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