1 /*
2 * Copyright 2017 The WebRTC Project Authors. All rights reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "rtc_base/string_to_number.h"
12
13 #include <ctype.h>
14
15 #include <cerrno>
16 #include <cstdlib>
17
18 #include "rtc_base/checks.h"
19
20 namespace rtc {
21 namespace string_to_number_internal {
22
ParseSigned(const char * str,int base)23 absl::optional<signed_type> ParseSigned(const char* str, int base) {
24 RTC_DCHECK(str);
25 if (isdigit(str[0]) || str[0] == '-') {
26 char* end = nullptr;
27 errno = 0;
28 const signed_type value = std::strtoll(str, &end, base);
29 if (end && *end == '\0' && errno == 0) {
30 return value;
31 }
32 }
33 return absl::nullopt;
34 }
35
ParseUnsigned(const char * str,int base)36 absl::optional<unsigned_type> ParseUnsigned(const char* str, int base) {
37 RTC_DCHECK(str);
38 if (isdigit(str[0]) || str[0] == '-') {
39 // Explicitly discard negative values. std::strtoull parsing causes unsigned
40 // wraparound. We cannot just reject values that start with -, though, since
41 // -0 is perfectly fine, as is -0000000000000000000000000000000.
42 const bool is_negative = str[0] == '-';
43 char* end = nullptr;
44 errno = 0;
45 const unsigned_type value = std::strtoull(str, &end, base);
46 if (end && *end == '\0' && errno == 0 && (value == 0 || !is_negative)) {
47 return value;
48 }
49 }
50 return absl::nullopt;
51 }
52
53 template <typename T>
54 T StrToT(const char* str, char** str_end);
55
56 template <>
StrToT(const char * str,char ** str_end)57 inline float StrToT(const char* str, char** str_end) {
58 return std::strtof(str, str_end);
59 }
60
61 template <>
StrToT(const char * str,char ** str_end)62 inline double StrToT(const char* str, char** str_end) {
63 return std::strtod(str, str_end);
64 }
65
66 template <>
StrToT(const char * str,char ** str_end)67 inline long double StrToT(const char* str, char** str_end) {
68 return std::strtold(str, str_end);
69 }
70
71 template <typename T>
ParseFloatingPoint(const char * str)72 absl::optional<T> ParseFloatingPoint(const char* str) {
73 RTC_DCHECK(str);
74 if (*str == '\0')
75 return absl::nullopt;
76 char* end = nullptr;
77 errno = 0;
78 const T value = StrToT<T>(str, &end);
79 if (end && *end == '\0' && errno == 0) {
80 return value;
81 }
82 return absl::nullopt;
83 }
84
85 template absl::optional<float> ParseFloatingPoint(const char* str);
86 template absl::optional<double> ParseFloatingPoint(const char* str);
87 template absl::optional<long double> ParseFloatingPoint(const char* str);
88
89 } // namespace string_to_number_internal
90 } // namespace rtc
91