Line data    Source code

       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             : //
       6             : 
       7             : // numeric_lex.h: Functions to extract numeric values from string.
       8             : 
       9             : #ifndef COMPILER_PREPROCESSOR_NUMERICLEX_H_
      10             : #define COMPILER_PREPROCESSOR_NUMERICLEX_H_
      11             : 
      12             : #include <cmath>
      13             : #include <sstream>
      14             : 
      15             : namespace pp {
      16             : 
      17           0 : inline std::ios::fmtflags numeric_base_int(const std::string &str)
      18             : {
      19           0 :     if ((str.size() >= 2) &&
      20           0 :         (str[0] == '0') &&
      21           0 :         (str[1] == 'x' || str[1] == 'X'))
      22             :     {
      23           0 :         return std::ios::hex;
      24             :     }
      25           0 :     if ((str.size() >= 1) && (str[0] == '0'))
      26             :     {
      27           0 :         return std::ios::oct;
      28             :     }
      29           0 :     return std::ios::dec;
      30             : }
      31             : 
      32             : // The following functions parse the given string to extract a numerical
      33             : // value of the given type. These functions assume that the string is
      34             : // of the correct form. They can only fail if the parsed value is too big,
      35             : // in which case false is returned.
      36             : 
      37             : template<typename IntType>
      38           0 : bool numeric_lex_int(const std::string &str, IntType *value)
      39             : {
      40           0 :     std::istringstream stream(str);
      41             :     // This should not be necessary, but MSVS has a buggy implementation.
      42             :     // It returns incorrect results if the base is not specified.
      43           0 :     stream.setf(numeric_base_int(str), std::ios::basefield);
      44             : 
      45           0 :     stream >> (*value);
      46           0 :     return !stream.fail();
      47             : }
      48             : 
      49             : template<typename FloatType>
      50           0 : bool numeric_lex_float(const std::string &str, FloatType *value)
      51             : {
      52             : // On 64-bit Intel Android, istringstream is broken.  Until this is fixed in
      53             : // a newer NDK, don't use it.  Android doesn't have locale support, so this
      54             : // doesn't have to force the C locale.
      55             : // TODO(thakis): Remove this once this bug has been fixed in the NDK and
      56             : // that NDK has been rolled into chromium.
      57             : #if defined(ANGLE_PLATFORM_ANDROID) && __x86_64__
      58             :     *value = strtod(str.c_str(), nullptr);
      59             :     return errno != ERANGE;
      60             : #else
      61           0 :     std::istringstream stream(str);
      62             :     // Force "C" locale so that decimal character is always '.', and
      63             :     // not dependent on the current locale.
      64           0 :     stream.imbue(std::locale::classic());
      65             : 
      66           0 :     stream >> (*value);
      67           0 :     return !stream.fail() && std::isfinite(*value);
      68             : #endif
      69             : }
      70             : 
      71             : } // namespace pp.
      72             : 
      73             : #endif // COMPILER_PREPROCESSOR_NUMERICLEX_H_