The Tor Browser: gfx/angle/src/compiler/preprocessor/numeric

     1 //

     2 // Copyright (c) 2012 The ANGLE Project Authors. All rights reserved.

     3 // Use of this source code is governed by a BSD-style license that can be

     4 // found in the LICENSE file.

     5 //

     7 // numeric_lex.h: Functions to extract numeric values from string.

     9 #ifndef COMPILER_PREPROCESSOR_NUMERIC_LEX_H_

    10 #define COMPILER_PREPROCESSOR_NUMERIC_LEX_H_

    12 #include <sstream>

    14 namespace pp {

    16 inline std::ios::fmtflags numeric_base_int(const std::string& str)

    17 {

    18     if ((str.size() >= 2) &&

    19         (str[0] == '0') &&

    20         (str[1] == 'x' || str[1] == 'X'))

    21     {

    22         return std::ios::hex;

    23     }

    24     else if ((str.size() >= 1) && (str[0] == '0'))

    25     {

    26         return std::ios::oct;

    27     }

    28     return std::ios::dec;

    29 }

    31 // The following functions parse the given string to extract a numerical

    32 // value of the given type. These functions assume that the string is

    33 // of the correct form. They can only fail if the parsed value is too big,

    34 // in which case false is returned.

    36 template<typename IntType>

    37 bool numeric_lex_int(const std::string& str, IntType* value)

    38 {

    39     std::istringstream stream(str);

    40     // This should not be necessary, but MSVS has a buggy implementation.

    41     // It returns incorrect results if the base is not specified.

    42     stream.setf(numeric_base_int(str), std::ios::basefield);

    44     stream >> (*value);

    45     return !stream.fail();

    46 }

    48 template<typename FloatType>

    49 bool numeric_lex_float(const std::string& str, FloatType* value)

    50 {

    51     std::istringstream stream(str);

    52     // Force "C" locale so that decimal character is always '.', and

    53     // not dependent on the current locale.

    54     stream.imbue(std::locale::classic());

    56     stream >> (*value);

    57     return !stream.fail();

    58 }

    60 } // namespace pp.

    61 #endif // COMPILER_PREPROCESSOR_NUMERIC_LEX_H_

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