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 14namespace pp { 15 16inline 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 36template<typename IntType> 37bool 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 48template<typename FloatType> 49bool 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