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_NUMERIC_LEX_H_ 10 #define COMPILER_PREPROCESSOR_NUMERIC_LEX_H_ 11 12 #include <sstream> 13 14 namespace pp { 15 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 if ((str.size() >= 1) && (str[0] == '0')) 25 { 26 return std::ios::oct; 27 } 28 return std::ios::dec; 29 } 30 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. 35 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); 43 44 stream >> (*value); 45 return !stream.fail(); 46 } 47 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()); 55 56 stream >> (*value); 57 return !stream.fail(); 58 } 59 60 } // namespace pp. 61 #endif // COMPILER_PREPROCESSOR_NUMERIC_LEX_H_ 62
