| // 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. | |
| namespace double_conversion { | |
| class DoubleToStringConverter { | |
| public: | |
| // When calling ToFixed with a double > 10^kMaxFixedDigitsBeforePoint | |
| // or a requested_digits parameter > kMaxFixedDigitsAfterPoint then the | |
| // function returns false. | |
| static const int kMaxFixedDigitsBeforePoint = 60; | |
| static const int kMaxFixedDigitsAfterPoint = 60; | |
| // When calling ToExponential with a requested_digits | |
| // parameter > kMaxExponentialDigits then the function returns false. | |
| static const int kMaxExponentialDigits = 120; | |
| // When calling ToPrecision with a requested_digits | |
| // parameter < kMinPrecisionDigits or requested_digits > kMaxPrecisionDigits | |
| // then the function returns false. | |
| static const int kMinPrecisionDigits = 1; | |
| static const int kMaxPrecisionDigits = 120; | |
| enum Flags { | |
| NO_FLAGS = 0, | |
| EMIT_POSITIVE_EXPONENT_SIGN = 1, | |
| EMIT_TRAILING_DECIMAL_POINT = 2, | |
| EMIT_TRAILING_ZERO_AFTER_POINT = 4, | |
| UNIQUE_ZERO = 8 | |
| }; | |
| // Flags should be a bit-or combination of the possible Flags-enum. | |
| // - NO_FLAGS: no special flags. | |
| // - EMIT_POSITIVE_EXPONENT_SIGN: when the number is converted into exponent | |
| // form, emits a '+' for positive exponents. Example: 1.2e+2. | |
| // - EMIT_TRAILING_DECIMAL_POINT: when the input number is an integer and is | |
| // converted into decimal format then a trailing decimal point is appended. | |
| // Example: 2345.0 is converted to "2345.". | |
| // - EMIT_TRAILING_ZERO_AFTER_POINT: in addition to a trailing decimal point | |
| // emits a trailing '0'-character. This flag requires the | |
| // EXMIT_TRAILING_DECIMAL_POINT flag. | |
| // Example: 2345.0 is converted to "2345.0". | |
| // - UNIQUE_ZERO: "-0.0" is converted to "0.0". | |
| // | |
| // Infinity symbol and nan_symbol provide the string representation for these | |
| // special values. If the string is NULL and the special value is encountered | |
| // then the conversion functions return false. | |
| // | |
| // The exponent_character is used in exponential representations. It is | |
| // usually 'e' or 'E'. | |
| // | |
| // When converting to the shortest representation the converter will | |
| // represent input numbers in decimal format if they are in the interval | |
| // [10^decimal_in_shortest_low; 10^decimal_in_shortest_high[ | |
| // (lower boundary included, greater boundary excluded). | |
| // Example: with decimal_in_shortest_low = -6 and | |
| // decimal_in_shortest_high = 21: | |
| // ToShortest(0.000001) -> "0.000001" | |
| // ToShortest(0.0000001) -> "1e-7" | |
| // ToShortest(111111111111111111111.0) -> "111111111111111110000" | |
| // ToShortest(100000000000000000000.0) -> "100000000000000000000" | |
| // ToShortest(1111111111111111111111.0) -> "1.1111111111111111e+21" | |
| // | |
| // When converting to precision mode the converter may add | |
| // max_leading_padding_zeroes before returning the number in exponential | |
| // format. | |
| // Example with max_leading_padding_zeroes_in_precision_mode = 6. | |
| // ToPrecision(0.0000012345, 2) -> "0.0000012" | |
| // ToPrecision(0.00000012345, 2) -> "1.2e-7" | |
| // Similarily the converter may add up to | |
| // max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid | |
| // returning an exponential representation. A zero added by the | |
| // EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit. | |
| // Examples for max_trailing_padding_zeroes_in_precision_mode = 1: | |
| // ToPrecision(230.0, 2) -> "230" | |
| // ToPrecision(230.0, 2) -> "230." with EMIT_TRAILING_DECIMAL_POINT. | |
| // ToPrecision(230.0, 2) -> "2.3e2" with EMIT_TRAILING_ZERO_AFTER_POINT. | |
| DoubleToStringConverter(int flags, | |
| const char* infinity_symbol, | |
| const char* nan_symbol, | |
| char exponent_character, | |
| int decimal_in_shortest_low, | |
| int decimal_in_shortest_high, | |
| int max_leading_padding_zeroes_in_precision_mode, | |
| int max_trailing_padding_zeroes_in_precision_mode) | |
| : flags_(flags), | |
| infinity_symbol_(infinity_symbol), | |
| nan_symbol_(nan_symbol), | |
| exponent_character_(exponent_character), | |
| decimal_in_shortest_low_(decimal_in_shortest_low), | |
| decimal_in_shortest_high_(decimal_in_shortest_high), | |
| max_leading_padding_zeroes_in_precision_mode_( | |
| max_leading_padding_zeroes_in_precision_mode), | |
| max_trailing_padding_zeroes_in_precision_mode_( | |
| max_trailing_padding_zeroes_in_precision_mode) { | |
| // When 'trailing zero after the point' is set, then 'trailing point' | |
| // must be set too. | |
| ASSERT(((flags & EMIT_TRAILING_DECIMAL_POINT) != 0) || | |
| !((flags & EMIT_TRAILING_ZERO_AFTER_POINT) != 0)); | |
| } | |
| // Returns a converter following the EcmaScript specification. | |
| static const DoubleToStringConverter& EcmaScriptConverter(); | |
| // Computes the shortest string of digits that correctly represent the input | |
| // number. Depending on decimal_in_shortest_low and decimal_in_shortest_high | |
| // (see constructor) it then either returns a decimal representation, or an | |
| // exponential representation. | |
| // Example with decimal_in_shortest_low = -6, | |
| // decimal_in_shortest_high = 21, | |
| // EMIT_POSITIVE_EXPONENT_SIGN activated, and | |
| // EMIT_TRAILING_DECIMAL_POINT deactived: | |
| // ToShortest(0.000001) -> "0.000001" | |
| // ToShortest(0.0000001) -> "1e-7" | |
| // ToShortest(111111111111111111111.0) -> "111111111111111110000" | |
| // ToShortest(100000000000000000000.0) -> "100000000000000000000" | |
| // ToShortest(1111111111111111111111.0) -> "1.1111111111111111e+21" | |
| // | |
| // Note: the conversion may round the output if the returned string | |
| // is accurate enough to uniquely identify the input-number. | |
| // For example the most precise representation of the double 9e59 equals | |
| // "899999999999999918767229449717619953810131273674690656206848", but | |
| // the converter will return the shorter (but still correct) "9e59". | |
| // | |
| // Returns true if the conversion succeeds. The conversion always succeeds | |
| // except when the input value is special and no infinity_symbol or | |
| // nan_symbol has been given to the constructor. | |
| bool ToShortest(double value, StringBuilder* result_builder) const { | |
| return ToShortestIeeeNumber(value, result_builder, SHORTEST); | |
| } | |
| // Same as ToShortest, but for single-precision floats. | |
| bool ToShortestSingle(float value, StringBuilder* result_builder) const { | |
| return ToShortestIeeeNumber(value, result_builder, SHORTEST_SINGLE); | |
| } | |
| // Computes a decimal representation with a fixed number of digits after the | |
| // decimal point. The last emitted digit is rounded. | |
| // | |
| // Examples: | |
| // ToFixed(3.12, 1) -> "3.1" | |
| // ToFixed(3.1415, 3) -> "3.142" | |
| // ToFixed(1234.56789, 4) -> "1234.5679" | |
| // ToFixed(1.23, 5) -> "1.23000" | |
| // ToFixed(0.1, 4) -> "0.1000" | |
| // ToFixed(1e30, 2) -> "1000000000000000019884624838656.00" | |
| // ToFixed(0.1, 30) -> "0.100000000000000005551115123126" | |
| // ToFixed(0.1, 17) -> "0.10000000000000001" | |
| // | |
| // If requested_digits equals 0, then the tail of the result depends on | |
| // the EMIT_TRAILING_DECIMAL_POINT and EMIT_TRAILING_ZERO_AFTER_POINT. | |
| // Examples, for requested_digits == 0, | |
| // let EMIT_TRAILING_DECIMAL_POINT and EMIT_TRAILING_ZERO_AFTER_POINT be | |
| // - false and false: then 123.45 -> 123 | |
| // 0.678 -> 1 | |
| // - true and false: then 123.45 -> 123. | |
| // 0.678 -> 1. | |
| // - true and true: then 123.45 -> 123.0 | |
| // 0.678 -> 1.0 | |
| // | |
| // Returns true if the conversion succeeds. The conversion always succeeds | |
| // except for the following cases: | |
| // - the input value is special and no infinity_symbol or nan_symbol has | |
| // been provided to the constructor, | |
| // - 'value' > 10^kMaxFixedDigitsBeforePoint, or | |
| // - 'requested_digits' > kMaxFixedDigitsAfterPoint. | |
| // The last two conditions imply that the result will never contain more than | |
| // 1 + kMaxFixedDigitsBeforePoint + 1 + kMaxFixedDigitsAfterPoint characters | |
| // (one additional character for the sign, and one for the decimal point). | |
| bool ToFixed(double value, | |
| int requested_digits, | |
| StringBuilder* result_builder) const; | |
| // Computes a representation in exponential format with requested_digits | |
| // after the decimal point. The last emitted digit is rounded. | |
| // If requested_digits equals -1, then the shortest exponential representation | |
| // is computed. | |
| // | |
| // Examples with EMIT_POSITIVE_EXPONENT_SIGN deactivated, and | |
| // exponent_character set to 'e'. | |
| // ToExponential(3.12, 1) -> "3.1e0" | |
| // ToExponential(5.0, 3) -> "5.000e0" | |
| // ToExponential(0.001, 2) -> "1.00e-3" | |
| // ToExponential(3.1415, -1) -> "3.1415e0" | |
| // ToExponential(3.1415, 4) -> "3.1415e0" | |
| // ToExponential(3.1415, 3) -> "3.142e0" | |
| // ToExponential(123456789000000, 3) -> "1.235e14" | |
| // ToExponential(1000000000000000019884624838656.0, -1) -> "1e30" | |
| // ToExponential(1000000000000000019884624838656.0, 32) -> | |
| // "1.00000000000000001988462483865600e30" | |
| // ToExponential(1234, 0) -> "1e3" | |
| // | |
| // Returns true if the conversion succeeds. The conversion always succeeds | |
| // except for the following cases: | |
| // - the input value is special and no infinity_symbol or nan_symbol has | |
| // been provided to the constructor, | |
| // - 'requested_digits' > kMaxExponentialDigits. | |
| // The last condition implies that the result will never contain more than | |
| // kMaxExponentialDigits + 8 characters (the sign, the digit before the | |
| // decimal point, the decimal point, the exponent character, the | |
| // exponent's sign, and at most 3 exponent digits). | |
| bool ToExponential(double value, | |
| int requested_digits, | |
| StringBuilder* result_builder) const; | |
| // Computes 'precision' leading digits of the given 'value' and returns them | |
| // either in exponential or decimal format, depending on | |
| // max_{leading|trailing}_padding_zeroes_in_precision_mode (given to the | |
| // constructor). | |
| // The last computed digit is rounded. | |
| // | |
| // Example with max_leading_padding_zeroes_in_precision_mode = 6. | |
| // ToPrecision(0.0000012345, 2) -> "0.0000012" | |
| // ToPrecision(0.00000012345, 2) -> "1.2e-7" | |
| // Similarily the converter may add up to | |
| // max_trailing_padding_zeroes_in_precision_mode in precision mode to avoid | |
| // returning an exponential representation. A zero added by the | |
| // EMIT_TRAILING_ZERO_AFTER_POINT flag is counted for this limit. | |
| // Examples for max_trailing_padding_zeroes_in_precision_mode = 1: | |
| // ToPrecision(230.0, 2) -> "230" | |
| // ToPrecision(230.0, 2) -> "230." with EMIT_TRAILING_DECIMAL_POINT. | |
| // ToPrecision(230.0, 2) -> "2.3e2" with EMIT_TRAILING_ZERO_AFTER_POINT. | |
| // Examples for max_trailing_padding_zeroes_in_precision_mode = 3, and no | |
| // EMIT_TRAILING_ZERO_AFTER_POINT: | |
| // ToPrecision(123450.0, 6) -> "123450" | |
| // ToPrecision(123450.0, 5) -> "123450" | |
| // ToPrecision(123450.0, 4) -> "123500" | |
| // ToPrecision(123450.0, 3) -> "123000" | |
| // ToPrecision(123450.0, 2) -> "1.2e5" | |
| // | |
| // Returns true if the conversion succeeds. The conversion always succeeds | |
| // except for the following cases: | |
| // - the input value is special and no infinity_symbol or nan_symbol has | |
| // been provided to the constructor, | |
| // - precision < kMinPericisionDigits | |
| // - precision > kMaxPrecisionDigits | |
| // The last condition implies that the result will never contain more than | |
| // kMaxPrecisionDigits + 7 characters (the sign, the decimal point, the | |
| // exponent character, the exponent's sign, and at most 3 exponent digits). | |
| bool ToPrecision(double value, | |
| int precision, | |
| StringBuilder* result_builder) const; | |
| enum DtoaMode { | |
| // Produce the shortest correct representation. | |
| // For example the output of 0.299999999999999988897 is (the less accurate | |
| // but correct) 0.3. | |
| SHORTEST, | |
| // Same as SHORTEST, but for single-precision floats. | |
| SHORTEST_SINGLE, | |
| // Produce a fixed number of digits after the decimal point. | |
| // For instance fixed(0.1, 4) becomes 0.1000 | |
| // If the input number is big, the output will be big. | |
| FIXED, | |
| // Fixed number of digits (independent of the decimal point). | |
| PRECISION | |
| }; | |
| // The maximal number of digits that are needed to emit a double in base 10. | |
| // A higher precision can be achieved by using more digits, but the shortest | |
| // accurate representation of any double will never use more digits than | |
| // kBase10MaximalLength. | |
| // Note that DoubleToAscii null-terminates its input. So the given buffer | |
| // should be at least kBase10MaximalLength + 1 characters long. | |
| static const int kBase10MaximalLength = 17; | |
| // Converts the given double 'v' to ascii. 'v' must not be NaN, +Infinity, or | |
| // -Infinity. In SHORTEST_SINGLE-mode this restriction also applies to 'v' | |
| // after it has been casted to a single-precision float. That is, in this | |
| // mode static_cast<float>(v) must not be NaN, +Infinity or -Infinity. | |
| // | |
| // The result should be interpreted as buffer * 10^(point-length). | |
| // | |
| // The output depends on the given mode: | |
| // - SHORTEST: produce the least amount of digits for which the internal | |
| // identity requirement is still satisfied. If the digits are printed | |
| // (together with the correct exponent) then reading this number will give | |
| // 'v' again. The buffer will choose the representation that is closest to | |
| // 'v'. If there are two at the same distance, than the one farther away | |
| // from 0 is chosen (halfway cases - ending with 5 - are rounded up). | |
| // In this mode the 'requested_digits' parameter is ignored. | |
| // - SHORTEST_SINGLE: same as SHORTEST but with single-precision. | |
| // - FIXED: produces digits necessary to print a given number with | |
| // 'requested_digits' digits after the decimal point. The produced digits | |
| // might be too short in which case the caller has to fill the remainder | |
| // with '0's. | |
| // Example: toFixed(0.001, 5) is allowed to return buffer="1", point=-2. | |
| // Halfway cases are rounded towards +/-Infinity (away from 0). The call | |
| // toFixed(0.15, 2) thus returns buffer="2", point=0. | |
| // The returned buffer may contain digits that would be truncated from the | |
| // shortest representation of the input. | |
| // - PRECISION: produces 'requested_digits' where the first digit is not '0'. | |
| // Even though the length of produced digits usually equals | |
| // 'requested_digits', the function is allowed to return fewer digits, in | |
| // which case the caller has to fill the missing digits with '0's. | |
| // Halfway cases are again rounded away from 0. | |
| // DoubleToAscii expects the given buffer to be big enough to hold all | |
| // digits and a terminating null-character. In SHORTEST-mode it expects a | |
| // buffer of at least kBase10MaximalLength + 1. In all other modes the | |
| // requested_digits parameter and the padding-zeroes limit the size of the | |
| // output. Don't forget the decimal point, the exponent character and the | |
| // terminating null-character when computing the maximal output size. | |
| // The given length is only used in debug mode to ensure the buffer is big | |
| // enough. | |
| static void DoubleToAscii(double v, | |
| DtoaMode mode, | |
| int requested_digits, | |
| char* buffer, | |
| int buffer_length, | |
| bool* sign, | |
| int* length, | |
| int* point); | |
| private: | |
| // Implementation for ToShortest and ToShortestSingle. | |
| bool ToShortestIeeeNumber(double value, | |
| StringBuilder* result_builder, | |
| DtoaMode mode) const; | |
| // If the value is a special value (NaN or Infinity) constructs the | |
| // corresponding string using the configured infinity/nan-symbol. | |
| // If either of them is NULL or the value is not special then the | |
| // function returns false. | |
| bool HandleSpecialValues(double value, StringBuilder* result_builder) const; | |
| // Constructs an exponential representation (i.e. 1.234e56). | |
| // The given exponent assumes a decimal point after the first decimal digit. | |
| void CreateExponentialRepresentation(const char* decimal_digits, | |
| int length, | |
| int exponent, | |
| StringBuilder* result_builder) const; | |
| // Creates a decimal representation (i.e 1234.5678). | |
| void CreateDecimalRepresentation(const char* decimal_digits, | |
| int length, | |
| int decimal_point, | |
| int digits_after_point, | |
| StringBuilder* result_builder) const; | |
| const int flags_; | |
| const char* const infinity_symbol_; | |
| const char* const nan_symbol_; | |
| const char exponent_character_; | |
| const int decimal_in_shortest_low_; | |
| const int decimal_in_shortest_high_; | |
| const int max_leading_padding_zeroes_in_precision_mode_; | |
| const int max_trailing_padding_zeroes_in_precision_mode_; | |
| DISALLOW_IMPLICIT_CONSTRUCTORS(DoubleToStringConverter); | |
| }; | |
| 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 | |
| }; | |
| // 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 spaces. | |
| // - ALLOW_TRAILING_SPACES: ignore trailing spaces. | |
| // - ALLOW_SPACES_AFTER_SIGN: ignore spaces after the sign. | |
| // Ex: StringToDouble("- 123.2") -> -123.2. | |
| // StringToDouble("+ 123.2") -> 123.2 | |
| // | |
| // 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. | |
| // | |
| // 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. | |
| StringToDoubleConverter(int flags, | |
| double empty_string_value, | |
| double junk_string_value, | |
| const char* infinity_symbol, | |
| const char* nan_symbol) | |
| : flags_(flags), | |
| empty_string_value_(empty_string_value), | |
| junk_string_value_(junk_string_value), | |
| infinity_symbol_(infinity_symbol), | |
| nan_symbol_(nan_symbol) { | |
| } | |
| // 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 { | |
| return StringToIeee(buffer, length, processed_characters_count, true); | |
| } | |
| // 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 { | |
| return static_cast<float>(StringToIeee(buffer, length, | |
| processed_characters_count, false)); | |
| } | |
| private: | |
| const int flags_; | |
| const double empty_string_value_; | |
| const double junk_string_value_; | |
| const char* const infinity_symbol_; | |
| const char* const nan_symbol_; | |
| double StringToIeee(const char* buffer, | |
| int length, | |
| int* processed_characters_count, | |
| bool read_as_double) const; | |
| DISALLOW_IMPLICIT_CONSTRUCTORS(StringToDoubleConverter); | |
| }; | |
| } // namespace double_conversion | |