1 // Copyright 2016 The SwiftShader Authors. All Rights Reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 // numeric_lex.h: Functions to extract numeric values from string. 16 17 #ifndef COMPILER_PREPROCESSOR_NUMERIC_LEX_H_ 18 #define COMPILER_PREPROCESSOR_NUMERIC_LEX_H_ 19 20 #include <sstream> 21 #include <cmath> 22 23 namespace pp { 24 25 inline std::ios::fmtflags numeric_base_int(const std::string& str) 26 { 27 if ((str.size() >= 2) && 28 (str[0] == '0') && 29 (str[1] == 'x' || str[1] == 'X')) 30 { 31 return std::ios::hex; 32 } 33 else if ((str.size() >= 1) && (str[0] == '0')) 34 { 35 return std::ios::oct; 36 } 37 return std::ios::dec; 38 } 39 40 // The following functions parse the given string to extract a numerical 41 // value of the given type. These functions assume that the string is 42 // of the correct form. They can only fail if the parsed value is too big, 43 // in which case false is returned. 44 45 template<typename IntType> 46 bool numeric_lex_int(const std::string& str, IntType* value) 47 { 48 std::istringstream stream(str); 49 // This should not be necessary, but MSVS has a buggy implementation. 50 // It returns incorrect results if the base is not specified. 51 stream.setf(numeric_base_int(str), std::ios::basefield); 52 53 stream >> (*value); 54 return !stream.fail(); 55 } 56 57 template<typename FloatType> 58 bool numeric_lex_float(const std::string& str, FloatType* value) 59 { 60 std::istringstream stream(str); 61 // Force "C" locale so that decimal character is always '.', and 62 // not dependent on the current locale. 63 stream.imbue(std::locale::classic()); 64 65 stream >> (*value); 66 return !stream.fail() && std::isfinite(*value); 67 } 68 69 } // namespace pp. 70 #endif // COMPILER_PREPROCESSOR_NUMERIC_LEX_H_ 71
