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 // Copyright 2012 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.
 
 #ifndef DOUBLE_CONVERSION_STRING_TO_DOUBLE_H_
 #define DOUBLE_CONVERSION_STRING_TO_DOUBLE_H_
 
 #include "utils.h"
 
 namespace arrow_vendored {
 namespace double_conversion {
 
 class StringToDoubleConverter {
  public:
   // Enumeration for allowing octals and ignoring junk when converting
   // strings to numbers.
   enum Flags {
     NO_FLAGS = 0,
     ALLOW_HEX = 1,
     ALLOW_OCTALS = 2,
     ALLOW_TRAILING_JUNK = 4,
     ALLOW_LEADING_SPACES = 8,
     ALLOW_TRAILING_SPACES = 16,
     ALLOW_SPACES_AFTER_SIGN = 32,
     ALLOW_CASE_INSENSITIVITY = 64,
     ALLOW_CASE_INSENSIBILITY = 64,  // Deprecated
     ALLOW_HEX_FLOATS = 128,
   };
 
   static const uc16 kNoSeparator = '\0';
 
   // Flags should be a bit-or combination of the possible Flags-enum.
   //  - NO_FLAGS: no special flags.
   //  - ALLOW_HEX: recognizes the prefix "0x". Hex numbers may only be integers.
   //      Ex: StringToDouble("0x1234") -> 4660.0
   //          In StringToDouble("0x1234.56") the characters ".56" are trailing
   //          junk. The result of the call is hence dependent on
   //          the ALLOW_TRAILING_JUNK flag and/or the junk value.
   //      With this flag "0x" is a junk-string. Even with ALLOW_TRAILING_JUNK,
   //      the string will not be parsed as "0" followed by junk.
   //
   //  - ALLOW_OCTALS: recognizes the prefix "0" for octals:
   //      If a sequence of octal digits starts with '0', then the number is
   //      read as octal integer. Octal numbers may only be integers.
   //      Ex: StringToDouble("01234") -> 668.0
   //          StringToDouble("012349") -> 12349.0  // Not a sequence of octal
   //                                               // digits.
   //          In StringToDouble("01234.56") the characters ".56" are trailing
   //          junk. The result of the call is hence dependent on
   //          the ALLOW_TRAILING_JUNK flag and/or the junk value.
   //          In StringToDouble("01234e56") the characters "e56" are trailing
   //          junk, too.
   //  - ALLOW_TRAILING_JUNK: ignore trailing characters that are not part of
   //      a double literal.
   //  - ALLOW_LEADING_SPACES: skip over leading whitespace, including spaces,
   //                          new-lines, and tabs.
   //  - ALLOW_TRAILING_SPACES: ignore trailing whitespace.
   //  - ALLOW_SPACES_AFTER_SIGN: ignore whitespace after the sign.
   //       Ex: StringToDouble("-   123.2") -> -123.2.
   //           StringToDouble("+   123.2") -> 123.2
   //  - ALLOW_CASE_INSENSITIVITY: ignore case of characters for special values:
   //      infinity and nan.
   //  - ALLOW_HEX_FLOATS: allows hexadecimal float literals.
   //      This *must* start with "0x" and separate the exponent with "p".
   //      Examples: 0x1.2p3 == 9.0
   //                0x10.1p0 == 16.0625
   //      ALLOW_HEX and ALLOW_HEX_FLOATS are indented.
   //
   // empty_string_value is returned when an empty string is given as input.
   // If ALLOW_LEADING_SPACES or ALLOW_TRAILING_SPACES are set, then a string
   // containing only spaces is converted to the 'empty_string_value', too.
   //
   // junk_string_value is returned when
   //  a) ALLOW_TRAILING_JUNK is not set, and a junk character (a character not
   //     part of a double-literal) is found.
   //  b) ALLOW_TRAILING_JUNK is set, but the string does not start with a
   //     double literal.
   //
   // infinity_symbol and nan_symbol are strings that are used to detect
   // inputs that represent infinity and NaN. They can be null, in which case
   // they are ignored.
   // The conversion routine first reads any possible signs. Then it compares the
   // following character of the input-string with the first character of
   // the infinity, and nan-symbol. If either matches, the function assumes, that
   // a match has been found, and expects the following input characters to match
   // the remaining characters of the special-value symbol.
   // This means that the following restrictions apply to special-value symbols:
   //  - they must not start with signs ('+', or '-'),
   //  - they must not have the same first character.
   //  - they must not start with digits.
   //
   // If the separator character is not kNoSeparator, then that specific
   // character is ignored when in between two valid digits of the significant.
   // It is not allowed to appear in the exponent.
   // It is not allowed to lead or trail the number.
   // It is not allowed to appear twice next to each other.
   //
   // Examples:
   //  flags = ALLOW_HEX | ALLOW_TRAILING_JUNK,
   //  empty_string_value = 0.0,
   //  junk_string_value = NaN,
   //  infinity_symbol = "infinity",
   //  nan_symbol = "nan":
   //    StringToDouble("0x1234") -> 4660.0.
   //    StringToDouble("0x1234K") -> 4660.0.
   //    StringToDouble("") -> 0.0  // empty_string_value.
   //    StringToDouble(" ") -> NaN  // junk_string_value.
   //    StringToDouble(" 1") -> NaN  // junk_string_value.
   //    StringToDouble("0x") -> NaN  // junk_string_value.
   //    StringToDouble("-123.45") -> -123.45.
   //    StringToDouble("--123.45") -> NaN  // junk_string_value.
   //    StringToDouble("123e45") -> 123e45.
   //    StringToDouble("123E45") -> 123e45.
   //    StringToDouble("123e+45") -> 123e45.
   //    StringToDouble("123E-45") -> 123e-45.
   //    StringToDouble("123e") -> 123.0  // trailing junk ignored.
   //    StringToDouble("123e-") -> 123.0  // trailing junk ignored.
   //    StringToDouble("+NaN") -> NaN  // NaN string literal.
   //    StringToDouble("-infinity") -> -inf.  // infinity literal.
   //    StringToDouble("Infinity") -> NaN  // junk_string_value.
   //
   //  flags = ALLOW_OCTAL | ALLOW_LEADING_SPACES,
   //  empty_string_value = 0.0,
   //  junk_string_value = NaN,
   //  infinity_symbol = NULL,
   //  nan_symbol = NULL:
   //    StringToDouble("0x1234") -> NaN  // junk_string_value.
   //    StringToDouble("01234") -> 668.0.
   //    StringToDouble("") -> 0.0  // empty_string_value.
   //    StringToDouble(" ") -> 0.0  // empty_string_value.
   //    StringToDouble(" 1") -> 1.0
   //    StringToDouble("0x") -> NaN  // junk_string_value.
   //    StringToDouble("0123e45") -> NaN  // junk_string_value.
   //    StringToDouble("01239E45") -> 1239e45.
   //    StringToDouble("-infinity") -> NaN  // junk_string_value.
   //    StringToDouble("NaN") -> NaN  // junk_string_value.
   //
   //  flags = NO_FLAGS,
   //  separator = ' ':
   //    StringToDouble("1 2 3 4") -> 1234.0
   //    StringToDouble("1  2") -> NaN // junk_string_value
   //    StringToDouble("1 000 000.0") -> 1000000.0
   //    StringToDouble("1.000 000") -> 1.0
   //    StringToDouble("1.0e1 000") -> NaN // junk_string_value
   StringToDoubleConverter(int flags,
                           double empty_string_value,
                           double junk_string_value,
                           const char* infinity_symbol,
                           const char* nan_symbol,
                           uc16 separator = kNoSeparator)
       : flags_(flags),
         empty_string_value_(empty_string_value),
         junk_string_value_(junk_string_value),
         infinity_symbol_(infinity_symbol),
         nan_symbol_(nan_symbol),
         separator_(separator) {
   }
 
   // Performs the conversion.
   // The output parameter 'processed_characters_count' is set to the number
   // of characters that have been processed to read the number.
   // Spaces than are processed with ALLOW_{LEADING|TRAILING}_SPACES are included
   // in the 'processed_characters_count'. Trailing junk is never included.
   double StringToDouble(const char* buffer,
                         int length,
                         int* processed_characters_count) const;
 
   // Same as StringToDouble above but for 16 bit characters.
   double StringToDouble(const uc16* buffer,
                         int length,
                         int* processed_characters_count) const;
 
   // Same as StringToDouble but reads a float.
   // Note that this is not equivalent to static_cast<float>(StringToDouble(...))
   // due to potential double-rounding.
   float StringToFloat(const char* buffer,
                       int length,
                       int* processed_characters_count) const;
 
   // Same as StringToFloat above but for 16 bit characters.
   float StringToFloat(const uc16* buffer,
                       int length,
                       int* processed_characters_count) const;
 
   // Same as StringToDouble for T = double, and StringToFloat for T = float.
   template <typename T>
   T StringTo(const char* buffer,
              int length,
              int* processed_characters_count) const;
 
   // Same as StringTo above but for 16 bit characters.
   template <typename T>
   T StringTo(const uc16* buffer,
              int length,
              int* processed_characters_count) const;
 
  private:
   const int flags_;
   const double empty_string_value_;
   const double junk_string_value_;
   const char* const infinity_symbol_;
   const char* const nan_symbol_;
   const uc16 separator_;
 
   template <class Iterator>
   double StringToIeee(Iterator start_pointer,
                       int length,
                       bool read_as_double,
                       int* processed_characters_count) const;
 
   DOUBLE_CONVERSION_DISALLOW_IMPLICIT_CONSTRUCTORS(StringToDoubleConverter);
 };
 
 }  // namespace double_conversion
 }  // namespace arrow_vendored
 
 #endif  // DOUBLE_CONVERSION_STRING_TO_DOUBLE_H_

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