summaryrefslogtreecommitdiffstats
path: root/mfbt/double-conversion/double-conversion/string-to-double.cc
diff options
context:
space:
mode:
Diffstat (limited to 'mfbt/double-conversion/double-conversion/string-to-double.cc')
-rw-r--r--mfbt/double-conversion/double-conversion/string-to-double.cc818
1 files changed, 818 insertions, 0 deletions
diff --git a/mfbt/double-conversion/double-conversion/string-to-double.cc b/mfbt/double-conversion/double-conversion/string-to-double.cc
new file mode 100644
index 0000000000..972956ca69
--- /dev/null
+++ b/mfbt/double-conversion/double-conversion/string-to-double.cc
@@ -0,0 +1,818 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <climits>
+#include <locale>
+#include <cmath>
+
+#include "string-to-double.h"
+
+#include "ieee.h"
+#include "strtod.h"
+#include "utils.h"
+
+#ifdef _MSC_VER
+# if _MSC_VER >= 1900
+// Fix MSVC >= 2015 (_MSC_VER == 1900) warning
+// C4244: 'argument': conversion from 'const uc16' to 'char', possible loss of data
+// against Advance and friends, when instantiated with **it as char, not uc16.
+ __pragma(warning(disable: 4244))
+# endif
+# if _MSC_VER <= 1700 // VS2012, see IsDecimalDigitForRadix warning fix, below
+# define VS2012_RADIXWARN
+# endif
+#endif
+
+namespace double_conversion {
+
+namespace {
+
+inline char ToLower(char ch) {
+ static const std::ctype<char>& cType =
+ std::use_facet<std::ctype<char> >(std::locale::classic());
+ return cType.tolower(ch);
+}
+
+inline char Pass(char ch) {
+ return ch;
+}
+
+template <class Iterator, class Converter>
+static inline bool ConsumeSubStringImpl(Iterator* current,
+ Iterator end,
+ const char* substring,
+ Converter converter) {
+ DOUBLE_CONVERSION_ASSERT(converter(**current) == *substring);
+ for (substring++; *substring != '\0'; substring++) {
+ ++*current;
+ if (*current == end || converter(**current) != *substring) {
+ return false;
+ }
+ }
+ ++*current;
+ return true;
+}
+
+// Consumes the given substring from the iterator.
+// Returns false, if the substring does not match.
+template <class Iterator>
+static bool ConsumeSubString(Iterator* current,
+ Iterator end,
+ const char* substring,
+ bool allow_case_insensitivity) {
+ if (allow_case_insensitivity) {
+ return ConsumeSubStringImpl(current, end, substring, ToLower);
+ } else {
+ return ConsumeSubStringImpl(current, end, substring, Pass);
+ }
+}
+
+// Consumes first character of the str is equal to ch
+inline bool ConsumeFirstCharacter(char ch,
+ const char* str,
+ bool case_insensitivity) {
+ return case_insensitivity ? ToLower(ch) == str[0] : ch == str[0];
+}
+} // namespace
+
+// Maximum number of significant digits in decimal representation.
+// The longest possible double in decimal representation is
+// (2^53 - 1) * 2 ^ -1074 that is (2 ^ 53 - 1) * 5 ^ 1074 / 10 ^ 1074
+// (768 digits). If we parse a number whose first digits are equal to a
+// mean of 2 adjacent doubles (that could have up to 769 digits) the result
+// must be rounded to the bigger one unless the tail consists of zeros, so
+// we don't need to preserve all the digits.
+const int kMaxSignificantDigits = 772;
+
+
+static const char kWhitespaceTable7[] = { 32, 13, 10, 9, 11, 12 };
+static const int kWhitespaceTable7Length = DOUBLE_CONVERSION_ARRAY_SIZE(kWhitespaceTable7);
+
+
+static const uc16 kWhitespaceTable16[] = {
+ 160, 8232, 8233, 5760, 6158, 8192, 8193, 8194, 8195,
+ 8196, 8197, 8198, 8199, 8200, 8201, 8202, 8239, 8287, 12288, 65279
+};
+static const int kWhitespaceTable16Length = DOUBLE_CONVERSION_ARRAY_SIZE(kWhitespaceTable16);
+
+
+static bool isWhitespace(int x) {
+ if (x < 128) {
+ for (int i = 0; i < kWhitespaceTable7Length; i++) {
+ if (kWhitespaceTable7[i] == x) return true;
+ }
+ } else {
+ for (int i = 0; i < kWhitespaceTable16Length; i++) {
+ if (kWhitespaceTable16[i] == x) return true;
+ }
+ }
+ return false;
+}
+
+
+// Returns true if a nonspace found and false if the end has reached.
+template <class Iterator>
+static inline bool AdvanceToNonspace(Iterator* current, Iterator end) {
+ while (*current != end) {
+ if (!isWhitespace(**current)) return true;
+ ++*current;
+ }
+ return false;
+}
+
+
+static bool isDigit(int x, int radix) {
+ return (x >= '0' && x <= '9' && x < '0' + radix)
+ || (radix > 10 && x >= 'a' && x < 'a' + radix - 10)
+ || (radix > 10 && x >= 'A' && x < 'A' + radix - 10);
+}
+
+
+static double SignedZero(bool sign) {
+ return sign ? -0.0 : 0.0;
+}
+
+
+// Returns true if 'c' is a decimal digit that is valid for the given radix.
+//
+// The function is small and could be inlined, but VS2012 emitted a warning
+// because it constant-propagated the radix and concluded that the last
+// condition was always true. Moving it into a separate function and
+// suppressing optimisation keeps the compiler from warning.
+#ifdef VS2012_RADIXWARN
+#pragma optimize("",off)
+static bool IsDecimalDigitForRadix(int c, int radix) {
+ return '0' <= c && c <= '9' && (c - '0') < radix;
+}
+#pragma optimize("",on)
+#else
+static bool inline IsDecimalDigitForRadix(int c, int radix) {
+ return '0' <= c && c <= '9' && (c - '0') < radix;
+}
+#endif
+// Returns true if 'c' is a character digit that is valid for the given radix.
+// The 'a_character' should be 'a' or 'A'.
+//
+// The function is small and could be inlined, but VS2012 emitted a warning
+// because it constant-propagated the radix and concluded that the first
+// condition was always false. By moving it into a separate function the
+// compiler wouldn't warn anymore.
+static bool IsCharacterDigitForRadix(int c, int radix, char a_character) {
+ return radix > 10 && c >= a_character && c < a_character + radix - 10;
+}
+
+// Returns true, when the iterator is equal to end.
+template<class Iterator>
+static bool Advance (Iterator* it, uc16 separator, int base, Iterator& end) {
+ if (separator == StringToDoubleConverter::kNoSeparator) {
+ ++(*it);
+ return *it == end;
+ }
+ if (!isDigit(**it, base)) {
+ ++(*it);
+ return *it == end;
+ }
+ ++(*it);
+ if (*it == end) return true;
+ if (*it + 1 == end) return false;
+ if (**it == separator && isDigit(*(*it + 1), base)) {
+ ++(*it);
+ }
+ return *it == end;
+}
+
+// Checks whether the string in the range start-end is a hex-float string.
+// This function assumes that the leading '0x'/'0X' is already consumed.
+//
+// Hex float strings are of one of the following forms:
+// - hex_digits+ 'p' ('+'|'-')? exponent_digits+
+// - hex_digits* '.' hex_digits+ 'p' ('+'|'-')? exponent_digits+
+// - hex_digits+ '.' 'p' ('+'|'-')? exponent_digits+
+template<class Iterator>
+static bool IsHexFloatString(Iterator start,
+ Iterator end,
+ uc16 separator,
+ bool allow_trailing_junk) {
+ DOUBLE_CONVERSION_ASSERT(start != end);
+
+ Iterator current = start;
+
+ bool saw_digit = false;
+ while (isDigit(*current, 16)) {
+ saw_digit = true;
+ if (Advance(&current, separator, 16, end)) return false;
+ }
+ if (*current == '.') {
+ if (Advance(&current, separator, 16, end)) return false;
+ while (isDigit(*current, 16)) {
+ saw_digit = true;
+ if (Advance(&current, separator, 16, end)) return false;
+ }
+ }
+ if (!saw_digit) return false;
+ if (*current != 'p' && *current != 'P') return false;
+ if (Advance(&current, separator, 16, end)) return false;
+ if (*current == '+' || *current == '-') {
+ if (Advance(&current, separator, 16, end)) return false;
+ }
+ if (!isDigit(*current, 10)) return false;
+ if (Advance(&current, separator, 16, end)) return true;
+ while (isDigit(*current, 10)) {
+ if (Advance(&current, separator, 16, end)) return true;
+ }
+ return allow_trailing_junk || !AdvanceToNonspace(&current, end);
+}
+
+
+// Parsing integers with radix 2, 4, 8, 16, 32. Assumes current != end.
+//
+// If parse_as_hex_float is true, then the string must be a valid
+// hex-float.
+template <int radix_log_2, class Iterator>
+static double RadixStringToIeee(Iterator* current,
+ Iterator end,
+ bool sign,
+ uc16 separator,
+ bool parse_as_hex_float,
+ bool allow_trailing_junk,
+ double junk_string_value,
+ bool read_as_double,
+ bool* result_is_junk) {
+ DOUBLE_CONVERSION_ASSERT(*current != end);
+ DOUBLE_CONVERSION_ASSERT(!parse_as_hex_float ||
+ IsHexFloatString(*current, end, separator, allow_trailing_junk));
+
+ const int kDoubleSize = Double::kSignificandSize;
+ const int kSingleSize = Single::kSignificandSize;
+ const int kSignificandSize = read_as_double? kDoubleSize: kSingleSize;
+
+ *result_is_junk = true;
+
+ int64_t number = 0;
+ int exponent = 0;
+ const int radix = (1 << radix_log_2);
+ // Whether we have encountered a '.' and are parsing the decimal digits.
+ // Only relevant if parse_as_hex_float is true.
+ bool post_decimal = false;
+
+ // Skip leading 0s.
+ while (**current == '0') {
+ if (Advance(current, separator, radix, end)) {
+ *result_is_junk = false;
+ return SignedZero(sign);
+ }
+ }
+
+ while (true) {
+ int digit;
+ if (IsDecimalDigitForRadix(**current, radix)) {
+ digit = static_cast<char>(**current) - '0';
+ if (post_decimal) exponent -= radix_log_2;
+ } else if (IsCharacterDigitForRadix(**current, radix, 'a')) {
+ digit = static_cast<char>(**current) - 'a' + 10;
+ if (post_decimal) exponent -= radix_log_2;
+ } else if (IsCharacterDigitForRadix(**current, radix, 'A')) {
+ digit = static_cast<char>(**current) - 'A' + 10;
+ if (post_decimal) exponent -= radix_log_2;
+ } else if (parse_as_hex_float && **current == '.') {
+ post_decimal = true;
+ Advance(current, separator, radix, end);
+ DOUBLE_CONVERSION_ASSERT(*current != end);
+ continue;
+ } else if (parse_as_hex_float && (**current == 'p' || **current == 'P')) {
+ break;
+ } else {
+ if (allow_trailing_junk || !AdvanceToNonspace(current, end)) {
+ break;
+ } else {
+ return junk_string_value;
+ }
+ }
+
+ number = number * radix + digit;
+ int overflow = static_cast<int>(number >> kSignificandSize);
+ if (overflow != 0) {
+ // Overflow occurred. Need to determine which direction to round the
+ // result.
+ int overflow_bits_count = 1;
+ while (overflow > 1) {
+ overflow_bits_count++;
+ overflow >>= 1;
+ }
+
+ int dropped_bits_mask = ((1 << overflow_bits_count) - 1);
+ int dropped_bits = static_cast<int>(number) & dropped_bits_mask;
+ number >>= overflow_bits_count;
+ exponent += overflow_bits_count;
+
+ bool zero_tail = true;
+ for (;;) {
+ if (Advance(current, separator, radix, end)) break;
+ if (parse_as_hex_float && **current == '.') {
+ // Just run over the '.'. We are just trying to see whether there is
+ // a non-zero digit somewhere.
+ Advance(current, separator, radix, end);
+ DOUBLE_CONVERSION_ASSERT(*current != end);
+ post_decimal = true;
+ }
+ if (!isDigit(**current, radix)) break;
+ zero_tail = zero_tail && **current == '0';
+ if (!post_decimal) exponent += radix_log_2;
+ }
+
+ if (!parse_as_hex_float &&
+ !allow_trailing_junk &&
+ AdvanceToNonspace(current, end)) {
+ return junk_string_value;
+ }
+
+ int middle_value = (1 << (overflow_bits_count - 1));
+ if (dropped_bits > middle_value) {
+ number++; // Rounding up.
+ } else if (dropped_bits == middle_value) {
+ // Rounding to even to consistency with decimals: half-way case rounds
+ // up if significant part is odd and down otherwise.
+ if ((number & 1) != 0 || !zero_tail) {
+ number++; // Rounding up.
+ }
+ }
+
+ // Rounding up may cause overflow.
+ if ((number & ((int64_t)1 << kSignificandSize)) != 0) {
+ exponent++;
+ number >>= 1;
+ }
+ break;
+ }
+ if (Advance(current, separator, radix, end)) break;
+ }
+
+ DOUBLE_CONVERSION_ASSERT(number < ((int64_t)1 << kSignificandSize));
+ DOUBLE_CONVERSION_ASSERT(static_cast<int64_t>(static_cast<double>(number)) == number);
+
+ *result_is_junk = false;
+
+ if (parse_as_hex_float) {
+ DOUBLE_CONVERSION_ASSERT(**current == 'p' || **current == 'P');
+ Advance(current, separator, radix, end);
+ DOUBLE_CONVERSION_ASSERT(*current != end);
+ bool is_negative = false;
+ if (**current == '+') {
+ Advance(current, separator, radix, end);
+ DOUBLE_CONVERSION_ASSERT(*current != end);
+ } else if (**current == '-') {
+ is_negative = true;
+ Advance(current, separator, radix, end);
+ DOUBLE_CONVERSION_ASSERT(*current != end);
+ }
+ int written_exponent = 0;
+ while (IsDecimalDigitForRadix(**current, 10)) {
+ // No need to read exponents if they are too big. That could potentially overflow
+ // the `written_exponent` variable.
+ if (abs(written_exponent) <= 100 * Double::kMaxExponent) {
+ written_exponent = 10 * written_exponent + **current - '0';
+ }
+ if (Advance(current, separator, radix, end)) break;
+ }
+ if (is_negative) written_exponent = -written_exponent;
+ exponent += written_exponent;
+ }
+
+ if (exponent == 0 || number == 0) {
+ if (sign) {
+ if (number == 0) return -0.0;
+ number = -number;
+ }
+ return static_cast<double>(number);
+ }
+
+ DOUBLE_CONVERSION_ASSERT(number != 0);
+ double result = Double(DiyFp(number, exponent)).value();
+ return sign ? -result : result;
+}
+
+template <class Iterator>
+double StringToDoubleConverter::StringToIeee(
+ Iterator input,
+ int length,
+ bool read_as_double,
+ int* processed_characters_count) const {
+ Iterator current = input;
+ Iterator end = input + length;
+
+ *processed_characters_count = 0;
+
+ const bool allow_trailing_junk = (flags_ & ALLOW_TRAILING_JUNK) != 0;
+ const bool allow_leading_spaces = (flags_ & ALLOW_LEADING_SPACES) != 0;
+ const bool allow_trailing_spaces = (flags_ & ALLOW_TRAILING_SPACES) != 0;
+ const bool allow_spaces_after_sign = (flags_ & ALLOW_SPACES_AFTER_SIGN) != 0;
+ const bool allow_case_insensitivity = (flags_ & ALLOW_CASE_INSENSITIVITY) != 0;
+
+ // To make sure that iterator dereferencing is valid the following
+ // convention is used:
+ // 1. Each '++current' statement is followed by check for equality to 'end'.
+ // 2. If AdvanceToNonspace returned false then current == end.
+ // 3. If 'current' becomes equal to 'end' the function returns or goes to
+ // 'parsing_done'.
+ // 4. 'current' is not dereferenced after the 'parsing_done' label.
+ // 5. Code before 'parsing_done' may rely on 'current != end'.
+ if (current == end) return empty_string_value_;
+
+ if (allow_leading_spaces || allow_trailing_spaces) {
+ if (!AdvanceToNonspace(&current, end)) {
+ *processed_characters_count = static_cast<int>(current - input);
+ return empty_string_value_;
+ }
+ if (!allow_leading_spaces && (input != current)) {
+ // No leading spaces allowed, but AdvanceToNonspace moved forward.
+ return junk_string_value_;
+ }
+ }
+
+ // Exponent will be adjusted if insignificant digits of the integer part
+ // or insignificant leading zeros of the fractional part are dropped.
+ int exponent = 0;
+ int significant_digits = 0;
+ int insignificant_digits = 0;
+ bool nonzero_digit_dropped = false;
+
+ bool sign = false;
+
+ if (*current == '+' || *current == '-') {
+ sign = (*current == '-');
+ ++current;
+ Iterator next_non_space = current;
+ // Skip following spaces (if allowed).
+ if (!AdvanceToNonspace(&next_non_space, end)) return junk_string_value_;
+ if (!allow_spaces_after_sign && (current != next_non_space)) {
+ return junk_string_value_;
+ }
+ current = next_non_space;
+ }
+
+ if (infinity_symbol_ != DOUBLE_CONVERSION_NULLPTR) {
+ if (ConsumeFirstCharacter(*current, infinity_symbol_, allow_case_insensitivity)) {
+ if (!ConsumeSubString(&current, end, infinity_symbol_, allow_case_insensitivity)) {
+ return junk_string_value_;
+ }
+
+ if (!(allow_trailing_spaces || allow_trailing_junk) && (current != end)) {
+ return junk_string_value_;
+ }
+ if (!allow_trailing_junk && AdvanceToNonspace(&current, end)) {
+ return junk_string_value_;
+ }
+
+ *processed_characters_count = static_cast<int>(current - input);
+ return sign ? -Double::Infinity() : Double::Infinity();
+ }
+ }
+
+ if (nan_symbol_ != DOUBLE_CONVERSION_NULLPTR) {
+ if (ConsumeFirstCharacter(*current, nan_symbol_, allow_case_insensitivity)) {
+ if (!ConsumeSubString(&current, end, nan_symbol_, allow_case_insensitivity)) {
+ return junk_string_value_;
+ }
+
+ if (!(allow_trailing_spaces || allow_trailing_junk) && (current != end)) {
+ return junk_string_value_;
+ }
+ if (!allow_trailing_junk && AdvanceToNonspace(&current, end)) {
+ return junk_string_value_;
+ }
+
+ *processed_characters_count = static_cast<int>(current - input);
+ return sign ? -Double::NaN() : Double::NaN();
+ }
+ }
+
+ bool leading_zero = false;
+ if (*current == '0') {
+ if (Advance(&current, separator_, 10, end)) {
+ *processed_characters_count = static_cast<int>(current - input);
+ return SignedZero(sign);
+ }
+
+ leading_zero = true;
+
+ // It could be hexadecimal value.
+ if (((flags_ & ALLOW_HEX) || (flags_ & ALLOW_HEX_FLOATS)) &&
+ (*current == 'x' || *current == 'X')) {
+ ++current;
+
+ if (current == end) return junk_string_value_; // "0x"
+
+ bool parse_as_hex_float = (flags_ & ALLOW_HEX_FLOATS) &&
+ IsHexFloatString(current, end, separator_, allow_trailing_junk);
+
+ if (!parse_as_hex_float && !isDigit(*current, 16)) {
+ return junk_string_value_;
+ }
+
+ bool result_is_junk;
+ double result = RadixStringToIeee<4>(&current,
+ end,
+ sign,
+ separator_,
+ parse_as_hex_float,
+ allow_trailing_junk,
+ junk_string_value_,
+ read_as_double,
+ &result_is_junk);
+ if (!result_is_junk) {
+ if (allow_trailing_spaces) AdvanceToNonspace(&current, end);
+ *processed_characters_count = static_cast<int>(current - input);
+ }
+ return result;
+ }
+
+ // Ignore leading zeros in the integer part.
+ while (*current == '0') {
+ if (Advance(&current, separator_, 10, end)) {
+ *processed_characters_count = static_cast<int>(current - input);
+ return SignedZero(sign);
+ }
+ }
+ }
+
+ bool octal = leading_zero && (flags_ & ALLOW_OCTALS) != 0;
+
+ // The longest form of simplified number is: "-<significant digits>.1eXXX\0".
+ const int kBufferSize = kMaxSignificantDigits + 10;
+ DOUBLE_CONVERSION_STACK_UNINITIALIZED char
+ buffer[kBufferSize]; // NOLINT: size is known at compile time.
+ int buffer_pos = 0;
+
+ // Copy significant digits of the integer part (if any) to the buffer.
+ while (*current >= '0' && *current <= '9') {
+ if (significant_digits < kMaxSignificantDigits) {
+ DOUBLE_CONVERSION_ASSERT(buffer_pos < kBufferSize);
+ buffer[buffer_pos++] = static_cast<char>(*current);
+ significant_digits++;
+ // Will later check if it's an octal in the buffer.
+ } else {
+ insignificant_digits++; // Move the digit into the exponential part.
+ nonzero_digit_dropped = nonzero_digit_dropped || *current != '0';
+ }
+ octal = octal && *current < '8';
+ if (Advance(&current, separator_, 10, end)) goto parsing_done;
+ }
+
+ if (significant_digits == 0) {
+ octal = false;
+ }
+
+ if (*current == '.') {
+ if (octal && !allow_trailing_junk) return junk_string_value_;
+ if (octal) goto parsing_done;
+
+ if (Advance(&current, separator_, 10, end)) {
+ if (significant_digits == 0 && !leading_zero) {
+ return junk_string_value_;
+ } else {
+ goto parsing_done;
+ }
+ }
+
+ if (significant_digits == 0) {
+ // octal = false;
+ // Integer part consists of 0 or is absent. Significant digits start after
+ // leading zeros (if any).
+ while (*current == '0') {
+ if (Advance(&current, separator_, 10, end)) {
+ *processed_characters_count = static_cast<int>(current - input);
+ return SignedZero(sign);
+ }
+ exponent--; // Move this 0 into the exponent.
+ }
+ }
+
+ // There is a fractional part.
+ // We don't emit a '.', but adjust the exponent instead.
+ while (*current >= '0' && *current <= '9') {
+ if (significant_digits < kMaxSignificantDigits) {
+ DOUBLE_CONVERSION_ASSERT(buffer_pos < kBufferSize);
+ buffer[buffer_pos++] = static_cast<char>(*current);
+ significant_digits++;
+ exponent--;
+ } else {
+ // Ignore insignificant digits in the fractional part.
+ nonzero_digit_dropped = nonzero_digit_dropped || *current != '0';
+ }
+ if (Advance(&current, separator_, 10, end)) goto parsing_done;
+ }
+ }
+
+ if (!leading_zero && exponent == 0 && significant_digits == 0) {
+ // If leading_zeros is true then the string contains zeros.
+ // If exponent < 0 then string was [+-]\.0*...
+ // If significant_digits != 0 the string is not equal to 0.
+ // Otherwise there are no digits in the string.
+ return junk_string_value_;
+ }
+
+ // Parse exponential part.
+ if (*current == 'e' || *current == 'E') {
+ if (octal && !allow_trailing_junk) return junk_string_value_;
+ if (octal) goto parsing_done;
+ Iterator junk_begin = current;
+ ++current;
+ if (current == end) {
+ if (allow_trailing_junk) {
+ current = junk_begin;
+ goto parsing_done;
+ } else {
+ return junk_string_value_;
+ }
+ }
+ char exponen_sign = '+';
+ if (*current == '+' || *current == '-') {
+ exponen_sign = static_cast<char>(*current);
+ ++current;
+ if (current == end) {
+ if (allow_trailing_junk) {
+ current = junk_begin;
+ goto parsing_done;
+ } else {
+ return junk_string_value_;
+ }
+ }
+ }
+
+ if (current == end || *current < '0' || *current > '9') {
+ if (allow_trailing_junk) {
+ current = junk_begin;
+ goto parsing_done;
+ } else {
+ return junk_string_value_;
+ }
+ }
+
+ const int max_exponent = INT_MAX / 2;
+ DOUBLE_CONVERSION_ASSERT(-max_exponent / 2 <= exponent && exponent <= max_exponent / 2);
+ int num = 0;
+ do {
+ // Check overflow.
+ int digit = *current - '0';
+ if (num >= max_exponent / 10
+ && !(num == max_exponent / 10 && digit <= max_exponent % 10)) {
+ num = max_exponent;
+ } else {
+ num = num * 10 + digit;
+ }
+ ++current;
+ } while (current != end && *current >= '0' && *current <= '9');
+
+ exponent += (exponen_sign == '-' ? -num : num);
+ }
+
+ if (!(allow_trailing_spaces || allow_trailing_junk) && (current != end)) {
+ return junk_string_value_;
+ }
+ if (!allow_trailing_junk && AdvanceToNonspace(&current, end)) {
+ return junk_string_value_;
+ }
+ if (allow_trailing_spaces) {
+ AdvanceToNonspace(&current, end);
+ }
+
+ parsing_done:
+ exponent += insignificant_digits;
+
+ if (octal) {
+ double result;
+ bool result_is_junk;
+ char* start = buffer;
+ result = RadixStringToIeee<3>(&start,
+ buffer + buffer_pos,
+ sign,
+ separator_,
+ false, // Don't parse as hex_float.
+ allow_trailing_junk,
+ junk_string_value_,
+ read_as_double,
+ &result_is_junk);
+ DOUBLE_CONVERSION_ASSERT(!result_is_junk);
+ *processed_characters_count = static_cast<int>(current - input);
+ return result;
+ }
+
+ if (nonzero_digit_dropped) {
+ buffer[buffer_pos++] = '1';
+ exponent--;
+ }
+
+ DOUBLE_CONVERSION_ASSERT(buffer_pos < kBufferSize);
+ buffer[buffer_pos] = '\0';
+
+ // Code above ensures there are no leading zeros and the buffer has fewer than
+ // kMaxSignificantDecimalDigits characters. Trim trailing zeros.
+ Vector<const char> chars(buffer, buffer_pos);
+ chars = TrimTrailingZeros(chars);
+ exponent += buffer_pos - chars.length();
+
+ double converted;
+ if (read_as_double) {
+ converted = StrtodTrimmed(chars, exponent);
+ } else {
+ converted = StrtofTrimmed(chars, exponent);
+ }
+ *processed_characters_count = static_cast<int>(current - input);
+ return sign? -converted: converted;
+}
+
+
+double StringToDoubleConverter::StringToDouble(
+ const char* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return StringToIeee(buffer, length, true, processed_characters_count);
+}
+
+
+double StringToDoubleConverter::StringToDouble(
+ const uc16* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return StringToIeee(buffer, length, true, processed_characters_count);
+}
+
+
+float StringToDoubleConverter::StringToFloat(
+ const char* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return static_cast<float>(StringToIeee(buffer, length, false,
+ processed_characters_count));
+}
+
+
+float StringToDoubleConverter::StringToFloat(
+ const uc16* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return static_cast<float>(StringToIeee(buffer, length, false,
+ processed_characters_count));
+}
+
+
+template<>
+double StringToDoubleConverter::StringTo<double>(
+ const char* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return StringToDouble(buffer, length, processed_characters_count);
+}
+
+
+template<>
+float StringToDoubleConverter::StringTo<float>(
+ const char* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return StringToFloat(buffer, length, processed_characters_count);
+}
+
+
+template<>
+double StringToDoubleConverter::StringTo<double>(
+ const uc16* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return StringToDouble(buffer, length, processed_characters_count);
+}
+
+
+template<>
+float StringToDoubleConverter::StringTo<float>(
+ const uc16* buffer,
+ int length,
+ int* processed_characters_count) const {
+ return StringToFloat(buffer, length, processed_characters_count);
+}
+
+} // namespace double_conversion