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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/strings/string_number_conversions.h"
#include <ctype.h>
#include <errno.h>
#include <stdlib.h>
#include <wctype.h>
#include <limits>
#include <type_traits>
#include "base/logging.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 "double-conversion/double-conversion.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);
}
string16 NumberToString16(int value) {
return IntToStringT<string16, int>::IntToString(value);
}
std::string NumberToString(unsigned value) {
return IntToStringT<std::string, unsigned>::IntToString(value);
}
string16 NumberToString16(unsigned value) {
return IntToStringT<string16, unsigned>::IntToString(value);
}
std::string NumberToString(long value) {
return IntToStringT<std::string, long>::IntToString(value);
}
string16 NumberToString16(long value) {
return IntToStringT<string16, long>::IntToString(value);
}
std::string NumberToString(unsigned long value) {
return IntToStringT<std::string, unsigned long>::IntToString(value);
}
string16 NumberToString16(unsigned long value) {
return IntToStringT<string16, unsigned long>::IntToString(value);
}
std::string NumberToString(long long value) {
return IntToStringT<std::string, long long>::IntToString(value);
}
string16 NumberToString16(long long value) {
return IntToStringT<string16, long long>::IntToString(value);
}
std::string NumberToString(unsigned long long value) {
return IntToStringT<std::string, unsigned long long>::IntToString(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();
}
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());
}
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()]);
}
bool StringToInt(StringPiece input, int* output) {
return StringToIntImpl(input, output);
}
bool StringToInt(StringPiece16 input, int* output) {
return String16ToIntImpl(input, output);
}
bool StringToUint(StringPiece input, unsigned* output) {
return StringToIntImpl(input, output);
}
bool StringToUint(StringPiece16 input, unsigned* output) {
return String16ToIntImpl(input, output);
}
bool StringToInt64(StringPiece input, int64_t* output) {
return StringToIntImpl(input, output);
}
bool StringToInt64(StringPiece16 input, int64_t* output) {
return String16ToIntImpl(input, output);
}
bool StringToUint64(StringPiece input, uint64_t* output) {
return StringToIntImpl(input, output);
}
bool StringToUint64(StringPiece16 input, uint64_t* output) {
return String16ToIntImpl(input, output);
}
bool StringToSizeT(StringPiece input, size_t* output) {
return 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]);
}
bool StringToDouble(StringPiece input, double* output) {
return StringToDoubleImpl(input, input.data(), output);
}
bool StringToDouble(StringPiece16 input, double* output) {
return StringToDoubleImpl(
input, reinterpret_cast<const uint16_t*>(input.data()), output);
}
std::string HexEncode(const void* bytes, size_t size) {
static const char kHexChars[] = "0123456789ABCDEF";
// Each input byte creates two output hex characters.
std::string ret(size * 2, '\0');
for (size_t i = 0; i < size; ++i) {
char b = reinterpret_cast<const char*>(bytes)[i];
ret[(i * 2)] = kHexChars[(b >> 4) & 0xf];
ret[(i * 2) + 1] = kHexChars[b & 0xf];
}
return ret;
}
std::string HexEncode(base::span<const uint8_t> bytes) {
return HexEncode(bytes.data(), bytes.size());
}
bool HexStringToInt(StringPiece input, int* output) {
return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke(
input.begin(), input.end(), output);
}
bool HexStringToUInt(StringPiece input, uint32_t* output) {
return IteratorRangeToNumber<HexIteratorRangeToUIntTraits>::Invoke(
input.begin(), input.end(), output);
}
bool HexStringToInt64(StringPiece input, int64_t* output) {
return IteratorRangeToNumber<HexIteratorRangeToInt64Traits>::Invoke(
input.begin(), input.end(), 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;
}
bool HexStringToBytes(StringPiece input, std::vector<uint8_t>* output) {
return HexStringToByteContainer(input, output);
}
bool HexStringToString(StringPiece input, std::string* output) {
return HexStringToByteContainer(input, output);
}
bool HexStringToSpan(StringPiece input, base::span<uint8_t> output) {
size_t count = input.size();
if (count == 0 || (count % 2) != 0)
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;
}
} // namespace base