michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "base/strings/string_number_conversions.h"
michael@0: 
michael@0: #include <ctype.h>
michael@0: #include <errno.h>
michael@0: #include <stdlib.h>
michael@0: #include <wctype.h>
michael@0: 
michael@0: #include <limits>
michael@0: 
michael@0: #include "base/logging.h"
michael@0: #include "base/scoped_clear_errno.h"
michael@0: #include "base/strings/utf_string_conversions.h"
michael@0: #include "base/third_party/dmg_fp/dmg_fp.h"
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: template <typename STR, typename INT, typename UINT, bool NEG>
michael@0: struct IntToStringT {
michael@0:   // This is to avoid a compiler warning about unary minus on unsigned type.
michael@0:   // For example, say you had the following code:
michael@0:   //   template <typename INT>
michael@0:   //   INT abs(INT value) { return value < 0 ? -value : value; }
michael@0:   // Even though if INT is unsigned, it's impossible for value < 0, so the
michael@0:   // unary minus will never be taken, the compiler will still generate a
michael@0:   // warning.  We do a little specialization dance...
michael@0:   template <typename INT2, typename UINT2, bool NEG2>
michael@0:   struct ToUnsignedT {};
michael@0: 
michael@0:   template <typename INT2, typename UINT2>
michael@0:   struct ToUnsignedT<INT2, UINT2, false> {
michael@0:     static UINT2 ToUnsigned(INT2 value) {
michael@0:       return static_cast<UINT2>(value);
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   template <typename INT2, typename UINT2>
michael@0:   struct ToUnsignedT<INT2, UINT2, true> {
michael@0:     static UINT2 ToUnsigned(INT2 value) {
michael@0:       return static_cast<UINT2>(value < 0 ? -value : value);
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   // This set of templates is very similar to the above templates, but
michael@0:   // for testing whether an integer is negative.
michael@0:   template <typename INT2, bool NEG2>
michael@0:   struct TestNegT {};
michael@0:   template <typename INT2>
michael@0:   struct TestNegT<INT2, false> {
michael@0:     static bool TestNeg(INT2 value) {
michael@0:       // value is unsigned, and can never be negative.
michael@0:       return false;
michael@0:     }
michael@0:   };
michael@0:   template <typename INT2>
michael@0:   struct TestNegT<INT2, true> {
michael@0:     static bool TestNeg(INT2 value) {
michael@0:       return value < 0;
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   static STR IntToString(INT value) {
michael@0:     // log10(2) ~= 0.3 bytes needed per bit or per byte log10(2**8) ~= 2.4.
michael@0:     // So round up to allocate 3 output characters per byte, plus 1 for '-'.
michael@0:     const int kOutputBufSize = 3 * sizeof(INT) + 1;
michael@0: 
michael@0:     // Allocate the whole string right away, we will right back to front, and
michael@0:     // then return the substr of what we ended up using.
michael@0:     STR outbuf(kOutputBufSize, 0);
michael@0: 
michael@0:     bool is_neg = TestNegT<INT, NEG>::TestNeg(value);
michael@0:     // Even though is_neg will never be true when INT is parameterized as
michael@0:     // unsigned, even the presence of the unary operation causes a warning.
michael@0:     UINT res = ToUnsignedT<INT, UINT, NEG>::ToUnsigned(value);
michael@0: 
michael@0:     for (typename STR::iterator it = outbuf.end();;) {
michael@0:       --it;
michael@0:       DCHECK(it != outbuf.begin());
michael@0:       *it = static_cast<typename STR::value_type>((res % 10) + '0');
michael@0:       res /= 10;
michael@0: 
michael@0:       // We're done..
michael@0:       if (res == 0) {
michael@0:         if (is_neg) {
michael@0:           --it;
michael@0:           DCHECK(it != outbuf.begin());
michael@0:           *it = static_cast<typename STR::value_type>('-');
michael@0:         }
michael@0:         return STR(it, outbuf.end());
michael@0:       }
michael@0:     }
michael@0:     NOTREACHED();
michael@0:     return STR();
michael@0:   }
michael@0: };
michael@0: 
michael@0: // Utility to convert a character to a digit in a given base
michael@0: template<typename CHAR, int BASE, bool BASE_LTE_10> class BaseCharToDigit {
michael@0: };
michael@0: 
michael@0: // Faster specialization for bases <= 10
michael@0: template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, true> {
michael@0:  public:
michael@0:   static bool Convert(CHAR c, uint8* digit) {
michael@0:     if (c >= '0' && c < '0' + BASE) {
michael@0:       *digit = c - '0';
michael@0:       return true;
michael@0:     }
michael@0:     return false;
michael@0:   }
michael@0: };
michael@0: 
michael@0: // Specialization for bases where 10 < base <= 36
michael@0: template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, false> {
michael@0:  public:
michael@0:   static bool Convert(CHAR c, uint8* digit) {
michael@0:     if (c >= '0' && c <= '9') {
michael@0:       *digit = c - '0';
michael@0:     } else if (c >= 'a' && c < 'a' + BASE - 10) {
michael@0:       *digit = c - 'a' + 10;
michael@0:     } else if (c >= 'A' && c < 'A' + BASE - 10) {
michael@0:       *digit = c - 'A' + 10;
michael@0:     } else {
michael@0:       return false;
michael@0:     }
michael@0:     return true;
michael@0:   }
michael@0: };
michael@0: 
michael@0: template<int BASE, typename CHAR> bool CharToDigit(CHAR c, uint8* digit) {
michael@0:   return BaseCharToDigit<CHAR, BASE, BASE <= 10>::Convert(c, digit);
michael@0: }
michael@0: 
michael@0: // There is an IsWhitespace for wchars defined in string_util.h, but it is
michael@0: // locale independent, whereas the functions we are replacing were
michael@0: // locale-dependent. TBD what is desired, but for the moment let's not introduce
michael@0: // a change in behaviour.
michael@0: template<typename CHAR> class WhitespaceHelper {
michael@0: };
michael@0: 
michael@0: template<> class WhitespaceHelper<char> {
michael@0:  public:
michael@0:   static bool Invoke(char c) {
michael@0:     return 0 != isspace(static_cast<unsigned char>(c));
michael@0:   }
michael@0: };
michael@0: 
michael@0: template<> class WhitespaceHelper<char16> {
michael@0:  public:
michael@0:   static bool Invoke(char16 c) {
michael@0:     return 0 != iswspace(c);
michael@0:   }
michael@0: };
michael@0: 
michael@0: template<typename CHAR> bool LocalIsWhitespace(CHAR c) {
michael@0:   return WhitespaceHelper<CHAR>::Invoke(c);
michael@0: }
michael@0: 
michael@0: // IteratorRangeToNumberTraits should provide:
michael@0: //  - a typedef for iterator_type, the iterator type used as input.
michael@0: //  - a typedef for value_type, the target numeric type.
michael@0: //  - static functions min, max (returning the minimum and maximum permitted
michael@0: //    values)
michael@0: //  - constant kBase, the base in which to interpret the input
michael@0: template<typename IteratorRangeToNumberTraits>
michael@0: class IteratorRangeToNumber {
michael@0:  public:
michael@0:   typedef IteratorRangeToNumberTraits traits;
michael@0:   typedef typename traits::iterator_type const_iterator;
michael@0:   typedef typename traits::value_type value_type;
michael@0: 
michael@0:   // Generalized iterator-range-to-number conversion.
michael@0:   //
michael@0:   static bool Invoke(const_iterator begin,
michael@0:                      const_iterator end,
michael@0:                      value_type* output) {
michael@0:     bool valid = true;
michael@0: 
michael@0:     while (begin != end && LocalIsWhitespace(*begin)) {
michael@0:       valid = false;
michael@0:       ++begin;
michael@0:     }
michael@0: 
michael@0:     if (begin != end && *begin == '-') {
michael@0:       if (!std::numeric_limits<value_type>::is_signed) {
michael@0:         valid = false;
michael@0:       } else if (!Negative::Invoke(begin + 1, end, output)) {
michael@0:         valid = false;
michael@0:       }
michael@0:     } else {
michael@0:       if (begin != end && *begin == '+') {
michael@0:         ++begin;
michael@0:       }
michael@0:       if (!Positive::Invoke(begin, end, output)) {
michael@0:         valid = false;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return valid;
michael@0:   }
michael@0: 
michael@0:  private:
michael@0:   // Sign provides:
michael@0:   //  - a static function, CheckBounds, that determines whether the next digit
michael@0:   //    causes an overflow/underflow
michael@0:   //  - a static function, Increment, that appends the next digit appropriately
michael@0:   //    according to the sign of the number being parsed.
michael@0:   template<typename Sign>
michael@0:   class Base {
michael@0:    public:
michael@0:     static bool Invoke(const_iterator begin, const_iterator end,
michael@0:                        typename traits::value_type* output) {
michael@0:       *output = 0;
michael@0: 
michael@0:       if (begin == end) {
michael@0:         return false;
michael@0:       }
michael@0: 
michael@0:       // Note: no performance difference was found when using template
michael@0:       // specialization to remove this check in bases other than 16
michael@0:       if (traits::kBase == 16 && end - begin > 2 && *begin == '0' &&
michael@0:           (*(begin + 1) == 'x' || *(begin + 1) == 'X')) {
michael@0:         begin += 2;
michael@0:       }
michael@0: 
michael@0:       for (const_iterator current = begin; current != end; ++current) {
michael@0:         uint8 new_digit = 0;
michael@0: 
michael@0:         if (!CharToDigit<traits::kBase>(*current, &new_digit)) {
michael@0:           return false;
michael@0:         }
michael@0: 
michael@0:         if (current != begin) {
michael@0:           if (!Sign::CheckBounds(output, new_digit)) {
michael@0:             return false;
michael@0:           }
michael@0:           *output *= traits::kBase;
michael@0:         }
michael@0: 
michael@0:         Sign::Increment(new_digit, output);
michael@0:       }
michael@0:       return true;
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   class Positive : public Base<Positive> {
michael@0:    public:
michael@0:     static bool CheckBounds(value_type* output, uint8 new_digit) {
michael@0:       if (*output > static_cast<value_type>(traits::max() / traits::kBase) ||
michael@0:           (*output == static_cast<value_type>(traits::max() / traits::kBase) &&
michael@0:            new_digit > traits::max() % traits::kBase)) {
michael@0:         *output = traits::max();
michael@0:         return false;
michael@0:       }
michael@0:       return true;
michael@0:     }
michael@0:     static void Increment(uint8 increment, value_type* output) {
michael@0:       *output += increment;
michael@0:     }
michael@0:   };
michael@0: 
michael@0:   class Negative : public Base<Negative> {
michael@0:    public:
michael@0:     static bool CheckBounds(value_type* output, uint8 new_digit) {
michael@0:       if (*output < traits::min() / traits::kBase ||
michael@0:           (*output == traits::min() / traits::kBase &&
michael@0:            new_digit > 0 - traits::min() % traits::kBase)) {
michael@0:         *output = traits::min();
michael@0:         return false;
michael@0:       }
michael@0:       return true;
michael@0:     }
michael@0:     static void Increment(uint8 increment, value_type* output) {
michael@0:       *output -= increment;
michael@0:     }
michael@0:   };
michael@0: };
michael@0: 
michael@0: template<typename ITERATOR, typename VALUE, int BASE>
michael@0: class BaseIteratorRangeToNumberTraits {
michael@0:  public:
michael@0:   typedef ITERATOR iterator_type;
michael@0:   typedef VALUE value_type;
michael@0:   static value_type min() {
michael@0:     return std::numeric_limits<value_type>::min();
michael@0:   }
michael@0:   static value_type max() {
michael@0:     return std::numeric_limits<value_type>::max();
michael@0:   }
michael@0:   static const int kBase = BASE;
michael@0: };
michael@0: 
michael@0: template<typename ITERATOR>
michael@0: class BaseHexIteratorRangeToIntTraits
michael@0:     : public BaseIteratorRangeToNumberTraits<ITERATOR, int, 16> {
michael@0: };
michael@0: 
michael@0: template<typename ITERATOR>
michael@0: class BaseHexIteratorRangeToInt64Traits
michael@0:     : public BaseIteratorRangeToNumberTraits<ITERATOR, int64, 16> {
michael@0: };
michael@0: 
michael@0: template<typename ITERATOR>
michael@0: class BaseHexIteratorRangeToUInt64Traits
michael@0:     : public BaseIteratorRangeToNumberTraits<ITERATOR, uint64, 16> {
michael@0: };
michael@0: 
michael@0: typedef BaseHexIteratorRangeToIntTraits<StringPiece::const_iterator>
michael@0:     HexIteratorRangeToIntTraits;
michael@0: 
michael@0: typedef BaseHexIteratorRangeToInt64Traits<StringPiece::const_iterator>
michael@0:     HexIteratorRangeToInt64Traits;
michael@0: 
michael@0: typedef BaseHexIteratorRangeToUInt64Traits<StringPiece::const_iterator>
michael@0:     HexIteratorRangeToUInt64Traits;
michael@0: 
michael@0: template<typename STR>
michael@0: bool HexStringToBytesT(const STR& input, std::vector<uint8>* output) {
michael@0:   DCHECK_EQ(output->size(), 0u);
michael@0:   size_t count = input.size();
michael@0:   if (count == 0 || (count % 2) != 0)
michael@0:     return false;
michael@0:   for (uintptr_t i = 0; i < count / 2; ++i) {
michael@0:     uint8 msb = 0;  // most significant 4 bits
michael@0:     uint8 lsb = 0;  // least significant 4 bits
michael@0:     if (!CharToDigit<16>(input[i * 2], &msb) ||
michael@0:         !CharToDigit<16>(input[i * 2 + 1], &lsb))
michael@0:       return false;
michael@0:     output->push_back((msb << 4) | lsb);
michael@0:   }
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: template <typename VALUE, int BASE>
michael@0: class StringPieceToNumberTraits
michael@0:     : public BaseIteratorRangeToNumberTraits<StringPiece::const_iterator,
michael@0:                                              VALUE,
michael@0:                                              BASE> {
michael@0: };
michael@0: 
michael@0: template <typename VALUE>
michael@0: bool StringToIntImpl(const StringPiece& input, VALUE* output) {
michael@0:   return IteratorRangeToNumber<StringPieceToNumberTraits<VALUE, 10> >::Invoke(
michael@0:       input.begin(), input.end(), output);
michael@0: }
michael@0: 
michael@0: template <typename VALUE, int BASE>
michael@0: class StringPiece16ToNumberTraits
michael@0:     : public BaseIteratorRangeToNumberTraits<StringPiece16::const_iterator,
michael@0:                                              VALUE,
michael@0:                                              BASE> {
michael@0: };
michael@0: 
michael@0: template <typename VALUE>
michael@0: bool String16ToIntImpl(const StringPiece16& input, VALUE* output) {
michael@0:   return IteratorRangeToNumber<StringPiece16ToNumberTraits<VALUE, 10> >::Invoke(
michael@0:       input.begin(), input.end(), output);
michael@0: }
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: std::string IntToString(int value) {
michael@0:   return IntToStringT<std::string, int, unsigned int, true>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: string16 IntToString16(int value) {
michael@0:   return IntToStringT<string16, int, unsigned int, true>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: std::string UintToString(unsigned int value) {
michael@0:   return IntToStringT<std::string, unsigned int, unsigned int, false>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: string16 UintToString16(unsigned int value) {
michael@0:   return IntToStringT<string16, unsigned int, unsigned int, false>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: std::string Int64ToString(int64 value) {
michael@0:   return IntToStringT<std::string, int64, uint64, true>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: string16 Int64ToString16(int64 value) {
michael@0:   return IntToStringT<string16, int64, uint64, true>::IntToString(value);
michael@0: }
michael@0: 
michael@0: std::string Uint64ToString(uint64 value) {
michael@0:   return IntToStringT<std::string, uint64, uint64, false>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: string16 Uint64ToString16(uint64 value) {
michael@0:   return IntToStringT<string16, uint64, uint64, false>::
michael@0:       IntToString(value);
michael@0: }
michael@0: 
michael@0: std::string DoubleToString(double value) {
michael@0:   // According to g_fmt.cc, it is sufficient to declare a buffer of size 32.
michael@0:   char buffer[32];
michael@0:   dmg_fp::g_fmt(buffer, value);
michael@0:   return std::string(buffer);
michael@0: }
michael@0: 
michael@0: bool StringToInt(const StringPiece& input, int* output) {
michael@0:   return StringToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToInt(const StringPiece16& input, int* output) {
michael@0:   return String16ToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToUint(const StringPiece& input, unsigned* output) {
michael@0:   return StringToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToUint(const StringPiece16& input, unsigned* output) {
michael@0:   return String16ToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToInt64(const StringPiece& input, int64* output) {
michael@0:   return StringToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToInt64(const StringPiece16& input, int64* output) {
michael@0:   return String16ToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToUint64(const StringPiece& input, uint64* output) {
michael@0:   return StringToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToUint64(const StringPiece16& input, uint64* output) {
michael@0:   return String16ToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToSizeT(const StringPiece& input, size_t* output) {
michael@0:   return StringToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToSizeT(const StringPiece16& input, size_t* output) {
michael@0:   return String16ToIntImpl(input, output);
michael@0: }
michael@0: 
michael@0: bool StringToDouble(const std::string& input, double* output) {
michael@0:   // Thread-safe?  It is on at least Mac, Linux, and Windows.
michael@0:   ScopedClearErrno clear_errno;
michael@0: 
michael@0:   char* endptr = NULL;
michael@0:   *output = dmg_fp::strtod(input.c_str(), &endptr);
michael@0: 
michael@0:   // Cases to return false:
michael@0:   //  - If errno is ERANGE, there was an overflow or underflow.
michael@0:   //  - If the input string is empty, there was nothing to parse.
michael@0:   //  - If endptr does not point to the end of the string, there are either
michael@0:   //    characters remaining in the string after a parsed number, or the string
michael@0:   //    does not begin with a parseable number.  endptr is compared to the
michael@0:   //    expected end given the string's stated length to correctly catch cases
michael@0:   //    where the string contains embedded NUL characters.
michael@0:   //  - If the first character is a space, there was leading whitespace
michael@0:   return errno == 0 &&
michael@0:          !input.empty() &&
michael@0:          input.c_str() + input.length() == endptr &&
michael@0:          !isspace(input[0]);
michael@0: }
michael@0: 
michael@0: // Note: if you need to add String16ToDouble, first ask yourself if it's
michael@0: // really necessary. If it is, probably the best implementation here is to
michael@0: // convert to 8-bit and then use the 8-bit version.
michael@0: 
michael@0: // Note: if you need to add an iterator range version of StringToDouble, first
michael@0: // ask yourself if it's really necessary. If it is, probably the best
michael@0: // implementation here is to instantiate a string and use the string version.
michael@0: 
michael@0: std::string HexEncode(const void* bytes, size_t size) {
michael@0:   static const char kHexChars[] = "0123456789ABCDEF";
michael@0: 
michael@0:   // Each input byte creates two output hex characters.
michael@0:   std::string ret(size * 2, '\0');
michael@0: 
michael@0:   for (size_t i = 0; i < size; ++i) {
michael@0:     char b = reinterpret_cast<const char*>(bytes)[i];
michael@0:     ret[(i * 2)] = kHexChars[(b >> 4) & 0xf];
michael@0:     ret[(i * 2) + 1] = kHexChars[b & 0xf];
michael@0:   }
michael@0:   return ret;
michael@0: }
michael@0: 
michael@0: bool HexStringToInt(const StringPiece& input, int* output) {
michael@0:   return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke(
michael@0:     input.begin(), input.end(), output);
michael@0: }
michael@0: 
michael@0: bool HexStringToInt64(const StringPiece& input, int64* output) {
michael@0:   return IteratorRangeToNumber<HexIteratorRangeToInt64Traits>::Invoke(
michael@0:     input.begin(), input.end(), output);
michael@0: }
michael@0: 
michael@0: bool HexStringToUInt64(const StringPiece& input, uint64* output) {
michael@0:   return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke(
michael@0:       input.begin(), input.end(), output);
michael@0: }
michael@0: 
michael@0: bool HexStringToBytes(const std::string& input, std::vector<uint8>* output) {
michael@0:   return HexStringToBytesT(input, output);
michael@0: }
michael@0: 
michael@0: }  // namespace base