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-rw-r--r--base/string_number_conversions.cc545
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diff --git a/base/string_number_conversions.cc b/base/string_number_conversions.cc
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+// Copyright (c) 2011 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/string_number_conversions.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <wctype.h>
+
+#include <limits>
+
+#include "base/logging.h"
+#include "base/third_party/dmg_fp/dmg_fp.h"
+#include "base/utf_string_conversions.h"
+
+namespace base {
+
+namespace {
+
+template <typename STR, typename INT, typename UINT, bool NEG>
+struct IntToStringT {
+ // This is to avoid a compiler warning about unary minus on unsigned type.
+ // For example, say you had the following code:
+ // template <typename INT>
+ // INT abs(INT value) { return value < 0 ? -value : value; }
+ // Even though if INT is unsigned, it's impossible for value < 0, so the
+ // unary minus will never be taken, the compiler will still generate a
+ // warning. We do a little specialization dance...
+ template <typename INT2, typename UINT2, bool NEG2>
+ struct ToUnsignedT {};
+
+ template <typename INT2, typename UINT2>
+ struct ToUnsignedT<INT2, UINT2, false> {
+ static UINT2 ToUnsigned(INT2 value) {
+ return static_cast<UINT2>(value);
+ }
+ };
+
+ template <typename INT2, typename UINT2>
+ struct ToUnsignedT<INT2, UINT2, true> {
+ static UINT2 ToUnsigned(INT2 value) {
+ return static_cast<UINT2>(value < 0 ? -value : value);
+ }
+ };
+
+ // This set of templates is very similar to the above templates, but
+ // for testing whether an integer is negative.
+ template <typename INT2, bool NEG2>
+ struct TestNegT {};
+ template <typename INT2>
+ struct TestNegT<INT2, false> {
+ static bool TestNeg(INT2 value) {
+ // value is unsigned, and can never be negative.
+ return false;
+ }
+ };
+ template <typename INT2>
+ struct TestNegT<INT2, true> {
+ static bool TestNeg(INT2 value) {
+ return value < 0;
+ }
+ };
+
+ 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 int kOutputBufSize = 3 * sizeof(INT) + 1;
+
+ // Allocate the whole string right away, we will right back to front, and
+ // then return the substr of what we ended up using.
+ STR outbuf(kOutputBufSize, 0);
+
+ bool is_neg = TestNegT<INT, NEG>::TestNeg(value);
+ // Even though is_neg will never be true when INT is parameterized as
+ // unsigned, even the presence of the unary operation causes a warning.
+ UINT res = ToUnsignedT<INT, UINT, NEG>::ToUnsigned(value);
+
+ for (typename STR::iterator it = outbuf.end();;) {
+ --it;
+ DCHECK(it != outbuf.begin());
+ *it = static_cast<typename STR::value_type>((res % 10) + '0');
+ res /= 10;
+
+ // We're done..
+ if (res == 0) {
+ if (is_neg) {
+ --it;
+ DCHECK(it != outbuf.begin());
+ *it = static_cast<typename STR::value_type>('-');
+ }
+ return STR(it, outbuf.end());
+ }
+ }
+ NOTREACHED();
+ return STR();
+ }
+};
+
+// 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* digit) {
+ if (c >= '0' && c < '0' + BASE) {
+ *digit = 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* 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* digit) {
+ return BaseCharToDigit<CHAR, BASE, BASE <= 10>::Convert(c, digit);
+}
+
+// There is an IsWhitespace 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 (!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 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 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 increment, value_type* output) {
+ *output += increment;
+ }
+ };
+
+ class Negative : public Base<Negative> {
+ public:
+ static bool CheckBounds(value_type* output, uint8 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 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;
+};
+
+typedef BaseIteratorRangeToNumberTraits<std::string::const_iterator, int, 10>
+ IteratorRangeToIntTraits;
+typedef BaseIteratorRangeToNumberTraits<string16::const_iterator, int, 10>
+ WideIteratorRangeToIntTraits;
+typedef BaseIteratorRangeToNumberTraits<std::string::const_iterator, int64, 10>
+ IteratorRangeToInt64Traits;
+typedef BaseIteratorRangeToNumberTraits<string16::const_iterator, int64, 10>
+ WideIteratorRangeToInt64Traits;
+
+typedef BaseIteratorRangeToNumberTraits<const char*, int, 10>
+ CharBufferToIntTraits;
+typedef BaseIteratorRangeToNumberTraits<const char16*, int, 10>
+ WideCharBufferToIntTraits;
+typedef BaseIteratorRangeToNumberTraits<const char*, int64, 10>
+ CharBufferToInt64Traits;
+typedef BaseIteratorRangeToNumberTraits<const char16*, int64, 10>
+ WideCharBufferToInt64Traits;
+
+template<typename ITERATOR>
+class BaseHexIteratorRangeToIntTraits
+ : public BaseIteratorRangeToNumberTraits<ITERATOR, int, 16> {
+ public:
+ // Allow parsing of 0xFFFFFFFF, which is technically an overflow
+ static unsigned int max() {
+ return std::numeric_limits<unsigned int>::max();
+ }
+};
+
+typedef BaseHexIteratorRangeToIntTraits<std::string::const_iterator>
+ HexIteratorRangeToIntTraits;
+typedef BaseHexIteratorRangeToIntTraits<const char*>
+ HexCharBufferToIntTraits;
+
+template<typename STR>
+bool HexStringToBytesT(const STR& input, std::vector<uint8>* 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 msb = 0; // most significant 4 bits
+ uint8 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;
+}
+
+} // namespace
+
+std::string IntToString(int value) {
+ return IntToStringT<std::string, int, unsigned int, true>::
+ IntToString(value);
+}
+
+string16 IntToString16(int value) {
+ return IntToStringT<string16, int, unsigned int, true>::
+ IntToString(value);
+}
+
+std::string UintToString(unsigned int value) {
+ return IntToStringT<std::string, unsigned int, unsigned int, false>::
+ IntToString(value);
+}
+
+string16 UintToString16(unsigned int value) {
+ return IntToStringT<string16, unsigned int, unsigned int, false>::
+ IntToString(value);
+}
+
+std::string Int64ToString(int64 value) {
+ return IntToStringT<std::string, int64, uint64, true>::
+ IntToString(value);
+}
+
+string16 Int64ToString16(int64 value) {
+ return IntToStringT<string16, int64, uint64, true>::IntToString(value);
+}
+
+std::string Uint64ToString(uint64 value) {
+ return IntToStringT<std::string, uint64, uint64, false>::
+ IntToString(value);
+}
+
+string16 Uint64ToString16(uint64 value) {
+ return IntToStringT<string16, uint64, uint64, false>::
+ IntToString(value);
+}
+
+std::string DoubleToString(double value) {
+ // According to g_fmt.cc, it is sufficient to declare a buffer of size 32.
+ char buffer[32];
+ dmg_fp::g_fmt(buffer, value);
+ return std::string(buffer);
+}
+
+bool StringToInt(const std::string& input, int* output) {
+ return IteratorRangeToNumber<IteratorRangeToIntTraits>::Invoke(input.begin(),
+ input.end(),
+ output);
+}
+
+bool StringToInt(std::string::const_iterator begin,
+ std::string::const_iterator end,
+ int* output) {
+ return IteratorRangeToNumber<IteratorRangeToIntTraits>::Invoke(begin,
+ end,
+ output);
+}
+
+#if !defined(STD_STRING_ITERATOR_IS_CHAR_POINTER)
+bool StringToInt(const char* begin, const char* end, int* output) {
+ return IteratorRangeToNumber<CharBufferToIntTraits>::Invoke(begin,
+ end,
+ output);
+}
+#endif
+
+bool StringToInt(const string16& input, int* output) {
+ return IteratorRangeToNumber<WideIteratorRangeToIntTraits>::Invoke(
+ input.begin(), input.end(), output);
+}
+
+bool StringToInt(string16::const_iterator begin,
+ string16::const_iterator end,
+ int* output) {
+ return IteratorRangeToNumber<WideIteratorRangeToIntTraits>::Invoke(begin,
+ end,
+ output);
+}
+
+#if !defined(BASE_STRING16_ITERATOR_IS_CHAR16_POINTER)
+bool StringToInt(const char16* begin, const char16* end, int* output) {
+ return IteratorRangeToNumber<WideCharBufferToIntTraits>::Invoke(begin,
+ end,
+ output);
+}
+#endif
+
+bool StringToInt64(const std::string& input, int64* output) {
+ return IteratorRangeToNumber<IteratorRangeToInt64Traits>::Invoke(
+ input.begin(), input.end(), output);
+}
+
+bool StringToInt64(std::string::const_iterator begin,
+ std::string::const_iterator end,
+ int64* output) {
+ return IteratorRangeToNumber<IteratorRangeToInt64Traits>::Invoke(begin,
+ end,
+ output);
+}
+
+#if !defined(STD_STRING_ITERATOR_IS_CHAR_POINTER)
+bool StringToInt64(const char* begin, const char* end, int64* output) {
+ return IteratorRangeToNumber<CharBufferToInt64Traits>::Invoke(begin,
+ end,
+ output);
+}
+#endif
+
+bool StringToInt64(const string16& input, int64* output) {
+ return IteratorRangeToNumber<WideIteratorRangeToInt64Traits>::Invoke(
+ input.begin(), input.end(), output);
+}
+
+bool StringToInt64(string16::const_iterator begin,
+ string16::const_iterator end,
+ int64* output) {
+ return IteratorRangeToNumber<WideIteratorRangeToInt64Traits>::Invoke(begin,
+ end,
+ output);
+}
+
+#if !defined(BASE_STRING16_ITERATOR_IS_CHAR16_POINTER)
+bool StringToInt64(const char16* begin, const char16* end, int64* output) {
+ return IteratorRangeToNumber<WideCharBufferToInt64Traits>::Invoke(begin,
+ end,
+ output);
+}
+#endif
+
+bool StringToDouble(const std::string& input, double* output) {
+ errno = 0; // Thread-safe? It is on at least Mac, Linux, and Windows.
+ char* endptr = NULL;
+ *output = dmg_fp::strtod(input.c_str(), &endptr);
+
+ // Cases to return false:
+ // - If errno is ERANGE, there was an overflow or underflow.
+ // - If the input string is empty, there was nothing to parse.
+ // - If endptr does not point to the end of the string, there are either
+ // characters remaining in the string after a parsed number, or the string
+ // does not begin with a parseable number. endptr is compared to the
+ // expected end given the string's stated length to correctly catch cases
+ // where the string contains embedded NUL characters.
+ // - If the first character is a space, there was leading whitespace
+ return errno == 0 &&
+ !input.empty() &&
+ input.c_str() + input.length() == endptr &&
+ !isspace(input[0]);
+}
+
+// Note: if you need to add String16ToDouble, first ask yourself if it's
+// really necessary. If it is, probably the best implementation here is to
+// convert to 8-bit and then use the 8-bit version.
+
+// Note: if you need to add an iterator range version of StringToDouble, first
+// ask yourself if it's really necessary. If it is, probably the best
+// implementation here is to instantiate a string and use the string version.
+
+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;
+}
+
+bool HexStringToInt(const std::string& input, int* output) {
+ return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke(
+ input.begin(), input.end(), output);
+}
+
+bool HexStringToInt(std::string::const_iterator begin,
+ std::string::const_iterator end,
+ int* output) {
+ return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke(begin,
+ end,
+ output);
+}
+
+#if !defined(STD_STRING_ITERATOR_IS_CHAR_POINTER)
+bool HexStringToInt(const char* begin, const char* end, int* output) {
+ return IteratorRangeToNumber<HexCharBufferToIntTraits>::Invoke(begin,
+ end,
+ output);
+}
+#endif
+
+bool HexStringToBytes(const std::string& input, std::vector<uint8>* output) {
+ return HexStringToBytesT(input, output);
+}
+
+} // namespace base