>::IntToString(value);
+ return internal::IntToStringT<std::string>(value);
}
string16 NumberToString16(unsigned long long value) {
- return IntToStringT<string16, unsigned long long>::IntToString(value);
-}
-
-static const double_conversion::DoubleToStringConverter*
-GetDoubleToStringConverter() {
- static NoDestructor<double_conversion::DoubleToStringConverter> converter(
- double_conversion::DoubleToStringConverter::EMIT_POSITIVE_EXPONENT_SIGN,
- nullptr, nullptr, 'e', -6, 12, 0, 0);
- return converter.get();
+ return internal::IntToStringT<string16>(value);
}
std::string NumberToString(double value) {
- char buffer[32];
- double_conversion::StringBuilder builder(buffer, sizeof(buffer));
- GetDoubleToStringConverter()->ToShortest(value, &builder);
- return std::string(buffer, builder.position());
+ return internal::DoubleToStringT<std::string>(value);
}
-base::string16 NumberToString16(double value) {
- char buffer[32];
- double_conversion::StringBuilder builder(buffer, sizeof(buffer));
- GetDoubleToStringConverter()->ToShortest(value, &builder);
-
- // The number will be ASCII. This creates the string using the "input
- // iterator" variant which promotes from 8-bit to 16-bit via "=".
- return base::string16(&buffer[0], &buffer[builder.position()]);
+string16 NumberToString16(double value) {
+ return internal::DoubleToStringT<string16>(value);
}
bool StringToInt(StringPiece input, int* output) {
- return StringToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToInt(StringPiece16 input, int* output) {
- return String16ToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToUint(StringPiece input, unsigned* output) {
- return StringToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToUint(StringPiece16 input, unsigned* output) {
- return String16ToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToInt64(StringPiece input, int64_t* output) {
- return StringToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToInt64(StringPiece16 input, int64_t* output) {
- return String16ToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToUint64(StringPiece input, uint64_t* output) {
- return StringToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToUint64(StringPiece16 input, uint64_t* output) {
- return String16ToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToSizeT(StringPiece input, size_t* output) {
- return StringToIntImpl(input, output);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToSizeT(StringPiece16 input, size_t* output) {
- return String16ToIntImpl(input, output);
-}
-
-template <typename STRING, typename CHAR>
-bool StringToDoubleImpl(STRING input, const CHAR* data, double* output) {
- static NoDestructor<double_conversion::StringToDoubleConverter> converter(
- double_conversion::StringToDoubleConverter::ALLOW_LEADING_SPACES |
- double_conversion::StringToDoubleConverter::ALLOW_TRAILING_JUNK,
- 0.0, 0, nullptr, nullptr);
-
- int processed_characters_count;
- *output = converter->StringToDouble(data, input.size(),
- &processed_characters_count);
-
- // Cases to return false:
- // - If the input string is empty, there was nothing to parse.
- // - If the value saturated to HUGE_VAL.
- // - If the entire string was not processed, there are either characters
- // remaining in the string after a parsed number, or the string does not
- // begin with a parseable number.
- // - If the first character is a space, there was leading whitespace
- return !input.empty() && *output != HUGE_VAL && *output != -HUGE_VAL &&
- static_cast<size_t>(processed_characters_count) == input.size() &&
- !IsUnicodeWhitespace(input[0]);
+ return internal::StringToIntImpl(input, *output);
}
bool StringToDouble(StringPiece input, double* output) {
- return StringToDoubleImpl(input, input.data(), output);
+ return internal::StringToDoubleImpl(input, input.data(), *output);
}
bool StringToDouble(StringPiece16 input, double* output) {
- return StringToDoubleImpl(
- input, reinterpret_cast<const uint16_t*>(input.data()), output);
+ return internal::StringToDoubleImpl(
+ input, reinterpret_cast<const uint16_t*>(input.data()), *output);
}
std::string HexEncode(const void* bytes, size_t size) {
@@ -477,69 +139,36 @@
}
bool HexStringToInt(StringPiece input, int* output) {
- return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke(
- input.begin(), input.end(), output);
+ return internal::HexStringToIntImpl(input, *output);
}
bool HexStringToUInt(StringPiece input, uint32_t* output) {
- return IteratorRangeToNumber<HexIteratorRangeToUIntTraits>::Invoke(
- input.begin(), input.end(), output);
+ return internal::HexStringToIntImpl(input, *output);
}
bool HexStringToInt64(StringPiece input, int64_t* output) {
- return IteratorRangeToNumber<HexIteratorRangeToInt64Traits>::Invoke(
- input.begin(), input.end(), output);
+ return internal::HexStringToIntImpl(input, *output);
}
bool HexStringToUInt64(StringPiece input, uint64_t* output) {
- return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke(
- input.begin(), input.end(), output);
-}
-
-template <typename Container>
-static bool HexStringToByteContainer(StringPiece input, Container* output) {
- DCHECK_EQ(output->size(), 0u);
- size_t count = input.size();
- if (count == 0 || (count % 2) != 0)
- return false;
- for (uintptr_t i = 0; i < count / 2; ++i) {
- uint8_t msb = 0; // most significant 4 bits
- uint8_t lsb = 0; // least significant 4 bits
- if (!CharToDigit<16>(input[i * 2], &msb) ||
- !CharToDigit<16>(input[i * 2 + 1], &lsb)) {
- return false;
- }
- output->push_back((msb << 4) | lsb);
- }
- return true;
+ return internal::HexStringToIntImpl(input, *output);
}
bool HexStringToBytes(StringPiece input, std::vector<uint8_t>* output) {
- return HexStringToByteContainer(input, output);
+ DCHECK(output->empty());
+ return internal::HexStringToByteContainer(input, std::back_inserter(*output));
}
bool HexStringToString(StringPiece input, std::string* output) {
- return HexStringToByteContainer(input, output);
+ DCHECK(output->empty());
+ return internal::HexStringToByteContainer(input, std::back_inserter(*output));
}
bool HexStringToSpan(StringPiece input, base::span<uint8_t> output) {
- size_t count = input.size();
- if (count == 0 || (count % 2) != 0)
+ if (input.size() / 2 != output.size())
return false;
- if (count / 2 != output.size())
- return false;
-
- for (uintptr_t i = 0; i < count / 2; ++i) {
- uint8_t msb = 0; // most significant 4 bits
- uint8_t lsb = 0; // least significant 4 bits
- if (!CharToDigit<16>(input[i * 2], &msb) ||
- !CharToDigit<16>(input[i * 2 + 1], &lsb)) {
- return false;
- }
- output[i] = (msb << 4) | lsb;
- }
- return true;
+ return internal::HexStringToByteContainer(input, output.begin());
}
} // namespace base
