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1 // Copyright 2015 Google Inc. 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 #include "commandlineflags.h"
16 
17 #include <algorithm>
18 #include <cctype>
19 #include <cstdlib>
20 #include <cstring>
21 #include <iostream>
22 #include <limits>
23 #include <map>
24 #include <utility>
25 
26 #include "../src/string_util.h"
27 
28 namespace benchmark {
29 namespace {
30 
31 // Parses 'str' for a 32-bit signed integer.  If successful, writes
32 // the result to *value and returns true; otherwise leaves *value
33 // unchanged and returns false.
ParseInt32(const std::string & src_text,const char * str,int32_t * value)34 bool ParseInt32(const std::string& src_text, const char* str, int32_t* value) {
35   // Parses the environment variable as a decimal integer.
36   char* end = nullptr;
37   const long long_value = strtol(str, &end, 10);  // NOLINT
38 
39   // Has strtol() consumed all characters in the string?
40   if (*end != '\0') {
41     // No - an invalid character was encountered.
42     std::cerr << src_text << " is expected to be a 32-bit integer, "
43               << "but actually has value \"" << str << "\".\n";
44     return false;
45   }
46 
47   // Is the parsed value in the range of an Int32?
48   const int32_t result = static_cast<int32_t>(long_value);
49   if (long_value == std::numeric_limits<long>::max() ||
50       long_value == std::numeric_limits<long>::min() ||
51       // The parsed value overflows as a long.  (strtol() returns
52       // LONG_MAX or LONG_MIN when the input overflows.)
53       result != long_value
54       // The parsed value overflows as an Int32.
55   ) {
56     std::cerr << src_text << " is expected to be a 32-bit integer, "
57               << "but actually has value \"" << str << "\", "
58               << "which overflows.\n";
59     return false;
60   }
61 
62   *value = result;
63   return true;
64 }
65 
66 // Parses 'str' for a double.  If successful, writes the result to *value and
67 // returns true; otherwise leaves *value unchanged and returns false.
ParseDouble(const std::string & src_text,const char * str,double * value)68 bool ParseDouble(const std::string& src_text, const char* str, double* value) {
69   // Parses the environment variable as a decimal integer.
70   char* end = nullptr;
71   const double double_value = strtod(str, &end);  // NOLINT
72 
73   // Has strtol() consumed all characters in the string?
74   if (*end != '\0') {
75     // No - an invalid character was encountered.
76     std::cerr << src_text << " is expected to be a double, "
77               << "but actually has value \"" << str << "\".\n";
78     return false;
79   }
80 
81   *value = double_value;
82   return true;
83 }
84 
85 // Parses 'str' into KV pairs. If successful, writes the result to *value and
86 // returns true; otherwise leaves *value unchanged and returns false.
ParseKvPairs(const std::string & src_text,const char * str,std::map<std::string,std::string> * value)87 bool ParseKvPairs(const std::string& src_text, const char* str,
88                   std::map<std::string, std::string>* value) {
89   std::map<std::string, std::string> kvs;
90   for (const auto& kvpair : StrSplit(str, ',')) {
91     const auto kv = StrSplit(kvpair, '=');
92     if (kv.size() != 2) {
93       std::cerr << src_text << " is expected to be a comma-separated list of "
94                 << "<key>=<value> strings, but actually has value \"" << str
95                 << "\".\n";
96       return false;
97     }
98     if (!kvs.emplace(kv[0], kv[1]).second) {
99       std::cerr << src_text << " is expected to contain unique keys but key \""
100                 << kv[0] << "\" was repeated.\n";
101       return false;
102     }
103   }
104 
105   *value = kvs;
106   return true;
107 }
108 
109 // Returns the name of the environment variable corresponding to the
110 // given flag.  For example, FlagToEnvVar("foo") will return
111 // "BENCHMARK_FOO" in the open-source version.
FlagToEnvVar(const char * flag)112 static std::string FlagToEnvVar(const char* flag) {
113   const std::string flag_str(flag);
114 
115   std::string env_var;
116   for (size_t i = 0; i != flag_str.length(); ++i)
117     env_var += static_cast<char>(::toupper(flag_str.c_str()[i]));
118 
119   return env_var;
120 }
121 
122 }  // namespace
123 
124 BENCHMARK_EXPORT
BoolFromEnv(const char * flag,bool default_val)125 bool BoolFromEnv(const char* flag, bool default_val) {
126   const std::string env_var = FlagToEnvVar(flag);
127   const char* const value_str = getenv(env_var.c_str());
128   return value_str == nullptr ? default_val : IsTruthyFlagValue(value_str);
129 }
130 
131 BENCHMARK_EXPORT
Int32FromEnv(const char * flag,int32_t default_val)132 int32_t Int32FromEnv(const char* flag, int32_t default_val) {
133   const std::string env_var = FlagToEnvVar(flag);
134   const char* const value_str = getenv(env_var.c_str());
135   int32_t value = default_val;
136   if (value_str == nullptr ||
137       !ParseInt32(std::string("Environment variable ") + env_var, value_str,
138                   &value)) {
139     return default_val;
140   }
141   return value;
142 }
143 
144 BENCHMARK_EXPORT
DoubleFromEnv(const char * flag,double default_val)145 double DoubleFromEnv(const char* flag, double default_val) {
146   const std::string env_var = FlagToEnvVar(flag);
147   const char* const value_str = getenv(env_var.c_str());
148   double value = default_val;
149   if (value_str == nullptr ||
150       !ParseDouble(std::string("Environment variable ") + env_var, value_str,
151                    &value)) {
152     return default_val;
153   }
154   return value;
155 }
156 
157 BENCHMARK_EXPORT
StringFromEnv(const char * flag,const char * default_val)158 const char* StringFromEnv(const char* flag, const char* default_val) {
159   const std::string env_var = FlagToEnvVar(flag);
160   const char* const value = getenv(env_var.c_str());
161   return value == nullptr ? default_val : value;
162 }
163 
164 BENCHMARK_EXPORT
KvPairsFromEnv(const char * flag,std::map<std::string,std::string> default_val)165 std::map<std::string, std::string> KvPairsFromEnv(
166     const char* flag, std::map<std::string, std::string> default_val) {
167   const std::string env_var = FlagToEnvVar(flag);
168   const char* const value_str = getenv(env_var.c_str());
169 
170   if (value_str == nullptr) return default_val;
171 
172   std::map<std::string, std::string> value;
173   if (!ParseKvPairs("Environment variable " + env_var, value_str, &value)) {
174     return default_val;
175   }
176   return value;
177 }
178 
179 // Parses a string as a command line flag.  The string should have
180 // the format "--flag=value".  When def_optional is true, the "=value"
181 // part can be omitted.
182 //
183 // Returns the value of the flag, or nullptr if the parsing failed.
ParseFlagValue(const char * str,const char * flag,bool def_optional)184 const char* ParseFlagValue(const char* str, const char* flag,
185                            bool def_optional) {
186   // str and flag must not be nullptr.
187   if (str == nullptr || flag == nullptr) return nullptr;
188 
189   // The flag must start with "--".
190   const std::string flag_str = std::string("--") + std::string(flag);
191   const size_t flag_len = flag_str.length();
192   if (strncmp(str, flag_str.c_str(), flag_len) != 0) return nullptr;
193 
194   // Skips the flag name.
195   const char* flag_end = str + flag_len;
196 
197   // When def_optional is true, it's OK to not have a "=value" part.
198   if (def_optional && (flag_end[0] == '\0')) return flag_end;
199 
200   // If def_optional is true and there are more characters after the
201   // flag name, or if def_optional is false, there must be a '=' after
202   // the flag name.
203   if (flag_end[0] != '=') return nullptr;
204 
205   // Returns the string after "=".
206   return flag_end + 1;
207 }
208 
209 BENCHMARK_EXPORT
ParseBoolFlag(const char * str,const char * flag,bool * value)210 bool ParseBoolFlag(const char* str, const char* flag, bool* value) {
211   // Gets the value of the flag as a string.
212   const char* const value_str = ParseFlagValue(str, flag, true);
213 
214   // Aborts if the parsing failed.
215   if (value_str == nullptr) return false;
216 
217   // Converts the string value to a bool.
218   *value = IsTruthyFlagValue(value_str);
219   return true;
220 }
221 
222 BENCHMARK_EXPORT
ParseInt32Flag(const char * str,const char * flag,int32_t * value)223 bool ParseInt32Flag(const char* str, const char* flag, int32_t* value) {
224   // Gets the value of the flag as a string.
225   const char* const value_str = ParseFlagValue(str, flag, false);
226 
227   // Aborts if the parsing failed.
228   if (value_str == nullptr) return false;
229 
230   // Sets *value to the value of the flag.
231   return ParseInt32(std::string("The value of flag --") + flag, value_str,
232                     value);
233 }
234 
235 BENCHMARK_EXPORT
ParseDoubleFlag(const char * str,const char * flag,double * value)236 bool ParseDoubleFlag(const char* str, const char* flag, double* value) {
237   // Gets the value of the flag as a string.
238   const char* const value_str = ParseFlagValue(str, flag, false);
239 
240   // Aborts if the parsing failed.
241   if (value_str == nullptr) return false;
242 
243   // Sets *value to the value of the flag.
244   return ParseDouble(std::string("The value of flag --") + flag, value_str,
245                      value);
246 }
247 
248 BENCHMARK_EXPORT
ParseStringFlag(const char * str,const char * flag,std::string * value)249 bool ParseStringFlag(const char* str, const char* flag, std::string* value) {
250   // Gets the value of the flag as a string.
251   const char* const value_str = ParseFlagValue(str, flag, false);
252 
253   // Aborts if the parsing failed.
254   if (value_str == nullptr) return false;
255 
256   *value = value_str;
257   return true;
258 }
259 
260 BENCHMARK_EXPORT
ParseKeyValueFlag(const char * str,const char * flag,std::map<std::string,std::string> * value)261 bool ParseKeyValueFlag(const char* str, const char* flag,
262                        std::map<std::string, std::string>* value) {
263   const char* const value_str = ParseFlagValue(str, flag, false);
264 
265   if (value_str == nullptr) return false;
266 
267   for (const auto& kvpair : StrSplit(value_str, ',')) {
268     const auto kv = StrSplit(kvpair, '=');
269     if (kv.size() != 2) return false;
270     value->emplace(kv[0], kv[1]);
271   }
272 
273   return true;
274 }
275 
276 BENCHMARK_EXPORT
IsFlag(const char * str,const char * flag)277 bool IsFlag(const char* str, const char* flag) {
278   return (ParseFlagValue(str, flag, true) != nullptr);
279 }
280 
281 BENCHMARK_EXPORT
IsTruthyFlagValue(const std::string & value)282 bool IsTruthyFlagValue(const std::string& value) {
283   if (value.size() == 1) {
284     char v = value[0];
285     return isalnum(v) &&
286            !(v == '0' || v == 'f' || v == 'F' || v == 'n' || v == 'N');
287   }
288   if (!value.empty()) {
289     std::string value_lower(value);
290     std::transform(value_lower.begin(), value_lower.end(), value_lower.begin(),
291                    [](char c) { return static_cast<char>(::tolower(c)); });
292     return !(value_lower == "false" || value_lower == "no" ||
293              value_lower == "off");
294   }
295   return true;
296 }
297 
298 }  // end namespace benchmark
299